Stent apparatus having self-pleated skirt, processing method therefor, skirt pleating method, and cardiac valve

Abstract

Disclosed in the present invention are a stent apparatus having a self-pleated skirt, a processing method therefor, a skirt pleating method, and a cardiac valve. The stent apparatus comprises a stent, and is further provided with a flexible skirt. The skirt comprises: an unfolded state, where the skirt extends axially and surrounds the periphery of the stent before release; and a stacked state, where the skirt is driven by deformation during release of the stent, and gathers and is stacked along an axial direction of the released stent to form an annular perivalvular leakage blocking part. The stent apparatus is further provided with a pull-wire which is merely threaded on the skirt, and the pull-wire may react to the radial deformation during the release of the stent to drive the skirt to enter the stacked state. According to the present invention, based on perivalvular leakage prevention technology, an interventional stent is fitted with the lining of the blood vessels, so that the stent will not easily be migrated and is more stable, the scope of the applicable population is expanded, additional surgical risks are lowered, and perivalvular leakage, thrombi and other complications are prevented. Better hemodynamic performance is provided, the coverage function of endothelial cells of the host is enhanced, the probability of occurrence of endocarditis is lowered, and the normal blood supply function of the heart and blood vessels is recovered.

Claims

1. A stent apparatus with a self-folded skirt, comprising a stent which has a first configuration before being released and a second configuration after being released that is different from the first configuration, characterized by the stent apparatus having a flexible skirt, wherein the flexible skirt has: an unfolded configuration, in which the skirt is axially unfolded and surrounds an outer periphery of the stent before being released; a stacked configuration, in which the skirt is folded and stacked in an axial direction of the stent after being released and forms an annular peripheral leakage occluder; wherein at least a portion of the skirt is fixed on the stent, and the stent apparatus is further provided with a pulling string that only threads though the skirt, wherein the pulling string undulates in the axial direction of the stent while extending in a circumferential direction of the stent, thereby forming a wave-like configuration, and a wave shape of the pulling string is changed when the pulling string is driven by deforming the stent during release so as to pull the skirt into the stacked configuration.

2. The stent apparatus with a self-folded skirt according to claim 1, wherein a portion of the skirt in the axial direction is configured as a fixing band which is stitched on the stent; and the fixing band is stitched on the stent in a circumferential direction continuously or discontinuously with intervals.

3. The stent apparatus with a self-folded skirt according to claim 2, wherein, at least one section of the skirt in the axial direction is configured as a floating section around the outer periphery of the stent, and the floating section is folded axially in the stacked configuration of the skirt; and wherein, both axial sides of the floating section are configured as fixing bands; or one axial side of the floating section is configured as a fixing band, and the other axial side of the floating section is floatable.

4. The stent apparatus with a self-folded skirt according to claim 3, wherein, a proximal end of the skirt which is to be released later is fixed on the stent, and a distal end of the skirt which is to be released first floats around the outer periphery of the stent; or a distal end of the skirt which is to be released first is fixed on the stent, and a proximal end of the skirt which is to be released later floats around the outer periphery of the stent.

5. The stent apparatus with a self-folded skirt according to claim 4, wherein, one section of the stent in the axial direction is configured as a flared driving structure that is configured to drive the skirt to be folded and stacked; and the flared driving structure extends to a distal end of the stent which is to be released first.

6. The stent apparatus with a self-folded skirt according to claim 1, wherein, at least one section of the skirt in the axial direction is configured as a floating section around the outer periphery of the stent.

7. The stent apparatus with a self-folded skirt according to claim 6, wherein, the floating section has two axial edges, one of which is fixed on the stent, and the other serves as a floating edge; or both of the two axial edges of the floating section are fixed on the stent.

8. The stent apparatus with a self-folded skirt according to claim 6, wherein, the pulling string which serves to act on the floating section comprises one or more pulling units, and each pulling unit includes at least two threading ends interacting with the skirt, a circumferential span between the two threading ends changes after the stent is released relative to the stent being unreleased, and at least one force exerting portion is formed by at least a part of the pulling unit between the two threading ends and connected to the skirt, and a relative displacement in the axial direction of the stent between the force exerting portion and the threading ends is produced during the release of the stent to pull the skirt to be stacked.

9. The stent apparatus with a self-folded skirt according to claim 8, wherein, the at least one force exerting portion is fixed on the skirt or movably threads through the skirt.

10. The stent apparatus with a self-folded skirt according to claim 8, wherein, the at least one force exerting portion comprises a plurality of force exerting portions which are distributed continuously or discontinuously with intervals therebetween; wherein, when the force exerting portions of the pulling string are distributed discontinuously, force is transmitted across the intervals through the skirt.

11. The stent apparatus with a self-folded skirt according to claim 7, wherein, the skirt is provided with one or more threading holes, and the at least one force exerting portion movably threads through the one or more the threading holes; and at least one of the one or more threading holes is arranged offset from a line connecting the two threading ends.

12. The stent apparatus with a self-folded skirt according to claim 7, wherein, the force exerting portion is located between the two threading ends along an extension direction of the pulling string.

13. The stent apparatus with a self-folded skirt according to claim 7, wherein, the two threading ends extend along two sides of a V-shaped course respectively and join together at the force exerting portion, and the two threading ends pull a vertex of the V-shaped course to move axially during the deforming of the stent.

14. The stent apparatus with a self-folded skirt according to claim 1, wherein, the wave-like configuration has one or more waves and each wave has a triangle, trapezoid, rectangle or arc shape.

15. The stent apparatus with a self-folded skirt according to claim 1, wherein, the skirt is provided with a first set of threading holes and a second set of threading holes, with each set of threading holes comprising a plurality of threading holes arranged in a circumferential direction, the two set of threading holes are arranged one above the other in the axial direction, and the pulling string threads through the first set of threading holes and the second set of threading holes in an alternating manner and forms the wave-like configuration.

16. The stent apparatus with a self-folded skirt according to claim 15, wherein, the pulling string threads into and out of the surfaces of the skirt in an alternating manner.

17. The stent apparatus with a self-folded skirt according to claim 16, wherein, the two sets of threading holes have the same number of threading holes and the threading holes of the first set are arranged offset from the threading holes of the second set.

18. The stent apparatus with a self-folded skirt according to claim 1, wherein, the skirt is made of a flexible material and constrains around the outer periphery of the stent in a released configuration.

19. The stent apparatus with a self-folded skirt according to claim 1, wherein, the skirt is made of a porcine pericardium, or a bovine pericardium, or other flexible biocompatible materials.

20. A heart valve, comprising the stent apparatus with a skirt according to claim 1, the stent is provided with a valve and/or a coverage membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1a is a schematic structural view of a traditional aortic stent.

(2) FIG. 1b is a schematic structural view of a stent apparatus according to a first embodiment of the present disclosure, showing a stent thereof before being released.

(3) FIG. 1c is a schematic structural view of the stent apparatus according to the first embodiment, showing the stent after being released.

(4) FIG. 1d is a schematic structural view of the stent apparatus according to the first embodiment, showing the stent during release.

(5) FIG. 1e is a schematic structural view of a stent apparatus with the sharp tips at the bottom end of the stent covered compared to the first embodiment.

(6) FIG. 2a is a schematic structural view of a stent apparatus according to a second embodiment of the present disclosure, showing a stent thereof before being released.

(7) FIG. 2b is a schematic structural view of the stent apparatus according to the second embodiment, showing a pulling unit before being released.

(8) FIG. 2c is a schematic structural view of the stent apparatus according to the second embodiment, showing the pulling unit after being released

(9) FIG. 2d is a schematic structural view of the stent apparatus according to the second embodiment, showing the stent after being released.

(10) FIG. 2e is a schematic structural view of a stent apparatus, the pulling unit of which has a different circumferential span compared to the second embodiment.

(11) FIG. 2f is another schematic structural view of a stent apparatus, the pulling unit of which has a different circumferential span compared to the second embodiment.

(12) FIG. 2g is a further schematic structural view of a stent apparatus, the pulling unit of which has a different circumferential span compared to the second embodiment.

(13) FIG. 2h is a schematic structural view of a stent apparatus, in which, compared to the second embodiment, both ends of the skirt are fixed.

(14) FIG. 3a is a schematic structural view of a stent apparatus according to a third embodiment of the present disclosure, showing a stent thereof before being released.

(15) FIG. 3b is a schematic structural view of the stent apparatus according to the third embodiment, showing the stent thereof after being released.

(16) FIG. 4a is a schematic structural view of a stent apparatus according to a fourth embodiment of the present disclosure, showing a stent thereof before being released.

(17) FIG. 4b is a schematic structural view of the stent apparatus according to the fourth embodiment, showing the stent thereof after being released.

(18) FIG. 5a is a schematic structural view of a stent apparatus according to a fifth embodiment of the present disclosure.

(19) FIG. 5b is a schematic structural view of a stent, in which, compared to the stent shown in FIG. 5a, both ends thereof are flared.

(20) FIG. 6 is a schematic structural view of a stent apparatus according to a sixth embodiment of the present disclosure.

(21) FIG. 7a is a schematic structural view of a stent apparatus according to a seventh embodiment of the present disclosure, showing the stent before being released.

(22) FIG. 7b is a schematic structural view of the stent apparatus according to the seventh embodiment, showing the stent after being released.

(23) FIG. 7c is a schematic structural view of the stent apparatus according to the seventh embodiment, showing the stent after being expanded.

(24) FIG. 8 is a schematic structural view of a stent apparatus according to an eighth embodiment of the present disclosure.

(25) FIG. 9 is a schematic structural view of a stent apparatus according to a ninth embodiment of the present disclosure.

