Catheter valve, catheter and method of assembly

Abstract

A catheter valve includes a valve housing defining a fluid passage, where the housing includes asymmetric leaflets that pivot between a first position for allowing fluid flow through the fluid passage and a second position for closing the fluid passage, where the housing and leaflets are connected by a snap connection. Furthermore, a method for assembling a catheter flap is provided, the method comprising: providing a catheter housing; providing a valve leaflet; and clamping the valve leaflets into the housing.

Description

[0001] The present invention relates to a catheter valve.

[0002] WO2005 / 021078 discloses a catheter having a check valve that can be used to close a catheter passage. The valve can be positioned away from the catheter inlet and the catheter outlet. In a known configuration, the catheter is used for cardiac treatment, for example, for controlling the direction of blood flow. This document discloses a catheter extending through the ventricular valve of a beating heart, wherein a check valve having a movable valve body is provided between the inlet passage and the outlet passage of the catheter (in this case, to avoid forming a large open passage across the ventricular valve). According to an example, the valve body 45 is pivotally suspended to rotate about an axis extending through the passage between a closed position substantially closing the catheter passage and an open position allowing fluid to pass through the valve. In the open position, the known valve body extends in a plane parallel to the passage, and in an axial view, has a central portion spaced from the pivot axis, and in a side view, the valve body projects more from the pivot axis in the distal direction than in the proximal direction. Starting from the closed position of the valve body, since (at least in the open state) the valve body projects more from the pivot axis in the distal direction than in the proximal direction, the blood pressure in the distal direction causes a couple of forces to be applied to the valve body, which causes the valve body to pivot to its open position and keeps it in this position by the blood flow in the distal direction. After the displacement structure that pushes the blood in the distal direction has completed its stroke, the displacement structure starts to draw blood in the proximal direction. The small amount of backflow at the valve body caused by the reversal of the action of the displacement structure causes the valve body to pivot back to its closed position. The initial movement of the valve body is considered to be caused by the difference in flow velocity between the center and the periphery of the passage. Once the valve body is slightly tilted in the closing direction, the fluid pushes against the surface of the valve body away from the axis, which causes the valve body to pivot to its closed position, thereby preventing any significant backflow.

[0003] Since the known valve body in the open position extends in a plane parallel to the passage and has a central portion spaced from the pivot axis in the axial view, the valve keeps most of the lumen of the catheter open for the passage of tools and causes minimal resistance to blood flow. In addition, the opening and closing of the known valve do not require any bending of materials, which is advantageous for obtaining reliable operation over a long period of time.

[0004] To close a passage having a circular cross-section, it is advantageous for the pivot axis to extend across the widest part of the passage (measured in the axial direction), because this allows the known valve body to be wide enough to close the passage along the entire perimeter of the passage while still allowing pivotal movement between the closed position and the open position about the axis. In addition, the passage section containing the valve body can have a constant cross-section, thereby minimizing the flow resistance, and nevertheless, the valve body in the closed state substantially abuts against the continuous inner wall surface of the passage along the entire perimeter of the passage.

[0005] The known valve body is a curved panel. In the open position, the valve body leaves an open passage between the panel and the catheter wall on both sides of the panel, allowing blood to flow through on both sides of the panel, which helps to avoid areas with little flow and an increased risk of thrombosis. When the panel is in the open position, the space between the panel and the inner wall of the channel also allows the panel to pivot to its closed position.

[0006] An example of a catheter valve assembly is the iVaC2L of PulseCath (see https: / / www.pulsecath.com / products / ivac-2l / ), which is designed for patients with impaired left ventricular function who require left ventricular mechanical circulatory support for up to 24 hours. The iVAC 2L is a short-term, fully percutaneous, 17Fr transfemoral left ventricular assist device (LVAD) that can effectively generate a blood flow of up to 2 liters per minute. By actively reducing the ventricular burden, the iVAC 2L provides critical hemodynamic support in cases of high-risk revascularization surgery, acute myocardial infarction, and cardiogenic shock, as well as in high-risk patients. The iVAC 2L incorporates a rotary two-way valve that is connected to an extracorporeal membrane pump via a 17Fr, single-lumen, 100cm-long catheter. It can be used with any standard intra-aortic balloon pump (IABP) console without the need for dedicated hardware.

