Radially compressible and expandable rotor for a fluid pump

Abstract

In a rotor for a fluid pump which is made radially-compressible and expandable and has a hub (4) and at least one conveying element (10, 11, 19, 20) which has a plurality of struts (12, 13, 14, 15, 16, 21, 22, 27, 28) and at least one membrane (18) which can be spanned between them, provision is made for a design in accordance with the invention which is as simple and inexpensive as possible that at least one first group of struts is pivotable in a pivot plane, starting from a common base, and can thus be spanned open in the manner of a fan, wherein the conveying element lies along the hub and contacts it over its full length in the expanded state to avoid a pressure loss at the margin of the conveying element between it and the hub and thus to realize an optimum efficiency.

Claims

1. A radially compressible and expandable rotor for a percutaneous blood pump, comprising: a hub; and a first conveying element comprising a first group of struts coupled to the hub, the first conveying element having a compressed state and an expanded state; wherein each strut in the first group of struts has a base which overlaps with at least one base of at least one other strut in the first group of struts.

2. The rotor of claim 1, wherein in the compressed state each strut in the first group of struts is folded along the hub.

3. The rotor of claim 2, wherein in the expanded state each strut in the first group of struts extends radially from the hub.

4. The rotor of claim 3, wherein in the expanded state the first group of struts forms a spiral about the hub.

5. The rotor of claim 4, wherein the base of each strut in the first group of struts is configured as a planar surface and is slanted on a surface of the hub relative to a longitudinal axis of the hub.

6. The rotor of claim 3, wherein a majority of the first group of struts are pivotable about a common pivot plane, and wherein at least one of the struts in the first group of struts is angled out of the pivot plane.

7. The rotor of claim 6, wherein the common pivot plane is about an axis which is non-parallel to a longitudinal axis of the hub.

8. The rotor of claim 6, wherein the common pivot plane is about an axis parallel to a longitudinal axis of the hub.

9. The rotor of claim 1, the rotor further comprising a second conveying element, wherein the second conveying element comprises a second group of struts, each strut in the second group of struts having a base which overlaps with at least one base of at least one other strut in the second group of struts.

10. The rotor of claim 9, wherein in the expanded state the second group of struts extends radially from the hub to form a spiral about the hub.

11. The rotor of claim 10, wherein the second conveying element is disposed on the hub radially opposite the first conveying element.

12. The rotor of claim 9, wherein the first conveying element and the second conveying element are radially offset.

13. The rotor of claim 1, the rotor further comprising at least one membrane which spans between the struts of the first group of struts.

14. The rotor of claim 13, wherein the at least one membrane is inclined at least sectionally with respect to a longitudinal axis of the hub in the expanded state of the first group of struts.

15. The rotor of claim 1, wherein the first conveying element lies along the hub and contacts the hub over a full length of the first conveying element in the expanded state.

16. The rotor of claim 1, wherein the base of each strut of the first group of struts is connected to at least one base of at least one other strut in the first group of struts by a film hinge.

17. The rotor of claim 1, wherein at least one strut in the first group of struts has a different length than at least one other strut in the first group of struts.

18. The rotor of claim 1, wherein a base of each strut in the first group of struts is curved.

19. The rotor of claim 1, wherein a distal end of each strut in the first group of struts is curved.

20. The rotor of claim 1, wherein in the compressed state the struts in the first group of struts are approximately parallel.

Description

(1) The invention will be shown and subsequently described in more detail in the following with reference to an embodiment in a drawing. There are shown

(2) FIG. 1 schematically, a view of a fluid pump on use as a heart catheter pump;

(3) FIG. 2 a rotor in a view in the compressed state;

(4) FIG. 3 an embodiment of a rotor in the expanded state;

(5) FIG. 4 a view of a further embodiment of a rotor in the expanded state;

(6) FIG. 5 a side view of a rotor in the compressed state;

(7) FIG. 6 a view of the arrangement of FIG. 5 rotated by 90 about the longitudinal rotor axis;

(8) FIG. 7 a view as in FIGS. 5 and 6, shown three-dimensionally in an oblique view;

(9) FIG. 8 the arrangement of FIGS. 5, 6 and 7 in an axial plan view of the rotor;

(10) FIG. 9 a side view of the rotor of FIGS. 5 to 8 in the expanded state;

(11) FIG. 10 the view of FIG. 9 rotated by 90 about the longitudinal axis of the rotor;

(12) FIG. 11 an oblique view of the arrangement of FIGS. 9 and 10;

(13) FIG. 12 an axial plan view of the rotor of FIGS. 9 to 11;

(14) FIG. 13 a side view of a rotor with an inclined pivot plane of the struts;

(15) FIG. 14 a further embodiment with a fan and a fastening to the hub; and

(16) FIG. 15 a three-dimensional view of the conveying element as a folded membrane.

