Sutureless inflow cannula assembly for connecting a ventricular assist device to the human circulation

Abstract

The present invention relates to an inflow conduit assembly for connecting a ventricular assist device (VAD) to a ventricle without the need for suturing anastomosis. The inflow conduit assembly comprises a deformable conduit having a funnel-shaped bell-shaped opening at a first end thereof and an interface with a port of a VAD having minimal interface discontinuity at a second end thereof; a pair of male and female fasteners threadably secured for securing and sealing the bell-shaped opening of the conduit and the endocardium of the heart wall for hemostatic purposes; and a VAD coupler and a VAD inlet connector enabling quick connection of the conduit to the VAD.

Description

TECHNICAL FIELD

[0001] The present invention relates to an inflow conduit assembly, in particular a conduit assembly comprising a deformable conduit. BACKGROUND

[0002] Mechanical circulatory support systems, such as ventricular assist devices (VADs), particularly left ventricular assist devices (LVADs), have evolved into a standard of care for the treatment of end-stage heart failure. Currently, heart failure patients requiring VAD therapy are those who are non-responsive to medical therapy; without access to heart transplantation or mechanical circulatory support, they are classified as end-stage heart failure and are at imminent risk of death. To date, over 25,000 VAD implantations have been registered globally since the approval of continuous flow, long-term implanted LVADs (rotary pumps) including Heartmate 2, Heartmate 3, and HVAD. It is anticipated that LVADs as a treatment for end-stage heart failure will be more widely accepted as VAD technology advances.

[0003] VAD implantation usually requires the establishment of an inflow conduit and an outflow conduit to connect the VAD in series or in parallel to the patient's native circulatory system. Parallel connection is widely accepted in VAD implantation due to its anatomical and hemodynamic advantages. To establish this artificial flow circuit, the inflow conduit is implanted with its first end connected to the ventricle or atrium and its second end connected to the VAD inlet connector. Thus, blood flow is drawn from the heart (ventricle or atrium), enters the pump actuator and is energized by the pump actuator, and finally returns to the aorta of the assisted circulation via the outflow conduit. Intraoperatively, the establishment of the LVAD inflow conduit is the most invasive and technically dependent, usually requiring apical coring of a large hole (20-30 mm in diameter) on the apical wall of the ventricle, followed by a careful and time-consuming suturing step to secure and seal the inflow conduit around the cored myocardial wall. Intraoperative bleeding and air embolization at the suture site are usually related to the surgeon's suturing skills and experience. Blood pump malposition or migration during the perioperative or postoperative period is also related to the design of the inflow conduit, the introduction planning and execution. Adverse events related to conduit implantation include, but are not limited to, intraoperative surgical bleeding and postoperative inflow obstruction and thrombotic complications that occur during the perioperative period. Usually, such conduit-induced complications can lead to devastating postoperative pump thrombosis, thromboembolism and infarction, as well as severe stroke or neurological injury and cerebral dysfunction.

[0004] Figures 1A-1C show a representative example of a ventricular assist device (VAD) 10, specifically a centrifugal rotary pump implanted in a left ventricle (LV). Generally, the VAD 10 features a rotary blood pump including an inflow conduit 11, an outflow conduit 15, a rotor or impeller 12 embedded in a permanent magnet, a wire-wound stator 13, and a controller 14 that adjusts the rotor speed to achieve a specified blood flow delivery capacity. As the rotor 12 rotates, it creates a hemodynamic suction that expels blood stored in the LV chamber through the inflow conduit 11 into the VAD 10. This blood pump inflow is powered by the mechanical energy conversion actuated by the impeller, which flows through the impeller and is concentrated in the volute 16, and finally delivered from the outflow conduit 15 into the aorta Ao to assist circulation. Similarly, other types of rotary pumps, whether employing axial or diagonal flow designs, will have similar inflow and outflow conduit designs that cause blood flow to flow through an artificially created bypass flow path. For the LVAD implant shown in Figures 1A-1C, the apex of the LV is first cored to create a through-hole 61 in the myocardial wall, and then a sleeve anchor 111 is inserted and sutured around the through-hole 61 as a connector to interface the inflow conduit 11 of the LVAD. The creation of this inflow conduit 11 involves several intraoperative surgical risks and postoperative catheter-related complications, as described below.

[0005] Inflow and outflow flow field characteristics and catheter design have been less studied in comparison to blood pump actuator design. According to empirical guidelines for inflow catheter design, first, it should protrude more than the endocardium of the ventricular wall, and second, it should be directed toward the mitral valve and parallel to the interventricular septum 62, as shown in FIG. 1A. The first guideline is suggested based on past experience that an inflow catheter 11 with a port below the endocardium (see FIG. IB) often leads to myocardial tissue 63 ingrowth into the inflow catheter 11, resulting in pannus overgrowth and obstruction of the inflow passage. In addition, in-situ clots will form on top of these ingrown tissues 63 and dislodged into the pump-boosted blood flow, becoming a source of thromboembolic complications, including brain dysfunction, stroke, and internal organ infarction. The second guideline aims to prevent the inflow catheter from tilting toward the interventricular septum 62, which, if not properly implemented, will impede inflow entrainment, jeopardize support efficacy, and create harmful low-velocity flow in the pump, leading to pump thrombosis. In fact, these two catheter design guidelines are mutually exclusive. A longer inflow catheter 11 is more likely to satisfy the first guideline of protruding more than the endocardium, but if the catheter angle is slightly misaligned, it can create an unfavorable outcome of obstructed flow.

