Abstract
The invention relates to a radially compressible and expandable rotor for a pump having at least one impeller blade, wherein the impeller blade has an impeller blade body whose material is elastically deformable as well as at least one stiffening strut which is at least partially embedded in the material of the impeller blade body. The struts are designed suitably in size, shape and arrangement and are integrated in suitable hollow spaces of the impeller blade body for stabilizing the impeller blade. Elements with tensile strength can additionally be provided.
Claims
1.-15. (canceled)
16. A radially compressible and expandable rotor for a blood pump, the rotor comprising: at least one impeller blade, wherein the at least one impeller blade has an axis of rotation and an impeller blade body made of a material that is elastically deformable; and a plurality of stiffening struts that are at least partially embedded in the material of the impeller blade body, wherein the plurality of stiffening struts comprise at least a first stiffening strut and a second stiffening strut, and the first stiffening strut is connected to the second stiffening strut.
17. The rotor of claim 16, wherein the first stiffening strut comprises a first end close to the axis of rotation of the at least one impeller blade and the second stiffening strut comprises a first end close to the axis of rotation of the at least one impeller blade, and the first stiffening strut and the second stiffening strut are connected to one another at their first ends.
18. The rotor of claim 16, wherein the first stiffening strut comprises a second end remote from the axis of rotation of the at least one impeller blade and the second stiffening strut comprises a second end remote from the axis of rotation of the at least one impeller blade, and the first stiffening strut and the second stiffening strut are connected to one another at their second ends.
19. The rotor of claim 18, wherein the first stiffening strut and the second stiffening strut are connected to one another to form a loop.
20. The rotor of claim 16, wherein the at least one impeller blade is connected to a hub and is configured to rotate about the hub.
21. The rotor of claim 20, wherein the plurality of the stiffening struts extend up to and into the hub.
22. The rotor of claim 21, wherein the plurality of the stiffening struts extend into a groove of the hub.
23. The rotor of claim 21, wherein the plurality of the stiffening struts extend radially from a first axial spacing outside the hub to a second axial spacing.
24. The rotor of claim 20, wherein the first stiffening strut and the second stiffening strut are connected to one another through a rail, wherein the rail is flexible and is close to the axis of rotation of the at least one impeller blade.
25. The rotor of claim 24, wherein the rail is configured to be drawn into a recess which runs around the hub.
26. The rotor of claim 16, wherein the first stiffening strut and the second stiffening strut extend at an angle of at least 90° with respect to an axial direction of the axis of rotation of the at least one impeller blade.
27. The rotor of claim 26, wherein the first stiffening strut and the second stiffening strut extend at an angle of about 90° with respect to an axial direction of the axis of rotation of the at least one impeller blade.
28. The rotor of claim 16, wherein the first stiffening strut and the second stiffening strut extend at an angle of less than 90° with respect to an axial direction of the axis of rotation of the at least one impeller blade.
29. The rotor of claim 28, wherein the first stiffening strut and the second stiffening strut extend at an angle of about 30° to about 60° with respect to an axial direction of the axis of rotation of the at least one impeller blade.
30. The rotor of claim 16, wherein the plurality of stiffening struts are completely embedded in the material of the impeller blade body.
31. The rotor of claim 16, wherein the rotor is hubless and the plurality of the stiffening struts extend in a radial direction with respect to the axis of rotation of the at least one impeller blade from a first axial spacing to a second axial spacing.
32. The rotor of claim 16, wherein the plurality of stiffening struts are insert molded with the material of the impeller blade body.
33. The rotor of claim 16, wherein the plurality of stiffening struts are comprised of a first material and the impeller blade body is comprised of a second material, wherein the first material is different from the second material.
