Blood pump

Abstract

A blood pump 10 has a tubular connection part 15 which is provided so as to protrude from a pump case 11 and which has a blood flow passage 20 that communicates a heart 3 with a pump chamber 12. On the distal-end side of the tubular connection part 15, a first cuff 21 is fitted to the tubular connection part 15. On the outer peripheral side surface 15c on the proximal-end side of the tubular connection part 15, an intra-cuff ring 25 is rotatably fitted to a rotating shaft part 15f, and in the intra-cuff ring 25, an annular recessed groove 25a is formed. To this annular recessed groove 25a, a second cuff 22 is fitted. Between the first cuff 21 and the intra-cuff ring 25, a cuff receiving nut 23 is provided which is screwed to the outer peripheral side surface 15c of the tubular connection part 15 while pressing one surface of the second cuff 22. This makes it possible to suppress generation of a blood clot between the heart 3 and the blood pump 10, makes the operation of attaching the blood pump 10 to the heart 3 easier, suppresses deviation of the angle at which to attach the blood pump 10 to the heart 3, and makes it possible to reduce the extent of a pump pocket.

Description

blood pump Cross Reference

[0001] This application claims priority based on Japanese Patent Application No. 2024-12428 filed on January 31, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a blood pump.

[0003] 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.

[0004] 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 a cannula, using a conduit forming unit equivalent to the inflow cannula (see, for example, Patent Document 1).

[0005] 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 and the second connecting tube. Pipe fittings are used to connect the first connecting tube to the cylindrical tube and to connect the cylindrical tube to the second connecting tube. These pipe fittings are cylindrical nuts that are tightened with a dedicated wrench or the like to connect the first connecting tube to the cylindrical tube and the cylindrical tube to the second connecting tube.

[0006] 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 cuff and the second cuff, 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.

[0007] Japanese Patent Application Laid-Open No. 2021-4633

[0008] The inflow cannula described in Patent Document 1 connects a first connecting tube, a cylindrical tube, and a second connecting tube in series by butting their end faces together. Even if the processing precision of each tube, such as the inner diameter of each connected 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, blood flow may stagnate in those areas, potentially leading to the formation of thrombi.

[0009] 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 because 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 misalignment of the blood pump relative to the heart, potentially causing the outflow graft to be misaligned relative to the heart.

[0010] 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.

[0011] Therefore, the present invention has been made to solve these problems, and aims to realize a blood pump 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, reduces deviations in the attachment angle of the blood pump to the heart, and reduces the area of ​​the pump pocket.

[0012] [1] The blood pump of the present invention is an implantable blood pump, characterized in that it comprises: a tubular connecting part protruding from a pump case and having a blood flow path connecting the heart and a pump chamber; a first annular cuff fitted to the distal end of the tubular connecting part; an inner-cuff ring rotatably fitted to the outer peripheral side surface of the tubular connecting part closer to the base end than the first cuff and having an annular groove formed on its outer peripheral side surface; a second annular cuff fitted to the annular groove; a cuff receiving nut disposed between the first cuff and the inner-cuff ring and screwed onto the outer peripheral side surface of the tubular connecting part while pressing against one side of the second cuff; and a cuff fixing nut screwed onto the inner-cuff ring while pressing against the other side of the second cuff.

[0013] [2] In the blood pump of the present invention, it is preferable that the tubular connecting portion has a flange-shaped return portion protruding radially from the tip portion, and that the axial movement of the first cuff is restricted between the return portion and the cuff receiving nut.

[0014] [3] In the blood pump of the present invention, it is preferable that the tubular connecting part has a rotating shaft part that supports the cuff inner ring, the rotating shaft part has a packing groove around the outer circumferential side surface, an O-ring is fitted in the packing groove, and grease is applied to the sliding surfaces of the rotating shaft part and the cuff inner ring, including the O-ring.

[0015] [4] In the blood pump of the present invention, it is preferable that the axial movement of the intra-cuff ring is restricted between the cuff receiving nut and a step formed on the outer peripheral side surface of the tubular connecting portion.

[0016] [5] In the blood pump of the present invention, it is preferable that the cuff receiving nut has a cross-sectional shape of a right triangle, with the surface that contacts the first cuff being the hypotenuse, and that flat surfaces facing each other on either side of the central axis are formed on the outer side surface.