[0006] Clinically, the diseased heart is often malshaped due to irregular wall thickness distribution, or transformed into fibrotic or weak tissue due to pathological dilation. Therefore, at the time of implantation, the establishment of the inflow catheter 11 often encounters difficulties. Typically, the recommended location of the insertion catheter and the actual pump implant orientation can be misaligned with the original plan. In addition, even if the inflow catheter 11 is positioned as planned, the altered intraventricular morphology (catheter protruding into the ventricle) can dismantle the natural vortex structure, thereby impeding the washout effect within the ventricle, or creating low-velocity zones or backflow zones around the base of the protruding catheter (see FIG. 1C), making the ventricle a source of thrombosis. In other words, the configuration of the inflow catheter 11 and the corresponding surgical method or catheter-induced ventricular disturbed blood flow are pathogenic factors leading to blood pump thrombosis and its thromboembolic complications.

[0007] The present invention aims to design a new type of inflow catheter that can make the implantation process simpler and safer without the need to rely on highly skilled suturing, and at the same time, improve intraventricular hemodynamics to mitigate the thromboembolic complications caused by the aforementioned devices associated with existing LVAD inflow catheter designs. SUMMARY

[0008] To address the shortcomings of conventional ventricular assist device (VAD) inflow blood dynamics, one embodiment of the present invention provides an inflow conduit assembly for transporting blood between a ventricle and a ventricular assist device (VAD), comprising a deformable polymer conduit, a pair of male and female fasteners, a ventricular assist device (VAD) coupler, and a ventricular assist device (VAD) inflow adapter. The conduit comprises a first end having a bellmouth for insertion into a ventricle, a second end having a flange ramp for interfacing with an inflow port of a VAD, and a flow conduit body. The first and second ends are connected to each other by the flow conduit body, and the entire inner surface of the flow conduit body is smooth and seamless. The male and female fasteners are connected by threads, with the male fastener secured to the conduit. The ventricular assist device (VAD) coupler connects the second end to the ventricular assist device (VAD) inflow adapter, and comprises a flange base and a pair of collars secured to the flange base, with the collars having grooved slots for receiving and compressing the flange base to engage the flange ramp of the conduit and a beak flange of the ventricular assist device (VAD) inflow adapter in a sandwich configuration. The ventricular assist device (VAD) inflow adapter comprises a wedge-shaped beak for interfacing with the second end, and a base for integrating with the ventricular assist device (VAD).

[0009] In some embodiments, the bellmouth has a wall thickness that tapers toward a tip of the bellmouth, and the tip has a wedge-edged.

[0010] In some embodiments, a covered portion of the conduit that contacts a cored myocardium is roughened to promote cell and tissue ingrowth for hemostasis and fixation purposes.

[0011] In some embodiments, a porous material is attached to the female fastener that contacts an epicardium for promoting cell and tissue ingrowth for hemostasis and fixation purposes.

[0012] In some embodiments, the beak of the ventricular assist device VAD inlet connector and the second end of the conduit interface on the flange ramp, the inner diameter of the beak is slightly larger than the inner diameter of the flow conduit body, wherein the flange ramp is inclined to the centerline of the flow conduit by 30 to 60 degrees.

[0013] In some embodiments, the ventricular assist device VAD coupler includes an anti-decoupling latch and a locking ring profile that synchronously embraces the entire peripheral edge of the flange base of the coupler during the locking ring closure to achieve a connection feature of minimal discontinuity of blood contact surfaces.

[0014] In some embodiments, the inflow conduit assembly further includes a stent insert disposed in the conduit.

[0015] In some embodiments, the stent is made of Nitinol material.

[0016] In some embodiments, the stent has a zig-zag ring structure, and the stent is distributed over the area of the bell-shaped opening and the flow conduit body.

[0017] In some embodiments, the stent includes at least one zig-zag ring array, wherein a zig-zag ring array having a tubular shape is disposed in the conduit wall, and a zig-zag ring array having a conical shape is disposed in the bell-shaped opening wall. BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. 1A is a schematic diagram of an implantable rotary pump VAD with a bypass path through the left ventricular apex to the ascending aorta;

[0019] FIG. 1B illustrates an inflow conduit of a rotary pump connected to the myocardium, and its conduit mounting position is below the endocardium of the heart wall; it describes the formation of growing tissue and in situ blood clots, showing the root cause of postoperative inflow obstruction and systemic thromboembolism and its complications;

[0020] FIG. 1C is a schematic diagram of a protruding inflow conduit connected to the myocardium; thrombotic neointima and blood clots can form around the protruding conduit root;

[0021] Figure 2A is the integrated inflow conduit assembly installed on a rotary pump VAD;

[0022] Figure 2B is a cross-sectional view of the integrated inflow conduit assembly installed on a rotary pump VAD;

