Catheter assembly

Abstract

Catheter assembly comprising:-a flexible outer tube having a distal suction tip; -a flexible inner tube insertable into the outer tube, the inner tube having a distal tip configured to protrude from the distal suction tip of the outer tube; the assembly preferably includes a guidewire for guiding the outer tube and the inner tube into the body of the patient.

Description

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

[0002] Percutaneous mechanical circulatory support (MCS) is increasingly recognized as an important adjunct to manage challenging coronary anatomy in high-risk patients.

[0003] The heart team may select patients for percutaneous coronary intervention (PCI) rather than coronary artery bypass grafting (CABG) despite the presence of high-risk features such as poor V function, high SYNTAX scores, and hemodynamic instability. Percutaneous MCS may also be used as an adjunct to the treatment of cardiogenic shock, either as a rescue or to limit the need for inotropes and vasopressors, which are known to increase myocardial oxygen consumption and worsen prognosis.

[0004] There is an international consensus on the use of percutaneous MCS in cardiovascular care, with the goal of reducing LV (left ventricular) stroke work and myocardial oxygen demand while maintaining systemic and coronary perfusion in the setting of cardiogenic shock or providing hemodynamic support during complex cardiac surgery, including HR-PCI and certain high-risk ablation procedures.

[0005] Pulsatile devices, such as intra-aortic balloon pumps (IABPs), provide diastolic enhancement to increase myocardial perfusion and reduce afterload during systole to promote forward flow from the LV. However, the hemodynamic support is only very modest. Known prior art catheter systems include the iVAC 2L (https: / / www.pulsecath.com / products / ivac-2l / ), which is a cardiac support catheter that is inserted into the LV through the aortic valve and driven by a true IABP (intra-aortic balloon pump) console. It can generate sufficient pulsatile flow based on the patient's existing cardiac output.

[0006] The iVAC system has shown good results. However, due to its diameter, only selected patients with reasonably good conditions at the insertion site and arterial internal dimensions are suitable for treatment with the support of a (17 Fr) iVAC 2L. Insertion using a sheathless technique is not feasible.

[0007] According to the publication "PulseCath iVAC2L: Next-Generation Pulsatile Mechanical Circulatory Support," Bastos et al., January 14, 2020, Future Cardiology, FutureMedicine Ltd., the iVAC2L system has produced favorable results. Furthermore, it is stated that a new version of the iVAC system will feature an improved 16F profile to accommodate insertion into smaller iliofemoral anatomy and reduce access-related complications. This new version will not require a separate (larger) sheath, but rather allows for "sheathless" insertion.

[0008] The present invention aims to provide an improved catheter assembly and system. In particular, one aspect of the present invention aims to further reduce the risk of vascular complications and achieve lower resistance in the LV outflow tract. In particular, the present invention aims to provide a catheter with a relatively small diameter (e.g. pulsatile cardiac support) in a cost-effective manner, preferably with a diameter of only 16Fr (i.e. 16 French scale). When used for the medical treatment of a patient, the resulting catheter can reduce the risk of vascular complications. In addition, an object is to provide a new catheter device that matches or exceeds the very good performance of prior art catheter systems in terms of safety, efficacy, usability and applicability. In addition, an object of the present invention is to provide a device for safely applying pulsatile cardiac support in high-risk patients, for example in the case of insertion via a calcified artery (e.g. femoral artery).

[0009] According to one aspect of the invention, one or more of these objects can be achieved by the features of claim 1 .

[0010] According to one aspect of the present invention, there is provided a catheter assembly comprising:

[0011] - a flexible outer tube with a distal suction tip;

[0012] - a flexible inner tube insertable into the outer tube, the inner tube having a distal tip configured to extend from a distal aspiration tip of the outer tube;

[0013] The assembly preferably includes a guidewire for guiding the outer tube and the inner tube into the patient's body.

[0014] It has been found that in this way, an improved catheter assembly and corresponding system can be provided. In particular, the catheter assembly can be used for "sheathless" insertion, wherein the extended tip of the flexible inner tube can provide safe insertion even in high-risk patient situations.