[0017] [6] In the blood pump of the present invention, it is preferable that the cuff fixing nut has flat portions on its outer side surface that face each other across the central axis, and that the flat portions are formed in a range that does not come into contact with the second cuff.

[0018] [7] In the blood pump of the present invention, it is preferable that the first cuff is fixed to the outer peripheral side surface of the tubular connecting portion by fixing both ends of a metal belt that passes through the first cuff in the circumferential direction.

[0019] [8] In the blood pump of the present invention, it is preferable that when the tubular connecting portion is attached to the heart, the tip end of the tubular connecting portion and the tip end surface of the first cuff are at the same plane position as the inner surface of the myocardium.

[0020] The blood pump has a tubular connecting portion that protrudes from the pump case and has a blood flow path that connects the heart and the pump chamber. A first cuff is fitted to the distal end of the tubular connecting portion. The tubular connecting portion also has an inner-cuff ring with an annular groove formed on its outer circumferential side, and a second cuff is fitted to the annular groove. A cuff receiving nut is threadedly fitted to the outer circumferential side of the tubular connecting portion between the first cuff and the inner-cuff ring, and the second cuff is sandwiched and fixed between the inner-cuff ring and the cuff fixing nut. The blood flow path formed in the tubular connecting portion seamlessly connects the heart and the pump chamber, so blood does not stagnate in the connection area between the heart and the blood pump due to a seam, making it possible to prevent the formation of thrombi.

[0021] The first and second cuffs are fitted to a tubular connector that is part of the blood pump. The first and second cuffs are used to suture the blood pump to the myocardium. In other words, the blood pump is directly attached to the heart via the first and second cuffs. This makes it easier to attach the blood pump to the heart even in a narrow surgical field, compared to the configuration described in Patent Document 1, which uses a special wrench to connect the heart and the blood pump.

[0022] The first cuff is fitted to the tubular connecting portion, and the second cuff is fitted to an intra-cuff ring rotatably fixed to the tubular connecting portion. Therefore, the blood pump can be rotated at the tubular connecting portion relative to the first and second cuffs, which are sutured to the myocardium, and the attachment angle of the blood pump relative to the heart can be easily adjusted.

[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 storing the blood pump inside the body can be reduced.

[0024] According to the blood pump 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.

[0025] FIG. 1 is an explanatory diagram schematically showing the configuration of an assist artificial heart system 1. FIG. 2 is an external perspective view showing the general configuration of a blood pump 10. FIG. 1 is a cross-sectional view taken along the A-A cutting line in FIG. 2 showing the configuration of an inflow cannula portion 4. FIG. 2 is a cross-sectional view taken along the A-A cutting line in FIG. 2 showing the configuration of a tubular connecting portion 15. FIG. 1 is a cross-sectional view showing the configuration of a first cuff 21. FIG. 1 is a cross-sectional view showing the configuration of a second cuff 22. FIG. 2 is a view showing the configuration of a cuff receiving nut 23. FIG. 2 is a view showing the configuration of an intra-cuff ring 25. FIG. 2 is a view showing the configuration of a cuff fixing nut 24. FIG. 1 is an explanatory diagram schematically explaining a method of attaching a blood pump 10 to a heart 3.

[0026] The configuration of a blood pump 10 according to an embodiment of the present invention and a method for attaching the blood pump 10 to a heart 3 will be described below with reference to FIGS. 1 to 10. Note that the figures described below are schematic diagrams that differ in scale from the actual figures. Furthermore, the embodiments described below do not limit the invention according to the claims. Furthermore, not all of the elements and combinations thereof described in each embodiment are necessarily essential to the solution of the present invention.

[0027] (Configuration of ventricular assist system 1) Figure 1 is an explanatory diagram showing a schematic configuration of the ventricular assist system 1. The ventricular assist system 1 has a blood pump 10 implanted in the body of a user 2, and an inflow cannula 4 that allows blood to flow into the blood pump 10 from the left ventricle 9 of the heart 3 (see Figure 10). The ventricular assist system 1 also comprises an outflow graft 5 that returns 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 that connects the control device 6 to the blood pump 10. The inflow cannula 4 is a part that has a function equivalent to that of a well-known inflow cannula, and is configured as part of the blood pump 10.