(17) FIG. 1 schematically shows a fluid pump in which the rotor in accordance with the invention is used after the introduction into a ventricle 1. The pump 2 has a housing 3 as well as a hub 4 to which the conveying elements are fastened. The hub 4 is connected to a shaft 5 which is conducted through a hollow catheter 6 within a blood vessel 7 and is conducted out of it and the patient's body by a sluice 8. The rotatable shaft 5 can be driven at high revolutions, for example in the order of 10,000 r.p.m., by means of a motor 9.

(18) Blood can be conveyed between the ventricle 1 and the blood vessel, for example sucked in by the pump 2 and pressed into the blood vessel 7, by means of the rotational movement transmitted onto the hub 4 and onto the conveying elements of the pump.

(19) The pump 2 can have a diameter or general dimensions in the operating state which would be too large to be transported through the blood vessel 7. The pump is radially compressible for this purpose. It is shown in FIG. 1 in the expanded state which it can adopt after the introduction into the ventricle 1 by means of the hollow catheter 6.

(20) The pump is pushed in the compressed state together with the hollow catheter 6 so far through the blood vessel 7 until it projects into the ventricle 1 before it is expanded.

(21) The pump 2 has to be compressed again, which can be done, for example, by corresponding pulling elements, not shown in detail, before the removal, which takes place by pulling out the catheter 6, or, if the pump is only expanded by centrifugal forces, it is stopped and then collapses in on itself.

(22) It is also conceivable to compress the pump at least a little by pulling it into the hollow catheter in that, for example, an introduction funnel is provided at the distal end of the hollow catheter 6.

(23) The design of the hub 4 is shown in more detail in FIG. 2, with the struts of the conveying element/elements being shown in the compressed state, i.e. in the state placed onto the hub. The front end of the hub, which faces the inner space of the ventricle 1, is marked by 4a.

(24) The struts can be placed so tightly on the hub that they only take up a vanishingly small space in the radial direction of the rotor. The membrane is rolled or folded in between the struts in the compressed state.

(25) FIG. 3 shows the at least partly expanded state of a rotor with the hub 4, with two conveying elements 10, 11 being provided which are disposed diametrically opposite one another at the periphery of the cylindrically formed hub 4. Each of the conveying elements generally has the shape of a quarter of an ellipse so that the individual struts 12, 13, 14, 15, 16 cover an angular range overall of approximately 90, starting from the base 17. However, other shapes, for example also rectangular shapes, can be achieved by a different design of the length of the struts.

(26) The membrane 18 is tautened flat and tight between the struts 12 to 16 in the expanded state. The conveying element 10 is exactly opposite the conveying elements 11 described in more detail so that both together form half an ellipse in interaction with the hub 4. The struts 16 contacting the hub 4 most closely can, for example, be fixed there by a reception apparatus or can at least be guided. Such a reception apparatus can, for example, be made in U shape with two limbs so that the strut 16 can dip into the conveying elements 11 on their expansion and is held there as required. It is thereby ensured that as good as no intermediate space arises between the strut 16 and the hub 4 which could cause a flowing off of the fluid between the hub and the conveying element and thus a pressure loss if it were present on the rotation of the rotor.

(27) FIG. 4 shows two semi-elliptical conveying elements 19, 20 which are disposed opposite one another at the periphery of the hub 4 which are made with the aid of the struts in the same way as shown in FIG. 3 and which axially contact the hub 4 axially at both sides of the respective base 17 such that a tight connection is present between the hub and the conveying element. Each of the conveying elements covers an angle of 180 in accordance with FIG. 4. Other shapes, for example, rectangular shapes, can also be achieved here by a different design of the length of the struts. The conveying elements of FIG. 4 can also be made in a similar manner from two respective conveying elements in accordance with FIG. 3, with in this case the respective pivot axes not having to be identical.