(26) FIG. 10 is a schematic structural view of a stent apparatus according to a tenth embodiment of the present disclosure.

(27) FIG. 11 is a schematic structural view of a stent apparatus according to an eleventh embodiment of the present disclosure.

(28) FIG. 12 is a schematic structural view of a stent apparatus according to a twelfth embodiment of the present disclosure.

(29) FIG. 13a is a schematic structural view of a stent apparatus according to a thirteenth embodiment of the present disclosure, showing the stent before being released.

(30) FIG. 13b is a schematic structural view of the stent apparatus according to the thirteenth embodiment, showing the stent after being released.

(31) FIG. 14a is a schematic structural view of a stent apparatus according to a fourteenth embodiment of the present disclosure.

(32) FIG. 14b is a schematic structural view showing a skirt of the stent apparatus according to the fourteenth embodiment in an unfolded configuration.

(33) FIG. 14c is a schematic structural view showing the skirt of the stent apparatus according to the fourteenth embodiment in a stacked configuration.

(34) FIG. 14d is a schematic structural view of a stent apparatus which, compared to that of FIG. 14b, shows a pulling string provided.

(35) FIG. 14e is a schematic structural view of a stent apparatus which, compared to that of FIG. 14c, shows a pulling string provided.

(36) FIG. 14f is a schematic structural view of a stent apparatus with a skirt having a double-layered structure.

(37) FIG. 14g is a schematic structural view of a stent apparatus with a skirt having a pleated structure.

(38) FIG. 14h is a schematic structural view of a skirt having an alternative double-layered structure.

(39) FIG. 14i is a schematic structural view of a skirt in another stacked manner.

(40) FIG. 15 is a schematic structural view of a stent apparatus according to a fifteenth embodiment of the present disclosure.

(41) FIG. 16a is a schematic structural view of a stent apparatus according to a sixteenth embodiment of the present disclosure.

(42) FIG. 16b is a schematic structural view of a pulling unit of the stent apparatus according to the sixteenth embodiment.

(43) FIG. 17 is a schematic structural view of a pulling unit of a stent apparatus according to a seventeenth embodiment of the present disclosure.

(44) FIG. 18a is a schematic structural view of a pulling unit of a stent apparatus according to a eighteenth embodiment of the present disclosure, showing the pulling unit before being released;

(45) FIG. 18b is a schematic structural view of a pulling unit of a stent apparatus according to the eighteenth embodiment, showing the pulling unit after being released;

(46) FIG. 19 is a schematic structural view of a pulling unit of a stent apparatus according to a nineteenth embodiment of the present disclosure.

(47) FIG. 20a is a schematic structural view of a stent apparatus according to a twentieth embodiment of the present disclosure, showing a stent before being released.

(48) FIG. 20b illustrates how the pulling string of the stent apparatus according to the twentieth embodiment threads through the skirt.

(49) FIG. 20c is a schematic structural view of the stent apparatus according to the twentieth embodiment, showing the stent after being released.

(50) FIG. 21 illustrates how the pulling string of the stent apparatus according to the twenty-first embodiment of the present disclosure threads through the skirt.

(51) FIG. 22 illustrates how the pulling string of the stent apparatus according to the twenty-second embodiment of the present disclosure threads through the skirt.

(52) FIG. 23 illustrates how the pulling string of the stent apparatus according to the twenty-third embodiment of the present disclosure threads through the skirt.

(53) FIG. 24 illustrates how the pulling string of the stent apparatus according to the twenty-fourth embodiment of the present disclosure threads through the skirt.

(54) FIG. 25 illustrates how the pulling string of the stent apparatus according to the twenty-fifth embodiment of the present disclosure threads through the skirt.

(55) FIG. 26 illustrates how the pulling string of the stent apparatus according to the twenty-sixth embodiment threads through the skirt.

(56) FIG. 27a illustrates how the pulling string of the stent apparatus according to the twenty-seventh embodiment of the present disclosure threads through the skirt.

(57) FIG. 27b shows how the pulling string threads through the skirt, wherein the pulling string has a different perimeter compared to that in the twenty-seventh embodiment.

(58) FIG. 27c shows how the pulling string threads through the skirt, wherein the pulling string has a different perimeter compared to that in the twenty-seventh embodiment.

(59) FIG. 28 is a schematic structural view of a stent apparatus according to a twenty-eighth embodiment of the present disclosure.

(60) FIG. 29 is a schematic structural view of a stent apparatus according to a twenty-ninth embodiment of the present disclosure.

(61) FIG. 30 is a schematic structural view of a stent apparatus according to a thirtieth embodiment of the present disclosure.

(62) FIG. 31 is a schematic structural view showing cutting areas of a skirt of a stent apparatus according to a thirty-first embodiment of the present disclosure.

(63) FIG. 32 is a schematic structural view showing cutting areas of a skirt of a stent apparatus according to a thirty-second embodiment of the present disclosure.

(64) FIG. 33 is a schematic structural view showing cutting areas of a skirt of a stent apparatus according to a thirty-third embodiment of the present disclosure.

(65) FIG. 34 is a schematic structural view showing cutting areas of a skirt of a stent apparatus according to a thirty-fourth embodiment of the present disclosure.

(66) FIG. 35 is a schematic structural view showing cutting areas of a skirt of a stent apparatus according to a thirty-fifth embodiment of the present disclosure.

(67) FIG. 36a is a schematic structural view of a stent apparatus according to a thirty-sixth embodiment of the present disclosure.

(68) FIG. 36b is a schematic structural view showing a part of a blocking pocket of the stent apparatus according to the thirty-sixth embodiment.

(69) FIG. 37 is a schematic structural view of a stent apparatus according to a thirty-seventh embodiment of the present disclosure.

(70) FIG. 38 is a schematic structural view showing a part of a blocking pocket of a stent apparatus according to a thirty-eighth embodiment of the present disclosure.

(71) FIG. 39 is a schematic structural view showing a part of a blocking pocket of a stent apparatus according to a thirty-ninth embodiment of the present disclosure.

(72) FIG. 40 is a schematic structural view showing a part of a blocking pocket of a stent apparatus according to a fortieth embodiment of the present disclosure.

(73) FIG. 41a is a schematic structural view of a stent apparatus according to a forty-first embodiment of the present disclosure.

(74) FIG. 41b is a schematic structural view showing a part of a pushing pocket of the stent apparatus according to the forty-first embodiment.

(75) FIG. 42 is a schematic structural view of a stent apparatus according to a forty-second embodiment of the present disclosure.

(76) FIG. 43 is a schematic structural view showing a part of a pushing pocket of a stent apparatus according to a forty-third embodiment of the present disclosure.

(77) FIG. 44 is a schematic structural view showing a part of a pushing pocket of a stent apparatus according to a forty-fourth embodiment of the present disclosure.

(78) FIG. 45a is a schematic diagram showing the relationship between the circumferential distance variation between a first acting portion and a second acting portion and the axial displacement of a force exerting portion according to a forty-fifth embodiment of the present disclosure.

(79) FIG. 45b is a schematic diagram showing the relationship between the circumferential distance variation between the first acting portion and the second acting portion and the axial displacement of the force exerting portion according to the forty-fifth embodiment after the shape of a pulling unit is changed.

(80) FIG. 45c is a schematic diagram showing the thickness of a peripheral leakage occluder after a skirt is folded according to the forty-fifth embodiment.

(81) FIGS. 46a to 46c are schematic diagrams according to a forty-sixth embodiment of the present disclosure.

(82) FIG. 47a is a schematic diagram of a delivery system according to a forty-seventh embodiment of the present disclosure.

(83) FIG. 47b is a schematic view according to the forty-seventh embodiment, in which a stent with a skirt is in a loaded configuration.

(84) FIG. 47c is a schematic view according to the forty-seventh embodiment, in which the stent with the skirt is in an intermediate state during release.

(85) FIG. 47d is a schematic view according to the forty-seventh embodiment, in which the stent with the skirt is in a released configuration.

(86) FIG. 47e is a schematic view according to the forty-seventh embodiment, showing the delivery system entering into the aortic valve.

(87) FIG. 47f is a schematic view according to the forty-seventh embodiment, in which the stent in the delivery system is being released to an intermediate state at the aortic valve.

(88) FIG. 47g is a schematic view according to the forty-seventh embodiment, in which the stent in the delivery system is fully released at the aortic valve.

DESCRIPTION OF THE EMBODIMENTS

(89) In the stent apparatus for preventing peripheral leakage according to the present invention, the stent may be any known stent in the art. After entering into the body, the distal axial end of the stent is released first, and then a proximal end is to be released later. During release of the stent, any axial end thereof may serve as the distal end, with the other end thereof as the proximal end, which depends on physiological structures of different lesion sites in the human body and operating methods of implantation surgeries. In FIG. 1a, an aortic stent including a stent 1 is taken as an example. The stent 1 is made of material such as nickel-titanium alloy. A fixing ear 1b is provided at the top of the stent (referring to the orientations shown in the figures) for connecting with a delivery system. Depending on the applications and requirements of the stent, a valve 1a or an inner coverage membrane 1c may be provided in the stent. The peripheral leakage referred in the present invention is not strictly limited to the aortic valve, but also may occur in other positions in the human body with similar physiological structures.

