Abstract
The invention relates to an intravascular blood pump. The blood pump comprises a pump section having a proximal portion with a blood flow inlet and a distal portion with a blood flow outlet and an impeller for causing blood to flow into the blood flow inlet and towards the blood flow outlet. The blood pump further comprises at least one filter connected to the proximal portion of the pump section and arranged with respect to the blood flow inlet so as to filter the blood before it enters the blood flow inlet. The filter may comprise an expandable mesh structure made of a shape-memory material.
Claims
1. An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising: a pump section having a proximal portion with a blood flow inlet and a distal portion with a blood flow outlet and an impeller for causing blood to flow into the blood flow inlet and towards the blood flow outlet; and at least one filter associated with the proximal portion of the pump section and arranged with respect to the blood flow inlet so as to filter the blood before it enters the pump section.
2. The blood pump of claim 1, wherein the filter comprises a mesh structure, preferably a regular mesh structure.
3. The blood pump of claim 1, wherein the filter is expandable from a compressed configuration to an expanded configuration.
4. The blood pump of claim 1, wherein the filter is expandable at least in a radial direction to abut against an inner wall of a blood vessel in which the filter is to be arranged during operation of the blood pump.
5. The blood pump of claim 1, wherein at least a portion of the filter comprises a shape-memory material, preferably Nitinol.
6. The blood pump of claim 1, wherein the filter is attached to an elongate extension member extending from the proximal portion of the pump section such that the filter is proximally spaced from the pump section, wherein the extension member preferably comprises a catheter.
7. The blood pump of claim 6, wherein the filter is fixedly attached to the extension member or releasably attached to the extension member so as to be displaceable along a longitudinal axis of the extension member.
8. The blood pump of claim 6, wherein the filter has a distal end and a proximal end, wherein the distal end is attached to the extension member and the proximal end is an open end in order to form an inlet opening for the blood flow into the filter.
9. The blood pump of claim 6, wherein the filter tapers from the proximal end towards the distal end.
10. The blood pump of claim 6, wherein the filter comprises a mesh structure defining a plurality of apertures, wherein the apertures at the distal end have a smaller cross-sectional dimension than the apertures at the proximal end.
11. The blood pump of claim 6, wherein the filter comprises a retaining device coupled to the open proximal end of the filter and extending in a proximal direction, such that actuation of the retaining device causes the filter to collapse from an expanded configuration to a collapsed configuration.
12. The blood pump of claim 6, wherein the filter comprises at least one filament, preferably a plurality of filaments, attached to the open proximal end of the filter, such that pulling the at least one filament causes the filter to collapse.
13. The blood pump of claim 1, wherein a cross-sectional dimension of the filter decreases in the direction of the blood flow.
14. The blood pump of claim 1, wherein the filter has a conical shape or has a funnel shape.
15. The blood pump of claim 1, wherein the filter has a distal end and a proximal end, wherein the proximal end of the filter is attached to the blood pump proximally with respect to the blood flow inlet.
16. The blood pump of claim 15, wherein the filter extends at least partially over the blood flow inlet.
17. The blood pump of claim 15, wherein the distal end of the filter is attached to the blood pump distally with respect to the blood flow inlet such that the filter encloses the blood flow inlet.
18. The blood pump of claim 1, comprising at least two filters that are arranged in series.
19. The blood pump of claim 18, wherein at least one of the filters is fixedly attached to the blood pump and at least another one of the filters is releasably attached to an extension member so as to be displaceable along the length of the extension member.
20. The blood pump of claim 19, wherein the fixedly attached filter is disposed distally with respect to the releasably attached filter.
21. The blood pump of claim 18, wherein each of the filters is releasably attached to an extension member so as to be displaceable along the length of the extension member.
22. The blood pump of claim 1, comprising at least two filters that are arranged to be independently placed in different blood vessels that lead to the blood flow inlet during operation.
23. The blood pump of claim 1, wherein the blood pump comprises at least one pressure sensor for measuring the blood pressure.
24. The blood pump of claim 1, wherein the blood pump comprises at least two pressure sensors for measuring the blood pressure, with at least one of the pressure sensors being located downstream of the at least one filter and at least another one of the pressure sensors located upstream of the at least one filter.