[0015] In particular, the inner tube is used only for inserting and positioning the catheter, for example in the LV. According to one embodiment, the elevated shape of the distal tip of the inner tube can provide the possibility of inserting the catheter through the skin percutaneously without using a sheath as an introducer. It has been found that this option of not using an introducer sheath can reduce the OD (outer diameter) size from 19.5 Fr to 17 or 16 Fr. The advantages are reduced puncture size, reduced risk of bleeding, and the possibility of using the device in smaller femoral artery ID (inner diameter) sizes, which significantly increases the potential number of patients that can be treated. In addition, according to one embodiment, the final change in the catheter tip (i.e., a larger hole cq increase in blood channel size) increases the surface area of ​​the inlet hole size, which will reduce the resistance during operation (i.e., under vacuum or negative pressure, especially during pumping blood from the LV). This can positively affect the efficacy of the pumping and can lead to an increase in volume and higher performance of the pump. This increases cardiac output and mean pressure.

[0016] Further additional advantageous embodiments of the invention are provided in the dependent claims.

[0017] A non-limiting example of the present invention will now be explained in more detail with reference to the accompanying drawings, in which:

[0018] Figure 1 is a side view of a prior art catheter assembly;

[0019] Figure 2 yes Figure 1 components of the pump;

[0020] Figure 3 is a schematic side view of components of a non-limiting embodiment of the present invention;

[0021] Figure 4 yes Figure 3 An open view of a schematic portion of an embodiment of the present invention after assembly;

[0022] Figure 5 Shown Figure 3 A perspective view of the aspiration tip of the outer tube of an embodiment of the invention;

[0023] Figure 6 Shown Figure 5 a longitudinal section of the aspiration tip as shown; and

[0024] Figure 7 Shown Figure 3 Longitudinal cross-section of an example detail of the inner tube of an embodiment.

[0025] In the present application, corresponding or similar components are denoted by corresponding or similar reference numerals.

[0026] Figure 1 A known catheter assembly is described (see Bastos et al.) comprising a flexible tube 1 (lumen) with a distal aspiration tip 2. The known catheter has a diameter of 17 French (Fr). Tube 1 includes a two-way valve 3 located at a relatively short distance (typically within the range of 6-8 cm, e.g., 73 mm) from the distal end of aspiration tip 2. Valve 3 has a lateral blood outlet port for draining blood during the diastolic pump phase (see below). Valve 3 closes the outlet port during the systolic pump phase.

[0027] A pump 8 is connected to the proximal end of the flexible tube 1 (via a suitable connector 9). Non-limiting examples of pumps 8 are shown in Figure 2 1 (partially opened view). Preferably, the pump 8 (e.g., catheter pump 8) has a relatively simple construction that provides a reliable and durable blood flow effect. To this end, the pump 8 may include a displacement structure 51 for alternately applying suction and pressure during operation, in particular for cyclically driving fluid displacement through the flexible tube 1, wherein the flow path between the displacement structure and the tube 1 is preferably unobstructed (i.e., continuously open) after assembly. The displacement structure 19 of the pump 8 preferably includes a (flexible) membrane 19.

[0028] For example, the pulsatile pump 8 may have a displacement structure in the form of a rigid housing 52 that encloses a chamber 18 separated by a flexible membrane 19. The pump 8 may be directly connected to a flexible tube 1 (or indirectly connected via an intermediate connector 9) extending from the displacement structure, wherein the tube 1 defines an internal flow channel for directing liquid (i.e., blood during operation) to and from a downstream valve 3 of the tube 1. The flow channel of the tube may communicate with a portion of the chamber 18 on the distal side of the membrane 19. A portion of the chamber 18 on the proximal side of the membrane 19 may communicate with a sleeve 21 for connection to a pneumatic conduit that communicates with a pneumatic drive system (known per se). For example, as will be understood by those skilled in the art, the system may include a drive configured to synchronize with the patient's heartbeat.