(90) Unless otherwise specified, in the figures of the following embodiments: solid rectangular boxes illustrate that the portions of a pulling string there are fixed to the skirt; hollow rectangular boxes illustrate that the portions of the pulling string there are movably threaded through the skirt. The pulling string does not thread through the interior of the stent, but only extends around the outer periphery of the stent. In some embodiments, descriptions of the pulling string or the skirt are omitted, in order to clearly show and highlight the key points. All solutions of embodiments in the present invention are provided with a skirt. In the cases where a pulling string is not specifically indicated as being provided or not, it should be understood that the pulling string may be omitted, or the pulling string may be provided in the same manner as referred to in the other embodiments as required.

First Embodiment

(91) Referring to FIGS. 1b and 1c, the stent apparatus according to the present embodiment includes a stent 1 with a flexible skirt 2 provided on the outer periphery. A pulling string may be provided to thread through the skirt 2, which is, however, not shown in FIGS. 1b and 1c. The pulling string may thread through the skirt in any one of the techniques described in combination with other embodiments. The pulling string operates in cooperation with radial deformation of the stent during release, driving the skirt into a stacked configuration. Before being released, the stent 1 is in a radially compressed configuration. Before implantation, the stent is loaded into a delivery system and generally retains said compressed configuration under the constraint of a sheath, in which case, the skirt is circumferentially folded (shown in the dashed box in FIG. 1b).

(92) Before the stent 1 is released, the skirt 2 is in an unfolded configuration in an axial direction, which is axially unfolded and surrounds the outer periphery of the stent 1. The axial unfolding of the skirt is caused by an inner wall of the sheath which axially drags the skirt during the loading process. In order to improve the compliance of the skirt, a skirt having an outer diameter as small as possible should be used. Further, the skirt is required to be unfolded as much as possible to avoid being folded or overlapped.

(93) During the release of the stent, the expanded stent is gradually constrained by at least a portion of the skirt, and in the mean time, the pulling string axially pulls the skirt to form a peripheral leakage occluder upon further release of the stent.

(94) Valves may be provided in the stent, depending on the practical application; for example, the resulting stent apparatus may serve as a heart valve for preventing perivalvular leakage.

(95) The stent apparatus may serve as a blood vessel stent for preventing peripheral leakage between the stent apparatus and the inner wall of the blood vessel.

(96) FIG. 1d shows the stent 1 in a configuration during release, in which the bottom of the stent 1 is first released from the sheath of the delivery system and begins to expand radially to form a flared configuration, and the bottom of the skirt 2 (shown in the dashed box) is gradually stacked.

(97) The stent 1 expands radially in the human body after being released from the delivery system. The skirt 2 is in a stacked configuration. The stacking of the skirt 2 is cooperative with the deforming of the stent during release. The skirt 2 is folded and stacked in the axial direction of the released stent to form an annular peripheral leakage occluder. The peripheral leakage occluder may reduce the gap between the outer wall of the stent and the inner wall of the body channel, and prevent regurgitation (i.e., the peripheral leakage). The peripheral leakage occluder formed by the skirt 2 is shown in FIG. 1c.

(98) Preferably, the skirt 2 is made of flexible material, such as a porcine pericardium, or a bovine pericardium, or other flexible biocompatible materials, which is configured for constraining the outer periphery of the stent after the stent is released. The skirt is substantially in a cylindrical shape, having a diameter smaller than the outer diameter of the portion of the stent in the released state which the skirt surrounds, such that a constraint force is formed by the skirt onto the stent. During the release of the stent, the stent expands radially and outwardly gradually and takes an intermediate configuration with the flared configuration formed at the distal end that is released first, which may guide the flexible skirt to stack in the axial direction.

(99) FIG. 1c shows a two-layer stacked configuration, which is only used for illustration. The practical application may be more complicated, depending on the size and the material of the skirt, which in any event, does not affect the implementation of the invention, i.e., the skirt stacks axially and expands radially to form a peripheral leakage occluder.

(100) In this embodiment, the stent 1 generally has a meshed structure, and one axial side thereof (bottom end in the figures) is provided with a sharp angled structure 1e. The corresponding side of the skirt 2 (bottom end) does not extend axially beyond the tips of the sharp angled structure 1e before the stent 1 is released. In other words, the sharp angled structure 1e is partially exposed to the outside of the skirt 2. When the stent is being released, the tips of the sharp angled structure 1e located at the distal end which is first released will turn outwardly. If the skirt in the unfolded configuration covers the tips of the sharp angled structure 1e, the tips of the sharp angled structure 1e may snag the inner side of the skirt, which would prevent the skirt from being folded axially.

(101) Actually, the skirt 2 may extend beyond the tips of the sharp angled structure 1e in the axial direction. In this case, a skirt sleeve ii may be provided and stitched at the bottom end of the stent, as shown in FIG. 1e, which covers the tips of the sharp angled structure to prevent the skirt from being snagged by the tips of the sharp angled structure during the release of the stent, ensuring the stacking of the skirt. Before the stent 1 is released, the skirt 2 in the unfolded configuration has a circumferentially folded structure (shown in the dashed box in FIG. 1b). After the stent 1 is released, the circumferentially folded structure is unfolded due to the radial expanding of the stent. In this embodiment, before the stent 1 is released, the skirt 2 in the unfolded configuration is generally unfolded in a single layer along the axial direction of the stent. The skirt 2 may also have a pleated structure in other embodiments.

(102) In this embodiment, the skirt 2 may generally float around the outer periphery of the stent 1. Alternatively, the top edge of the skirt may be fixed around the outer periphery of the stent by means of stitching.

Second Embodiment

(103) Referring to FIGS. 2a to 2d, in the second embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2 which may be seen in FIG. 2a. The top edge of the skirt 2 is fixed to the outer periphery of the stent 1. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the released stent 1 into a stacked configuration and forms an annular peripheral leakage occluder as shown in FIG. 2d. A pulling string 4 is provided to thread through the skirt 2 and cooperates with the radial deformation of the stent 1 during release.

(104) The pulling string 4 includes a driving portion 4a and a force exerting portion 4b. The driving portion 4a movably threads through the skirt 2. The force exerting portion 4b is connected to the skirt 2 and movably threads through the corresponding portion of the skirt. During the release of the stent 1, the force exerting portion 4b is pulled by the driving portion 4a and has an axial displacement relative to the stent 1 to drag the skirt 2 to be stacked.

(105) In this embodiment, other than the top of the skirt which is connected to the stent, the lower region of the skirt has a large movement degree relative to the stent. The lower region may be fixed or not fixed to the stent. For example, as shown in FIG. 2h, both the top edge 2a and the bottom edge 2b of the skirt 2 are fixed to the stent 1. Since the axial length of the skirt is longer than the length of the portion of the stent between the top edge 2a and the bottom edge 2b, the skirt may be folded in an axial direction to form a floating section around the outer periphery of the stent 1, wherein it is the floating section that forms the stacked configuration after being pulled by the pulling string 4.

(106) The pulling string 4 which serves to act on the floating section includes a plurality of pulling units arranged in the circumferential direction. A portion of the pulling string, or a single pulling string, may serve as a single unit to drive the floating section to be folded axially, wherein one example based on the triangular deformation is shown below.

(107) A single pulling unit is shown in FIG. 2b. Before release, the driving portion includes a first action portion X1 and a second action portion X2 respectively connected to the skirt, and the force exerting portion Y1 is movably connected to the skirt, wherein the first action portion X1 and the second action portion X2 may serve as threading ends, respectively, and the force exerting portion Y1 is located between the two threading ends.

(108) Referring to FIG. 2c, the overall length of the portion of the pulling string corresponding to the pulling unit is fixed, that is, the overall length of the sides L1 and L2 of the triangle is fixed. When the stent is being released, the first acting portion X1 and the second acting portion X2 move away from each other in the directions indicated by the respective arrows, and thus the distance between the first acting portion X1 and the second acting portion X2 increases, and the shape of the triangle will change. Therefore, the force exerting portion Y1 as a vertex will move towards a line connecting the first action portion X1 and the second action portion X2 in the direction as indicated by the upward arrow, that is, the force exerting portion Y1 will move axially relative to the stent, and pull the skirt. It may be concluded that the circumferential span between the two threading ends is changed after the release of the stent relative to the stent being unreleased, and a relative displacement between the force exerting portion and the driving portion along the axial direction of the stent is produced during the release of the stent which causes the skirt to be pulled and stacked.

(109) In order to obtain a larger deformation for the triangle of each pulling unit, the first acting portion X1 and the second acting portion X2 span one or more cells in the circumferential direction. For example, in this embodiment, the first acting portion X1 and the second acting portion X2 substantially span two cells. The central angle corresponding to the first acting portion X1 and the second acting portion X2 is 60 degrees after the stent is released. The pulling units circumferentially cover the entire skirt, however, only two pulling units are shown in the figures, with the others omitted for convenience of illustration.

(110) All the pulling units are connected in a wave-like manner with a plurality of waves and each wave having a triangle shape. Along the extension direction of the pulling string, the force exerting portion Y1 is located between the first action portion X1 and the second action portion X2, and the first action portion X1 and the second action portion X2 are opposite to each other (namely, they are located at the same level along the axial direction). Alternatively, pulling units may be arranged in such a manner that they are spaced from each other. In other words, two adjacent pulling units do not share any portion of the pulling string. For ease of identification, the pulling string is indicated as dashed lines. Actually, the pulling string threads through in such a manner that some sections thereof are arranged outside of the skirt, and some sections thread into the inner side of the skirt via threading holes, and the sections located outside and the sections located inside are arranged alternatively in the circumferential direction.

(111) Referring to FIG. 2e, in a further development, within the pulling string on the skirt 2, the central angle corresponding to the first acting portion X1 and the second acting portion X2 is 90 degrees.

(112) Referring to FIG. 2f, in a further development, within the pulling string on the skirt 2, the central angle corresponding to the first acting portion X1 and the second acting portion X2 is 180 degrees.

