Fitting structure of blood pump to heart

Abstract

To provide "a fitting structure of a blood pump to the heart" which is capable of suppressing generation of thrombus, eliminates deviation of angle at which the blood pump is fitted to the heart, and is capable of easily fitting the blood pump to the heart in a connection part between the heart and the blood pump.SOLUTION: A fitting structure of a blood pump 10 to a heart 3 has a tubular connection part 15 provided in a pump case 11 in a projecting manner and having a blood flow path 25 communicating with the heart 3 and a pump chamber 12; and a cannula unit 4 fitted to the tubular connection part. The tubular connection part 15 has an annular projection 26 and an annular recess 27. The cannula unit 4 has: a first cuff support member 24; a second cuff support member 22; a first cuff 20 fitted to the first cuff support member 24; and a second cuff 21 put between the first cuff support member 24 and the second cuff support member 22.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a structure for attaching a blood pump to a heart. [Background technology]

[0002] An artificial heart assist system is known to maintain a patient's life until a heart transplant is possible and to compensate for some of the heart's functions. This system consists of a blood pump implanted in the body, an inflow cannula and an outflow graft as blood flow paths connecting the heart and the blood pump, a control device placed outside the body, and a connecting cable connecting the control device and the blood pump.

[0003] Conventional inflow cannulas consist of a flexible cannula connected to the heart and a tube joint unit for connecting the cannula to a blood pump. In recent years, a structure has been disclosed in which a blood pump is directly attached to the heart without the need for the cannula, using a conduit forming unit equivalent to the inflow cannula (see, for example, Patent Document 1).

[0004] The conduit forming unit described in Patent Document 1 is composed of a first connecting tube for connection to the heart, a second connecting tube for connection to a blood pump, and a cylindrical tube (vent tube) that connects the first connecting tube to the second connecting tube. Pipe joints are used to join the first connecting tube to the cylindrical tube and to join the cylindrical tube to the second connecting tube. These pipe joints are cylindrical nuts that are tightened with a dedicated wrench or the like to join the first connecting tube to the cylindrical tube and the cylindrical tube to the second connecting tube.

[0005] Furthermore, a first cuff and a second cuff are attached to the first connecting tube for suturing the conduit forming unit to the heart. The method of attaching a blood pump to the heart in Patent Document 1 involves first suturing the first connecting tube to the myocardium via the first and second cuffs, and then using a cylindrical nut to connect the first connecting tube to a cylindrical tube connected to the second connecting tube connected to the blood pump. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-4633 Summary of the Invention [Problem to be solved by the invention]

[0007] The inflow cannula described in Patent Document 1 has a first connecting tube, a cylindrical tube, and a second connecting tube joined in series by butting their end faces together. In this configuration, even if the processing precision of each tube, such as the inner diameter of each joined tube and the flatness of the butted end faces, is improved, small steps or gaps may occur at the joints in the blood flow path. If there are steps or gaps in the blood flow path, the blood flow may stagnate in those areas, which may lead to the formation of thrombi.

[0008] The pipe joint is composed of a cylindrical nut, a male thread formed on the first connecting tubular member, and a male thread formed on the cylindrical nut and a second connecting tubular member. The heart and blood pump are connected by suturing the first connecting tubular member to the heart via the first and second cuffs, and then tightening the cylindrical nut onto the cylindrical tubular member connected to the blood pump via the second connecting tubular member. The joining process using the cylindrical nut is not easy, as it is performed using a special wrench or the like within a narrow surgical field. Furthermore, tightening the cylindrical nut onto the cylindrical tubular member may result in a deviation in the mounting angle of the blood pump relative to the heart, potentially resulting in misalignment of the outflow graft relative to the heart.

[0009] Furthermore, the inflow cannula described in Patent Document 1 has a first connecting tube, a cylindrical tube, and a second connecting tube connected in series, which increases the distance between the heart and the blood pump, potentially increasing the size of the pump pocket, which is the space for housing the blood pump inside the body.

[0010] Therefore, the present invention has been made to solve these problems, and aims to realize a "structure for attaching a blood pump to the heart" that can prevent the formation of blood clots between the heart and the blood pump, makes it possible to easily attach the blood pump to the heart, suppresses deviations in the attachment angle of the blood pump to the heart, and reduces the area of the pump pocket. [Means for solving the problem]

[0011] [1] The structure for attaching a blood pump to a heart of the present invention comprises a tubular connecting part protruding from a pump case and having a blood flow path connecting the heart and a pump chamber, and a cannula unit attached to the tubular connecting part, the tubular connecting part having an annular ridge formed on the outer periphery at a position close to the connection with the pump case, and an annular groove formed between the annular ridge and the pump case, the cannula unit comprising a first annular cuff support member that can be fitted to the distal end side of the tubular connecting part, and a second annular cuff support member that can be fitted to the proximal end side of the tubular connecting part. the first cuff support member has a first cuff attached to the outer periphery of the first cuff support member, and a second cuff sandwiched between the first cuff support member and the second cuff support member, the first cuff support member having a plurality of leaf spring portions extending toward the tip side of the tubular connecting portion and elastically deformable in the radial direction, the second cuff support member having a plurality of leaf spring portions extending toward the pump case and elastically deformable in the radial direction, and a protrusion that can be fitted into the annular groove portion is formed at the tip of the leaf spring portion of the second cuff support member.