34. The rotor of claim 33, wherein the first material is stiffer than the second material.
35. The rotor of claim 33, wherein the second material comprises an elastic polymer, a memory alloy or nitinol.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] The invention will be shown and subsequently described in the following with reference to embodiments in a drawing. There are shown
[0068] FIG. 1 schematically, a rotor blood pump which is introduced into the left ventricle of a heart by means of a hollow catheter:
[0069] FIG. 2 the pump, in a more detailed representation:
[0070] FIG. 3 schematically, an embodiment of a rotor with a hub;
[0071] FIG. 4 an embodiment of a rotor with a hubless impeller blade:
[0072] FIG. 5 the structure of a rotor with a hub and reinforcement struts for the impeller blade body;
[0073] FIG. 6 a configuration of struts for a rotor, with the struts projecting perpendicularly from the longitudinal axis of the rotor;
[0074] FIG. 7 a configuration with struts which are inclined with respect to the axis of rotation;
[0075] FIG. 8 a cross-section through a rotor with a solid hub;
[0076] FIG. 9 a cross-section through a rotor with a hollow hub;
[0077] FIG. 10 a cross-section through a rotor with a hollow hub and two impeller blades which are suspended in recesses of the hub;
[0078] FIG. 11 a rotor in cross-section with a hollow hub and abutment bodies;
[0079] FIG. 12 a rotor in cross-section with a hollow hub and struts of two impeller blades projecting into said hollow hub with a corresponding abutment configuration;
[0080] FIG. 13 in cross-section, a rotor with two impeller blades and struts embedded therein;
[0081] FIG. 14 in partial cross-section, a rotor with two impeller blades into which the struts are integrated within hollow spaces;
[0082] FIG. 15 in cross-section, a rotor with an impeller blade and a strut integrated therein in a hollow space which is longer than the strut;
[0083] FIG. 16 a three-dimensional outside view of a rotor with impeller blades and elements with tensile strength for supporting the impeller blades; and
[0084] FIG. 17 a rotor with a plurality of impeller blades and various tensile elements supporting them;
[0085] FIGS. 18 to 20 an embodiment of a reinforcement strut in different states, wherein the strut has recesses on the flow suction side for better compressibility, with the recesses being largely closed in the operating state and forming an abutment together with the embedded base material;
[0086] FIGS. 21 to 23 an embodiment of a reinforcement strut in different states, with the strut being optimized with respect to uniform stress distributions in the material;
[0087] FIGS. 24 to 26 an embodiment of a reinforcement strut in different states, with the strut and a flexible tensile element being formed in one part.
DETAILED DESCRIPTION OF THE INVENTION
[0088] FIG. 1 schematically shows the left ventricle 1 of a cardiac chamber 1 as well as a blood vessel 2 opening into it into which a hollow catheter 4 can be introduced by means of a lock 3. Said hollow catheter holds a pump 5 at its distal end and said pump projects at least partially into the ventricle 1. The pump 5 has a suction cage 8 at its distal end into which blood is sucked, as indicated by the arrows 6, 7. Said blood is pressed out by outflow openings 9 within the blood vessel 2 behind the cardiac valve. The pump 5 has a rotor having conveying elements which is rotatably drivable about its longitudinal axis by means of a flexible shaft 11 which extends through the hollow catheter 4 and is connected to a drive motor 10 outside the body of the patient. The typical speed of the rotor in operation is at some thousand up to approx. 50,000 r.p.m.
[0089] The pump 5 having the rotor 13 is shown in more detail in FIG. 2. The rotor 13 is in each case rotatably supported within a pump housing 12 by means of a rotor shaft 14 at the proximal end 15, i.e. at the end closer to the lock 3, as well as at the distal end 16. Past the bearing at the distal end 16 or between the distal end and the rotor 13 itself, suction openings for the blood are provided, for example in the form of a suction cage, i.e. a piercing of the housing 12.
[0090] The rotor 13 itself is made in one part, having a hub and two helical impeller blades connected in one piece to said hub.
[0091] An outflow hose 17 starts at the pump housing 12 and is positioned, on a correct positioning of the pump within the cardiac valve, at the transition between the blood vessel 2 and the ventricle 1 so that the outflow openings 18 lie within the blood vessel 2. At the distal end of the pump 5, there is an additional spacer part which is bent over at the free end, for example of spiral shape, to prevent the crashing of the pump at the body tissue and moreover to facilitate the pushing of the pump through a blood vessel. In addition, the element should prevent the pump from sucking tight to vessel walls or to the inner walls of the cardiac chamber.
[0092] FIG. 3 shows a rotor 13a having two helical impeller blades 19, 20 which are made from plastic, are made in one piece with the hub 21 and can, for example, receive support struts in their interior. The impeller blade body of the impeller blades 19, 20 can be made, for example, from polyurethane in solid form or from a foam and the struts can be integrated into the body. The manufacture can take place in that the struts are insert molded with a corresponding plastic.
[0093] FIG. 4 schematically shows in a three-dimensional view a rotor without a hub with a single impeller blade 22. Corresponding struts can also be embedded in it. The impeller blade 22 is driven at the end face via a shaft piece 23.