[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, 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) Figure 2 is an external perspective view showing the schematic configuration of the blood pump 10. 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 also Figure 3). Furthermore, although not shown, a motor is disposed inside the motor case 17. The space in which the motor is disposed is referred to as a motor chamber 16. In each of the figures described below, the upper side refers to the direction connected to the heart 3, and the lower side refers to the direction on the motor case 17 side with respect to the heart 3.

[0030] A tubular connection part 15 having a blood flow path 20 that connects the heart 3 (see FIGS. 1 and 10) to the pump chamber 12 is protruding from the pump case 11. An outflow graft connection part 13 that connects the heart 3 (see FIG. 1) to the pump chamber 12 and is used to connect the outflow graft 5 is protruding from the pump case 11. A connection cable introduction part 14 is protruding from the motor case 17, and is used to introduce the connection cable 7 from the control device 6 to the motor (not shown) in the motor chamber 16.

[0031] The inflow cannula 4 has a first cuff 21 attached to the tip side of the tubular connecting part 15, i.e., the tip side where the tubular connecting part 15 is inserted into the heart 3, and a second cuff 22 attached to the lower side of the first cuff 21, i.e., the base side of the tubular connecting part 15. The second cuff 22 is fixed to the tubular connecting part 15 by being sandwiched between a cuff receiving nut 23 and a cuff fixing nut 24. The detailed configurations of the tubular connecting part 15 and the inflow cannula 4 will be described with reference to Figures 3 to 9.

[0032] Figure 3 shows the configuration of the inflow cannula 4, and is a cross-sectional view taken along the line A-A in Figure 2. The inflow cannula 4 is disposed at the connection between the heart 3 and the blood pump 10. The inflow cannula 4 is constructed by attaching each element, described below, to a tubular connector 15 protruding from the pump case 11. A blood flow path 20 is formed in the tubular connector 15.

[0033] The inflow cannula part 4 has an annular first cuff 21 fitted onto the outer peripheral side surface 15c (see first cuff attachment part B in Figure 4) on the tip side of the tubular connecting part 15, and an inner cuff ring 25 rotatably fitted onto a rotating shaft part 15f on the base side of the tubular connecting part 15 relative to the first cuff 21. The first cuff 21 can be prevented from slipping out of the tubular connecting part 15 by fixing both ends of a metal belt 27 that passes circumferentially through the interior.

[0034] The intra-cuff ring 25 has an annular groove 25a (see FIG. 8( a)) formed on its outer periphery. The annular second cuff 22 is fitted into this annular groove 25a. Furthermore, the in-flow cannula portion 4 has a cuff receiving nut 23 that is disposed between the first cuff 21 and the intra-cuff ring 25 and presses the intra-cuff ring 25, and a cuff fixing nut 24 that presses the surface opposite the intra-cuff ring 25 with the second cuff 22 sandwiched between them. The cuff receiving nut 23 is threadedly attached to the tubular connecting portion 15. The cuff fixing nut 24 is threadedly attached to the intra-cuff ring 25. The second cuff 22 is attached to the tubular connecting portion 15 as a second cuff unit 40 in a state in which the cuff fixing nut 24 and the intra-cuff ring 25 are assembled.

[0035] The tubular connecting part 15 has a flange-shaped barb 15a that protrudes radially from its tip. The axial movement of the first cuff 21 is restricted between the barb 15a and the cuff receiving nut 23. The axial movement of the intra-cuff ring 25 is restricted by being sandwiched between the cuff receiving nut 23 and a stepped portion 15e (see FIG. 8(c) ) formed on the underside of the flange 25b of the tubular connecting part 15. The second cuff 22 is fitted into the annular groove 25a of the intra-cuff ring 25 and fixed within the annular groove 25a of the intra-cuff ring 25 by the cuff fixing nut 24. Next, the configuration of each element that constitutes the inflow cannula part 4 will be described.

[0036] (Configuration of Tubular Connector 15) Figure 4 shows the configuration of the tubular connector 15, and is a cross-sectional view taken along the line A-A in Figure 2. The tubular connector 15 is a truncated cone-shaped pipe-like portion that protrudes 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 character A on the pump case main body 18. In other words, the position indicated by the reference character A is the boundary between the pump case main body 18 and the tubular connector 15, in other words, the position indicating the boundary between the blood flow path 20 and the pump chamber 12. When the blood pump 10 is attached to the heart 3, the blood flow path 20 connects the left ventricle 9 (see Figure 10) and the pump chamber 12.