[0012] [2] In the structure for attaching a blood pump to the heart of the present invention, it is preferable that the first cuff support member has an upper cuff holding portion protruding radially outward from its end on the side of the second cuff support member, and the second cuff support member has a lower cuff holding portion protruding radially outward from its end on the side of the first cuff support member, and that the first cuff support member and the second cuff support member are integrated with each other by a fixing pin that passes through the upper cuff holding portion, the second cuff, and the lower cuff holding portion, with the second cuff sandwiched between the upper cuff holding portion and the lower cuff holding portion.

[0013] [3] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that the cannula unit further has an upper washer fixed to the first cuff support member while pressing the upper cuff holder toward the second cuff, and a lower washer fixed to the second cuff support member while pressing the lower cuff holder toward the second cuff.

[0014] [4] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that a wire guide portion for guiding a fixed wire that runs around the inside of the first cuff is protruded from an intermediate position of the plurality of leaf spring portions of the first cuff support member, and both ends of the fixed wire are fixed outside the first cuff.

[0015] [5] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that the convex portion formed on the second cuff support member has a cross section in the thickness direction curved into a semicircular shape, and that when the convex portion is fitted into the annular groove portion, it further has a fixed wire that circles around the recess portion on the opposite side.

[0016] [6] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that the tubular connecting portion has a truncated cone shape in which the opening area of the tip of the blood flow path is smaller than the opening area of the base at the connection position with the pump case main body, and the blood flow path provided in the tubular connecting portion is connected to the pump case main body by an arc.

[0017] [7] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that a flange-shaped return portion that engages the tip of the leaf spring portion of the first cuff support member is formed radially outward at the tip of the tubular connecting portion.

[0018] [8] In the structure for attaching a blood pump to the heart of the present invention, it is preferable that the cannula unit further has two wire guide pipes that penetrate the first cuff and the second cuff in the thickness direction, one of the two wire guide pipes has a fixed wire introduction section into which one end of the fixed wire that has run around the inside of the first cuff is introduced and a fixed wire outlet section from which the one end of the fixed wire is led out, and the other of the two wire guide pipes has the fixed wire introduction section into which the other end of the fixed wire that has run around the inside of the first cuff is introduced and the fixed wire outlet section from which the other end of the fixed wire is led out, and the first cuff and the second cuff are fixed by fastening the fixed wire that has run through the two wire guide pipes.

[0019] [9] In the structure for attaching the blood pump to the heart of the present invention, it is preferable that when the blood pump is attached to the heart, the tip of the tubular connecting portion and the tip surface of the first cuff are located at the same position as the inner surface of the myocardium. [Effects of the Invention]

[0020] The "structure for attaching a blood pump to a heart" comprises a tubular connector protruding from a pump case and having a blood flow path connecting the heart and the pump chamber, and a cannula unit attached to the tubular connector. The cannula unit has a first annular cuff support member that can be fitted to the distal end of the tubular connector, a second annular cuff support member that can be fitted to the proximal end of the tubular connector, a first cuff attached to the first cuff support member, and a second cuff sandwiched between the first and second cuff support members. The blood flow path formed in the tubular connector seamlessly connects the pump chamber and the heart, preventing blood stagnation due to seams or the like between the heart and the blood pump and preventing the formation of thrombi. The first and second cuffs are used to suture the cannula unit to the heart.

[0021] The first cuff support member and the second cuff support member each have a plurality of leaf springs arranged circumferentially. These leaf springs are capable of elastic deformation in the radial direction. The leaf springs formed on the first cuff support member elastically deform, allowing the cannula unit to be attached to the tubular connecting portion. After the leaf springs formed on the second cuff support member are attached to the tubular connecting portion, their protrusions fit into the annular grooves of the tubular connecting member due to their elastic force, thereby maintaining the attachment state to the tubular connecting portion. In other words, the blood pump can be attached to the cannula unit, which is sutured to the heart, by simply inserting the tubular connecting portion without using a special tool such as a wrench. This makes it easier to attach the blood pump to the heart, even in a narrow surgical field, compared to the method of connecting a heart to a blood pump described in Patent Document 1.

[0022] Furthermore, after the cannula unit is sutured to the heart via the first and second cuffs, the pump case (i.e., the blood pump) is inserted and attached. Therefore, since the blood pump can be rotated relative to the cannula unit sutured to the heart, it is possible to adjust the attachment angle of the blood pump relative to the heart to an appropriate angle.

[0023] Furthermore, since the distance between the heart and the blood pump is determined only by the length of the tubular connection, the distance between the heart and the blood pump can be shortened, and the area of the pump pocket for implanting the blood pump in the body can be reduced.