25. The blood pump of claim 1, comprising at least one suction port located in a downstream end portion of the filter permitting blood clots to be removed from the filter through the suction port.
26. The blood pump of claim 1, comprising at least one lysing port located in a downstream end portion of the filter in order to supply a lysing agent to the filter to lyse blood clots accumulated in the filter.
27. The blood pump of claim 1, wherein the at least one filter is formed in the blood flow inlet.
28. The blood pump of claim 1, wherein the at least one filter includes a plurality of apertures which form the blood flow inlet.
29. The blood pump of claim 27, wherein the at least one filter is integrally formed with the pump section.
30. The blood pump of claim 1, wherein the blood pump is a catheter pump.
31. The blood pump of claim 1, wherein the blood pump is a right ventricular blood pump, configured for insertion into the right ventricle (RV) of a patient's heart (H) through the inferior vena cava (IVC).
32. The blood pump of claim 1, wherein at least one of the at least one filter is sized and configured for being placed in the inferior vena cava (IVC).
33. The blood pump of claim 1, wherein the pump section is configured to extend through the right ventricle (RV) of a patient's heart (H) such that the blood flow inlet is disposed in the inferior vena cava (IVC) and the blood flow outlet is disposed in the pulmonary artery (PA).
34. A system of claim 1 comprising at least one additional filter which is separate from the blood pump, wherein the at least one filter of the blood pump and the at least one additional filter are arranged to be placed in different blood vessels that lead to the blood flow inlet during operation of the blood pump, wherein preferably one of the blood vessels is a patient's inferior vena cava (IVC) and another one of the blood vessels is the patient's superior vena cava (SVC), wherein further preferably the at least one additional filter is arranged to be placed in the superior vena cava (SVC).
35. The system of claim 34, wherein the at least one additional filter is attached to a catheter.
36. A filter for an intravascular blood pump, configured to be connected to a proximal portion of a pump section of the blood pump so as to be arranged with respect to a blood flow inlet of the blood pump to filter a blood flow before entering the blood flow inlet.
37. A kit, comprising an intravascular blood pump for percutaneous insertion into a patient's blood vessel and at least one filter, the blood pump comprising a pump section with a blood flow inlet and a blood flow outlet and an impeller for causing blood to flow into the blood flow inlet and towards the blood flow outlet, wherein the filter is sized and shaped to be arranged with respect to the blood flow inlet so as to filter the blood before it enters the pump section.
38. The kit of claim 37, wherein the filter is formed as a sleeve which is sized and shaped to be placed around the pump section.
39. The kit of claim 37, wherein the filter is slit along its length so as to allow the filter to be placed over the blood pump in a direction transverse to a central axis of the blood pump.
40. The kit of claim 37, wherein the pump section comprises a recess or shoulder such that the filter can be placed in the recess or against the shoulder to cover the blood flow inlet.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. The scope of the disclosure is not limited, however, to the specific embodiments disclosed in the drawings. In the drawings:
[0029] FIG. 1 shows a patient's heart with a blood pump inserted through the right ventricle.
[0030] FIG. 2 shows the blood pump of FIG. 1 in more detail.
[0031] FIG. 3 shows the filter of the blood pump of FIG. 1.
[0032] FIG. 4 shows another embodiment of a blood pump.
[0033] FIG. 5 shows the filter of the blood pump of FIG. 4.
[0034] FIG. 6 shows another embodiment of a blood pump having two filters.
[0035] FIG. 7 schematically shows a filter according to another embodiment.
[0036] FIG. 7a shows a schematic cross-sectional view of the catheter of the filter of FIG. 7.
[0037] FIG. 8 schematically shows a filter according to another embodiment.
[0038] FIG. 8a shows a schematic cross-sectional view of the catheter of the filter of FIG. 8.
[0039] FIG. 9 shows another embodiment of a blood pump.
[0040] FIG. 10 shows a patient's heart with a blood pump inserted through the right ventricle and an additional filter.
[0041] FIGS. 11a and 11b show yet another embodiments of a blood pump.
[0042] FIGS. 12a to 12b show assembly steps of a filter onto a blood pump.