(113) Referring to FIG. 2g, in a further development, within the pulling string on the skirt 2, the central angle corresponding to the first acting portion X1 and the second acting portion X2 is 30 degrees.

Third Embodiment

(114) Referring to FIGS. 3a and 3b, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the released stent 1 into an annular peripheral leakage occluder.

(115) In this embodiment, the stent is a blood vessel stent, which may be used in large vessels such as the aorta. The shape and the application of the stent in this embodiment are different from those disclosed in the previous embodiments, however, the arrangements of the skirt and the functions are similar.

(116) In this embodiment, the skirt 2 is made of flexible material, and constrains the outer periphery of the stent after the stent is released. During the release, the skirt has not yet constrained the stent, so it is possible for the skirt to adjust its position itself under the blood flow. In order to further limit the position of the skirt, a limiting string may be used in combination with the skirt.

(117) Alternatively, even under the action of the limiting string, the skirt forming the peripheral leakage occluder may also be able to adjust its position itself under the blood flow.

Fourth Embodiment

(118) Referring to FIGS. 4a and 4b, in this embodiment, the outer periphery of the stent 1 is provided with two flexible skirts. Before the stent 1 is released, the skirts are in unfolded configurations, which are axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirts are folded and stacked along the axial direction of the released stent into stacked configurations and form annular peripheral leakage occluders.

(119) This embodiment differs from the third embodiment in that the skirts here include a first skirt 2a and a second skirt 2b which are arranged one above the other in an axial direction, and each skirt in the stacked configuration forms a respective peripheral leakage occluder.

Fifth Embodiment

(120) Referring to FIG. 5a, in which the skirt is omitted, this embodiment differs from the first embodiment in the structure of the stent 1. In this embodiment, the bottom of the stent 1 is provided with a flared driving structure 1d, which extends from the middle portion of the stent to the end of the stent (the bottom end). The closer to the bottom end of the stent, the larger the diameter for the flared driving structure 1d. In this embodiment, the generatrix of the flared driving structure 1d is substantially straight. The wider side (the bottom end) of the flared driving structure 1d is released first, and the narrow side is released later. Due to such configuration, the flared structure of the stent may operate in cooperation with the skirt during the release of the stent and guides the skirt to stack axially and stay in the stacked configuration.

(121) As shown in FIG. 5b in which the skirt or skirts are omitted, in this embodiment, the skirts may be provided at one axial end or two axial ends of the stent such as in the third embodiment, and the stent 1 has flared driving structures 1d at both ends in the axial direction.

Sixth Embodiment

(122) Referring to FIG. 6, in which the skirt or skirts are omitted, this embodiment differs from the fifth embodiment in the structure of the flared driving structures 1d. In this embodiment, the generatrix of the flared driving structure 1d at the bottom of the stent 1 is substantially curved, and thus has a bottom end turning more outwardly relative to that shown in the fifth embodiment.

Seventh Embodiment

(123) Referring to FIGS. 7a and 7b, this embodiment differs from the first embodiment in that an axial end of the stent 1 has a smooth curved edge, instead of an edge with sharp tips shown in the first embodiment. Before the stent 1 is released, the corresponding side of the skirt 2 extends axially beyond the stent or just extends to the end of the stent.

(124) In this embodiment, the edge of the distal end of the stent 1 to be released first is formed by a plurality of arc sections if connected one another. Since the arc sections if would not pierce or snag the skirt 2, it is allowable for the skirt 2 to extend axially beyond or exactly to the distal end of the stent to be released first before the stent is released. As a result, a longer skirt may be obtained, which forms a peripheral leakage occluder with a higher profile and a larger volume, thereby improving the sealing effect.

Eighth Embodiment

(125) Referring to FIG. 8, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the released stent 1 into a stacked configuration and forms an annular peripheral leakage occluder.

(126) The top edge of the skirt 2 serves as a fixing band 3 which is stitched on the stent with spaced stitching portions 3a as shown in the figure. At least a part of the skirt 2 remains in a fixed position relative to the stent and is free of the influence of external factors such as blood flow, which functions to control the position of the peripheral leakage occluder.

(127) In this embodiment, there is a single fixing band 3 which is located at the middle portion of the stent, with the remaining skirt there below floating around the outer periphery of the stent 1 before being stacked. Alternatively, it is possible to provide several fixing bands.

(128) The skirt is fixed to the stent only at the fixing band, with the remaining skirt movable relative to the stent. In particular, at least a part of the skirt is movable axially so that it can be folded. In the case of only a single fixing band provided, the remaining skirt floats around the outer periphery of the stent. In the case of several fixing bands provided, the skirt may also be foldable provided that the axial length of the skirt between two adjacent fixing bands is sufficient. For example, in the second embodiment shown in FIG. 2h, the top edge 2a and the bottom edge 2b of the skirt 2 are both fixed on the stent 1. Since the length of the skirt is longer than the length of the corresponding portion of the stent, that is, the axial length of the skirt is sufficient, the skirt can be folded to form a floating section.

(129) The skirt may be foldable provided that the axial length of the skirt between two fixing bands is sufficient. For example, in the case that the axial length of the corresponding portion of the stent between the two fixing bands is L1 and the axial length of the skirt between the two fixing bands is L2, it is possible for the skirt to be axially stacked provided that L1 is less than L2. The redundant section of the skirt in an unfolded configuration may be overlapped and rested on the outer periphery of the stent, wherein the overlapped sections are folded axially, which will be further described hereinafter.

Ninth Embodiment

(130) Referring to FIG. 9, this embodiment differs from the eighth embodiment in that the fixing band 3 here is located at the bottom of the stent, and the remaining skirt above the fixing band floats around the outer periphery of the stent 1 before being stacked.

Tenth Embodiment

(131) Referring to FIG. 10, the stent in this embodiment has a meshed structure with a plurality of grids. This embodiment differs from the eighth embodiment in that the fixing band 3 here is stitched on the meshed stent by a continuous stitch line 3b. Corresponding to the grids of the meshed stent, the stitch line 3b undulates in the axial direction while extending in the circumferential direction, thereby forming a wave-like configuration.

Eleventh Embodiment

(132) Referring to FIG. 11, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder. The position of the peripheral leakage occluder corresponds to that of the valve cusps 1k.

(133) The stent is an aortic valve stent, and valves are provided in the stent. In operation, the stent is implanted at the lesion site at the aortic valve of a human heart. Since there is a coronary inlet 1j distributed around the aortic valve annulus, the stacked skirt should avoid the branch vessel in an axial position. Depending on the physiological structure of the lesion site, after the stent is released, a hollow area 1g should be free from coverage by the skirt 2, otherwise the skirt 2 would block the blood flow into the coronary entrance 1j. Thus, the skirt should be provided at an axial position which avoids the channel (the hollow area 1g) formed on the stent for blood flow.

(134) The skirt may be made of the same material as the valve, such as animal pericardium or other biocompatible flexible materials.

Twelfth Embodiment

(135) Referring to FIG. 12, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt. Before the stent 1 is released, the skirt is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 into a stacked configuration after release and forms an annular peripheral leakage occluder.

(136) This stent 1 is generally configured to be applied to the aortic arch. Due to the physiological structure of the aortic arch, the side wall of the stent would face the branch blood vessels 1h after the stent is released, which, should be free from coverage by the skirt 2, otherwise, the blood flow would be blocked. Therefore, the stacked skirt should be provided to avoid the branch blood vessels 1h in the axial position.

Thirteenth Embodiment

(137) Referring to FIGS. 13a and 13b, in this embodiment, the outer periphery of the stent 1 is provided with flexible skirts. Before the stent 1 is released, the skirts are in unfolded configurations, which are axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirts are folded and stacked along the axial direction of the stent after release into stacked configurations and form annular peripheral leakage occluders. In this embodiment, there are two skirts, i.e., a first skirt 2d and a second skirt 2e. Each of the first and second skirts 2d and 2e in the stacked configuration forms a respective peripheral leakage occluder.

(138) The top edges of the first and second skirts 2d and 2e are connected to the stent at two fixing bands 3d and 3e, respectively, by means of spaced stitching portions or continuous stitch lines. The ends of the first and second skirts 2d and 2e opposite to the top edges are floating edges.

(139) The first skirt 2d in the stacked condition is configured to form a first peripheral leakage occluder, and the second skirt 2e in the stacked condition is configured to form a second peripheral leakage occluder. The two peripheral leakage occluders are separated. The first peripheral leakage occluder is arranged closer to the top of the stent than the second peripheral leakage occluder. In the unfolded configurations, the first skirt 2d has an axial length of 1.5 to 3 times to the axial length of the second skirt 2e. After being stacked, the first peripheral leakage occluder generally has a larger cross section than the second peripheral leakage occluder. That is, after being stacked, the first peripheral leakage occluder at the top has a higher profile and the peripheral leakage occluder at the bottom has a lower profile. In the unfolded configurations, the bottom edge of the first skirt 2d extends to the top edge of the second skirt 2e, without overlapping one another. That is, the first and second skirts are arranged end to end, which not only maximizes the advantages of the sufficient axial lengths thereof, but also avoids an increased radial thickness caused by overlap of the first and second skirts so as to ensure smooth loading of the stent, i.e., compression of the stent into the delivery system.

Fourteenth Embodiment

(140) Referring to FIGS. 14a to 14c, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt. Before the stent 1 is released, the skirt is in unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder.