[0007] When the heart is in systole, blood is aspirated from the left ventricle through the catheter tip and lumen into the membrane pump.

[0008] During diastole, the membrane pump injects blood back through the catheter, and then the catheter valve is opened to deliver the blood to the ascending aorta through the side outflow port, thus creating an "extra beat of the heart". The pulsatile synchronization between the closure of the aortic valve and the opening of the catheter valve ensures that the aortic valve function is not impaired. The iVAC 2L actively reduces the heart burden by directly aspirating from the left ventricle and simultaneously creates a reverse pulsatile flow in the ascending aorta.

[0009] The known valves have opposing pivot axes that are part of the respective valve housings and are particularly welded to the housings.

[0010] These known valves perform relatively well. However, it has been found that the valve operation (i.e., the movement of the valve leaf between the open and closed positions) may be relatively slow, which may lead to (reflux) leakage, thereby reducing the outlet volume flow. In addition, the manufacture of the known valves is relatively complex. In particular, the manufacture includes: first, providing two holes in the valve leaf and two holes in the housing, and then inserting shafts from both sides to form a pivot connection. Then the welded shafts are welded to the housing from the outside to fix the shafts in place.

[0011] The present invention aims to provide an improved catheter valve. In particular, the present invention aims to provide a valve with lower leakage during operation and improved catheter outflow. Additionally, the goal is to improve the manufacturability of the valve. Further, the goal is to provide a durable and reliable catheter valve.

[0012] According to the present invention, one or more of these goals can be achieved by the features of the independent claims.

[0013] In particular, a catheter valve is provided, which includes a valve housing defining a fluid passage, wherein the housing includes asymmetric valve leaflets that pivot between a first position for allowing fluid to flow through the fluid passage and a second position for closing the passage, and wherein the housing and the valve leaflets are connected by a snap connection.

[0014] It has been found that improved valve manufacturing can be achieved in this way. In particular, according to one embodiment, the present valve does not require a dedicated pivot shaft to be welded to a position aligned with the valve housing. Instead, the housing can be provided with two opposing holes for receiving the valve pivot segments, and wherein the precise alignment of the two holes can be achieved in a straightforward manner during the manufacturing process (e.g., by holding the housing in a fixed position relative to a drilling tool, such as a CNC drilling device, when drilling the two pivot holes).

[0015] According to a preferred embodiment, the snap connection (integrally) includes the pivot joint segments (i.e., shafts, protrusions) of the valve leaflets and the housing.

[0016] According to a further embodiment, the valve leaflets can be made as a single piece, i.e., the corresponding pivot joint segments of the valve leaflets can be made as a single piece with the remaining (central) segments of the valve leaflets. For example, a suitable valve leaflet manufacturing process can be based on wire cutting technology (also known as wire electrical discharge machining, see, for example, https: / / en.wikipedia.org / wiki / Electrical_discharge_machining ). The resulting ("snap-in") valve leaflets can be assembled into the valve housing as springs without welding (wherein the assembly can involve spring biasing (e.g., elastic compression) of the valve leaflets). After assembly, the valve leaflets can be in a spring-relaxed state.

[0017] It has been found that this innovative improvement can significantly reduce shaft friction and achieve a relatively smooth pivoting motion of the valve leaflets. It can also increase the valve leaflet speed (between different pivot positions relative to the housing), and compared with prior art valve assemblies, the result can provide a more efficient valve and lower backflow leakage. Additionally, it is estimated that embodiments of the present invention can reduce the valve assembly time by 80% by eliminating additional production stages such as welding. This can also reduce the risk of failure due to welding heat that may affect the housing dimensions.

[0018] In particular, it has been found that the resulting valve can achieve relatively rapid leaflet repositioning, for example, during backflow of blood. In this way, a significant reduction in leakage can be achieved. Compared to the 4-10% leakage of prior art valves, valve prototype testing has achieved less than 1% leakage, which can result in a significant increase in the blood stroke volume by 4 cc (cubic centimeters) (from 22 cc to 26 cc) during valve operation.