[0029] For example, the displacement structure can be driven by a pneumatic tube to alternately apply suction and pressure, wherein the suction is used to move fluid (i.e., blood) from the aspiration tip of the tube toward valve 3 (diastole) and the pressure is used to move fluid (i.e., blood) from the displacement structure 51 into the tube 1 (systole), thereby driving a pulsating reverse flow through the tube 1.

[0030] Known catheters are typically inserted into a patient using an 18 Fr. sheath (not shown) and a guidewire.

[0031] Figure 3 An improved catheter assembly is shown (in a disassembled state) which may be of great advantage in high-risk patient situations.

[0032] The improved catheter assembly includes:

[0033] - a flexible outer tube 101 with a distal suction tip 102;

[0034] - a flexible inner tube 115 insertable into the outer tube 101 (through the proximal end of the inner tube), the inner tube having a distal tip 116 configured to protrude from the distal aspiration tip 102 of the outer tube 101 (the distal tip 116 protrudes from the distal aspiration tip 102 after assembly, see Figure 4 ).

[0035] The assembly preferably comprises a (flexible) guide wire 117 for (slidably) guiding the outer tube 101 and the inner tube 115 into the patient's body, the inner tube 115 being particularly configured to (slidably) receive (be guided by) the guide wire 117. Such guide wires 117 are well known; the length of the guide wire 117 is longer than the length of the outer tube 101 to be guided into the patient's body (as well as the length of the inner tube). The diameter of the guide wire 117 is smaller than the inner diameter of the outer tube 101 and smaller than the inner diameter of the inner tube 115. The guide wire 117 can be a solid metal or steel wire, or a composite wire, for example, having a core embedded in one or more layers.

[0036] Figure 4 The assembled state of the catheter system is shown, wherein the distal end of the outer tube 101 receives the inner tube 115 (relatively concentrically), and the two tubes 101, 115 are (slidably) guided by corresponding guide wires 117 (extending through the inner tube 115). Preferably, the inner tube 115 is arranged inside the outer tube 101 so that during the process of receiving and being guided by the guide wire 117 (for guiding the aspiration tip 102 toward and into the patient's heart), the distal end portion 116 of the inner tube 115 axially protrudes from the distal end opening 102c of the aspiration tip 102 of the outer tube 101 (as shown in FIG. Figure 4 After assembly, the inner tube 115 is removably retained within the outer tube 101 (such that once the outer tube 115 has been correctly positioned within the patient, the inner tube 115 can be removed / withdrawn from the outer tube 115 via the proximal end of the outer tube 115).

[0037] Figure 5 and Figure 6 An example of an aspiration tip 102 of an outer tube 101 is shown. Figure 7 An example distal portion of the inner tube 115 is shown.

[0038] The outer tube 101 may generally have the same characteristics as the known tube 1 (e.g. Figure 1The outer tube 101 has the same construction as that shown in FIG, but preferably has a maximum outer diameter R of less than 6 mm, for example, an outer diameter R of 16 Fr. In a non-limiting example, the outer tube 101 can be substantially made of PTFE (polytetrafluoroethylene).

[0039] The outer tube 101 can be connected to a blood pump 8 (known, see above), in particular a pump 8 comprising a displacement structure 19 (e.g., a membrane) for alternately applying suction and pressure during operation, in particular for cyclically driving fluid displacement through the outer tube 101. In addition, the outer tube 101 preferably has an integrated valve 103, which is located near the aspiration tip 102 (e.g., within a range of 6-8 cm from the distal end of the tip 102, such as 73 mm). The respective valve portion of the outer tube 101 can include a blood discharge port at the integrated valve 103 for discharging blood during the pump diastole (see above), wherein the valve 103 is configured to close the discharge port during the pump systole (allowing blood to pass from the pump 8 through the valve 103 to the aspiration tip 102). The outer tube 101 can provide an unobstructed integrated flow path between the displacement structure and the integrated valve.