[0023] Figure 3A is a side view of a polymer inflow conduit as an embodiment of the present application;

[0024] Figure 3B is a cross-sectional view of a polymer flow conduit as an embodiment of the present invention;

[0025] Figure 4A is a transparent view of a flow conduit reinforced by a Nitinol stent as a preferred embodiment of the present invention;

[0026] Figure 4B shows a side view of a Nitinol stent embedded in a catheter as shown in Figure 4A

[0027] Figure 4C shows a view of a Nitinol stent embedded in a catheter as shown in Figure 4A

[0028] Figure 4D shows a schematic view of a Nitinol stent embedding in Figure 4C prior to expansion, laid flat;

[0029] Figure 5A is a cross-sectional view of a male buckling element;

[0030] Figure 5B is a view of a male buckling element;

[0031] Figure 6A is a cross-sectional view of a female buckling element;

[0032] Figure 6B is a front and back view of a female buckling element;

[0033] Figure 6C shows a variation of the female buckling design described in Figure 6A , whose sheath is additionally supported by a Nitinol stent;

[0034] Figure 6D shows a variation of the female buckling design depicted in Figure 6B , whose sheath is additionally supported by a Nitinol stent;

[0035] Figure 7 is a cross-sectional view of an integrated buckling and bell opening and catheter body in a locked position as an embodiment of the present catheter invention;

[0036] Figure 8A is a view of a VAD inlet connector;

[0037] Figure 8B is a cross-sectional view of a VAD inlet connector;

[0038] Figure 9A is an exploded view of a coupler element; ​​

[0039] Figure 9B is a view of the coupler in an unlatched, open state;

[0040] Figure 9C is a view of the coupler in a latched, locked state;

[0041] Figure 10 is a cross-sectional view of the coupler in a locked position joining the conduit, coupler flange base, and VAD inlet connector; for clarity, the felt on the conduit is not shown. DETAILED DESCRIPTION

[0042] The making and using of the inflow conduit embodiments of the assist device are discussed in detail below. It should be understood, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the embodiments and do not limit the scope of the disclosure.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should be understood that every term that is defined in a dictionary or a general encyclopedia has to be interpreted in the context in which it is used and not isolated from the remainder of the disclosure. Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0044] If any term in this application contradicts with the term used in the application for which priority is claimed or in any application / file incorporated by reference into this application, the term based on the one used or defined in this application shall be interpreted.

[0045] As shown in FIGS. 1 and 2, a ventricular assist device (VAD) 10 is connected to a heart 60 using an inflow conduit assembly (CA) 100. The inflow conduit assembly (CA) 100 includes a deformable polymer conduit 20, a pair of male and female fasteners 31, 32, a VAD coupler 40, and a VAD inlet connector 50. Figure 2A As shown in FIGS. 1 and 2, a ventricular assist device (VAD) 10 is connected to a heart 60 using an inflow conduit assembly (CA) 100. The inflow conduit assembly (CA) 100 includes a deformable polymer conduit 20, a pair of male and female fasteners 31, 32, a VAD coupler 40, and a VAD inlet connector 50. 2B As shown in FIGS. 1 and 2, a ventricular assist device (VAD) 10 is connected to a heart 60 using an inflow conduit assembly (CA) 100. The inflow conduit assembly (CA) 100 includes a deformable polymer conduit 20, a pair of male and female fasteners 31, 32, a VAD coupler 40, and a VAD inlet connector 50. Figure 2A As shown in FIGS. 1 and 2, a ventricular assist device (VAD) 10 is connected to a heart 60 using an inflow conduit assembly (CA) 100. The inflow conduit assembly (CA) 100 includes a deformable polymer conduit 20, a pair of male and female fasteners 31, 32, a VAD coupler 40, and a VAD inlet connector 50. Figure 2B As shown in FIGS. 1 and 2, a ventricular assist device (VAD) 10 is connected to a heart 60 using an inflow conduit assembly (CA) 100. The inflow conduit assembly (CA) 100 includes a deformable polymer conduit 20, a pair of male and female fasteners 31, 32, a VAD coupler 40, and a VAD inlet connector 50.

[0046] The distal orifice, defined as the relatively more distal catheter end as seen from the connected ventricular assist device VAD 10, is configured as a bell-shaped opening 21 (first end of catheter 20) which tapers in diameter as the catheter 20 extends. The taper angle of the bell-shaped opening 21 is typically 30-75 degrees from the axis of rotation of the flow conduit body 22. The mid-section of the catheter 20 is the flow conduit body 22 which has an axisymmetric cross-sectional profile. The described funnel-shaped catheter 20 constitutes a geometric locking mechanism when inserted into a cored through-hole 61 in the ventricular wall of the heart 60. The original diameter of the cored through-hole 61 prior to catheter 20 insertion is typically in the range of 10-15 mm, which is substantially smaller than the outer diameter of the inserted flow conduit body 22. Therefore, the deformability of the present catheter is essential, which allows the catheter 20 to be crimped into a smaller pre-packaged delivery form for ease of insertion into the cored through-hole 61. Upon insertion of the bell-shaped opening 21 into the left ventricle and release of the crimping constraint, the compressed catheter 20 will recover to its original shape, causing its flow conduit to snugly fit into the cored through-hole 61 with an excess diameter. Likewise, due to the release of the crimping constraint, the bell-shaped opening 21 will self-expand, thus constituting an anti-migration positioning anchor against the contacted endocardium of the heart wall, as shown. Figure 2B