[0019] In addition, the present valve can provide reliable operation and can provide a durable connection between the leaflets and the housing.

[0020] There is also provided a catheter that includes a catheter wall defining a fluid passage (lumen), wherein a valve according to the present invention is integrated into the catheter wall.

[0021] Furthermore, in one aspect, there is provided a method for assembling a catheter valve according to the invention, the method comprising:

[0022] - providing a catheter housing;

[0023] - providing leaflets; and

[0024] - snapping the leaflets into the housing.

[0025] In this way, the above advantages can be achieved.

[0026] Further advantageous embodiments of the present invention are provided in the dependent claims.

[0027] The present invention will now be explained in more detail with reference to the accompanying drawings. In the drawings:

[0028] Figure 1 A top view of an embodiment of the present invention is shown, wherein the leaflets are in a first position;

[0029] Figure 2 A side view of the embodiment is shown;

[0030] Figure 3 A cross-sectional view taken along line III-III in Figure 1 is shown;

[0031] Figure 4 A cross-sectional view taken along line IV-IV in Figure 1 is shown;

[0032] Figure 5 A cross-sectional view similar to Figure 4 is shown, showing the leaflets in a second position;

[0033] Figure 6 An isometric view of the housing of the embodiment of Figure 1 is shown;

[0034] Figure 7 Shows a top view of the housing;

[0035] Figure 8 Shows a sectional view taken along Figure 7 line VIII - VIII in;

[0036] Figure 9 Shows a sectional view taken along Figure 7 line IX - IX in;

[0037] Figure 10 Shows a Figure 1 top view of the leaflet of an embodiment of;

[0038] Figure 11 Shows a front view of the leaflet;

[0039] Figure 12 Shows a side view of the leaflet; and

[0040] Figure 13 Schematically shows a part of a catheter including an embodiment of a valve.

[0041] In the present application, similar or corresponding features are denoted by similar or corresponding reference numerals.

[0042] Figure 1 - Figure 12 Shows a catheter valve 1, which includes a valve housing 2 defining a fluid passage FC. The housing 2 includes an asymmetric leaflet 3, which can pivot between a first position (see Figure 4 ) for allowing fluid to flow through the fluid passage FC and a second position (see Figure 5 ) for closing the passage. Advantageously, the housing 2 and the leaflet 3 are connected by snap - connection portions 2a, 3a. The housing 2 may include a cross - flow port CP, wherein the leaflet 3 is arranged such that the leaflet closes the cross - flow port CP when it is in its first position and opens the cross - flow port CP when it is in its second position. Figure 6 - Figure 9 The housing is shown in more detail in.

[0043] For example, the housing 2 may include a cylindrical (circular - cylindrical, positive cylindrical) wall 2b defining a (cylindrical) flow passage FC. The wall 2b may be made of stainless steel, for example. The cylindrical wall 2b may have an integral cylindrical sleeve section for receiving (and connecting) catheter segments 100p, 100d, i.e., integrated into the catheter 100. An example of the resulting catheter is shown in Figure 13As shown. The maximum outer diameter OD of the cylindrical wall 2b can be, for example, 6 mm, while the inner diameter can be, for example, 1 mm smaller than the outer diameter. The outer diameter of the end section 2c can be smaller than the said maximum outer diameter OD so as to fit (tightly receive) the catheter ends of the catheter sections 100p, 100d during catheter assembly. The total axial length L of the housing 2 can be less than 30 mm, for example less than 20 mm (e.g., 18 mm).

[0044] The cylindrical flap housing wall 2b has two opposite circular holes 2a. In this example, each hole 2a projects radially (i.e., perpendicularly) through the wall 2b, from the inner surface of the wall 2b to the outer surface of the wall 2b. Further, the holes 2a are centered, with their hole centers lying on the central longitudinal plane XP of the housing 2.