[0043] FIGS. 13a to 13c show different embodiments of placing a filter on the blood pump.
DETAILED DESCRIPTION
[0044] In FIG. 1 is illustrated a blood pump 1 inserted into a patient's heart H. More specifically, the blood pump 1 is connected to a catheter 100 by means of which the blood pump 1 is inserted into the right ventricle RV of the patient's heart H via the inferior vena cava IVC. In a different approach, the catheter may be inserted through the superior vena cava SVC. During its operation, the blood pump 1 is placed through the tricuspid valve TRV and the pulmonary valve PV. The blood pump 1 comprises a pump section 2 having a blood flow inlet 3 placed in the right atrium RA and a blood flow outlet 4 placed in the pulmonary artery PA. An impeller (not shown) is provided to cause the blood to flow into the blood flow inlet 3 towards and out of the blood flow outlet 4 (see arrows). A filter 10 is connected to the blood pump 1, more specifically attached to the catheter 100, and placed in the inferior vena cava IVC and abuts against the inner wall of the inferior vena cava IVC. Thus, the blood flow is filtered before it enters the blood flow inlet 3 and blood clots are prevented from entering the blood pump 1. The blood pump 1 according to this embodiment is designed as a right ventricular blood pump.
[0045] With reference to FIG. 2, the blood pump 1 shown in FIG. 1 is illustrated in more detail. The curved pump section 2 has a proximal portion 5 with the blood flow inlet 3 and a distal portion 6 with the blood flow outlet 4. In this embodiment, the catheter 100 extends from the proximal portion 5 of the pump section 2. The pump section 2 has a specific curvature which helps to prevent the blood pump 1 from backing out of the patient's heart H. The blood flow inlet 3 and the blood flow outlet 4 are formed as circumferential openings in this embodiment. It will be appreciated that other shapes, sizes or positions may be suitable for the blood flow inlet 3 and the blood flow outlet 4, possibly depending on the application. The filter 10 is located upstream of the blood flow inlet 3, i.e. proximally with respect to the blood flow inlet 3, so as to filter the blood before it enters the blood flow inlet 3. More specifically, the filter 10 is mounted on the catheter 100 in an end portion of the catheter 100 adjacent to the pump section 2.
[0046] The filter 10 is illustrated in more detail in FIG. 3. The filter 10 is attached to the catheter 100 with its distal end 12. Therefore, the distal end 12 of the filter 10 can be regarded as being closed. A bushing 14, sleeve or the like may be used to attach the distal end 12 to the catheter 100. The filter 10 may either be fixedly attached to the catheter 100 or may be movable along the length of the catheter 100, e.g. to allow adjustment of the position of the filter 10 and/or to allow removal of the filter 10. The proximal end 11 of the filter 10 is open such that blood can enter the filter 10. In the illustrated embodiment, the filter 10 tapers from the proximal end 11 to the distal end 12 and has a conical shape. It will be appreciated that the filter 10 may have another suitable shape that provides an attachment at the distal end and an open proximal end.
[0047] The filter 10 has a regular mesh structure that defines a plurality of apertures 13. In this embodiment, the apertures 13 are rectangular and get narrower in a direction towards the distal end 12. This is caused by the conical shape of the filter 10 since the number of apertures 13 in a circumferential direction is constant along the length of the filter 10. Alternatively or in addition, the mesh structure may change towards the distal end 12 to provide smaller apertures towards the distal end 12, e.g. by adding additional radial and/or axial struts, by varying the shape of the apertures, etc.
[0048] The filter 10 is expandable from a compressed configuration to an expanded configuration. In the compressed configuration, the blood pump 1 with the filter 10 can be delivered through an introducer sheath (not shown) to the patient's heart H. After the blood pump 1 has been put in place, the filter 10 can be expanded. This allows the filter 10 to abut against the inner wall of a blood vessel, such as the inferior vena cava IVC as shown in FIG. 1. In order to provide the desired expansion properties, the filter 10 preferably is made of Nitinol or other suitable shape-memory material.