[0040] Figure 5 and Figure 6 An example of an integrated aspiration tip 102 of a flexible outer tube 101 is shown. For example, the integrated tip 102 can be made of a metal (e.g., titanium or stainless steel). The tip 102 can be a generally cylindrical element (wall) having a plurality of side ports 102a that allow fluid communication through the wall of the tip 102. The integrated distal aspiration tip 102 of the outer tube 101 can have a maximum outer diameter R of less than 6 mm, such as an outer diameter R of 16 Fr. The inner diameter T1 of the tip 102 can be approximately 1 mm smaller than the outer diameter R of the tip, such as an inner diameter T1 in the range of about 4-5 mm (e.g., about 4.7 mm).

[0041] The suction tip 102 can be mounted to the axial end of the outer tube 101 in a variety of ways, such as using a suitable adhesive and / or a suitable welding process. In this example, the tip 102 has a proximal groove 102b for receiving the opposite end of the outer tube 101 (the tube 101 is attached to the tip 102 via this groove 102b after assembly). The distal end 102c of the suction tip 102 of the present invention is open, allowing axial passage of the distal portion 116 of the inner tube 115. In this example, the distal axial opening 102c of the suction tip 102 is defined by an internal flange (circular edge) 102d, and the resulting opening 102c has a circular profile / shape, whose diameter T2 is less than the inner diameter T1 of the main cross-section of the tip 102. The difference between the inner diameter T1 of the tip and the diameter T2 of the distal opening 102c can be relatively small, for example in the range of 0.1-2 mm, preferably in the range of 0.4-1.2 mm (for example, a difference of approximately 0.8 mm).

[0042] The inner tube 115 of the assembly can be configured in a variety of ways. The tip 116 of the inner tube 115 can be, for example, a tapered tip and / or a tip having an outer diameter that is smaller than the diameter of the proximal portion of the inner tube 115. The inner tube 115 can be made of a variety of materials, preferably PTFE. In addition, the inner tube can include one or more radiopaque (marker) materials (e.g., barium sulfate) for tracking / visibility using, for example, x-rays.

[0043] According to one embodiment, the inner tube 115 can have a length of, for example, at least 100 cm, such as a length in the range of 110-120 cm (e.g., a range of about 110-112 cm). Preferably, the inner tube 115 is longer than the corresponding outer tube 101 so that the proximal end of the inner tube extends from the proximal end of the outer tube after assembly.

[0044] The inner tube 115 can be composed of, for example, a proximal cylindrical tube portion (which extends through the aspiration tip 102 toward the valve portion of the outer tube 101) and an integral (e.g., integrally formed) distal cylindrical tip 116, which extends away from the outer tube 101 through the distal opening 102c of the aspiration tip 102. In this example, the structure of the inner tube 115 is relatively simple, comprising only two portions of different diameters. It should be understood that the inner tube 115 can also include more than two portions having mutually different diameters.

[0045] In particular, the inner tube 115 defines a central channel 115a (extending between the opposite open ends of the inner tube 115) for receiving a guide wire 117 (so that the inner tube 115 can be guided by the guide wire 117 during entry into the patient's body). It should be understood that the inner diameter D2 of the inner tube 115 is preferably greater than the outer diameter of the guide wire 117. For example, the inner diameter D2 of the inner tube can be 3 mm or less (e.g., the diameter D2 is in the range of 1-3 mm, such as 2 mm). In addition, the inner tube 115 preferably has opposite open ends (one of which is the distal end of the tube tip 116) for entry and exit of the guide wire 117.

[0046] Preferably, after assembly, the outside of the inner tube 115 sealingly engages the distal axial opening 102c of the aspiration tip 102 (to locally prevent blood from flowing between opposing sides or edges of the tip 102 and the inner tube 115).