[0045] The outlet (lateral flow) port CP of the housing 2 can be an opening that matches the shape of the flap 3. For example, the opening CP can be a saddle-shaped opening in the cylindrical wall 2b (i.e., the edges of the housing 2 that define the opening can be substantially saddle-shaped). In this example, when viewed from a top-down perspective (see Figure 7 ), the port CP can be defined by two semi-circular segments 2d that are joined by an intermediate spacer segment 3e. When viewed from a top-down perspective, the two holes 2a of the housing can be positioned (slightly) asymmetrically with respect to the lateral flow port CP, i.e., when viewed from a top-down or side-view perspective, the axial distance t1 between their pivot axes and the transverse plane that intersects the first longitudinal end of the port is less than the axial distance t2 between their pivot axes and the transverse plane that intersects the opposite second longitudinal end of the port.

[0046] Figure 10 - Figure 12 The flap 3 is shown in more detail. When viewed from a top-down perspective, the flap 3 can have two semi-circular flap segments 3d that are connected by an intermediate spacer segment 3e that extends parallel to the (virtual) pivot axis PA of the flap 3, and the pivot axis PA is positioned asymmetrically with respect to the two semi-circular segments. The pivot axis PA of the flap can be defined by two integral, aligned pivot shafts 3a, in particular cylindrical pivot joint segments 3a (the pivot axis PA extends centrally and concentrically through these segments 3a). Thus, the pivot axis can divide the flap 3 into a first part 3p1 and a second part 3p2 (see Figure 12 ), with the first part 3p1 being smaller (i.e., shorter) than the second part 3p2 (i.e., the length k1 of the first part 3p1 is less than the length k2 of the second part 3p2, and both lengths k1, k2 are measured along the virtual central plane H of the flap, which extends perpendicularly with respect to the pivot axis PA).

[0047] The two integral pivot joint segments (axes) 3a of the valve leaflet 3 can project, for example, in opposite directions from the respective intermediate part 3e of the valve leaflet.

[0048] The diameter W of each pivot joint segment 3a can be slightly smaller than the diameter of the respective cylindrical bore 2a of the valve housing 2, with a diameter difference of, for example, at most 0.1 mm, preferably in the range of 0.04 to 0.08 mm. The diameter W of each valve leaflet joint segment 3a can be, for example, less than 1 mm, for example in the range of 0.7 - 0.9 mm.

[0049] The valve leaflet (which can also be referred to as a "flap" or "valve element") can be composed of a sheet material with a thickness in the range of, for example, 100 - 500 microns, for example a thickness of approximately 0.2 mm. The radius Rs of each semi-circular segment 3d (viewed from a top-down perspective) can be the same, for example in the range of 2.3 - 2.5 mm, for example approximately 2.4 mm.

[0050] According to a highly preferred embodiment, welding is not used to provide the two (relatively small) pivot joint segments 3a. In this case, the two pivot joint segments (protrusions / axes) 3a can be made in one piece with the remainder of the valve leaflet 3, for example using wire electrical discharge machining.

[0051] Additionally, when viewed from a side perspective (i.e., along a direction normal to the virtual pivot axis PA of the valve leaflet, see Figure 13 ), the inner surface of the valve leaflet 3 can extend along a virtual cylindrical surface. Furthermore, when viewed from a front perspective (i.e., along a direction parallel to the pivot axis PA, see Figure 12 ), the outer surface of the valve leaflet 3 can be generally V-shaped.

[0052] Thus, the snap connection can include the pivot joint segment 3a of the valve leaflet and the joint segment of the housing 2, in this case the circular alignment bore 2a. In particular, the snap connection can have a cylindrical protrusion (axis) 3a of the valve leaflet 3, which is rotationally engaged through the opposing bore 2a of the housing 2.

[0053] (During the assembly process, when the valve leaflet is inserted into the housing,) the valve leaflet 3 can be spring-biased into the appropriate position in the valve housing 2. For example, the assembly can involve pressing the two sides of the valve leaflet carrying the shaft 3a towards each other (thereby elastically deforming the valve leaflet) against the internal spring force of the valve leaflet 3. Preferably, the valve leaflet is made of a resilient (flexible, elastic) material, such as spring steel, stainless steel, and / or 108 stainless steel, to provide the corresponding spring force. Once the valve leaflet has been placed in the housing, it is preferably in a spring-relaxed state (i.e., it does not then acquire a spring force axially outwards, i.e., axially along the respective pivot axis PA).