[0049] FIGS. 4 and 5 show another embodiment of a blood pump 1 with a filter 10 that is substantially identical to the previous embodiment. Like reference numerals refer to like parts. In this embodiment, the filter 10 has a retaining device that facilitates removal of the filter 10. The retaining device includes a plurality of filaments 16 or bands that are connected to the open proximal end 11 of the filter 10. In the illustrated embodiment, four filaments 16 are provided that are equally spaced about the circumference of the filter 10. It will be appreciated that more or fewer filaments may be provided. The filaments are preferably formed integrally with the filter. They may end in a bushing 15 that can slide along the catheter 100 (catheter not shown in FIG. 5). Further filaments 17, threads, wires or the like are provided that can be manipulated, in particular pulled, by an operating person to collapse the filter 10. The filter 10 may then be retracted into an introducer sheath (not shown). The collapsed configuration may be identical to the initial compressed configuration or may provide a larger diameter that is nonetheless sufficiently small to enable the filter 10 to be removed. Removal of the filter may be necessary e.g. for cleaning or simply if the blood pump 1 is to be finally removed from the patient.
[0050] Referring now to FIG. 6, another embodiment of a blood pump 1 is illustrated which is substantially similar to the previous embodiment. In contrast to the previous embodiments, more than one filter is provided. In particular, two filters 10 are provided that are arranged in series on the catheter 100. In the embodiment shown in FIG. 6, both filters 10 are formed like the filter of FIGS. 4 and 5. Alternatively, both filters 10 may be formed like the filter of FIGS. 2 and 3, or the filters 10 may be formed differently. Both filters 10 may be fixedly attached to the catheter 100 or both may be movable. In one embodiment, only one of the filters 10, preferably the proximal one, is movable or releasably attached to the catheter, while the other one, preferably the distal one, is fixed.
[0051] FIGS. 7 and 8 show further embodiments of a filter 10. The mesh structure is not shown for clarity purposes. The filter 10 shown in FIG. 7 includes a suction port 51 and a lysing port 52 near the distal end of the filter 10. Blood clots that accumulate in the downstream tip, i.e. the distal end, of the filter 10 can be removed by being sucked through the suction port 51. Alternatively or in addition, the blood clots may be lysed by a lysing agent that is supplied to the filter 10 through the lysing port 52. As shown in the schematic cross-sectional view of FIG. 7a, the suction port 51 and lysing port 52 may be connected to respective lines that extend through the catheter 100. It will be appreciated that only one of the ports 51, 52 may be provided.
[0052] The filter 10 shown in FIG. 8 includes two pressure sensors 53, 54. The pressure sensor 53 is located inside the filter 10, whereas the pressure sensor 54 is located downstream, i.e. distally, with respect to the filter 10. This arrangement of two pressure sensors 53, 54 allows measuring a pressure difference caused by the filter 10. If the pressure difference exceeds a predetermined threshold, this can indicate a blockage of the filter 10. As shown in the schematic cross-sectional view of FIG. 8a, the pressure sensors 53, 54 may be connected to respective lines that extend through the catheter 100. It will be appreciated that the features of the embodiments of FIGS. 7 and 8 may be combined in a single embodiment.
[0053] Another embodiment of a blood pump 1 is illustrated in FIG. 9. Rather than a tapered filter 10 that is disposed proximally with respect to the pump section 2, a filter 20 is provided that encloses the blood flow inlet 3. A proximal end 21 of the filter 20 is attached to the pump section 2 proximally with respect to the blood flow inlet 3 and a distal end 22 of the filter 20 is attached to the pump section 2 distally with respect to the blood flow inlet 3. In particular, the filter 20 may be formed like a cage and preferably has a mesh structure. The cage is preferably expandable and may be made of Nitinol or other shape-memory material as described above with respect to the filter 10. The filter 20 may be provided alternatively or in addition to any of the aforementioned filters 10.