[0024] According to the "structure for attaching a blood pump to the heart" described above, it is possible to prevent the occurrence of blood clots between the heart and the blood pump, it is possible to easily attach the blood pump to the heart, it is possible to prevent deviation in the attachment angle of the blood pump to the heart, and it is possible to reduce the area of the pump pocket. [Brief explanation of the drawings]

[0025] [Figure 1]FIG. 1 is an explanatory diagram schematically illustrating the configuration of an assist artificial heart system 1. [Figure 2] FIG. 2 is an external perspective view showing a state in which the cannula unit 4 is attached to the blood pump 10. [Figure 3] FIG. 2 is a vertical cross-sectional view showing the configuration of a pump case 11. [Figure 4] 3 is a diagram illustrating the configuration of a cannula unit 4. FIG. [Figure 5] 2 is a cross-sectional view showing the structure and method for attaching the blood pump 10 to the heart 3. FIG. [Figure 6] 3 is an explanatory diagram showing the structure and method for attaching the cannula unit 4 to the heart 3. FIG. [Figure 7] 2 is a cross-sectional view showing the structure of attaching the blood pump 10 to the heart 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a structure for attaching a blood pump 10 to a heart 3 according to an embodiment of the present invention will be described with reference to Figures 1 to 7. Note that the figures described below are schematic diagrams whose scales are different from the actual scales.

[0027] (Configuration of ventricular assist system 1) FIG. 1 is an explanatory diagram showing a schematic configuration of an auxiliary artificial heart system 1. The auxiliary artificial heart system 1 has a blood pump 10 implanted in the body of a user 2, and a cannula unit 4 for attaching the blood pump 10 to a heart 3. The auxiliary artificial heart system 1 further comprises an outflow graft 5 for returning blood from the blood pump 10 to the body of the user 2, a control device 6 provided outside the body of the user 2, and a connection cable 7 connecting the control device 6 and the blood pump 10. The portion consisting of the cannula unit 4 and a tubular connection part 15 (see FIG. 2) has a function equivalent to that of a well-known inflow cannula.

[0028] The control device 6 controls the operation of the blood pump 10, and has the function of collecting and filtering the cool seal liquid after supplying the cool seal liquid to the blood pump 10. Although not shown in the figure, the connection cable 7 contains a signal line connecting the control device 6 and the blood pump 10, and a seal liquid pipe line for circulating the cool seal liquid inside the blood pump 10.

[0029] (Configuration of blood pump 10 and cannula unit 4) FIG. 2 is an external perspective view showing the state in which the cannula unit 4 is attached to the blood pump 10. The "structure for attaching the blood pump 10 to the heart 3" is a structure that enables the blood pump 10 to be attached to the cannula unit 4 that is sutured to the heart 3. The blood pump 10 has a pump case 11 as a housing and a motor case 17. An impeller (not shown) is disposed inside the pump case 11. The space in which the impeller is disposed is referred to as a pump chamber 12 (see FIG. 3). A motor (not shown) is disposed inside the motor case 17. The space in which the motor is disposed is referred to as a motor chamber 16.

[0030] An outflow graft connection part 13 protrudes from the pump case 11, connecting the heart 3 (see FIG. 5) and the pump chamber 12 and for connecting the outflow graft 5. A connection cable introduction part 14 protrudes from the motor case 17, for introducing the connection cable 7 into the motor chamber 16. The cannula unit 4 is attached to the tubular connection part 15.

[0031] Cannula unit 4 has an annular first cuff 20 arranged on the distal end 15a side of tubular connecting part 15, an annular second cuff 21 arranged below first cuff 20 and having a larger diameter than first cuff 20, and first cuff support member 24 (see FIG. 4) and second cuff support member 22 that support second cuff 21. Note that the visible portion of second cuff support member 22 in FIG. 2 is a plurality of leaf spring portions 23. First cuff 20 can be attached to tubular connecting part 15 via first cuff support member 24 (see FIG. 4).

[0032] Meanwhile, the second cuff 21 is attached to the tubular connecting part 15 while being sandwiched between the first cuff support member 24 (see FIG. 4) and the second cuff support member 22. That is, the cannula unit 4 is integrally formed by the first cuff 20 and the second cuff 21 attached to the first cuff support member 24 and the second cuff support member 22, respectively. The tubular connecting part 15 has a blood flow path 25 that connects the pump chamber 12 to the heart 3 (see FIG. 5). The first cuff 20 is inserted into the heart 3 and is sometimes called a proximal cuff. The second cuff 21 is sutured and joined to the first cuff 20 with medical sutures 60 (see FIG. 6), and is sometimes called a sewing cuff. The detailed configuration of the cannula unit 4 will be described with reference to FIGS. 4 to 6.

[0033] (Configuration of pump case 11) FIG. 3 is a longitudinal cross-sectional view showing the configuration of the pump case 11. The tubular connecting portion 15 is a truncated cone-shaped pipe portion protruding from the pump case main body 18 of the pump case 11, and indicates the upward direction in the figure from the position indicated by the reference symbol A on the pump case main body 18. That is, the position indicated by the reference symbol A is the boundary between the pump case main body 18 and the tubular connecting portion 15, in other words, the boundary between the blood flow path 25 and the pump chamber 12. When the blood pump 10 is attached to the heart 3, the blood flow path 25 communicates between the left ventricle 9 (see FIG. 6) and the pump chamber 12. Note that the tip opening area S1 of the tubular connecting portion 15 on the upper side in the figure is smaller than the base opening area S2 at the connection position with the pump case main body 18 (the position indicated by the reference symbol A).