[0047] In some embodiments, the present catheter 20 can substantially reduce the required cored hole size (10-15 mm diameter) compared to the rigid-walled inflow catheter (20-30 mm diameter) associated with contemporary rotary blood pumps. The reduced amount of tissue excised from the heart wall is advantageous for surgical and anatomical reasons. It not only reduces the permanent loss of contractile muscle, but also mitigates the risk of injury to the papillary muscles and chordae tendineae, which are responsible for the opening and closing of the atrio-ventricular valves, as well as the blood flow regurgitation when the valves fail to close during systole.

[0048] ​There are two heart valves in the left ventricle, the aortic valve and the mitral valve, which regulate the unidirectional flow into and out of the ventricle. It is noted that aortic valve regurgitation can impair the support efficacy of the VAD and cause intraventricular thrombus formation. On the other hand, mitral valve regurgitation can cause pulmonary congestion and hypertension, and can lead to pulmonary edema and right heart failure that is life threatening. In recent years, the use of blood pump speed regulation strategies has effectively eliminated rotary pump thrombosis complications. Since the reduction of pump speed allows the valves to open and close intermittently, a normally functioning (opening / closing) valve is important. Coring-induced chordae tendineae and papillary muscle damage can adversely affect valve function, and its accompanying valve flow regurgitation can compromise the support efficacy and cause valve-related complications as described above. Therefore, as the purpose of the present invention, reducing the amount of tissue cored around the apex of the left ventricle can significantly improve the safety and effectiveness of VAD implantation and reduce the rate of postoperative thrombotic events.

[0049] Two embodiments of the funnel-shaped catheter 20 are shown in Figure 3A A side view of a polymer inflow catheter as an embodiment of the present invention, in which the velour on the catheter flow passage body is not shown in the figure for clarity. As in Figure 3B A side view of a polymer inflow catheter as an embodiment of the present invention, and Figure 4AA transparent view of an infusion catheter reinforced with a Nitinol stent, as a preferred embodiment of the present invention. For these embodiments, polymeric elastomers such as silicone or polyurethane can be used as materials, and the catheter 20 is a deformable polymeric material. Therefore, the flow channel body 22 of the catheter 20 is curved or flexible, and can be formed by casting or injection molding into a seamless catheter 20 with a smooth blood contact surface. At the distal end of the bell-shaped opening 21 is a wedge-shaped tip 27, which can attach to the endocardium of the heart wall and has minimal geometric discontinuity. Furthermore, since the wall thickness around the tip 27 of the bell-shaped opening 21 gradually decreases, the rigidity of the bell-shaped opening 21 decreases proportionally with the wall thickness toward the tip 27, causing the bell-shaped opening 21 to exhibit flexibility and shape-conformal characteristics when compressed toward the endocardium. Multiple protruding stubs 26 are provided in the middle area of ​​the guide tube channel body 22 to allow the male fastener 31 to lock into engagement.

[0050] like Figure 3B As shown, a covering portion 28 of the drainage tube body 22, which contacts the myocardium after core removal, can be roughened to promote inward tissue growth during wound healing. The surface of the covering portion 28 can be fabricated by attaching a felt with appropriate porosity or by polymer filaments generated from a deposited film (e.g., by electrospinning). This roughened covering portion 28 can help fix or seal the implanted catheter 20 through inward tissue growth, thereby maintaining long-term hemostasis postoperatively.

[0051] Another embodiment is to use the previous embodiment ( Figure 3A and 3B Embed a bracket 70 or a bracket-shaped reinforcing member, such as Figure 4AIn some embodiments, the stent 70 is flexible and has a metallic material, such as a super-elastic Nitinol material. By embedding the stent 70 within the catheter 20 wall, the catheter wall thickness can be further thinned to reduce the outer diameter of the catheter 20 (including the bell-shaped opening 21 and the shunt body 22). Thus, the implantability of the stent-in-catheter will be improved without compromising the hemodynamic performance dictated by the inner diameter 25 of the shunt body 22. In addition, the stent 70 can share a significant portion of the pulsatile pressure load exerted on the shunt body 22, thus enhancing the durability and safety of the catheter. In terms of mechanical properties, the stent 70 can withstand large deformation without structural yielding, thus meeting the collapsibility requirement of the present catheter 20.

[0052] A side view and a view of a representative Nitinol stent embedded in a catheter are shown in FIGS. 1 and 2, respectively. Figure 4B A side view and a view of a Nitinol stent embedded in a catheter are shown in FIGS. 1 and 2, respectively. Figure 4A A side view and a view of a Nitinol stent embedded in a catheter are shown in FIGS. 1 and 2, respectively. Figure 4C A side view and a view of a Nitinol stent embedded in a catheter are shown in FIGS. 1 and 2, respectively. Figure 4A A view of a Nitinol stent embedded in a catheter is shown in FIG. 3. The stent 70 has a zig-zag ring structure and includes at least one array of zig-zag rings 71, 73 and connecting members 72, although multiple arrays of zig-zag rings 71, 73 and connecting members 72 are used in the present embodiment.