(141) As shown in FIG. 14a, in this embodiment, valves 1a and an inner coverage membrane 1c are provided in the stent 1. The top edge of the skirt 2 is connected to the stent at a first fixing band 3f, and the bottom edge of the skirt 2 is connected to the bottom edge of the stent at a second fixing band 3g, wherein the first and second fixing bands 3f and 3g may be stitched by means of spaced stitching portions or continuous stitch lines, respectively.

(142) The inner coverage membrane 1c inside the stent extends to the bottom end of the stent, and the bottom edge of the skirt 2 outside the stent also extends to the bottom end of the stent. The inner coverage membrane 1c and the skirt 2 may be separately formed or integrally formed as a single piece. In this embodiment, it is preferred to form them as a single piece, in which case the inner coverage membrane inside the stent first extends to the end of the stent, and then turns outwards to form the skirt, which may simplify the cutting process during stitching and maintain the integrity of the stent apparatus.

(143) As shown in FIG. 14b, the inner coverage membrane 1c is integrally formed with the skirt 2 as a single piece. This embodiment differs from the embodiment shown in FIG. 14a in that only a single fixing band 3f is provided. The skirt 2 first extends upwardly from the position where the skirt 2 is connected with the inner cover 1c, i.e. the bottom edge of the stent 1, to the axially highest end of the skirt 2, i.e. the top of the skirt. The top edge of the skirt 2 is connected to the stent at the fixing band 3f. The skirt 2 then turns downwards from the highest end and forms an evaginated floating section 2f. The floating section 2f is axially extended before the stent 1 is released. After the stent 1 is released, the floating section 2f is stacked under elastic effect or blood flow. In addition, the floating section 2f may also be pulled and stacked in combination with the pulling string of the present invention to form an annular protrusion protruding radially to serve as a peripheral leakage occluder.

(144) The configuration in FIG. 14c may also be shaped by stitching in advance. The unfolded configuration of the skirt in the axial direction is obtained only by compressing radially, with the folded configuration still retained. After the stent is released, the floating section 2f in the human body will expand further through the influence of blood flow or the like.

(145) Referring to FIGS. 14d and 14e, the transition of the skirt 2 from the unfolded configuration to the stacked configuration will be described in a further development in combination with the arrangement of the skirts shown in FIGS. 14a to 14c.

(146) A pulling string 4 is provided on the floating section 2f of the skirt. The pulling string 4 generally threads through the floating section 2f in the circumferential direction. The pulling string 4 undulates in the axial direction while extending along the circumferential direction of the stent, forming a wave-like configuration with peaks and valleys. In the unfolded configuration, the peaks are at the same level in the axial position, and the valleys are at the same level in the axial position. Alternatively, the peaks (or the valleys) may be offset from each other.

(147) In order to facilitate the threading of the pulling string, a set of first threading holes is provided on the skirt corresponding to the peaks, and a set of second threading holes is provided corresponding to the valleys. The pulling string alternately threads the first threading hole and the second threading hole and forms a wave-like configuration. The pulling string alternatively threads into and out of the surfaces of the skirt.

(148) Two adjacent peaks serve as two threading ends operating in cooperation with the skirt. The circumferential span between the two threading ends is changed after the release of the stent relative to the stent being unreleased. During the release of the stent, driven by the deformed stent, the peaks move away from each other in the circumferential direction and thus drive the valleys to lift upwardly, thereby axially stacking the floating section 2f.

(149) The peaks and valleys are relative concepts. Actually, either one can be designated as the peak, and the other one can be designated as the valley. During the release of the stent, driven by the deformed stent, the valleys also move away from each other in the circumferential direction and thus drive the peaks to move axially. Therefore, the movements of the peaks and valleys are relative to each other. In any case, the intention is to drive the peaks and valleys to move axially towards each other.

(150) Referring to FIG. 14f, in a further development, the skirt 2 has a double-layered structure which is filled with a water-absorbing expansion material. After being released in the human body, the water-absorbing expansion material absorbs water and expands radially. Due to the coverage of the skirt made of a membrane material, the risk of the water-absorbing expansion material falling off can be avoided.

(151) Referring to FIG. 14g, in a further development, the skirt 2 may have folded sections in a circumferential direction which overlap one another in a radial direction to cooperatively form a radial protrusion.

(152) Referring to FIG. 14h, in a further development, an interlayer is provided between the skirt 2 and the inner coverage membrane 1c, which may be formed by folding a part of the skirt 2. Preferably, the inner coverage membrane c extends upwardly from the bottom edge of the stent. The top of the interlayer is fixed on the stent. The skirt turns downwards from the top of the interlayer and may be configured as a floating section that floats outside the interlayer. The skirt may be fixed on the interlayer or at a bottom of the interlayer, or may be fixed on the inner coverage membrane 1c. The floating section may be pulled and stacked in the technique shown in FIG. 14e to form an annular protrusion protruding radially to serve as a peripheral leakage occluder.

(153) Referring to FIG. 14i, in a further development, the skirt 2 extends upwardly from the position where the skirt 2 is connected with the inner coverage membrane 1c, that is, from the bottom edge of the stent 1. The entire upwardly extending portion of the skirt 2 is configured as a floating section 2f, with the end of the floating section 2f distant from the bottom edge being a floating edge. The floating section 2f is axially unfolded before the stent 1 is released, and may be pulled and stacked in the technique shown in FIG. 14e to form an annular protrusion protruding radially to serve as a peripheral leakage occluder. The difference there between is that it is the top edge of the floating section 2f that moves towards the bottom edge here, but the principles are the same.

Fifteenth Embodiment

(154) Referring to FIG. 15, in this embodiment, the outer periphery of the stent 1 is provided with flexible skirts. Before the stent 1 is released, the skirts are in unfolded configurations, which are axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirts are folded and stacked along the axial direction of the stent 1 after release into stacked configurations and form annular peripheral leakage occluders.

(155) In this embodiment, there are two skirts, i.e. a first skirt 2a and a second skirt 2b, which are arranged one above the other in an axial direction. During the release of the stent, the expanded stent is gradually constrained by at least portions of the skirts, and the skirts are driven to be axially pulled with the further release of the stent. Each skirt is axially pulled and stacked to form a respective peripheral leakage occluder. In order to adapt to the axial movement of the skirts and prevent the skirts from falling off the stent, flexible limiting strings 2c are respectively provided between the stent 1 and the first and second skirts 2a and 2b, and thus security is improved. The limiting string 2c may include a plurality of strips distributed in an axial direction, or a single strip stitched on the periphery of the skirt in a pattern of a rectangular wave. The first and second skirts 2a and 2b are provided with respective pulling strings.

Sixteenth Embodiment

(156) Referring to FIGS. 16a and 16b, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 which is configured to drive the skirt 2 to transform into the stacked configuration. The pulling string 4 cooperates with the radial deformation of the stent during release.

(157) In this embodiment, the entire pulling unit is in the shape of a trapezoid, with the force exerting portions Y1 and Y2 of the pulling string 4 respectively fixed on the skirt 2. The first acting portion X1 and the second acting portion X2 are arranged at the bottom end of the stent (i.e., the distal end which is to be released first). In other words, the driving portion is located at the distal end of the stent (and also of the skirt) which is to be released first, and the force exerting portions are located at the proximal end of the stent (and also of the skirt) which is to be released later.

(158) During the release of the stent, the perimeter of the stent increases. The first acting portion X1 and the second acting portion X2 move away from each other, and the shape of the pulling unit changes. The portions of the skirt connected with the first acting portion X1 and the second acting portion X2 move towards the force exerting portions Y1 and Y2. That is, the acting portions X1, X2 and the force exerting portions Y1, Y2 move axially towards each other, so as to pull the skirt.

Seventeenth Embodiment

(159) Referring to FIG. 17, this embodiment differs from the sixteenth embodiment in that the force exerting portions Y1 and Y2 here movably thread through the skirt 2 respectively, and the force exerting portions Y1 and Y2 may be respectively connected to adjacent pulling units.

Eighteenth Embodiment

(160) Referring to FIG. 18a and FIG. 18b, in this embodiment, the outer periphery of the stent is provided with a flexible skirt. Before the stent is released, the skirt is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent before release. After the stent is released, the skirt is folded and stacked along the axial direction of the stent after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 that is configured to drive the skirt into a stacked configuration. The pulling string 4 cooperates with the radial deformation of the stent during release.

(161) In this embodiment, the pulling string 4 movably threads through the skirt at the first acting portion X1 and the second acting portion X2. The two ends of the pulling string 4 are respectively fixed on the skirt 2 as force exerting portions Y1 and Y2.

(162) The entire pulling unit is in the shape of a rectangle or trapezoid. During the release of the stent, the perimeter of the stent increases. The first acting portion X1 and the second acting portion X2 move away from each other, and the shape of the pulling unit changes. The force exerting portions Y1 and Y2 move towards a line connecting the first acting portion X1 and the second acting portion X2, that is, move axially relative to the stent, so as to pull the skirt.

(163) In the case that the pulling string 4 has a long course, in order to limit the position thereof relative to the skirt or to limit the threading direction thereof, a plurality of threading holes 2g may be provided on the skirt based on a preset threading course, such that the pulling string may thread through the plurality of threading holes 2g so as to ensure the pulling performance.

Nineteenth Embodiment

(164) Referring to FIG. 19, in this embodiment, the outer periphery of the stent is provided with a flexible skirt. Before the stent is released, the skirt is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent before release. After the stent is released, the skirt is folded and stacked along the axial direction of the stent after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 that is configured to drive the skirt into a stacked configuration. The pulling string 4 cooperates with the radial deformation of the stent during release.