[0034] Furthermore, the connection between the tubular connecting part 15 and the pump chamber 12 of the blood flow path 25 is made by an arc R. That is, the blood flow path 25 has no seams or steps, and the connection with the pump chamber 12 is smoothly connected without any abrupt changes in the flow path. Therefore, blood flows smoothly from the left ventricle 9 (see FIG. 6) into the pump chamber 12, making it possible to prevent the occurrence of thrombus.

[0035] A flange-like return portion 15b that protrudes radially outward is formed at the tip portion 15a of the tubular connecting portion 15 on the left ventricle 9 (see Figure 6) side. An annular ridge portion 26 is formed on the base side of the tubular connecting portion 15. Furthermore, an annular groove portion 27 is formed at a position closer to the pump case main body 18 than the annular ridge portion 26. Note that a joint portion 19 with the motor case 17 (see Figure 2) is formed below the pump case main body 18 in the figure. Next, the configuration of the cannula unit 4 will be described.

[0036] (Configuration of cannula unit 4) FIG. 4 is an explanatory diagram showing the configuration of the cannula unit 4. FIG. 4(a) is an exploded view, and FIG. 4(b) is a cross-sectional view showing the assembled state. The configuration of the cannula unit 4 will be described with reference to FIG. 7, which shows the cannula unit 4 attached to a blood pump 10 (specifically, a tubular connector 15). The cannula unit 4 is configured to be detachable from the tubular connector 15 (see FIG. 3) protruding from the blood pump 10. The cannula unit 4 has a first cuff support member 24 to which a first cuff 20, which is provided for suturing to the myocardium 8 (see FIG. 6), is attached, and a second cuff support member 22 which cooperates with the first cuff support member 24 to sandwich and support the second cuff 21 in the thickness direction.

[0037] First cuff 20 is an annular member formed of nonwoven fabric such as PTFE resin and having an opening 20a. First cuff 20 has a distal end surface 20b that is convex in a semicircular shape, and an outer peripheral side surface 20c that is gently curved in the thickness direction (see FIG. 4(b)). The inner wall surface of opening 20a has a shape that follows the outline of leaf spring portion 28 of first cuff support member 24.

[0038] The first cuff support member 24 has a band-shaped ring portion 35 serving as a base, a plurality of leaf spring portions 28 extending upward in the figure from the band-shaped ring portion 35, and an upper cuff retainer portion 36 protruding radially outward from the lower end of the band-shaped ring portion 35. The band-shaped ring portion 35 is divided midway through a slit 37 and has a ring spring shape. The plurality of leaf spring portions 28 and the band-shaped ring portion 35 are arranged to surround the outer periphery of the tubular connecting portion 15 and are configured to be elastically deformable in the radial direction of the tubular connecting portion 15. Note that although FIG. 4 shows seven leaf spring portions 28, this number can be increased or decreased to six or eight.

[0039] A wire guide portion 38 projects radially outward from the extending portion of each leaf spring portion 28 to guide a fixing wire 40 that passes through the first cuff 20 in the circumferential direction. A wire insertion hole 39 is formed in the wire guide portion 38, through which the fixing wire 40 is inserted. In addition, a through hole 36a (see FIG. 4(a)) is formed in the upper cuff retainer 36, through which a fixing pin 50 (see FIG. 4(b)) is inserted.

[0040] The cannula unit 4 has an upper washer 55 that can be fitted onto the band-shaped ring portion 35 of the first cuff support member 24. The upper washer 55 is pushed in until it abuts against the upper cuff retainer 36 of the first cuff support member 24. The first cuff 20 can be attached to the first cuff support member 24 from the distal end side of the leaf spring portion 28. During attachment, the wire guide portion 38 bites into the first cuff 20, so the first cuff 20 cannot easily rotate circumferentially relative to the first cuff support member 24. After the first cuff 20 abuts against the upper washer 55, it is fixed to the first cuff support member 24 by the fixing wire 40. The upper washer 55 has through-holes 55a and 55b that penetrate through the thickness direction. The upper washer 55 has through-holes 55a and 55b that penetrate through the thickness direction. Wire guide pipes 57 and 58 are inserted into the through holes 55a and 55b (see FIG. 5(a)).

[0041] The second cuff support member 22 has a band-shaped ring portion 45 serving as a base, a plurality of leaf spring portions 23 extending downward from the band-shaped ring portion 45 in the drawing, and a lower cuff retainer portion 46 protruding radially outward from the upper end of the band-shaped ring portion 45. The band-shaped ring portion 45 is divided midway through by a slit 47, giving it a ring spring shape. The plurality of leaf spring portions 23 are arranged to surround the outer periphery of the tubular connecting portion 15 and are configured to be elastically deformable in the radial direction of the tubular connecting portion 15. Note that while FIG. 4 shows an example in which seven leaf spring portions 23 are included, the number can be increased or decreased to six or eight.