[0054] During assembly (i.e., installing the leaflet 3 into the housing), the spring force generated by the leaflet can be directed so that it counteracts the inward movement of the two joint segments 3a of the leaflet 3. After assembly, the leaflet (as Figure 12 ) is preferably in a spring-relaxed (undeformed) state.

[0055] In particular, the assembly of the catheter valve 1 can involve: providing a catheter housing 2 (as Figure 7 - Figure 9 ) and providing a leaflet 3 ( Figure 10 - Figure 12 ). Next, the leaflet 3 can simply be snapped into place in two holes 2a of the housing. The snapping can involve: deforming the leaflet 3 inwardly (i.e., compressing), and the leaflet counteracts the leaflet deformation by the overall spring force of the leaflet spring material. As mentioned above, preferably, once the leaflet 3 is snapped into place (the shaft 3a is received in the corresponding opening 2a of the housing 2), the leaflet 3 can be in a spring-relaxed (undeformed) state.

[0056] For example, the leaflet 3 can be introduced into the housing 2 through a side port CP or through one of the axial ports PA1, PA2 of the housing 2.

[0057] Preferably, when the leaflet 3 is in its first position (engaging the housing 2), the leaflet 3 is positioned such that the longest leaflet segment 3p2 is closest to the second side port PA2, and the shortest leaflet partial segment 3p1 is closest to the first side port PA1 of the housing.

[0058] Preferably, the leaflet is positioned such that at any leaflet pivot position, the longest leaflet segment 3p2 is positioned away from the bottom 2g of the housing 2 (see Figure 5 ), and when the leaflet pivots from its first position to its second position, the shorter leaflet segment 3p1 can move towards the bottom side 2g of the housing (also see Figure 5 ). As can be seen from the figure, the bottom side 2g of the housing can be defined as the inner surface of the housing 2 that extends on the side opposite the outlet side port CP (the virtual pivot axis PA of the leaflet 3 extends between the side port CP and the bottom side 2g).

[0059] For example, this configuration can be such that after assembly, when the leaflet is in its second position ( Figure 5 ), the (axial) edge of the shorter leaflet segment 3p1 mechanically contacts the inner surface of the housing 2, i.e., the bottom side 2g. This configuration can also be such that after assembly, when the leaflet 3 is in its second position ( Figure 5 ), the (axial) edge of the longer leaflet segment 3p2 mechanically contacts the first axial inner edge 2h of the side port CP. For example, the latter first axial inner edge 2h can provide a first end stop for the longer leaflet segment 3p2 to limit further rotation of the leaflet (i.e., in the Figure 5 counterclockwise direction).

[0060] Similarly, this configuration can be such that, after assembly, when the leaflet 3 is in its first position ( Figure 4 ), the (axial) edge of the shorter leaflet segment 3p1 mechanically contacts the first axial inner edge 2h of the side port CP. Additionally, this configuration can be such that, after assembly, when the leaflet is in its first position ( Figure 4 ), the (axial) edge of the longer leaflet segment 3p2 mechanically contacts the opposite second axial inner edge 2i of the side port CP. For example, the latter second axial inner edge 2i can provide a second end stop (opposite the first end stop) for the longer leaflet segment 3p2 to limit further rotation of the leaflet (i.e., in the Figure 4 clockwise direction in

[0061] Figure 4 and Figure 5 depict leaflet operation. As can be seen from Figure 4 , when the valve 1 is in the first state, the leaflet 2 is in its first position, and fluid f (e.g., blood) can flow from the first axial end port PA1 of the housing 2 to the second end port PA2 of the housing 2, while the leaflet 3 substantially closes the side port CP. Due to the fluid pressure of the fluid f from the first end port PA1 to the second end port PA2, the leaflet 3 can be held in this position.

[0062] Figure 5 shows the position of the leaflet when the fluid flow direction is reversed. Due to the pressure change on the leaflet 3 caused by the reversed flow direction, the asymmetric leaflet 3 has quickly pivoted to its second position, thus closing the passage in front of the first axial outlet port PA1 and opening the side port CP.