[0047] In one example, if Figure 7As shown, the outer diameter D3 of the proximal portion of the inner tube 115 can be smaller than the inner diameter of the corresponding outer tube 101 and smaller than the inner diameter T1 of the aspiration tip 102 of the outer tube 101. In order to achieve stable axial positioning, it is preferred that the outer diameter D3 of the proximal portion of the inner tube 115 is larger than the diameter T2 of the outlet 102c of the aspiration tip 102. In this way, the inner flange (circular edge) 102d of the aspiration tip 102 can serve as an end stop for positioning the inner tube 115 relative to the outer tube 101, in particular for mechanically contacting (and preferably fluid-sealing) the outer edge 115b of the inner tube 115. In this example, the outer edge 115b is provided by the distal edge of the proximal portion of the inner tube 115 (i.e., it is located at the proximal beginning of the axially protruding distal portion (tip) 116 of the tube 115).

[0048] In a case where the outer diameter D3 of the proximal portion of the inner tube 115 is smaller than the inner diameter of the corresponding outer tube 101, the opposite sides of the two tubes 101, 115 can define an intermediate blood flow channel, allowing blood to flow from the distal suction opening (side port) 102a of the tip 102 of the outer tube to the corresponding proximal ends of the two tubes (which can be used for blood pressure detection during catheter insertion).

[0049] The outer diameter D1 of the distal tip 116 of the inner tube 115 is preferably smaller than the outer diameter D3 of the proximal portion of the tube 115 and is preferably equal to or smaller than the diameter T2 of the distal opening 102 of the aspiration tip 102 so that the distal tip 116 of the inner tube 115 can be directed toward its operative position (e.g., Figure 7 ) through the distal opening 102c of the aspiration tip 102, at least during assembly.

[0050] exist Figure 7 In the example shown, the distal tip 116 of the inner tube 115 has a substantially constant outer diameter D3 (alternatively, a varying outer diameter may be provided, such as a tapered or conical tip 116). For example, the maximum outer diameter D1 of at least one butt end of the tip 116 of the inner tube 115 (which is axially located distal to the aspiration tip 102 of the outer tube 101 after assembly) may be, for example, 4 mm, for example, an outer diameter D1 within the range of 3.9-3.1 mm, for example, an outer diameter D1 of 3.4 mm.

[0051] After assembly, the tip 116 of the inner tube preferably protrudes from the flexible outer tube 101 by a distance L of at least 2 cm (i.e., the distance L is measured in the axial direction between the thick ends of the two tips 115, 116, see Figure 4 ), preferably, the distance L is in the range of 2-5 cm, more preferably, the distance L is in the range of 2-4 cm, for example a distance L of about 3 cm.

[0052] The resulting protruding tip 116 of the flexible inner tube 115 can provide significant advantages over known percutaneous mechanical circulatory support catheter systems. As previously mentioned, the resulting catheter assembly can be used for "sheathless" insertion, wherein the protruding tip of the flexible inner tube can provide safe insertion even in high-risk patient situations.

[0053] During insertion into the patient, the operator can hold the proximal portion of the catheter assembly and prevent the inner tube 115 from shifting within the outer tube 101 until the (tip 102) is finally positioned in the LV of the heart. Insertion is typically performed using a guide wire 117 (located in the inner tube, see Figure 4 ). Next, the operator can remove (withdraw) the inner tube 115 from the outer tube 101 (and the guidewire 117) while maintaining the distal tip of the outer tube in the LV. After complete removal of the inner tube (and the guidewire), the outer tube can be connected to the membrane pump 8. The holes in the distal tip 102 of the outer tube, including the distal opening 102c initially used by the inner tube during assembly placement, can then provide a suction path for blood to enter the outer tube 102 (due to the pump action).

[0054] Thus, the inner tube 115 provides for improved insertion and positioning of the outer tube 101 , followed by removal of the inner tube from the outer tube.