[0042] A protrusion 48 is formed at the tip of the leaf spring portion 23, which can be fitted into the annular groove portion 27 (see FIG. 3) formed in the tubular connecting portion 15. The protrusion 48 is formed by pressing the leaf spring portion 23 into a semicircular shape, and therefore the opposite surface becomes a recessed portion 49. As shown in FIG. 7, by wrapping around the multiple recessed portions 49 and fastening with a fixing wire 41 (see FIG. 7), the protrusion 48 is fitted into the annular groove portion 27 of the tubular connecting portion 15, and the fixation of the cannula unit 4 to the tubular connecting portion 15 can be reinforced.

[0043] Second cuff 21 is an annular member formed of a nonwoven fabric such as PTFE resin and has opening 21a. Upper surface 21b and lower surface 21c have annular recesses 21d and 21e (see FIG. 4(b)), respectively, that reach opening 21a. Upper cuff holder 36 of first cuff support member 24 can be fitted into recess 21d, and lower cuff holder 46 of second cuff support member 22 can be fitted into recess 21e. In this way, by providing recesses 21d and 21e, second cuff 21 can determine the relative position of second cuff 21 with respect to first cuff support member 24 and second cuff support member 22. However, since the second cuff 21 is formed from nonwoven fabric or the like, it can be deformed by a depth corresponding to the recesses 21d, 21e by pressing it with the upper cuff holding portion 36 and the lower cuff holding portion 46, so it is not necessarily necessary to provide the recesses 21d, 21e.

[0044] The upper cuff holder 36 of the first cuff support member 24 and the lower cuff holder 46 of the second cuff support member 22 are provided with through-holes 36a, 46a, respectively. The upper cuff holder 36 and the lower cuff holder 46 are arranged to overlap each other, and the through-holes 36a, 46a are positioned in the same plane. The first cuff support member 24, the second cuff 21, and the second cuff support member 22 can be integrated by passing the fixing pin 50 through the through-hole 36a, the second cuff 21, and the through-hole 46a in that order. Because the first cuff 20 is attached to the first cuff support member 24, the cannula unit 4 can be integrated, including the first cuff 20 and the second cuff 21.

[0045] The lower side of second cuff 21 has lower washer 56 that can be fitted onto band-shaped ring portion 45 of second cuff support member 22. Lower washer 56 has grooves 56b and 56c formed in an upper surface 56a on the second cuff 21 side. Grooves 56b and 56c guide wire guide pipes 57 and 58 (see FIG. 5). Fixed wire 42 (see FIG. 5) is inserted through wire guide pipes 57 and 58.

[0046] FIG. 5 is an explanatory diagram illustrating a structure for reinforcing the fixation of the first cuff 20 and the second cuff 21 by using wire guide pipes 57, 58. FIG. 5(a) is a front view showing the cannula unit 4, and FIG. 5(b) is a side view showing the insertion portions of the wire guide pipes 57, 58. When molding the first cuff 20, the wire guide pipes 57, 58 with the fixing wire 42 passing through them are inserted. The fixing wire 42 is routed as far upward as possible inside the first cuff 20 during the molding process. One end of the fixing wire 42 is inserted through the fixing wire introduction portion 57a of the wire guide pipe 57 and led out from the fixing wire lead-out portion 57b. The other end of the fixing wire 42 is inserted through the fixing wire introduction portion 58a of the wire guide pipe 58 and led out from the fixing wire lead-out portion 58b.

[0047] The fixing wire introduction portions 57a, 58a face in opposite directions along the outer periphery of the first cuff 20. The fixing wire guide portion 57b faces in a direction that allows it to be inserted into a groove 56b formed in the lower washer 56. On the other hand, the fixing wire guide portion 58b faces in a direction that allows it to be attached to a groove 56c formed in the lower washer 56. The wire guide pipe 57 is composed of the fixing wire introduction portion 57a, the fixing wire guide portion 57b, and a linear main body portion 57c that connects the fixing wire introduction portion 57a and the fixing wire guide portion 57b. Similarly, the wire guide pipe 58 is composed of the fixing wire introduction portion 58a, the fixing wire guide portion 58b, and a linear main body portion 58c that connects the fixing wire introduction portion 58a and the fixing wire guide portion 58b.

[0048] The wire guide pipe 57 passes through the slit 37 of the first cuff support member 24, penetrates the through-hole 55a of the upper washer 55, and passes through the opening 21a of the second cuff 21, with the fixing wire lead-out portion 57b attached to the groove 56b of the lower washer 56. The wire guide pipe 58 passes through the slit 37 of the first cuff support member 24 and penetrates the through-hole 55b of the upper washer 55. The wire guide pipe 58 further passes between the opening 21a of the second cuff 21 and the slit 37 of the first cuff support member 24, with the fixing wire lead-out portion 58b attached to the groove 56c of the lower washer 56. The fixing wire 42 led out from the fixing wire lead-out portion 57b and the fixing wire lead-out portion 58b is then fixed. The fixing wire 42 can be reinforced by pulling the fixing wire 42 strongly in the direction of the arrow in the figure and fastening it.