(165) In this embodiment, the motions of adjacent pulling units are cooperative to each other during deformation. Two pulling units are taken as an example in FIG. 19, and the same principle is applicable to more than two pulling units.

(166) Within the first pulling unit: an action portion X3 is fixed on the skirt; an action portion X4 movably threads through the skirt; and a force exerting portion Y3 movably threads through the skirt.

(167) Within the second pulling unit: an action portion X4, as a common action portion X4 shared with the first pulling unit, movably threads through the skirt; an action portion X5 is fixed on the skirt; and a force exerting portion Y4 movably threads through the skirt.

(168) This portion of the pulling string 4 is generally W-shaped, and the overall length of the W-shaped pulling string is fixed. When the stent is being released, the three action portions move away from each other. As the common action portion X4 movably threads through the skirt, the portions of the pulling string corresponding to the two pulling units may be pulled against each other and possibly with a displacement there between. As a result, the two pulling units influence and interact with each other when deforming. Therefore, the two pulling units move in cooperation with each other. The same principle is applicable to more than two pulling units.

Twentieth Embodiment

(169) Referring to FIGS. 20a to 20c, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. Preferably, the perimeter of the skirt is equal to or slightly greater than the perimeter of a corresponding portion of the stent so that the skirt conforms around the corresponding portion of the stent. Also provided on the skirt is a pulling string 4 that is configured to drive the skirt into a stacked configuration. The pulling string 4 cooperates with the radial deformation of the stent 1 during release. When the stent is being released in the human body, the bottom edge of the skirt 2 is released first, and then the top edge of the skirt 2 is released later. After the stent 1 is released, the skirt 2 is in the stacked configuration, which is folded and stacked along the axial direction of the stent 1 after release and forms an annular peripheral leakage occluder.

(170) The top edge of the skirt 2 serves as a fixing band 3, which may be stitched on the stent in the same stitching technique as shown in FIG. 8 with spaced stitching portions. At least a part of the skirt 2 remains in a fixed position relative to the stent and is free of the influence of external factors such as blood flow, which functions to control the position of the peripheral leakage occluder. In this embodiment, there is a single fixing band 3 provided at the middle portion of the stent, and the portion of the skirt below the fixing band 3 floats around the outer periphery of the stent 1 before being stacked.

(171) Alternatively, the fixing band may be fixed on the stent in the same stitching technique as shown in the tenth embodiment. The stitch line on the fixing band 3 may undulate in the axial direction while extending in the circumferential direction. In other words, the corresponding portion of the stent has a meshed structure with a plurality of grids, and the stitch line extends along the edges of the grids and forms a wave-like configuration.

(172) The hollow boxes in the figures illustrate that the portion of the pulling string here threads through the skirt without threading through the stent.

(173) In this embodiment, the pulling string generally threads through the skirt in a circumferential direction, which undulates in the axial direction of the stent while extending in the circumferential direction, thereby forming a wave-like configuration with peaks and valleys.

(174) Within a periodic portion of the pulling string 4, peak X6, valley Y5, peak X7, valley Y6, peak X8 are distributed in the circumferential direction one after the other while undulating in the axial direction. In the unfolded configuration, the peaks are at the same level in the axial position, and the valleys are at the same level in the axial position. Alternatively, the peaks (or the valleys) may also be offset from each other.

(175) In order to facilitate the threading of the pulling string, a set of first threading holes is provided on the skirt corresponding to the peaks, and a set of second threading holes is provided corresponding to the valleys. The pulling string alternatively threads the first threading hole and the second threading hole and forms the wave-like configuration. The pulling string alternatively threads into and out of the surfaces of the skirt.

(176) Two adjacent peaks may serve as the driving portion of the pulling string, i.e., the two threading ends interacting with the skirt. The circumferential span between two threading ends such as the above-mentioned peaks X6 and X8 is changed after the stent is released relative to the stent being unreleased. Both the circumferential span and the axial length of the entire pulling unit are changed after the stent is released relative to the stent being unreleased.

(177) During the release of the stent, the stent drives the pulling string on the skirt. Driven by the deformed stent, the peaks of the pulling string move away from each other in the circumferential direction and thus drive the valleys to lift upwardly. Since the pulling string movably threads through the skirt, the periodic portions thereof are configured for driving and operating in cooperation with one another, thereby generally moving the pulling string. The peaks and valleys are relative concepts. Actually, either one may be designated as the peak, and the other one can be designated as the valley. During the release of the stent, driven by the deformed stent, the valleys move away from each other in the circumferential direction and thus drive the peaks to move axially. Therefore, the movements of the peaks and valleys are relative to each other. In any case, the intention is to drive the peaks and valleys to move axially towards each other.

(178) During manufacturing, the top edge of the skirt is first fixed on the preformed stent, the pulling string is circumferentially provided on the skirt, then the pulling string is tensioned to fold the skirt and finally the two ends of the pulling string are connected.

Twenty-First Embodiment

(179) Referring to FIG. 21, this embodiment differs from the twentieth embodiment in that two sets of pulling strings 4 are provided here, one above the other in an axial direction, which are configured to pull the corresponding portions of the skirt 2 at different stages during releasing of the stent, respectively. The peaks of the lower pulling string are located higher than the valleys of the upper pulling string. Each pulling string moves together in the circumferential direction to pull the skirt.

(180) In order to further show the threading of the pulling string through the skirt, the dashed lines in FIG. 21 indicate the portions of the pulling string located beneath the skirt, and the solid lines indicate the portions of the pulling string located above the skirt. Since the pulling strings are not fixed on or thread through the stent, and thus other than the fixing band, the remaining portions of the skirt may serve as floating sections, the two sets of pulling strings may interact with each other via force transmitted by the skirt.

Twenty-Second Embodiment

(181) Referring to FIG. 22, this embodiment differs from the twentieth embodiment in the wave shape of the undulation of the pulling string 4. In this embodiment, the pulling string follows a course having a wave shape with sharp peaks and flat valleys.

Twenty-Third Embodiment

(182) Referring to FIG. 23, this embodiment differs from the twentieth embodiment in the wave shape of the undulation of the pulling string 4. In this embodiment, the pulling string follows a course having a wave shape with flat peaks and flat valleys.

Twenty-Fourth Embodiment

(183) Referring to FIG. 24, this embodiment differs from the twentieth embodiment in the wave shape of the undulation of the pulling string 4. In this embodiment, the pulling string follows a course having a wave shape with flat peaks and sharp valleys.

Twenty-Fifth Embodiment

(184) Referring to FIG. 25, this embodiment differs from the twenty-second embodiment in that portions of the pulling string 4 corresponding to the peaks here are fixed on the skirt 2.

Twenty-Sixth Embodiment

(185) Referring to FIG. 26, this embodiment differs from the twentieth embodiment in that portions of the pulling string 4 corresponding to the valleys here are fixed on the skirt 2.

Twenty-Seventh Embodiment

(186) Referring to FIG. 27a, this embodiment differs from the twentieth embodiment in that the pulling string 4 here is routed around the stent for less than a perimeter of the stent to form substantially an annular driving portion. Opposite ends of the driving portion movably thread through the skirt 2 respectively, and then extend downwards and join together to form a force exerting portion after movably threading through the bottom of the skirt. The annular driving portion may thread through the stent, or may be just surrounding the outer periphery of the stent. A single force exerting portion is provided as shown in FIG. 27a. Alternatively, more than one force exerting portion may be provided. It is also possible to provide a plurality of pulling strings 4, which pull the corresponding force exerting portions at the bottom of the skirt, respectively.

(187) Referring to FIG. 27b, in a further development, the pulling string 4 extends further in the circumferential direction compared to that shown in FIG. 27a. In particular, the pulling string 4 in this embodiment extends for the entire perimeter of the stent and forms an annular driving portion surrounding the stent.

(188) Referring to FIG. 27c, in a further development, the pulling string 4 extends further in the circumferential direction compared to that shown in FIG. 27a. In particular, the pulling string 4 in this embodiment extends in the circumferential direction for 1.5 times of a perimeter of the stent, and forms an annular driving portion.

Twenty-Eighth Embodiment

(189) Referring to FIG. 28, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 that is configured to drive the skirt 2 to transform into the stacked configuration. The pulling string 4 cooperates with the radial deformation of the stent during release. When being released in the human body, the bottom edge of the skirt 2 is released first, and the top edge of the skirt 2 is released later.

(190) In this embodiment, the pulling string generally threads through the skirt in the circumferential direction. The pulling string undulates in the axial direction while extending in the circumferential direction, forming a wave-like configuration with peaks and valleys.

(191) During the release of the stent, driven by the deformed stent, the peaks of the pulling string move away from each other in the circumferential direction and thus drive the valleys to lift upwardly. Since the pulling string movably threads through the skirt, the periodic portions thereof are configured for driving and operating in cooperation with one another, thereby generally moving the pulling string.

(192) The top edge of the skirt 2 is fixed on the stent. The skirt 2 is provided with a plurality of cutting areas 5 at the bottom side of the skirt, arranged in the circumferential direction. The cutting areas may reduce the radial stacking thickness of the skirt in the unfolded configuration, facilitating loading onto the stent and delivery of the stent apparatus.

(193) The bottom edge of the skirt 2 is generally in a tooth-shaped structure extending in the circumferential direction, with a cutting area formed between two adjacent teeth. In this embodiment, the teeth are triangular and evenly arranged in the circumferential direction.

(194) Before the stent is released, the distal end of the skirt to be released first extends beyond the stent in the axial direction, and it is the tooth-shaped structure that extends beyond the stent.