[0053] The arrays of zig-zag rings 71, 73 are responsible for resisting radial loads, while the connecting members 72 cluster the arrays of rings 71, 73 to resist axial stretching forces. In particular, the array of zig-zag rings 71 is tubular and embedded in the wall of the shunt body 22, while the array of rings 73 is conical and embedded in the wall of the bell-shaped opening 21. For a thin-walled bell-shaped opening 21, the radial strength is gradually weakened as the cone diameter increases toward the distal tip 27. Note that when the bell-shaped opening 21 is locked by the female fitting 32, the bell-shaped opening 21 can structurally buckle and lose shape conformability if the radial strength is insufficient, resulting in excessive bleeding during use. The stent 70 can improve the strength of such a polymer material by providing sufficient buckling resistance without increasing the wall thickness of the bell-shaped opening 21.

[0054] In the manufacture of stent 70, an array of connected zigzag ring structures 71, 73 are first cut from a thin-walled nitinol straight tube using a laser cutting machine. The tube-like zigzag array structure is shown in a flattened view in Figure 4D , and Figure 4C , respectively. The tube-like array assembly 71, 73 is gradually shaped into a stent 70 with a bell-shaped opening following standard expansion and heat treatment procedures. Surface grinding and electrolytic polishing are then applied to remove the oxide layer formed on the surface of stent 70 during heat treatment. The final product is completed by mold co-injection of stent 70 with silicone or polyurethane elastomer, as shown in Figure 4A .

[0055] Unlike the current inflow cannula connection design, past surgeries to connect LVAD to heart 60 typically required 10-12 sutures to be placed side-by-side around the circumference of core access hole 61. The present invention innovates a sutureless inflow cannula assembly that can be completed without sutures. Traditional suture fixation relies on the tension created in the string by the tensioned anchoring sutures. In sharp contrast, the present sutureless blood pump connection employs a completely different fixation and force generation mechanism provided by male-female clip pair 31, 32. This new connection design simultaneously locks and seals the inflow cannula 20 to the myocardium at the connection site. Sutureless fixation of cannula 20 to the myocardium is accomplished by a pair of male-female clips 31, 32, shown in Figure 5A is a cross-sectional view of a male clip element, Figure 5B is a view of a male clip element, and Figure 6A is a cross-sectional view of a female clip element, Figure 6B is a front view and a rear view of a female clip element, Figure 6C is a variant of the female clip design described in Figure 6A , whose sheath is additionally supported by a nitinol stent, and Figure 6D is a variant of the female clip design described in Figure 6B , whose sheath is additionally supported by a nitinol stent.

[0056] Figure 5A and 5BFigure 1 is a cross-sectional view of the male fastener 31 and the female fastener 32. A thread 34 is cut into the outer surface of the male fastener 31 from end to end. The flow conduit body 22 has a plurality of protruding seats 26 protruding from its outer wall, approximately in the middle region of the male fastener 31, and a plurality of slots 33 corresponding to the protruding seats 26, which are engaged with the protruding seats 26. The inner diameter of the male fastener 31 is substantially equal to the outer diameter 29 of the flow conduit body 22, with a small gap between them. When installed on the catheter 20, the protruding seats 26 on the flow conduit body 22 will interlock with the slots 33 (as can be seen in Figure 7 , and act as a support base to provide the axial and lateral reaction forces required for the thread locking of the female fastener 32.

[0057] Referring to Figure 6A and 6B , the female fastener 32 is a lock nut with a funnel-shaped distal cap 36, which is pressed against the epicardium for locking and sealing purposes. The angle of the funnel-shaped distal cap 36 is approximately equal to the angle of the bell-shaped opening 21. When the threads of the male and female fasteners 31, 32 are tightened together, a compression force is generated and evenly distributed in the myocardium sandwiched between the funnel-shaped distal cap 36 and the bell-shaped opening 21. Furthermore, the taper of the bell-shaped opening 21 is slightly deformed to conform to the endocardial terrain, while achieving the functions of sealing (preventing bleeding) and catheter fixation. Around the outer edge of the funnel-shaped distal cap 36, a conical-shaped soft cuff 35 made of surgical felt is attached. The soft contact and porous nature of the felt is another assurance of hemostasis. Tissues or cells can grow inward into the porous interstices of the conical-shaped soft cuff 35 during the postoperative wound healing process. Some stay sutures can be placed around the cuff edges to further assist in fixing the locked female fastener 32 to the epicardium during acute healing.

[0058] Postoperative tissue atrophy can occur at the clamped connection site after the present sutureless catheter is implanted. This tissue atrophy can compromise the effectiveness of the seal and can cause bleeding at the connection site. In Figure 6C and 6D , another embodiment of the female fastener 32 is shown, which is intended to mitigate postoperative bleeding caused by such atrophy. The soft cuff 35 is further supported by a conical-shaped nitinol stent 35N, similar to Figure 4B and 4CThe zigzag ring 73 is shown embedded in the bell-shaped opening 21 of the catheter. When the female fitting 32 is compressed against the epicardium, the deformed super-elastic Nitinol stent 35N will provide an elastic contact load to ensure that the soft sheath 35 remains adhered to the epicardium throughout the wound healing process, thereby avoiding the risk of blood leakage due to post-operative shrinkage.