[0049] (Method of attaching the cannula unit 4 to the heart 3) FIG. 6 is an explanatory diagram showing the structure and method for attaching the cannula unit 4 to the heart 3. The cannula unit 4 is inserted into the perforated portion 8a of the myocardium 8 from the first cuff 20 side. In this example, the blood pump 10 is attached to the left ventricle 9. The cannula unit 4 is preferably inserted to a position where the distal end surface 20b of the first cuff 20 is on an extension of the inner surface 8b of the myocardium 8. Here, "on an extension" does not necessarily mean that the distal end surface 20b and the inner surface 8b are aligned; some deviation is acceptable. For example, it is more preferable that the deviation be within a range of ±5 mm. After inserting the cannula unit 4 into the heart 3, the myocardium 8, the first cuff 20, and the second cuff 21 are sutured together using medical sutures 60. Typically, sutures are performed at 12 locations around the circumference of the cannula unit 4. After the cannula unit 4 is sutured to the heart 3, the blood pump 10 is attached to the cannula unit 4.

[0050] (Attachment structure of blood pump 10 to heart 3) Next, a method for attaching the blood pump 10 to the cannula unit 4, which is sutured to the heart 3, will be described.

[0051] FIG. 7 is a cross-sectional view showing the attachment structure of the blood pump 10 to the heart 3. Note that FIG. 7 shows only the pump case 11 of the blood pump 10. The distal end of the tubular connecting portion 15 of the blood pump 10 is inserted into the space 4a (see FIG. 4(b)) surrounded by the first cuff support member 24 and the second cuff support member 22 from the leaf spring portion 23 side of the second cuff support member 22. Then, the convex portion 48 formed on the distal end of the leaf spring portion 23 rides over the annular ridge portion 26 formed on the tubular connecting portion 15 and fits into the annular groove portion 27. The leaf spring portion 28 of the first cuff support member 24 rides over the return portion 15b formed on the distal end 15a of the tubular connecting portion 15 and is engaged by the return portion 15b. In other words, the axial position of the cannula unit 4 is regulated by the return portion 15b and the annular ridge portion 26.

[0052] After the blood pump 10 is attached to the cannula unit 4, the recessed portion 49 formed in the second cuff support member 22 is tightened with the fixing wire 41 that surrounds it, and the protrusion 48 is pressed against the tubular connecting portion 15 (annular groove portion 27). The fixing wire 41 reinforces the connection between the cannula unit 4 and the blood pump 10. In other words, the reliability of the connection of the blood pump 10 to the heart 3 can be improved.

[0053] When the blood pump 10 is attached to the cannula unit 4, the elastic force of the first cuff support member 24 causes the lower end of the band-shaped ring portion 35 to abut against the tubular connecting portion 15. The elastic force of the second cuff support member 22 causes the lower end of the band-shaped ring portion 45 to abut against the tubular connecting portion 15. The convex portion 48 of the second cuff support member 22 then abuts against the annular groove portion 27 of the tubular connecting portion 15. Therefore, the blood pump 10 is supported at at least three points in the axial direction relative to the cannula unit 4, allowing for a stable posture after attachment.

[0054] The aforementioned fixing wires 40, 41, and 42 can be made of a shape memory alloy. Using a shape memory alloy for the fixing wires 40, 41, and 42 can simplify the process of fastening the fixing wires. For example, if the transformation temperature is set to be close to body temperature, the fixing wires 40, 41, and 42 will assume a fastened shape over time after the blood pump 10 is attached to the heart 3, thereby enhancing the reinforcing effect. In particular, using a shape memory alloy for the fixing wire 41, which is used in a narrow surgical field after the blood pump 10 is attached to the heart 3, can improve operability.

[0055] The "structure for attaching blood pump 10 to heart 3" according to this embodiment is composed of tubular connecting part 15, which protrudes from pump case 11 and has blood flow path 25 connecting heart 3 and pump chamber 12, and cannula unit 4 attached to tubular connecting part 15. Cannula unit 4 has first cuff support member 24 attachable to the distal end of tubular connecting part 15, second cuff support member 22 attachable to the proximal end of tubular connecting part 15, first cuff 20 attached to first cuff support member 24, and second cuff 21 sandwiched between first cuff support member 24 and second cuff support member 22. Blood flow path 25 formed in tubular connecting part 15 seamlessly connects pump chamber 12 and heart 3, so that blood does not stagnate between heart 3 and blood pump 10 due to seams or the like, making it possible to prevent the formation of thrombi.

[0056] The first cuff support member 24 and the second cuff support member 22 each have a plurality of leaf springs 28 and 23 arranged in the circumferential direction. These leaf springs 28, 23 are capable of elastic deformation in the radial direction. The leaf springs 28 formed on the first cuff support member 24 elastically deform, thereby enabling the cannula unit 4 to be attached to the tubular connecting portion 15. After the leaf springs 23 formed on the second cuff support member 22 are attached to the tubular connecting portion 15, the protrusions 48 of the leaf springs 23 fit into the annular grooves 27 of the tubular connecting portion 15 due to their elastic force, thereby maintaining the attachment state to the tubular connecting portion 15. In other words, the blood pump 10 can be attached to the cannula unit 4, which is sutured to the heart 3, by inserting the tubular connecting portion 15 without using a special tool such as a wrench. This makes it easier to attach the blood pump 10 to the heart 3, even in a narrow surgical field, compared to the method of connecting the heart 3 to the blood pump 10 described in Patent Document 1 mentioned above.