[0037] The opening area S1 of the tip end of the tubular connecting part 15 on the upper side in the figure is smaller than the opening area S2 of the base end at the connection position with the pump case main body 18. Furthermore, the blood flow path 20 is connected by an arc R at the connection point between the tubular connecting part 15 and the pump chamber 12. That is, the blood flow path 20 has no seams or steps, and the connection point with the pump chamber 12 is smoothly connected without any abrupt changes in the flow path. Therefore, the blood flowing from the left ventricle 9 (see FIG. 10) into the pump chamber 12 is rectified, making it possible to prevent the formation of thrombi.

[0038] A first cuff attachment section B for attaching the first cuff 21 is formed below the return portion 15a formed on the tubular connecting section 15. An outer peripheral side surface 15c directly below the return portion 15a is an area for fixing the first cuff 21 to the tubular connecting section 15 with a metal belt 27 (see FIG. 3). A male thread 30 for threading the cuff receiving nut 23 (see FIG. 3) is formed below the first cuff attachment section B. A step 15d having a larger diameter than the outer peripheral side surface 15c is formed below the male thread 30. This step 15d serves as a stop when fastening the cuff receiving nut 23 to the tubular connecting section 15.

[0039] A rotary shaft 15f that supports the intra-cuff ring 25 (see FIG. 3) is formed below the step 15d. A step 15e having a larger diameter than the rotary shaft 15f is formed below the rotary shaft 15f. The step 15e serves as a stop that restricts downward movement of the intra-cuff ring 25. The rotary shaft 15f is provided with a packing groove 32 in which an O-ring 35 serving as a sealing member is fitted. Note that a joint 19 for connecting to the motor case 17 (see FIG. 2) is formed below the pump case main body 18 in the drawing.

[0040] (Configuration of First Cuff 21 and Second Cuff 22) FIG. 5 is a cross-sectional view showing the configuration of the first cuff 21. The first cuff 21 is an annular member formed of a nonwoven fabric such as PTFE resin. The first cuff 21 is sometimes called an in-flow cuff because it is inserted into the myocardium 8 (see FIG. 10). The outer peripheral side surface 21a of the first cuff 21 is curved in the thickness direction, and the distal end surface 21b is smoothly rounded and continuous with the outer peripheral side surface 21a. The inner peripheral surface 21c of the first cuff 21 is configured with a cylindrical contact surface 21d that can be attached to the first cuff attachment part B (see FIG. 4) of the tubular connecting part 15, and a sloped portion 21e that widens from the contact surface 21d toward the second cuff 22.

[0041] When the first cuff 21 is attached to the tubular connecting part 15, the lower end of the sloped part 21e opens larger than the return part 15a (see FIG. 4) of the tubular connecting part 15, allowing for easy insertion of the tubular connecting part 15. The first cuff 21 is configured such that the inner circumferential surface 21c deforms to conform to the shape of the outer circumferential side surface of the first cuff attachment part B (see FIG. 4) of the tubular connecting part 15, and most of the first cuff 21 fits tightly against the first cuff attachment part B. As shown in FIG. 3, axial movement of the first cuff 21 is restricted between the return part 15a of the tubular connecting part 15 and the cuff receiving nut 23. The configuration of the cuff receiving nut 23 will be described with reference to FIG. 7.

[0042] FIG. 6 is a cross-sectional view showing the configuration of the second cuff 22. The second cuff 22 is an annular member formed of a nonwoven fabric such as PTFE resin. The second cuff 22 is sometimes called a sewing cuff because it is sutured together with the first cuff 21 to the myocardium 8 (see FIG. 10) using medical sutures 28 (see FIG. 10). The second cuff 22 has a simple disk shape with a central opening 22a. The central opening 22a is sized to fit into the annular groove portion 25a of the intra-cuff ring 25 (see FIGS. 3 and 8). The configuration of the intra-cuff ring 25 will be described with reference to FIG. 8. The thickness of the second cuff 22 is designated as thickness t1.