Twenty-Ninth Embodiment

(195) Referring to FIG. 29, this embodiment differs from the twenty-eighth embodiment in that the top edge of the skirt 2 here is fixed on the stent and has a plurality of cutting areas 5. The top edge of the skirt 2 corresponds to the edges of the grids of the stent, and is continuously stitched on the stent along the edges of the grids.

Thirtieth Embodiment

(196) Referring to FIG. 30, the top edge of the skirt 2 has a tooth-shaped structure with triangular teeth. This embodiment differs from the twenty-ninth embodiment in that the top tips of the triangular teeth at the top edge of the skirt 2 are fixed on the stent with a plurality of fixing points 3h spaced from each other.

Thirty-First Embodiment

(197) Referring to FIG. 31, this embodiment differs from the twenty-eighth embodiment in that each of the cutting areas 5 here includes a plurality of through holes arranged along the axial direction of the stent, with solid materials arranged between the through holes, which facilitates the overall shaping of the peripheral leakage occluder and maintenance of necessary pull at various areas.

(198) The through hole may be in a circular or an elliptical shape. Among the through holes in the same cutting area, the closer to the corresponding side edge of the skirt, the larger the size of the through hole.

Thirty-Second Embodiment

(199) Referring to FIG. 32, this embodiment differs from the thirty-first embodiment in that the cutting area here includes a single through hole. The inner edge of the through hole is relatively smooth. The closer to the corresponding side edge of the skirt, the larger the width of the through hole.

Thirty-Third Embodiment

(200) Referring to FIG. 33, this embodiment differs from the thirty-first embodiment in that there is no obvious boundary between the cutting areas 5 here, and the cutting areas 5 are provided with a plurality of through holes that are densely arranged.

Thirty-Fourth Embodiment

(201) Referring to FIG. 34, this embodiment differs from the twenty-eighth embodiment in that the teeth between two adjacent cutting areas are trapezoid-shaped here.

Thirty-Fifth Embodiment

(202) Referring to FIG. 35, this embodiment differs from the twenty-eighth embodiment in that the teeth between two adjacent cutting areas are rectangle-shaped here.

Thirty-Sixth Embodiment

(203) Referring to FIG. 36a, the outer periphery of the stent 1 in this embodiment is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder.

(204) The top of the skirt is further provided with a blocking pocket 6 configured for receiving the back-flow blood from peripheral leakage. The blocking pocket 6 is made of flexible material such as the same material as the skirt. In this embodiment, the blocking pocket 6 is separately provided and has a double-layered structure, which may receive the back-flow blood from peripheral leakage and expand radially to abut against the annulus to further prevent the regurgitation. Alternatively, the blocking pocket 6 may be integrally formed with the skirt as a single piece; for example, the bottom of the blocking pocket 6 may be stitched on the stent to serve as a top fixing band of the skirt.

(205) Alternatively, the coverage membrane provided inside the stent may also simultaneously serve as the blocking pocket. For example, a portion of the blocking pocket is integrally formed by the material of the skirt, and the other portion of the blocking pocket is formed by the material of the inner coverage membrane.

(206) The blocking pocket 6 has inlets 6a for allowing back-flow blood to flow therein, by means of which the blocking pocket 6 is self-expandable to prevent further regurgitation. After the stent is released, the peripheral leakage occluder is located at the side of the blocking pocket 6 facing the bottom of the stent 1, and abuts against the blocking pocket 6 to operate in cooperation therewith.

(207) The side of the blocking pocket 6 facing away from the top of the stent 1 is closed, and the opposite side thereof facing the top of the stent 1 is provided with a plurality of stitching portions 6b fixed to the stent 1. Adjacent stitching portions are spaced from each other, with an inlet 6a for allowing back-flow blood to flow therein defined therebetween. Therefore, a plurality of inlets are provided and the inlets are evenly arranged in the circumferential direction.

(208) The peripheral leakage occluder in this embodiment may be formed in any technique described in the above embodiments. For example, the skirt 2 may be driven to transform into the stacked configuration by an optional pulling string 4, which cooperates with the radial deformation of the stent 1 during release. When being released in the human body, the bottom edge of the skirt 2 is released first, and the top edge of the skirt 2 is released later.

(209) In this embodiment, the pulling string generally threads through the skirt in the circumferential direction. The pulling string undulates in the axial direction while extending in the circumferential direction, forming a wave-like configuration with peaks and valleys. The peaks are located at the top edge of the skirt 2 and fixed on the stent together with the skirt 2. The valleys movably thread through the skirt 2.

(210) During the release of the stent, driven by the deformed stent, the peaks of the pulling string move away from each other in the circumferential direction and thus drive the valleys to lift upwardly.

(211) Referring to FIG. 36b, which schematically illustrates a cross section of the blocking pocket 6, the dashed line indicates the stent 1, and the blocking pocket 6 is separately provided relative to the material of the skirt 2. The blocking pocket 6 has a double-layered structure including an inner layer 6e and an outer layer 6d. The two layers 6e and 6d may be formed as one single piece. The two layers are integrally connected with a bend at the bottom. In this embodiment, the inner layer 6e and the outer layer 6d are separately formed, and are connected and sealed by stitching the bottoms 6c together.

Thirty-Seventh Embodiment

(212) Referring to FIG. 37, this embodiment differs from the thirty-sixth embodiment in that the skirt 2 here is provided with a plurality of cutting areas 5 at the axial bottom side of the skirt, arranged in the circumferential direction. The cutting areas may reduce the radial stacking thickness of the skirt in the unfolded configuration, facilitating the load and delivery. The bottom edge of the skirt 2 is generally in a tooth-shaped structure extending in the circumferential direction, with a cutting area formed between two adjacent teeth. The teeth are triangular and evenly arranged in the circumferential direction. Before the stent is released, the distal end of the skirt to be released first extends beyond the stent in the axial direction, and it is the tooth-shaped structure that extends beyond the stent.

Thirty-Eighth Embodiment

(213) Referring to FIG. 38, the dashed line indicates the stent 1. This embodiment differs from the thirty-sixth embodiment in that the inner layer 6e of the blocking pocket here is integrally formed by a top material of the skirt which extends upwardly, and the outer layer 6d of the blocking pocket is a separate piece.

Thirty-Ninth Embodiment

(214) Referring to FIG. 39, the dashed line indicates the stent 1. Different from the thirty-sixth embodiment, in this embodiment, an inner coverage membrane 1c is provided at the inner wall of the stent 1, which simultaneously serves as the inner layer 6e. The outer layer 6d of the blocking pocket is a separate piece.

Fortieth Embodiment

(215) Referring to FIG. 40, the dashed line indicates the stent 1. Different from the thirty-sixth embodiment, in this embodiment, an inner coverage membrane 1c is provided at the inner wall of the stent 1, which simultaneously serves as the inner layer 6e of the blocking pocket. The outer layer 6d of the blocking pocket is formed by a top material of the skirt 2 which extends upwardly.

Forty-First Embodiment

(216) Referring to FIG. 41a, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 that is configured to drive the skirt 2 to transform into the stacked configuration. The pulling string 4 cooperates with radial deformation of the stent during release. The top edge of the skirt 2 has a tooth-shaped structure with triangular teeth, and the top tips of the triangular teeth are fixed on the stent with a plurality of fixing points 3i spaced from each other. The lower portion of the skirt 2 is a floating section. When being released in the human body, the bottom edge of the skirt 2 is released first, and the top edge of the skirt 2 is released later.

(217) In this embodiment, the pulling string generally threads through the skirt in the circumferential direction. The pulling string undulates in the axial direction while extending in the circumferential direction, forming a wave-like configuration with peaks and valleys. The peaks are located at the top edge of the skirt 2. Both peaks and valleys movably thread through the skirt 2. However, the pulling string does not thread through the stent. During the release of the stent, driven by the deformed stent, the peaks move away from each other in the circumferential direction and thus drive the valleys to lift upwardly.

(218) The normal blood inflow side of the stent 1, i.e., the bottom end thereof, is surrounded by a pushing pocket 7 for facilitating the skirt 2 to transform into the stacked configuration. The pushing pocket 7 has inlets for allowing blood to flow in, such that the pushing pocket 7 is self-expandable to push the skirt. The pushing pocket is made of flexible material, which may be the same material as the skirt. The pushing pocket has a double-layered structure, so it can be filled with blood and expanded radially.

(219) One side of the pushing pocket 7 is closed, and the other side is provided with a plurality of stitching portions 7b fixed to the stent 1. Adjacent stitching portions are spaced from each other, with an inlet defined therebetween. Therefore, a plurality of inlets 7a for allowing back-flow blood to flow therein are provided in this embodiment, which are evenly arranged along the circumferential direction. In an unfolded configuration of the skirt, the bottom edge of the skirt extends beyond the pushing pocket, so that the bottom edge of the skirt covers the pushing pocket 7 fully or partially.

(220) Referring to FIG. 41b, which schematically illustrates a cross section of the pushing pocket 7, the dashed line indicates the stent 1. The pushing pocket 7 is separately provided with respect to the material of the skirt 2. The pushing pocket 7 has a double-layered structure, including an inner layer 7d and an outer layer 7c. The two layers 7d and 7c may be formed as one single piece. The two layers are integrally connected with a bend at the bottom. In this embodiment, the inner layer 7d and the outer layer 7c are separately formed, and are connected and sealed by stitching the tops together.

Forty-Second Embodiment

(221) Referring to FIG. 42, this embodiment differs from the forty-first embodiment in that the skirt 2 does not have a tooth-shaped structure at the top edge.

Forty-Third Embodiment

(222) Referring to FIG. 43, the dashed line indicates the stent 1. Different from the forty-first embodiment, in this embodiment, an inner coverage membrane 1c is provided at the inner wall of the stent 1, the material of which is turned outwards and folded to form the pushing pocket 7.