[0057] Furthermore, the cannula unit 4 is sutured to the heart 3 via the first cuff 20 and the second cuff 21, and then the pump case 11 (i.e., the blood pump 10) is inserted and attached. Therefore, the blood pump 10 can be rotated relative to the cannula unit 4 sutured to the heart 3. This makes it possible to adjust the attachment angle of the blood pump 10 relative to the heart 3 to an appropriate angle. Specifically, the attachment angles of the outflow graft 5 and the connection cable introduction part 14 of the blood pump 10 relative to the heart 3 can be adjusted.

[0058] Furthermore, the distance between the heart 3 and the blood pump 10 is determined only by the length of the tubular connecting part 15. This allows the distance between the heart 3 and the blood pump 10 to be shortened, and the area of the pump pocket for implanting the blood pump 10 in the body to be reduced.

[0059] According to the "structure for attaching the blood pump 10 to the heart 3" described above, it is possible to prevent the occurrence of blood clots between the heart 3 and the blood pump 10, and to easily attach the blood pump 10 to the heart 3. It is also possible to prevent deviation in the attachment angle of the blood pump 10 to the heart 3, and to reduce the size of the pump pocket.

[0060] First cuff support member 24 has upper cuff holding portion 36 protruding radially outward. Second cuff support member 22 has lower cuff holding portion 46 protruding radially outward. First cuff support member 24 and second cuff support member 22 are integrated with fixing pin 50 passing through through-hole 36a in upper cuff holding portion 36, second cuff 21, and through-hole 46a in lower cuff holding portion 46, with second cuff 21 sandwiched between upper cuff holding portion 36 and lower cuff holding portion 46 in the thickness direction. Therefore, cannula unit 4 to which blood pump 10 can be attached can be configured with a simple structure.

[0061] The cannula unit 4 also has an upper washer 55 and a lower washer 56 that are disposed on either side of the second cuff 21. The upper washer 55 presses against the upper surface 21b of the second cuff 21 via the upper cuff retainer 36. The lower washer 56 presses against the second cuff 21 via the lower cuff retainer 46. This configuration makes it possible to increase the bonding strength between the second cuff 21, the first cuff support member 24, and the second cuff support member 22. The fixing pin 50 may be configured to pass through the upper washer 55 and the lower washer 56.

[0062] Furthermore, wire guide portions 38 that guide a fixing wire 40 that runs around inside the first cuff 20 protrude from intermediate positions of the multiple leaf spring portions 28 of the first cuff support member 24. The fixing wire 40 has both ends that pass through the first cuff 20 fixed (fastened) together. With this configuration, the first cuff 20 can be reliably fixed to the first cuff support member 24.

[0063] Furthermore, the protrusion 48 formed on the second cuff support member 22 has a curved semicircular cross section in the thickness direction. With the protrusion 48 fitted into the annular groove 27 of the tubular connecting part 15, the second cuff support member 22 wraps around the fixing wire 41 in a recessed part 49 on the opposite side of the protrusion 48, thereby fixing (fastening) both ends of the fixing wire 41. With this configuration, it is possible to fix the blood pump 10 so that it does not come off from the second cuff support member 22, i.e., the cannula unit 4.

[0064] Tubular connecting part 15 has a truncated cone shape in which a tip opening area S1 on the side of blood flow path 25 that is inserted into heart 3 is smaller than a base opening area S2 at the connection position with pump case main body 18. Blood flow path 25 is connected to pump case main body 18 by a circular arc R. Blood flow path 25 configured in this manner does not stagnate when introducing blood from heart 3 into pump chamber 12, making it possible to maintain a rectified flow and suppress the occurrence of thrombus.

[0065] Furthermore, a return portion 15b capable of locking the tip of the leaf spring portion 28 of the first cuff support member 24 is formed at the tip portion 15a of the tubular connecting portion 15. On the blood pump 10 side of the cannula unit 4, the protrusion 48 of the second cuff support member 22 is fitted into the annular groove portion 27 of the tubular connecting portion 15. On the heart 3 side, the return portion 15b locks the tip of the first cuff support member 24. Therefore, the axial movement of the cannula unit 4 relative to the tubular connecting portion 15 is restricted.

[0066] The cannula unit 4 has two wire guide pipes 57, 58 that penetrate the first cuff 20 and the second cuff 21 in the thickness direction. The wire guide pipe 57 has a fixing wire introduction section 57a into which one end of the fixing wire 42 that has wound around the inside of the first cuff 20 is introduced, and a fixing wire outlet section 57b from which the one end of the fixing wire 42 is led out. The wire guide pipe 58 has a fixing wire introduction section 58a into which the other end of the fixing wire 42 that has wound around the inside of the first cuff 20 is introduced, and a fixing wire outlet section 58b from which the other end of the fixing wire 42 is led out. By fastening the fixing wire 42 that has passed through the wire guide pipes 57, 58, the first cuff 20 and the second cuff 21 are fixed together and the cannula unit 4 is reinforced, thereby making it possible to increase the reliability of the fixation between the cannula unit 4 and the blood pump 10.