[0043] (Configuration of the Cuff Receiving Nut 23) Figure 7 shows the configuration of the cuff receiving nut 23. Figure 7(a) is a plan view seen from above, and Figure 7(b) is a cross-sectional view taken along the A-P-A section line in Figure 7(a). The cuff receiving nut 23 is an annular member, and flat surfaces 23b facing each other across the central axis P are formed on a circular outer peripheral side surface 23a. The flat surfaces 23b are formed in four locations and are used when screwing the cuff receiving nut 23 onto the tubular connecting part 15 with a fastener such as a wrench. Furthermore, the cuff receiving nut 23 has a female thread 23c formed in a central opening, and the female thread 23c can be screwed onto the male thread 30 (see Figure 4) of the tubular connecting part 15. As shown in FIG. 7( b), the cross-sectional shape of cuff receiving nut 23 is a right triangle with inclined surface 23d that abuts first cuff 21 (see FIG. 3) as the hypotenuse, base 23e that abuts against step portion 15d (see FIG. 4) of tubular connecting portion 15 as the adjacent side, and female thread 23c as the opposite side.

[0044] (Configuration of In-Cuff Ring 25) Figure 8 shows the configuration of the intra-cuff ring 25. Figure 8(a) is a plan view, Figure 8(b) is a partial cross-sectional view, and Figure 8(c) is an enlarged view of the portion surrounded by circle D in Figure 8(b). The intra-cuff ring 25 has an annular groove 25a into which the second cuff 22 can be fitted. The annular groove 25a is a groove surrounded by a flange 25b formed on the upper side and a male thread 25c formed on the lower side, and a bottom peripheral surface 25d at the bottom of the groove serves as a rotational sliding surface for the second cuff 22. The intra-cuff ring 25 is disposed between the step 15e of the tubular connecting portion 15 and the cuff securement nut 24 (see Figure 3), and its axial movement is restricted by threading the male thread 25c of the intra-cuff ring 25 into the female thread 24c of the cuff securement nut 24 (see Figure 9). The central opening 25f of the intra-cuff ring 25 is inserted onto and axially supported by the rotating shaft 15f (see FIG. 4) of the tubular connecting part 15.

[0045] 8(c), the intra-cuff ring 25 has a ridge 25e that protrudes inward from the annular groove 25a of the flange 25b. The ridge 25e is provided to bite into the second cuff 22 and reinforce the fixation of the second cuff 22 when the second cuff 22 is attached to the intra-cuff ring 25 and fixed with the cuff fixation nut 24 (see FIG. 3).

[0046] (Configuration of the Cuff Fixing Nut 24) Figure 9 illustrates the configuration of the cuff fixation nut 24. Figure 9(a) is a plan view, Figure 9(b) is a cross-sectional view taken along the line A-A in Figure 9(a), and Figure 9(c) is a side view of Figure 9(a) viewed from the direction of the arrow. The cuff fixation nut 24 is an annular member, and flat portions 24b are formed on the outer peripheral side surface 24a by cutting out portions of the outer peripheral side surface 24a at positions facing each other across the central axis P. The cuff fixation nut 24 has female threads 24c that threadably engage with the male threads 25c of the intra-cuff ring 25. The flat portions 24b are formed in four locations and are used to thread the cuff fixation nut 24 onto the intra-cuff ring 25 using a fastener such as a wrench. The flat portions 24b illustrated in Figure 9 extend partway along the thickness of the outer peripheral side surface 24a. In other words, the flat portions 24b are threaded onto the intra-cuff ring 25 in a direction that does not contact the second cuff 22. However, the flat surface portion 24b may be formed over the entire thickness direction, which allows the cuff fixing nut 24 to be assembled without distinguishing between the front and back sides.