[0055] According to one embodiment (as described above), the difference in the outer diameter size of the inner tube 115 and the inner diameter size of the outer tube 101 allows blood to flow during operation via a blood flow channel defined between the two tubes 101, 115 (the blood flow channel extends from the side port 102a of the aspiration tip 102 to the proximal end of the tube). In addition, a second blood flow channel is available (extending between the opposite ends of the inner tube 115), provided by the interior of the inner tube 115. The two blood flow channels are separated by the inner tube 115 (after assembly) and can be used, for example, to measure the corresponding blood pressure of blood flowing from these channels to the proximal portion of the assembly located outside the patient's body (using commonly known blood pressure measuring equipment). During insertion of the catheter assembly, blood pressure monitoring can be performed through the catheter assembly, for example to verify whether the distal end of the inner tube 115 has passed through the aortic valve. The pressure in the LV of the heart is typically different from the aortic pressure, so when the distal tip of the inner tube 115 has passed through the aortic valve and the aspiration tip of the outer tube has not passed through the valve, the resulting blood pressure difference (of blood emitted at the proximal ends of the two tubes) can be detected (at the proximal ends of the tubes) so that the operator knows that the tip is in the LV (for example, without having to rely on x-ray monitoring).

[0056] Although the present disclosure includes specific exemplary embodiments, it will be apparent to those skilled in the art that various changes in form and details may be made in these exemplary embodiments without departing from the scope of the claims. The exemplary embodiments described herein are to be considered in an illustrative and not restrictive sense only.

[0057] For example, the outer tube may be referred to as a catheter and may alternatively be defined as an elongated tubular (flexible) medical device for percutaneous coronary intervention, for example in conjunction with a pulsatile device such as an intra-aortic balloon pump (IABP). In particular, the outer tube may be composed of a cylindrical wall concentrically surrounding a single fluid channel (e.g., a single lumen for conducting blood or another fluid).

Claims

1. Catheter assembly, including: - a flexible outer tube with a distal suction tip; - a flexible inner tube insertable into the outer tube, the inner tube having a distal tip configured to extend from a distal aspiration tip of the outer tube; The assembly preferably includes a guidewire for guiding the outer tube and the inner tube into the patient's body.

2. The catheter assembly according to claim 1, wherein The maximum outer diameter of the thick end of the tip of the inner tube is 4 mm, for example, an outer diameter in the range of 3.9-3.1 mm, for example a diameter of 3.4 mm.

3. The catheter assembly according to any one of the preceding claims, wherein The length of the inner tube is at least 100 cm.

4. The catheter assembly of any one of the preceding claims, wherein: The tip of the flexible inner tube extends from the suction tip of the outer tube by a distance of at least 2 cm.

5. The catheter assembly of any one of the preceding claims, wherein: The proximal portion of the outer tube includes a blood removal port and preferably an integrated valve.

6. The catheter assembly of any one of the preceding claims, wherein: The outer tube may be connected to a blood pump, for example a pump comprising a displacement structure for alternately applying suction and pressure during operation, in particular for cyclically driving fluid displacement through the outer tube.

7. The catheter assembly according to claim 6, wherein The outer tube comprises an integrated flow path between the displacement structure and the integrated valve of the outer tube, wherein the integrated flow path is unobstructed, wherein the displacement structure is preferably a membrane.

8. The catheter assembly of any one of the preceding claims, wherein: The flexible inner tube is detachably connected to the flexible outer tube.

9. The catheter assembly of any one of the preceding claims, wherein: The inner tube is made of PTFT and preferably comprises a radiopaque material.

10. The catheter assembly of any one of the preceding claims, wherein: The outer side of the inner tube sealingly engages the distal opening of the aspiration tip of the outer tube.

11. The catheter assembly of any one of the preceding claims, wherein: The outer diameter of the proximal portion of the inner tube is smaller than the inner diameter of the outer tube, particularly such that opposing sides of the two tubes define an intermediate blood flow channel.

12. The catheter assembly of claim 11, wherein: The inner tube defines a second blood flow channel separate from the intermediate blood flow channel.

13. A cardiac assist catheter pump system comprising a catheter according to any one of the preceding claims and a pump having a displacement structure, wherein the displacement structure is used to alternately apply suction and pressure during operation, in particular to cyclically drive fluid displacement through the outer tube of the catheter.

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