[0067] It is preferable that the cannula unit 4 and the blood pump 10 are attached so that the distal end 15a of the tubular connecting part 15 and the distal end surface 20b of the first cuff 20 do not protrude from the inner surface 8b of the heart 3 (i.e., the myocardium 8). By attaching the blood pump 10 under these conditions, it is possible to prevent the formation of thrombi due to blood stagnation and the occurrence of blood turbulence at the connecting part between the heart 3 and the blood pump 10. [Explanation of symbols]

[0068] 3...heart, 4...cannula unit, 8...myocardium, 8b...inner surface, 10...blood pump, 11...pump case, 12...pump chamber, 15...tubular connection portion, 15a...tip portion, 15b...barbed portion, 18...pump case main body, 20...first cuff, 20b...tip surface, 21...second cuff, 22...second cuff support member, 23, 28...leaf spring portion, 24...first cuff support member, 25...blood Liquid flow path, 26...annular ridge portion, 27...annular groove portion, 36...upper cuff holding portion, 38...wire guide portion, 40, 41, 42...fixed wire, 46...lower cuff holding portion, 48...projection portion, 49...recessed portion, 50...fixed pin, 55...upper washer, 56...lower washer, 57, 58...wire guide pipe, R...circular arc, S1...tip processing area, S2...base opening area

Claims

1. a tubular connection part protruding from the pump case and having a blood flow path connecting the heart and the pump chamber; a cannula unit attached to the tubular connection portion, the tubular connecting portion has an annular ridge portion formed on an outer periphery at a position close to the connection with the pump case, and an annular groove portion formed between the annular ridge portion and the pump case, the cannula unit includes a first annular cuff support member that can be fitted onto the distal end side of the tubular connecting portion, a second annular cuff support member that can be fitted onto the proximal end side of the tubular connecting portion, a first cuff that is attached to the outer periphery of the first cuff support member, and a second cuff that is sandwiched between the first cuff support member and the second cuff support member, the first cuff support member has a plurality of leaf spring portions extending toward a distal end side of the tubular connecting portion and elastically deformable in a radial direction; the second cuff support member extends toward the pump case and has a plurality of leaf spring portions that are elastically deformable in a radial direction; a protrusion that can be fitted into the annular groove portion is formed at a tip of the leaf spring portion of the second cuff support member; A structure for attaching a blood pump to a heart.

2. 2. The blood pump mounting structure according to claim 1, the first cuff support member has an upper cuff pressing portion that protrudes radially outward from an end portion on the second cuff support member side, the second cuff support member has a lower cuff pressing portion that protrudes radially outward from an end portion on the first cuff support member side, The first cuff support member and the second cuff support member are integrated with each other by a fixing pin that penetrates the upper cuff holding portion, the second cuff, and the lower cuff holding portion with the second cuff sandwiched between the upper cuff holding portion and the lower cuff holding portion. A structure for attaching a blood pump to a heart.

3. 2. The blood pump mounting structure according to claim 1, The cannula unit further includes an upper washer fixed to the first cuff support member while pressing an upper cuff holder toward the second cuff, and a lower washer fixed to the second cuff support member while pressing a lower cuff holder toward the second cuff. A structure for attaching a blood pump to a heart.

4. 2. The blood pump mounting structure according to claim 1, a wire guide portion that guides a fixed wire that runs around inside the first cuff is protruded from an intermediate position of the plurality of leaf spring portions of the first cuff support member; The fixed wire has both ends fixed outside the first cuff. A structure for attaching a blood pump to a heart.

5. 2. The blood pump mounting structure according to claim 1, The protrusion formed on the second cuff support member has a cross section in a thickness direction that is curved in a semicircular shape, The device further includes a fixed wire that runs around the recessed portion on the opposite side in a state where the protrusion is fitted into the annular groove portion. A structure for attaching a blood pump to a heart.

6. 2. The blood pump mounting structure according to claim 1, the tubular connecting portion has a truncated cone shape in which an opening area at a tip end of the blood flow path is smaller than an opening area at a base end of the blood flow path at a connection position with the pump case main body; The blood flow path provided in the tubular connecting portion is connected to the pump case main body portion in an arc. A structure for attaching a blood pump to a heart.

7. 2. The blood pump mounting structure according to claim 1, a flange-shaped return portion that engages a tip of the leaf spring portion of the first cuff support member is formed at a tip end of the tubular connecting portion and extends radially outward; A structure for attaching a blood pump to a heart.

8. 2. The blood pump mounting structure according to claim 1, the cannula unit further includes two wire guide pipes that penetrate the first cuff and the second cuff in a thickness direction; one of the two wire guide pipes has a fixing wire introduction portion into which one end of the fixing wire that has wound around the inside of the first cuff is introduced, and a fixing wire lead-out portion from which the one end of the fixing wire is led out, the other of the two wire guide pipes has the fixing wire introduction portion into which the other end of the fixing wire that has wound around the inside of the first cuff is introduced, and the fixing wire lead-out portion from which the other end of the fixing wire is led out, The first cuff and the second cuff are fixed by fastening the fixing wire passing through the two wire guide pipes. A structure for attaching a blood pump to a heart.

9. 2. The blood pump mounting structure according to claim 1, When the blood pump is attached to the heart, the distal end of the tubular connecting portion and the distal end surface of the first cuff are located at the same position as the inner surface of the myocardium. A structure for attaching a blood pump to a heart.

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