(28) The struts of an individual conveying element 19, 20 are by all means of different length so that the base 17 does not have to lie axially at the center of the conveying element. As shown in FIG. 4, the strut 21 is, for example, shorter than the oppositely disposed strut 22.

(29) The individual struts can, for example, be manufactured from a plastic in injection molding technology, e.g. can also be contiguous at the base 17, with a membrane being spanned between the struts, either by dipping the struts into a liquid plastic or by one-piece manufacture of the individual conveying elements 19, 20 in the whole from the same material, with the membrane then being provided as a film between the struts.

(30) FIG. 5 shows a side view of a hub 4 having two cut-outs 23, 24 on both sides of the hub which are connected through the hub to form a common opening.

(31) Two shafts 25, 26 on which the struts are pivotably mounted are fastened in this opening. The individual struts are substantially accommodated within the cut-outs 23, 24 in the compressed state, as can be seen much more clearly in the view of FIG. 6 which is rotated by 90 about the axis of rotation 40 with respect to the representation of FIG. 5.

(32) It moreover becomes clear from FIG. 6 that some of the struts 27, 28 are angled a little, at least at their respective ends remote from the pivot axis 25, 26, out of the common pivot plane of the struts which corresponds to the extent of the plane of the drawing in FIG. 5. This design of the struts has the consequence that the struts cannot be completely accommodated in the cut-outs 23, 24, but effects a three-dimensional, optimized design of the conveying element.

(33) A three-dimensional representation of the rotor can be seen in FIG. 7 which clearly shows the ends of the struts which are angled in a projecting manner.

(34) FIG. 8, which shows an axial plan view of the rotor of FIGS. 5 to 7, also clearly shows the projecting ends of the struts 27, 28 and of the struts of the further conveying element disposed opposite them.

(35) FIG. 9 shows in the expanded state of the rotor of FIGS. 5 to 8 how the angled struts 27, 28 effect a curvature of the front edge of the conveying element out of the plane of the membrane, whereby a structure of the conveying element results which is spiral in approach.

(36) This can be seen particularly clearly from FIGS. 10 and 11 respectively. FIG. 12 also clearly shows in plan view that the membrane spanned between the struts is not present in a planar form, but is rather curved.

(37) FIG. 13 makes it clear with reference to another embodiment that the struts 29, 30 can also be slanted with respect to their pivot plane as regards the longitudinal axis/axis of rotation 40 of the hub 4. This is possible, for example, by a corresponding oblique position of the shaft 31 on which the struts 29, 30 are pivotably mounted, as shown in FIG. 13.

(38) A spiral revolution of the conveying element/of the membrane about the hub 4 thus also results on the presence of a planar membrane between the struts 29, 30 so that an axial propulsion of the fluid to be conveyed arises on the rotation of the hub.

(39) The respective other pivot axis which belongs to the oppositely disposed conveying element is then likewise slanted in mirror symmetry to the pivot axis 31.

(40) FIG. 14 shows a design of a conveying element 32 in the form of a folded membrane, with the individual kinks of the membrane which form the struts being marked by 33, 34. In the present example, the kinks are made in parallel. However, they can also be made at an angle to one another or curved.

(41) The membrane can be clamped in a cut-out 35 of the hub 4 in the manner of a fan and can be folded in axially at both sides of the hub, with the membrane stretching. A particularly simple manner of manufacture for the conveying element thus results.

(42) The arrows 36, 37 mark the folding movements of the conveying element to the hub 4 at both sides of the cut-out 35.

(43) FIG. 15 shows the conveying element 38 again in isolated form as a kinked membrane with the kinks/struts 33, 34 before the installation into the cut-out 35 of the hub 4. The cut-out 35 can be introduced into the hub as a slit, for example, with the slit also being able to extend in oblique or curved form with respect to the longitudinal axis 27 to achieve a spiral revolution of the conveying element about the hub.

(44) A particularly inexpensive and simple manner of manufacture of the conveying elements is provided by the design in accordance with the invention of a rotor with corresponding conveying elements which moreover allows a simple compression and expansion of the conveying elements. The space requirements of the rotor on the transport into the operating position are minimized by the invention.