[0054] With reference to FIG. 10, a system including a blood pump 1 with a filter 10 and an additional filter 30 is illustrated. The blood pump 1 may be formed in accordance with any one of the aforementioned embodiments. The illustrated blood pump 1 is the blood pump of FIG. 1. The additional filter 30 is provided for also filtering blood that comes from the superior vena cava SVC. The filter 30 is attached to an additional catheter 101 that is inserted through the inferior vena cava IVC which allows using the same vascular access that is used for the blood pump 1. The catheter 101 extends past the filter 10. Alternatively, an additional access can be used and the catheter 101 along with the filter 30 can be inserted though the superior vena cava SVC, which could be advantageous for securely holding the filter 30 in place. Of course, in the latter case the filter 30 will be attached to the catheter 101 in the opposite direction. The filter 30 is designed like any of the aforementioned filters 10. More than one, such as two or three, filters 30 may be provided on the catheter 101. The filter 30 may be identical to or different from the filter 10 of the blood pump 1. It will be appreciated that the arrangement can be vice versa, i.e. the catheter 100 with the blood pump 1 is inserted through the superior vena cava SVC, while the additional filter 30 is placed in the inferior vena cava IVC.
[0055] Yet another embodiment of a blood pump 1 is illustrated in FIGS. 11a and 11b. In contrast to the aforementioned embodiments, the blood pump 1 of this embodiment has a filter 40 that is integrated directly in the blood flow inlet 3. The filter 40 is integrally formed with the pump section 2, which provides an easy-to-manufacture structure. It is also possible to provide the filter 40 as an insert for the blood flow inlet 3. The apertures of the filter 40 may be elongate slots that extend in the longitudinal direction and that are separated by struts as shown in FIG. 11a. However, other shapes may be suitable for the apertures, such as circumferential slots or rectangular or circular openings as shown in FIG. 11b. The width of the slots or openings is chosen to prevent clots from entering the pump section 2. In other words, the blood flow inlet 3 is formed by the apertures of the filter 40. It will be appreciated that a blood pump that includes the filter 40 can further include any one of the aforementioned filters 10, 20 and 30.
[0056] Referring to FIGS. 12a to 12c, a kit including a blood pump 1 and a filter 50 is shown. As illustrated in FIG. 12a, a filter 50 may be provided separately from he blood pump 1 and may have a longitudinal slit 51 to allow the filter 50 to be put onto the catheter 100 in a lateral direction, i.e. from the side as indicated by the arrow in FIG. 12a. The filter 50 is made of an elastic material or shape memory material, such as nitinol, in order to allow bending the filter into an open configuration and close it once placed over the catheter 100. The filter 50 may then be advanced in a distal direction towards the pump section 2 of the blood pump 1 as shown in FIG. 12b and indicated by the arrow. In the final position as shown in FIG. 12c, the filter 50 covers the blood flow inlet 3 of the blood pump 1 to prevent clots from entering the pump section 2, which helps to avoid failure of the blood pump by clogging. Referring again to FIG. 12b, it will be appreciated that the filter 50 may not have a slot but may be a circumferentially closed sleeve that is advanced onto the catheter 100 from the proximal end of the catheter 100 towards the pump section 2. For instance, the filter 50 may be preassembled on the catheter 100. The filter 50 may have any suitable mesh structure and aperture configuration as described above.
[0057] The filter 50 may simply be press fit onto the pump section 2 as shown in FIG. 13a, wherein the inner diameter of the filter substantially corresponds to or is slightly smaller than the outer diameter of the pump section 2. Since the blood pump 1 is preferably a right ventricular assist device, the increased diameter of the blood pump 1 is not as crucial as in other applications. In order to facilitate insertion, the filter 50 may be tapered at its distal end. As shown in FIG. 13b, the pump section 2 may have a step or shoulder 52. The filter 50 may abut the shoulder 52, which acts as a stop for the filter 50. Preferably, the outer circumference of the filter 50 and the pump section 2 are flush. Alternatively, as shown in FIG. 13c, a circumferential recess 53 may be provided which is sized and shaped to receive the filter 50 in a snap fit manner. The blood flow inlet 3 is disposed in the recess 53 such that the filter 50 covers the blood flow inlet 3 when received in the recess 53.
[0058] A kit with a separate filter 50 that is assembled onto a blood pump 1 provides a modular and flexible system. For instance, a surgeon can choose an appropriate filter just before inserting the blood pump based on the patient's needs. Alternatively, the kit provides an easy way of manufacturing a blood pump with a filter because the filter is formed like a sleeve that can simply be pushed onto the pump section.