[0063] Figure 13 Schematically shows a partial catheter 100 (in a cut-away side view angle), which is provided with a catheter valve 1. In particular, the catheter 100 can include a catheter wall that defines a fluid passage (e.g., for conducting blood), wherein the valve 1 is integrated into the catheter wall, for example, by connecting (e.g., welding) a valve housing 2 to a proximal catheter segment 100p and a distal catheter segment 100d. In the same manner as the iVaC2L system (described above), for example, the catheter 100 can be used for patients with impaired left ventricular function who require left ventricular mechanical circulation. For such applications, preferably, the valve 1 is located at a distance D in the range of about 6 to 60 cm from the distal end 100a of the catheter.

[0064] Although the present disclosure includes specific exemplary embodiments, it will be apparent to those skilled in the art that various changes in form and detail can be made to these exemplary embodiments without departing from the scope of the claims. The exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation.

Claims

1. A catheter valve, the catheter valve comprising a valve housing defining a fluid passage, wherein, the housing includes an asymmetric valve leaflet that pivots between a first position for allowing fluid to flow through the fluid passage and a second position for closing the fluid passage, wherein the housing and the valve leaflet are connected by a snap connection.

2. The catheter valve according to claim 1, characterized in that, during assembly, the valve leaflet is spring-biased in place in the housing, and the valve leaflet is made of an elastic material in particular to provide a corresponding spring force.

3. The catheter valve according to any one of the preceding claims, characterized in that, the snap connection includes a pivot joint section of the valve leaflet and the housing.

4. The catheter valve according to any one of the preceding claims, characterized in that, the snap connection is provided by an integral cylindrical protrusion of the valve leaflet, and the protrusion is rotatably engaged through opposite holes of the housing.

5. The catheter valve according to any one of the preceding claims, characterized in that, the housing includes a transverse flow port, wherein the valve leaflet is arranged such that the valve leaflet closes the transverse flow port when the valve leaflet is in its first position, and the valve leaflet opens the transverse flow port when the valve leaflet is in its second position.

6. The catheter valve according to any one of the preceding claims, characterized in that, when viewed from a top-down perspective, the valve leaflet has two semi-circular segments that are connected by an intermediate spacer segment that extends parallel to the pivot axis of the valve leaflet, and the pivot axis is positioned asymmetrically with respect to the two semi-circular segments.

7. The catheter valve according to claims 5 and 6, characterized in that, the transverse flow port is an opening that matches the shape of the valve leaflet, and when viewed from a top-down perspective, the port is particularly defined by two semi-circular segments connected by an intermediate spacer segment.

8. The catheter valve according to any one of the preceding claims, characterized in that, when viewed from a side perspective, the inner surface of the valve leaflet extends along a virtual cylindrical surface.

9. A catheter, the catheter comprising a catheter wall defining a fluid passage, wherein, a catheter valve according to at least one of the preceding claims is integrated in the catheter wall.

10. A method for assembling a catheter valve according to any one of claims 1 to 8, the method comprising: - providing the housing of the catheter; - providing the valve leaflet; and - snapping the valve leaflet into the housing, for example against the internal spring force of the valve leaflet.

11. The method according to claim 10, characterized in that, the method comprises: - drilling two opposite holes in the housing for receiving the valve pivot section of the valve leaflet.

12. The method according to claim 11, characterized in that, the method comprises: - keeping the housing in a fixed position relative to the drilling tool during the drilling of the two opposite holes.

13. The method according to any one of claims 10 to 12, characterized in that, the method comprises: For example, using a wire electrical discharge machining process, the leaflet and any corresponding pivot joint segment of the leaflet are made as a single piece from a sheet material.

14. A kit of parts, the kit comprising: a catheter leaflet of a catheter valve according to any one of claims 1 to 8, the leaflet including an integral pivot joint segment; and a catheter valve housing of a catheter valve according to any one of claims 1 - 8, the housing including a hole for pivotally receiving the integral pivot joint segment of the leaflet.

15. A method for manufacturing a leaflet of a catheter valve according to any one of claims 1 - 8, for example, used in the method according to any one of claims 10 - 13, the method comprising: For example, using a wire electrical discharge machining process, the leaflet and any corresponding pivot joint segment are made as a single piece from a sheet material.

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