Forty-Fourth Embodiment

(223) Referring to FIG. 44, the dashed line indicates the stent 1. Different from the forty-first embodiment, in this embodiment, an inner coverage membrane 1c is provided at the inner wall of the stent 1, which simultaneously serves as the inner layer 7d of the pushing pocket 7. The outer layer 7c of the pushing pocket 7 is separately provided. A top edge of the outer layer 7c is stitched and sealed to the corresponding portion of the inner coverage membrane 1c.

Forty-Fifth Embodiment

(224) As shown in FIGS. 45a and 45b, in this embodiment, a single pulling unit is taken as an example for illustration. Assuming that the length of the pulling string is I, the distance between the first acting portion X1 and the second acting portion X2 before being pulled is a, and the distance between the force exerting portion Y1 and a line connecting the first acting portion X1 and the second acting portion X2 before being pulled is h.

(225) Before being pulled, the distance between the first acting portion X1 and the force exerting portion Y1 is b.

(226) Before being pulled, the distance between the second acting portion X2 and the force exerting portion Y1 is b.

(227) Before being pulled, the overall length of the pulling string of the pulling unit in FIG. 45a is 2b, where 2b=I.

(228) After being pulled, the distance between the first acting portion X1 and the second acting portion X2 is A, and the distance between the force exerting portion Y1 and a line connecting the first acting portion X1 and the second acting portion X2 is H.

(229) After being pulled, the distance between the first acting portion X1 and the force exerting portion Y1 is B.

(230) After being pulled, the distance between the second acting portion X2 and the force exerting portion Y1 is B.

(231) After being pulled, the overall length of the pulling string of the pulling unit in FIG. 45b is 2B, where 2B=I.

(232) After being pulled, the circumferential distance variation between the first acting portion and the second acting portion is Δa, where Δa=A−a. The axial distance variation of the force exerting portion Y1 before and after being pulled is:

(233) $\begin{array}{c}\Delta h=h-H=\sqrt{b^2-{\left(\frac{a}{2}\right)}^2}-\sqrt{B^2-{\left(\frac{A}{2}\right)}^2}\\ =\sqrt{{\left(\frac{l}{2}\right)}^2-{\left(\frac{a}{2}\right)}^2}-\sqrt{{\left(\frac{l}{2}\right)}^2-{\left(\frac{A}{2}\right)}^2}\\ =\frac{\sqrt{l^2-a^2}-\sqrt{l^2-A^2}}{2}\\ =\frac{\sqrt{l^2-a^2}-\sqrt{l^2-{.Math.a+\Delta a.Math.}^2}}{2}\end{array}$

(234) It can be seen that the axial pulling length of the pulling unit is closely related to the circumferential distance variation between the first acting portion and the second acting portion. In most cases, the circumferential distance variation of the pulling string from the unfolded configuration to the stacked configuration is less than a perimeter of the stent.

(235) The thickness of the peripheral leakage occluder after being folded is related to the number of folds. Referring to FIG. 45c, assuming that there are three threading holes between the first acting portion X1 and the force exerting portion Y1, if the pulling string is tensioned, five layers of folds will be formed.

(236) In a further development, the stent apparatus is a balloon expandable stent, with the stent pre-compressed onto the balloon. During release, the balloon is expanded by injected saline solution to expand the stent. With reference to FIGS. 45a and 45b, the skirt is stitched on the stent, and when the whole stent is expanded, the distance between the first action portion X1 and the second action portion X2 increases, which pulls the force application portion Y1 to move axially.

Forty-Sixth Embodiment

(237) Referring to FIGS. 46a to 46c, in this embodiment, the outer periphery of the stent 1 is provided with a flexible skirt 2. Before the stent 1 is released, the skirt 2 is in an unfolded configuration, which is axially unfolded and surrounds the outer periphery of the stent 1 before release. After the stent 1 is released, the skirt 2 is folded and stacked along the axial direction of the stent 1 after release into a stacked configuration and forms an annular peripheral leakage occluder. Also provided is a pulling string 4 that is configured to drive the skirt 2 to transform into the stacked configuration. The pulling string 4 cooperates with radial deformation of the stent 1 during release. When being released in the human body, the bottom edge of the skirt 2 is released first, and the top edge of the skirt 2 is released later.

(238) FIG. 46a only illustrates the position of the skirt 2, in which the skirt 2 is substantially located at one axial end of the stent 1 which is adjacent to the blood inflow side (the direction of the hollow arrow in FIG. 46b indicates the normal blood flow direction when the stent is in use). The stent 1 has a meshed structure, for example, having a plurality of grids as shown in the figures. The axial length of the skirt in the unfolded configuration is half of the axial length of a grid.

(239) The top edge of the skirt 2 is fixed on the stent, and the skirt 2 is provided with a plurality of cutting areas 5 at the axial top side thereof, arranged in the circumferential direction. The cutting areas may reduce the radial stacking thickness of the skirt in the unfolded configuration, facilitating the load and delivery. The top edge of the skirt 2 is generally in a tooth-shaped structure extending in the circumferential direction, with a cutting area formed between two adjacent teeth, and the teeth are triangular or trapezoidal and evenly arranged in the circumferential direction.

(240) In the case that the top edge of the skirt 2 is fixed on the stent, stitching portions may be provided only at a middle portion of the top edge of the tooth-shaped structure, with the stitching portions circumferentially spaced from each other. Developing points are provided on the stent at the stitching portions.

(241) In this embodiment, the pulling string generally threads through the skirt in the circumferential direction. The pulling string undulates in the axial direction while extending in the circumferential direction, forming a wave-like configuration with peaks and valleys.

(242) During the release of the stent, driven by the deformed stent, the peaks of the pulling string move away from each other in the circumferential direction and thus drive the valleys to lift upwardly. Since the pulling string movably threads through the skirt, the periodic portions thereof are configured for driving and operating in cooperation with one another, thereby generally moving the pulling string.

(243) The portions indicated by broken line circles in the figures may serve as the threading holes 2g. The pulling string 4 only threads through the skirt, into and out of the threading holes.

(244) In a further development, the pulling string may thread through the stent at the uppermost threading holes in the figure, which also serves as the stitching portions and thus maintains the axial position of the skirt relative to the stent.

(245) In an unfolded configuration of the skirt, the skirt has a length indicated as a that is substantially equal to the perimeter of a corresponding portion of the stent, and the skirt has a width b which is half of the height of a grid of the stent. The length of the skirt is evenly divided into five parts, with the length of each part being c. The length of each part is equal to the length of two complete teeth. In other words, there are 10 teeth in total. Each tooth has a length d (the upper side of the trapezoid) which is equal to a distance between two adjacent teeth d. The width of the skirt is evenly divided into four parts, with the length of each part being e. The height of each tooth is e.

(246) In the stacked configuration, each pulling unit may be folded for three times (fold is generated between two adjacent threading holes in the axial direction) to form a four-layered stack provided that a plurality of threading holes 2g are provided. By providing a plurality of threading holes, the position limiting between the pulling string and the skirt can be increased, so that the skirt can be stacked more uniformly when the skirt is pulled.

(247) Specifically, taking a specific valve as an example, the skirt has a length a, where a=95 mm±0.2 mm, and the skirt has a width b, where b=8.80 mm±0.2 mm.

(248) The length of the skirt may be divided into five parts, with the length of each part being c, where c=95/5=19 mm±0.2 mm.

(249) The tooth has a length d, and the distance between two adjacent teeth is also d, where d=19/4=4.75 mm±0.2 mm.

(250) Each tooth has a height e, where e=8.81/4=2.2 mm±0.2 mm.

Forth-Seventh Embodiment

(251) Referring to FIGS. 47a to 47g, a delivery system is provided in this embodiment, which includes a handle 100, a core shaft 102 connected to the handle 100, and a sheath 101 slidably surrounding the outer periphery of the core shaft 102. The sheath 101 is able to slide axially relative to the core shaft 102 under the control of the handle 100. The distal end of the core shaft 102 is provided with a guide head 103 and a mounting head 104 adjacent to the guide head 103. The mounting head 104 is provided with a plurality of slots or protrusions for connecting with an implanted instrument. The implanting instrument may be, for example, the stent 105 with the skirt 107 in the above embodiments. The proximal end of the stent 105 is provided with a fixing ear 106 for engaging with the mounting head 104. In a loaded state, the stent 105 is radially compressed, located between the guide head 103 and the mounting head 104, and constrained by the sheath 101. Correspondingly, the skirt is in an unfolded configuration, and arranged around the outer periphery of the stent 105.

(252) After the stent 105 is delivered to a desired position in the human body such as a lesion site near the aortic valve 200 by the delivery system, the sheath 101 is withdrawn relative to the core shaft 102, and the distal end of the stent 105 is first released, and is gradually exposed and begins to expand radially. Under the action of the stent 105 itself or in combination with the pulling string, the skirt 107 begins to be axially pulled and stacked. After the stent 105 is completely released, the skirt 107 transitions into a stacked configuration and forms a peripheral leakage occluder, further preventing the regurgitation at the aortic valve 200.

(253) The embodiments of the present invention may be combined with each other without technical conflicts. The related principles and synergistic effects may be referred to the related description of the summary of the invention.

(254) The above disclosure is only specific embodiments of the present invention, but the present invention is not limited thereto. Those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Obviously, these modifications and variations should fall into the protection scope claimed by the present invention. In addition, although some specific terms are used in this specification, these terms are just for convenience of illustration and do not constitute any special limitation to the present invention.