[0094] FIG. 5 shows a rotor 13b having a hub 24 as well as two rows of struts 25, 26, 27 which are distributed circumferentially at the hub in the form of a helix in each case and project radially from said hub. The struts 26, 26, 27 can, for example, each comprise a pair of two individual struts which are connected to one another at their end remote from the axis of rotation. The axis of rotation is marked by 29 in FIG. 5.
[0095] Loops which can be anchored easily in an impeller blade body are formed by the struts 25, 26, 27 in this manner.
[0096] The struts can, for example, be fastened together on a respective rail per impeller blade, with the rail being flexible and being able to be drawn into a recess 28 which runs around the hub 24.
[0097] In the named example, respectively directly adjacent struts are thus connected to one another pair-wise and the pairs are connected to one another in their region close to the axis of rotation.
[0098] FIG. 7 shows struts 30, 31, 32, 33 which are each connected to one another pair-wise in their region remote from the axis of rotation 29 and are connected by means of a through going rail 34 in the region close to the axis of rotation. The individual struts 30, 31, 32, 33 extend at an inclination with respect to the axis of rotation 29, for example at an angle of approximately 30° to 60°. In contrast to this, FIG. 6 shows struts which project radially perpendicularly from the axis of rotation 29.
[0099] FIG. 8 shows a cross-section through a rotor having a solid hub 35 at whose surface at the jacket side two impeller blades 36, 37 are shown located in the second state, i.e. in a slightly pre-curved form. In operation, i.e. on rotation of the rotor in the direction of the arrow 38, the impeller blades 36, 37 are erected further almost up to extension.
[0100] The rotor can also be further compressed with respect to the configuration shown in FIG. 8 in that the impeller blades are pressed more closely toward the hub 35.
[0101] FIG. 9 shows two impeller blades 36a, 37a which project into a hollow space 39 of a hub 35a. The impeller blades 36a, 37a thereby form two-arm levers which are each supported in the wall of the hollow hub 35a.
[0102] FIG. 10 shows a further development of the embodiment of FIG. 9 in that the wall thickness is weakened in the hub 35b in the region 40, 41 where the impeller blades 36b, 37b pass through the wall of the hub 35b. The impeller blades are thereby pivotably supported in kinds of film hinges in corresponding regions of the hub.
[0103] FIG. 11 shows a corresponding constellation in which inner ends and abutment bodies 42, 43 fastened thereto of the two impeller blades 36c, 37c each project into the hollow space 44 of a hub 35c. In the inner space of the hub, the abutment bodies 42, 43 cooperate in the direction of the arrows 45, 46 in the operation of the rotor with corresponding abutments 47, 48 so that the impeller blades 36c, 37c are supported in the third state and so adopt the desired operation state.
[0104] On the compression movement, the abutment bodies 42, 43 release from the abutments 47, 48 and the impeller blades 36c, 37c can be brought into the positions drawn in dashed lines in FIG. 11. In this respect, the impeller blades are pivoted within the corresponding weakened regions of the hub body 35c.
[0105] The sense of rotation of the rotor shown in operation is shown in FIG. 11 by the arrow 49, whereas the fluid counter-pressure on the impeller blades is symbolized by the arrows 50, 51.
[0106] FIG. 12 shows a further embodiment of a rotor having a hub body 35d and two impeller blades 36d, 37d which each have the struts 52, 53. In the embodiment, the impeller blades end at the outer jacket surface of the hub 35d and only the struts 52, 53 project into the interior of the hub. The strut 53 there abuts an abutment 55 in the direction of the arrow 54 in the inner space of the hub when the third state of the rotor is reached. The corresponding impeller blade 37d is thereby supported.
[0107] Another configuration is shown oppositely disposed with reference to the impeller blade 36d. The representation of different configurations of impeller blades at a rotor is only done by way of example here.
[0108] The strut 52 of the impeller blade 36d extends in the interior of the hub 35d in an abutment body 52a of the shape of a circular disc which can be made in one piece with the strut 52 and can, for example, be stamped out of a metal sheet. The abutment body 52a is shaped so that, on a corresponding load in the third state, it abuts an abutment 56 which in this case does not require any special design for limiting the movement of the impeller blade 36d.
[0109] A plurality of the abutments 52a can also be connected to one another within a rotor to form a structure for the struts 52 and to hold them while they are, for example, being insert molded with the material of the impeller blade body.