[0047] (Method of Assembling the Inflow Cannula 4) Next, the method of assembling the inflow cannula 4 will be described with reference to FIGS. 2 to 9, with a focus on FIG. 3. The method of assembling the inflow cannula 4 begins with a preparation step in which the second cuff unit 40 is assembled. First, the second cuff 22 is inserted from the lower side of the intra-cuff ring 25 and fitted into the annular groove 25a. The diameter of the central opening 22a of the second cuff 22 is smaller than the outer diameter (thread diameter) of the male thread 25c of the intra-cuff ring 25. However, because the second cuff 22 is made of nonwoven fabric, it can be deformed to overcome the male thread 25c and fit into the annular groove 25a. Next, the cuff fixing nut 24 is tightened to the intra-cuff ring 25 with a wrench or the like. At this time, the second cuff 22 is crushed in the thickness direction by the flange 25b of the intra-cuff ring 25 and the cuff fixing nut 24, as shown in FIG. 3. Furthermore, the convex rib portion 25e (see FIG. 8(c)) formed on the flange portion 25b bites into the second cuff 22, thereby reinforcing the fixation of the second cuff 22 to the intra-cuff ring 25.

[0048] Next, the second cuff unit 40 is attached to the rotating shaft 15f from above the tubular connecting portion 15. An O-ring 35 (see FIG. 4) is attached to the packing groove 32 of the rotating shaft 15f, and a lubricant such as grease (not shown) is applied to the surfaces of the rotating shaft 15f and the O-ring 35. After the second cuff unit 40 is attached to the tubular connecting portion 15, the cuff receiving nut 23 is attached to the tubular connecting portion 15 from above. The cuff receiving nut 23 is then threaded onto the male thread 30 provided on the tubular connecting portion 15 and tightened with a wrench or the like. The second cuff unit 40 is rotatably fixed to the rotating shaft 15f of the tubular connecting portion 15 by the step 15e provided on the tubular connecting portion 15 and the cuff receiving nut 23.

[0049] Next, the first cuff 21 is attached to the tubular connecting part 15 from the distal end side. Because the first cuff 21 is made of nonwoven fabric or the like, it passes through the turned-up part 15a of the tubular connecting part 15 while deforming, and is pushed in until it abuts against the cuff receiving nut 23. Then, by fixing both ends of the metal belt 27 that runs around the inside of the first cuff 21, the first cuff 21 is fixed to the tubular connecting part 15. Through the assembly procedure described above, the blood pump 10 is ready to be attached to the heart 3.

[0050] (Method of Attaching the Blood Pump 10 to the Heart 3) FIG. 10 is an explanatory diagram illustrating a method of attaching the blood pump 10 to the heart 3. FIG. 10 illustrates the blood pump 10 attached to the heart 3. In this example, the blood pump 10 is attached to the left ventricle 9. The inflow cannula 4 is inserted into the heart 3 until the second cuff 22 contacts the myocardium 8. At this time, the barbed portion 15a at the tip of the tubular connecting portion 15 and the distal end surface 21b of the first cuff 21 are preferably positioned at the same plane as an extension of the inner surface 8a of the myocardium 8. Here, "same position" does not necessarily mean that they 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 first cuff 21 into the myocardium 8, the myocardium 8, the first cuff 21, and the second cuff 22 are sutured together using medical sutures 28.

[0051] By the above-described procedure, the blood pump 10 is attached to a predetermined position on the heart 3. The myocardium 8, the first cuff 21, and the second cuff 22 are sutured at, for example, 12 locations around the inflow cannula portion 4. The first cuff 21 and the second cuff 22 are not easily moved because they are sutured to the myocardium 8. However, the blood pump 10 includes an outflow graft connecting portion 13 and a connection cable introducing portion 14, and the protruding directions of the outflow graft connecting portion 13 and the connection cable introducing portion 14 may become misaligned during suturing.

[0052] As described above, the first cuff attachment portion B of the tubular connecting portion 15 is configured to be rotatable relative to the first cuff 21. Furthermore, the intra-cuff ring 25 that fixes the second cuff 22 is rotatable relative to the rotation shaft portion 15f of the tubular connecting portion 15. In other words, the blood pump 10 is configured to be rotatable after being attached to the heart 3 via the first cuff 21 and the second cuff 22.

[0053] The blood pump 10 described above has a tubular connection part 15 protruding from the pump case 11, and the tubular connection part 15 has a blood flow path 20 that connects the heart 3 and the pump chamber 12. The blood flow path 20 seamlessly connects the heart 3 and the pump chamber 12. Therefore, in the connection area between the heart 3 and the blood pump 10, blood does not stagnate due to the presence of a seam, and it is possible to prevent the occurrence of thrombus.