[0059] Figure 7 is a cross-sectional view of an integrated fitting of an embodiment of the present catheter in a locked position with the bell-shaped opening and the catheter body. The felt on the catheter is not shown for clarity. Figure 7 The integrated male and female fittings 31, 32 are shown installed on the catheter 20. The deformation of the catheter 20 and the resulting forces and strains impart special design features of the present invention. In fact, the elastic considerations of the materials need to be carefully incorporated into the current design. The deformation capability of the catheter 20 is a necessary prerequisite when installing these fittings onto the catheter body. The proximal or second end 24 of the catheter 20 should be crimped into a smaller profile so that the second end 24 can be passed through the ring-shaped male and female fittings 31, 32 in turn. The male fitting 31 is installed first and locked onto the catheter flow conduit body 22 by the engagement of the through-slots 33 on the fitting wall with the plurality of protruding seats 26 on the catheter flow conduit body 22 as the crimped profile is released. After the catheter second end 24 is crimped, the female fitting 32 is inserted, the catheter second end 24 is released, and then the female fitting 32 is threaded onto the male fitting 31.

[0060] The fixation with the catheter 20 and the heart 60 is accomplished by advancing the female fitting 32 forward until it makes contact with the epicardium at a predetermined compression force. The appropriate compression force required for successful locking fixation and leak-proof sealing can be determined by the surgeon or controlled using a torque wrench.

[0061] In terms of mechanism, the threaded locking of the male and female fittings 31, 32 sandwiches the myocardium between the bell-shaped opening 21 and the funnel-shaped distal cap 36 of the female fitting 32 from both sides of the coring through-hole 61 to meet the requirements of fixation and leak-proofing. It is worth noting that the bell-shaped opening 21 is shape-conformal with the endocardium when compressed. The semi-rigid (elastic) bell-shaped opening 21 can adapt to the endocardial terrain, forming a sealing barrier to avoid the problem of blood leakage. However, the male fitting 31 of the fitting pair, which is anchored on the protruding seats 26 of the catheter flow conduit body 22, serves as a supporting base to counteract the resulting locking force.

[0062] It is worth mentioning that the present seamless connection has a positive feedback mechanism built in to control bleeding. As the ventricle contracts and the ventricular blood pressure increases, the pressure acting on the bell-shaped opening 21 will increase accordingly and better seal the connected conduit 20. Thus, the concern of high pressure bleeding is virtually eliminated. This positive feedback effect is absent in the traditional fixation by suturing means as shown in FIGS. 1A to 1C. For traditional suture fixation, typically, the surgeon has to check the suture bleeding after the anastomosis of the conduit 20 is completed based on a drug-induced temporary high blood pressure. Figure 2B A cross-sectional view of how the present invention is in a locked position with a connected ventricular wall. The compression-type locking mechanism can exert an evenly distributed locking force around the contact clamped myocardial region. The soft contact on the bell-shaped opening 21 and the funnel-shaped distal cap 36 avoids the traditional problem of suture string cutting from suturing the myocardium, which often leads to bleeding from suture needle hole enlargement at high pressure. The myocardium is particularly susceptible to suture string cutting associated with traditional suture anastomosis, which problem depends largely on the surgeon's mastery of suturing skills.

[0063] Around the second end 24 of the conduit 20, the inner surface in contact with blood has a configuration with a geometrically smooth transition to the connected VAD 10 inlet. As shown in Figure 8A and Figure 8B The ventricular assist device VAD inlet connector 50 is a rotational body that includes a wedge-shaped beak 51, a beak flange 53, and a base 54, forming an extension of the ventricular assist device VAD inlet housing. A plurality of eyelets 58 are drilled on the base 54 for joining the ventricular assist device (VAD) inlet connector 50 with the ventricular assist device 10. The wedge-shaped beak 51 is the forwardmost portion of the connected blood pump or ventricular assist device (VAD) inlet connector 50, with an inner diameter 52 slightly larger than an inner diameter 25 of the flow conduit 20. See Figure 3B To enhance the fault tolerance capability associated with the step discontinuity created at the interface, the interface surface of the flange ramp 23 is inclined at an oblique angle outer diameter 29 to the stream direction. This ramp interface design avoids the step or gap created on the interface surface of the flange ramp 23 due to limited manufacturing precision or matching concentricity associated with conventional interfacing. However, this tapered flange ramp 23 has an inherent disadvantage in achieving the concentric centerline alignment with the connection. This problem is addressed by a special coupler design as described below.