[0110] FIG. 13 shows a rotor having a hub 35e in a solid construction, having two impeller blades 36e, 37e into which respective struts 547, 58 are integrated. The strut 57 extends from a first axial spacing, shown by the dashed line 59, up to a second axial spacing, shown by the line 60. The strut 57 accordingly does not extend up to the hub 35e.
[0111] The strut 58 extends up to and into the hub 35e and ends at the axial spacing 61, i.e. it is radially shorter than the impeller blade 37e with respect to the rotor axis. The differences of the struts 57, 58 are only shown by way of example in a single rotor.
[0112] In the named examples, the struts are each insert molded with the material of the impeller blade body and adhere partially or at all sides to the material.
[0113] In FIG. 14, a hub 35f is shown having two exemplary impeller blades 36f, 37f which each receive a strut 62, 63. The strut 62 is smaller with respect to the length and to the width than the hollow space 64 in which it is located within the impeller blade 36f The strut 63 is fixedly surrounded at its radially outer end 65 by the material of the impeller blade 37f and can move in the region 66 close to the axis or rotation within the hollow space of the impeller blade 37f and there adopt different positions in dependence on the state of compression or expansion, i.e. lie at different walls of the hollow space. This hollow space can be of asymmetrical design. [0114] It is made possible by this constellation that in a position, for example, in the third state of the rotor, the corresponding strut 63 can support the impeller blade 37f, whereas the rotor can be highly compressed without a support effect of the strut in that the strut can escape within the impeller blade. Provision can correspondingly also be made that that strut is fixedly surrounded and is fixed in the impeller blade only at its end close to the axis and has movement play in the region remote from the axis. [0115] In FIG. 15, a rotor having a hub 35g as well as an impeller blade 36g with a strut 67 integrated therein is shown. The strut 67 is made shorter in the radial direction than the hollow space 68 within the impeller blade 36g so that in operation the strut can slip, for example by centrifugal forces, radially outwardly and can there support the impeller blade. On a compression movement, for example by corresponding slopes at the radially outer end of the strut, said strut can then be displaced radially inwardly so that it impedes a compression less than in the radially outer region. The slopes are shown at the radially outer end of the strut 67 and are marked by 69. The rotary movement of the rotor is symbolized by the arrow 70 and the fluid counter-pressure against the impeller blade 36g by the arrow 71.
[0116] FIG. 16 shows in a three-dimensional view a rotor 72 which rotates in the direction of the arrow 73 in operation. Forces result accordingly at the impeller blades 74 as a consequence of the fluid counter-pressure which are shown by the arrows 75, 76.
[0117] In the Figure, tensile elements 77, 78, 79, 80 are shown which represent different examples for their alignment and fastening. The tensile elements 77, 78 extend, for example, from a radially outer point at the impeller blade 74 to a radially inner point close to the hub 81. The tensile element 79 is, on the one hand, fastened to a point 82 at the impeller blade 74; on the other hand, to the point 83 on the surface of the hub 81 at a distance from the foot of the impeller blade. The tensile element 80 is formed areally as a thin film and is fastened at a point 84 to the impeller blade, whereas the base 85 is fastened on the surface of the hub 81 at a spacing from the foot of the impeller blade 74. The film 80 can be aligned such that it does not impede the fluid flow.
[0118] In the compressed second state or in the first state of the rotor, the corresponding tensile elements are slack and do not impede any movement of the impeller blades 74. In the third state, when the impeller blades are extended, the tensile elements limit a further overextension and thus stabilize the impeller blades.
[0119] The tensile elements can, for example, comprise a band having glass fiber reinforcement or can substantially comprise only glass fibers or also polycarbonate fibers, for example Kevlar, to achieve a thickness which is as low as possible with a correspondingly high tensile force and strength. The tensile elements can, however, also comprise a polymer film, for example PEEK or also a metal film, for example nitinol or titanium, to achieve the desired effect.
[0120] Basically, those materials or material combinations are particularly suitable for these flexible tensile elements which are also used for so-called non-compliant balloon catheters, since these usually combine the mechanical properties desired here with the likewise required biocompatible and blood-compatible properties.
[0121] In addition, two tensile elements 86, 87 are drawn at the impeller blade 74, with the tensile element 86 being adhered, printed on or fastened in another way on the surface of the impeller blade 74 and having a winding form which is only present in this form in the first or second states of the impeller blade. If the impeller blade is extended to the third state, this tensile element adopts the extended form marked by 87 in order then to be taut and to prevent a further movement of the impeller blade beyond the extended state.