[0054] The first cuff 21 and the second cuff 22 are fitted onto the outer periphery of the tubular connecting portion 15, which is a part of the blood pump 10. The blood pump described in the aforementioned Patent Document 1 is sutured to the heart 3 via the first cuff 21 and the second cuff 22, and then a special wrench is used to tighten the cylindrical nut, thereby connecting the heart 3 and the blood pump 10. In contrast, the blood pump 10 of the present embodiment is sutured directly to the heart 3 via the first cuff 21 and the second cuff 22, making it possible to easily attach the blood pump 10 to the heart 3 even in a narrow surgical field.

[0055] Furthermore, the first cuff 21 is fitted to the tubular connecting part 15, and the second cuff 22 is fitted to an intra-cuff ring 25 that is rotatably fixed to the tubular connecting part 15. Therefore, the blood pump 10 can be rotated relative to the first cuff 21 and the second cuff 22 that are sutured to the myocardium 8, and therefore the mounting angle of the blood pump 10 relative to the heart 3 can be easily adjusted. That is, the blood pump 10 allows the outflow graft connecting part 13 and the connection cable entrance part 14 to be positioned appropriately relative to the heart 3.

[0056] The inflow cannula described in Patent Document 1 is composed of a first connecting tube, a cylindrical tube, and a second connecting tube. Therefore, the distance between the heart 3 and the blood pump 10 is long, which may increase the size of the pump pocket for accommodating the blood pump 10 inside the body. However, in this embodiment, the distance between the heart 3 and the blood pump 10 is determined only by the length of the tubular connecting portion 15. Therefore, the distance between the heart 3 and the blood pump 10 can be shortened, and the size of the pump pocket for accommodating the blood pump 10 inside the body can be reduced.

[0057] The tubular connecting part 15 also has a flange-shaped barb 15a that protrudes radially from its tip. The first cuff 21 is sandwiched between the barb 15a and the cuff receiving nut 23, restricting its axial movement. The first cuff 21 can be fixed so as to prevent axial displacement while being rotatable relative to the tubular connecting part 15. This improves the reliability of attachment of the blood pump 10 to the heart 3.

[0058] The tubular connecting part 15 also has a rotating shaft 15f that pivotally supports the intra-cuff ring 25. A packing groove 32 is formed in the rotating shaft 15f, and an O-ring 35 is fitted in the packing groove 32. A lubricant such as grease is applied to the sliding surfaces of the rotating shaft 15f and the intra-cuff ring 25, including the O-ring 35. With this configuration, the blood pump 10 can be rotated relative to the first cuff 21 and the second cuff 22 that are sutured to the myocardium 8, making it possible to easily adjust the mounting angle of the blood pump 10 relative to the heart 3.

[0059] The intra-cuff ring 25 is restricted from moving in the axial direction between the cuff receiving nut 23 and the step 15e formed on the tubular connecting part 15. The intra-cuff ring 25 can be rotatably fixed to the tubular connecting part 15 while being restricted from moving in the axial direction relative to the tubular connecting part 15. Therefore, after the first cuff 21 and the second cuff 22 are suturingly connected to the heart 3, the mounting angle of the blood pump 10 with respect to the heart 3 can be easily adjusted.

[0060] The cross-sectional shape of cuff receiving nut 23 is a right triangle with inclined surface 23d against which first cuff 21 abuts as the hypotenuse, base 23e that abuts against step 15d (see FIG. 4) of tubular connecting portion 15 as the adjacent side, and female thread 23c as the opposite side. By shaping cuff receiving nut 23 in this manner, it is possible to closely contact inner circumferential surface 21c of first cuff 21 with first cuff attachment portion B of tubular connecting portion 15 while reducing the distance between first cuff 21 and intra-cuff ring 25, and it is possible to further increase the reliability of fixation of first cuff 21 to tubular connecting portion 15.

[0061] The cuff fixation nut 24 also has flat portions 24b that face the outer peripheral side surface 24a across the central axis P. The flat portions 24b are formed in a range that does not contact the second cuff 22. In other words, the flat portions 24b are formed in a range that extends partway along the thickness direction of the outer peripheral side surface 24a, and the flat portions 24b are screwed onto the intra-cuff ring 25 in an orientation that does not contact the second cuff 22. This prevents the ridges of the flat portions 24b from scratching the second cuff 22 when the cuff fixation nut 24 is screwed. Furthermore, because the flat portions 24b are positioned on the lower side, the cuff fixation nut 24 can be gripped even with a wrench that is somewhat wide.