[0064] As shown in Figure 9Ais an exploded view of the coupler 40 components, Figure 9B is a view of the coupler in an unlatched, open state, and Figure 9C is a view of the coupler in a latched, locked state. The VAD coupler 40 is specifically designed to meet the hemodynamic and antithrombogenic requirements when connecting the second end 24 of the conduit 20 to the VAD inlet connector 50. Figure 9A Illustrated in FIG. 1 is the component VAD 10 that makes up the fully functional VAD coupler 40. The coupler 40 includes a flange base 42, a pair of collars 43, and a hinge 44 that connects the collars 43 to the flange base 42. A spring coil 45 is placed in the hinge joint 46 to keep the collars 43 in the open position when unlatched. Figure 9B ). The collars 43 have internal grooves 431, as shown in Figure 9A , 9B The collars 43 have internal grooves 431, as shown in

[0065] Quick connect type locking can be easily performed by closing the collars 43 without the fear of unintentional unlocking, as shown in Figure 9C A leaf spring latch 47 is mounted by welding a plate 471 to the top of the leaf spring latch 47 to achieve the desired spring force, which is fixed to the tip of a collar 43. During locking, the leaf spring latch 47 flexes as it slides over the ramp 49 on the other collar. When the leaf spring latch 47 clears the top of the ramp 49, it will drop to the bottom of the ramp 49 by the spring force, thereby acting as a safety measure to prevent accidental unlatching or collar opening due to pump vibration or shaking over time. When the pump is removed or replaced, the leaf spring latch 47 can be flexed and lifted upward by a special tool to create an unlatching force to rotate the collars 43 open, thereby decoupling the VAD 10 from the conduit 20.

[0066] For the design of a ventricular assist device (VAD) coupler 40 that is capable of concentrically connecting a rigid wedge beak 51 to a flange ramp 23 of a semi-rigid (elastomeric) conduit 20, it is critical to be able to simultaneously catch the entire perimeter edge of the flange base 42. Whenever a simultaneous catch / lock engagement is not achieved, the conduit flange ramp 23 that is initially caught will experience more strain than the other free portions and will tend to create a ramp surface tilt or shift of the uneven contact, resulting in a pump connection eccentricity. This eccentric connection is often the cause of interface step or gap creation and thrombosis. The remedy for this shortcoming is to configure the locking ring profile 41 of the distal flange of the ventricular assist device (VAD) coupler 40 to be able to simultaneously lock engage all circumferential contact areas. When locked, the edge of the metal wedge beak 51 will sink slightly into the compressed silicone ramp 23 at a controlled depth and further reduce the interface discontinuity when exposed to blood flow. Thus, by giving a small amount of anticoagulation regimen, the traditional interface thrombosis can be greatly reduced or eliminated.

[0067] The coupling of the conduit 20 to the ventricular assist device 10 is accomplished by a clamping mechanism that uses the deformed conduit 20 second end 24 as a "spacer" between the rigid flange base 42 and the beak flange 53 of the ventricular assist device (VAD) coupler 40 and the ventricular assist device (VAD) inlet connector 50. Figure 10 The complete junction between the conduit 20 and the ventricular assist device (VAD) inlet connector 50 of the ventricular assist device 10 locked by the ventricular assist device (VAD) coupler 40 is illustrated. This interface junction design between the blood pump and the conduit has two hemodynamic advantages in reducing in situ thrombosis. First, there is virtually no creation of a distinct step or gap type discontinuity junction as observed in conventional docking. Second, flow stasis at the beak leading edge 56 interface can be minimized. Thus, the blood flow through the connected interface will remain high velocity, greatly improving the docking shortcoming of the presence of a forward-facing or backward-facing step at the interface that stalls flow and causes thrombotic adverse events in situ and in the bloodstream.

[0068] The implantation of the inflow conduit 20 of the present invention and the connection of the conduit 20 to the ventricular assist device 10 is summarized as follows. The step-by-step procedure description of such implant (Implant) enablement is described as follows:

[0069] 1. Fold the conduit 20 into a smaller profile using a crimper or by hand and use a string to restrain or by looping the folded conduit 20 proximal end 24 and distal end 27 around, respectively;

[0070] 2. Core a through hole 61 in the myocardial wall (ventricle or atrium);

[0071] 3. Insert the crimped catheter through the core through hole 61 into the ventricle (or atrium). A trocar can be used to assist in the insertion of the catheter 20. Remove the trocar after insertion;

[0072] 4. Install the male and female clamps 31, 32 from the catheter proximal end 24 onto the crimped shunt conduit body 22;

[0073] 5. Release the tether constraint on the distal end 27, allowing the bell-shaped opening 21 to self-expand and return to its original shape;

[0074] 6. Release the tether constraint on the proximal end 24, allowing the catheter 20 to return to its original shape;

[0075] 7. Anchor the male clamp 31 to the protruding seat 26 on the shunt conduit body 22;

[0076] 8. Thread the female clamp 32 until the specified compression force on the epicardial wall is achieved. A torque wrench can be used to control the compression force;

[0077] 9. Install the ventricular assist device (VAD) coupler 40 from the catheter proximal end 24 onto the catheter 20;

[0078] 10. Prime the blood pump with heparin saline for air removal;

[0079] 11. Prime the ventricle and the interior of the catheter 20 with heparin saline to remove internal air;

[0080] 12. Connect the blood pump ventricular assist device (VAD) inlet connector 50 to the catheter proximal end 24 by closing the locking ring 43 of the ventricular assist device (VAD) coupler 40. Prime the pump and catheter 20 together to ensure that no air is entrained.