[0122] In FIG. 17, a rotor having a plurality of impeller blades 88, 89, 90 is shown which each run around the hub 91 only in part and which can individually be supported by means of tensile elements 92, 93, 94. The tensile elements 92 can be formed as films and continue the contour of the corresponding impeller blades 88 in a hydrodynamically favorable manner. They are positioned and tensioned so that they support the impeller blades in the extended state. In addition, the impeller blades 88, 89, 90 can have struts 95 integrated in them.
[0123] The named variants in the embodiment of the invention represent, individually and in combination with one another, efficient measures for supporting impeller blades built as composite bodies at a rotor of a pump.
[0124] The corresponding rotors can each be arranged in a compressible and expandable housing which can be expanded, for example, by means of the erecting impeller blades.
[0125] FIGS. 18 to 20 show a further embodiment of a stiffening strut. In this respect, the first state is shown in FIG. 18, that is the force-free state. In FIG. 19, the second state is shown, that is the state in which the stiffening strut/the impeller blade/the rotor is radially compressed.
[0126] This is primarily done in the present case by a tilting of the stiffening strut in FIG. 19 to the left, i.e. counter clockwise. In FIG. 20, the third state is shown, that is the operating state of the rotor/of the impeller blade/of the stiffening strut in which fluid is actually conveyed. In this respect, the fluid counter-pressure acts clockwise, i.e. the direction of rotation of the rotor is counter-clockwise. In this respect, a weakening on the flow suction side is shown (to be seen at the bottom in FIG. 20 at the radial outlier of the stiffening strut). The flow pressure side is not weakened in this case.
[0127] In FIGS. 18 to 20, only the stiffening strut is shown, without any additional material in which the stiffening strut is embedded. In the present case, this stiffening strut is attached to the axial front flow edge of the rotor and the radial outlier of the stiffening strut projecting to the right in FIG. 8 is completely surrounded by the embedding material, plastic in the present case. This is also the case between the weakening slits. The impeller blade surface is in this respect of a property such that no weakening is visible from the outside. It must additionally be noted that the compression (see FIG. 19) is particularly simple, whereas a “mechanical abutment” is present in the state shown in FIG. 20. In this respect, the inner walls of the slits do not have to abut one another since the embedding compound/embedding material/plastic located in this intermediate region is compressed and thus a deformation limitation is guaranteed.
[0128] FIG. 21 in turn shows the first state in which the deformation strut/the rotor projects in a force-free manner. All the features are formed as in the aforesaid embodiment in accordance with FIGS. 18-20, provided that nothing is otherwise stated in the following. In the embodiments in accordance with FIGS. 21-23 (FIG. 22 shows the second state; FIG. 23 in turn the third state), no weakening in the form of slits is shown; instead a kink is shown close to the circular hub region which shows a “reinforcement curvature”. This is designed so that, on the one hand, on the elastic deformation into the state shown in FIG. 22, a slight bending over is possible and, on the other hand, in the state in accordance with FIG. 23, a mechanical abutment is present without the plastic region of the material ever being entered, on which irreversible deformations would occur.
[0129] FIGS. 24 to 26 show a further embodiment which is similar to the embodiment in accordance with FIGS. 21-23, with, however, a radially inwardly weakening located in the hub ring being shown in the transition region from the annular hub region toward the radial outlier, said weakening facilitating the elasticity of the outlier above all on the movement from the first state shown in FIG. 24 to the second state shown in FIG. 25. In addition, the ensuring of the mechanical abutment in the third state shown in FIG. 26 is also ensured by a suitable configuration, said third state being able to take place, for example, by the design of the tapered region (100) as a tensile strut. The tapered region (100) is thereby easily bendable on the adoption of the first state, but adopts in the third state an approximately extended form which sets an increased resistance toward deflection under the flow pressure.
[0130] It must again be mentioned that it is in each case assumed in FIGS. 20, 23 and 26 that the direction of rotation of the rotor is counter clockwise and that thereby an expansion of the radial outlier in the clockwise direction results. The outline of an impeller blade 101 is furthermore schematically shown in FIG. 26 which completely surrounds the strut in the embodiment shown such that the fluid comes into contact with a homogeneous surface which is as uniform as possible. This ensures that the fluid undergoes an acceleration in the operating state which is as smooth as possible with small shear tension peaks.