[0062] The first cuff 21 is fixed to the tubular connecting part 15 by fixing both ends of the metal belt 27 that passes through the first cuff 21 in the circumferential direction. This makes it possible to prevent the first cuff 21 from having a gap with respect to the tubular connecting part 15 or being displaced.

[0063] It is preferable that the distal end of the tubular connecting part 15 (the distal end of the return part 15a) and the distal end surface 21b of the first cuff 21 are located at the same plane as the inner surface 8a of the myocardium 8. By attaching the blood pump 10 to the heart 3 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.

[0064] The blood pump 10 according to the embodiment described above can prevent the occurrence of thrombus between the heart 3 and the blood pump 10, and can easily perform the work of attaching the blood pump 10 to the heart 3. In addition, it can prevent deviation in the attachment angle of the blood pump 10 to the heart 3, and can reduce the area of ​​the pump pocket.

[0065] 1...assisted artificial heart system, 3...heart, 8...myocardium, 8a...inner surface of myocardium, 10...blood pump, 11...pump case, 12...pump chamber, 15...tubular connection portion, 15a...return portion, 15c...outer peripheral side surface of tubular connection portion, 15d, 15e...step portion of tubular connection portion, 15f...rotating shaft portion, 20...blood flow path, 21...first cuff, 21a...outer peripheral side surface of first cuff, 21b...tip surface of first cuff, 22...second cuff, 23 ...cuff receiving nut, 23a...outer peripheral side surface of cuff receiving nut, 23b...flat portion of cuff receiving nut, 23d...slope of cuff receiving nut, 24...cuff fixing nut, 24a...outer peripheral side surface of cuff fixing nut, 24b...flat portion of cuff fixing nut, 25...inner cuff ring, 25a...annular groove portion, 27...metal belt, 28...medical suture, 32...packing groove, 35...O-ring, 40...second cuff unit, P...central axis

Claims

1. An implantable blood pump comprising: a tubular connecting part protruding from a pump case and having a blood flow path connecting the heart and a pump chamber; a first annular cuff fitted to the distal end of the tubular connecting part; an inner-cuff ring rotatably fitted to the outer circumferential surface of the tubular connecting part closer to the base than the first cuff and having an annular groove formed on its outer circumferential surface; a second annular cuff fitted to the annular groove; a cuff receiving nut disposed between the first cuff and the inner-cuff ring and screwed onto the outer circumferential surface of the tubular connecting part while pressing against one surface of the second cuff; and a cuff fixing nut screwed onto the inner-cuff ring while pressing against the other surface of the second cuff.

2. A blood pump according to claim 1, wherein the tubular connecting portion has a flange-shaped return portion that protrudes radially from the tip, and the axial movement of the first cuff is restricted between the return portion and the cuff receiving nut.

3. A blood pump according to claim 1, wherein the tubular connecting part has a rotating shaft part that supports the cuff inner ring, the rotating shaft part has a packing groove that runs around the outer circumferential side surface, an O-ring is fitted in the packing groove, and grease is applied to the sliding surfaces of the rotating shaft part and the cuff inner ring, including the O-ring.

4. A blood pump according to claim 1, wherein the axial movement of the inner cuff ring is restricted between the cuff receiving nut and a step formed on the outer peripheral side surface of the tubular connecting portion.

5. A blood pump according to claim 1, wherein the cuff receiving nut has a cross-sectional shape of a right triangle with the hypotenuse being the surface that comes into contact with the first cuff, and has flat surfaces on the outer circumferential side that face each other across the central axis.

6. A blood pump according to claim 1, wherein the cuff fixing nut has flat surfaces on its outer circumferential side that face each other across the central axis, and the flat surfaces are formed in an area that does not come into contact with the second cuff.

7. A blood pump according to claim 1, wherein the first cuff is fixed to the outer peripheral side surface of the tubular connecting part by fixing both ends of a metal belt that passes through the first cuff in the circumferential direction.

8. A blood pump according to claim 1, characterized in that when the tubular connecting part is attached to the heart, the tip of the tubular connecting part and the tip surface of the first cuff are at the same level as the inner surface of the myocardium.

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