[0081] In summary, an embodiment of the present disclosure provides an inflow conduit assembly for transferring blood between a heart chamber and a ventricular assist device (VAD), which includes a deformable polymer conduit, a pair of male and female fasteners, a VAD coupler, and a VAD inlet connector. The conduit includes a first end with a bell-shaped opening to lock against the heart chamber wall, a second end with a flange bevel, and a flow conduit body, wherein the first and second ends are connected to each other by the flow conduit body, and the entire inner surface of the conduit is smooth and seamless. The male and female fasteners are connected to each other by threads and anchored to the conduit by the male fastener. The second end is equipped with an interface with the VAD inlet connector. The VAD coupler connects the second end and the VAD inlet connector, which includes a flange base and a pair of locking rings fixed on the flange base, wherein the locking rings have an internal groove for receiving and compressing and clamping the flange base, the flange bevel of the conduit, and a beak-shaped flange of the VAD inlet connector; and the VAD inlet connector includes a wedge-shaped beak that interfaces with the second end of the conduit, the beak-shaped flange received by the coupler, and a base mounted to the VAD.

[0082] In the claims, the use of the ordinal terms such as "first", "second", "third", etc. to modify a claim element does not indicate any priority, preference or order of one claim element to another, or the time sequence of performing method acts, but is merely used as labels to distinguish one claim element having a particular name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements.

[0083] It will be apparent to those skilled in the art that various modifications and variations can be made in the present application. It is intended that the standard and examples be considered as exemplary only, with the true scope of the disclosed embodiments being indicated by the following claims and their equivalents.

Claims

1. An inflow conduit assembly for transporting blood between a heart chamber and a ventricular assist device, comprising: a deformable polymeric conduit, wherein the conduit comprises: a first end having a bell-shaped open inlet for placement into the heart chamber; a second end having a flange bevel; and a flow conduit body, wherein the first and second ends are integrally connected by the flow conduit body, and the entire inner surface of the conduit is smooth and seamless; a male-female coupling, wherein the male-female coupling is threadably interlocked, the male coupling is anchored to the conduit; a ventricular assist device (VAD) coupler; and a ventricular assist device (VAD) inlet connector, wherein: the second end has an interface with the ventricular assist device (VAD) inlet connector; the ventricular assist device (VAD) coupler connects the second end with the ventricular assist device (VAD) inlet connector such that the second end is configured to mate with the ventricular assist device (VAD) inlet connector; the ventricular assist device (VAD) coupler comprises a clamped flange base and a pair of locking rings secured to the flange base, the clamped flange base is clamped by the locking rings, the flange bevel of the conduit, and a beak-shaped flange of the ventricular assist device (VAD) inlet connector, wherein the locking rings have at least one internal groove to receive and compress the clamped flange base, the flange bevel of the conduit, and the beak-shaped flange; the ventricular assist device (VAD) inlet connector comprises a wedge-shaped beak that interfaces with the second end, the beak-shaped flange is received by the ventricular assist device (VAD) coupler, and a base that is integral with the ventricular assist device (VAD).

2. The inflow conduit assembly of claim 1, wherein, the bell-shaped open inlet has a wall thickness that tapers toward a tip of the bell-shaped open inlet, and the tip is a wedge-shaped edge.

3. The inflow conduit assembly of claim 1, wherein, a surface portion of the flow conduit that is configured to contact myocardium of the heart is textured or covered with a porous material to promote cell and tissue ingrowth.

4. The inflow conduit assembly of claim 1, wherein, the female coupling has a female coupling cap configured to contact epicardium of the heart to promote cell and tissue ingrowth for hemostatic and securement purposes, wherein a porous material is attached to the female coupling cap.

5. The inflow conduit assembly of claim 4, wherein, the female coupling cap is supported by a nitinol stent that creates an elastic load when locked to the epicardium of the heart to keep the female coupling cap attached to the epicardium of the heart.

6. The inflow conduit assembly of claim 1, wherein, the beak-shaped flange of the ventricular assist device (VAD) inlet connector has a beak-shaped interface with the flange bevel, an inner diameter of the beak is larger than an inner diameter of the flow conduit body, and the flange bevel is inclined 30 to 60 degrees to a centerline of the flow conduit.

7. The inflow cannula assembly of claim 1, wherein, the ventricular assist device (VAD) coupler comprises an anti-decoupling latch and a locking ring profile that synchronously embraces an entire peripheral edge of the flange base of the coupler during locking ring closure to achieve a connection feature with minimal discontinuity of blood contact surfaces.

8. The inflow cannula assembly of claim 1, wherein, further comprising a stent insert disposed in a wall of the conduit.

9. The inflow conduit assembly of claim 8, wherein, the stent is made of a nitinol material.

10. The inflow cannula assembly of claim 8, wherein, the stent has a zigzag ring structure, and the stent is distributed over an area of the bell-shaped open inlet and the flow conduit body.

11. The inflow conduit assembly of claim 8, wherein, The stent includes at least one zigzag annular array, wherein a zigzag annular array having a tubular shape is disposed in the conduit wall, and a zigzag annular array having a conical shape is disposed in the bell opening wall.

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