Sheath assembly for introducing a catheter pump into a subject

Abstract

A sheath assembly for introducing a catheter pump into a subject is disclosed, comprising a first sheath and a second sheath, the first sheath comprising a first section, an inner wall of the first section forming a gap for a guidewire to pass through between an outer wall of the pump assembly at a first opening.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a sheath assembly for introducing a catheter pump into a subject. BACKGROUND

[0002] US9402942B2 discloses the common practice in the field of inserting a catheter pump into a subject: a guidewire is threaded from a pigtail through the pump assembly and out of the pump outlet, achieving the loading of the pump on the guidewire. By pushing the catheter forward, the pump is moved along the guidewire to be inserted into the subject's heart. During the movement of the pump along the guidewire, the pump outlet will scrape the guidewire, causing the coating of the guidewire to fall off. Especially when the pump passes through a tearable sheath, the tearable sheath tightly presses the guidewire against the outer wall of the pump outlet, making it as close as possible to the motor housing, the guidewire and the pump outlet have a strong scraping, and the coating falling off is particularly obvious. SUMMARY

[0003] The present application proposes a sheath assembly, aiming to minimize or even avoid the scraping of the coating of the guidewire by the catheter pump during the insertion into the subject, thereby reducing the risk of particulate matter entering the human body.

[0004] To achieve the above-mentioned purpose, the present application proposes a sheath assembly for introducing a catheter pump into a subject, the catheter pump comprising a catheter, a pump assembly connected to the distal end of the catheter and deliverable into the subject under the guidance of a guidewire, the pump assembly being provided with a first opening and a second opening located at the distal end of the first opening. The guidewire is removably threaded into the pump assembly from the second opening and outwardly from the first opening. The sheath assembly comprises a first sheath which can introduce the pump assembly into it outside the subject, and a second sheath which can be partially inserted into the subject through a puncture. The first sheath comprises a first sheath seat, a first sheath tube connected to the distal end of the first sheath seat, and a first repeatable seal provided in the first sheath seat. The second sheath comprises a second sheath seat, a second sheath tube connected to the distal end of the second sheath seat, and a second repeatable seal provided in the second sheath seat. The first sheath tube comprises a first section, the inner diameter of which is greater than the outer diameter of the part of the pump assembly corresponding to the first opening, so that a gap is formed between the inner wall of the first section and the outer wall of the part of the pump assembly corresponding to the first opening for the guidewire to pass through. When the pump assembly is introduced into the first sheath, at least the part of the pump assembly corresponding to the first opening is located in the first section and at the distal end of the first repeatable seal. The first sheath is operable to be inserted into the second sheath through the second repeatable seal, and at least part of the first section is located at the distal end of the second repeatable seal. BRIEF DESCRIPTION OF DRAWINGS

[0005] Figure 1 Schematic diagram for the insertion of the catheter pump of the first embodiment into a subject;

[0006] Figure 2 Schematic diagram for the insertion of the catheter pump of the second embodiment into a subject;Figure 1 Schematic view of a mid-catheter pump positioned within a subject's heart;

[0007] Figure 3 Schematic view of a catheter pump of the second embodiment being inserted into a subject;

[0008] Figure 4 Schematic view of the structure of the first sheath of the first embodiment;

[0009] Figure 5 Schematic view of the structure of the first sheath of the second embodiment;

[0010] Figure 6 Schematic view of the catheter pump of the first embodiment being introduced into the first sheath;

[0011] Figure 7 Schematic view of the catheter pump of the second embodiment being introduced into the first sheath;

[0012] Figure 8 Schematic view of the first sheath being inserted into the second sheath;

[0013] Figure 9 Schematic view of the first sheath after being inserted into the second sheath;

[0014] Figure 10 Schematic view of the catheter pump of the first embodiment being introduced into the second sheath;

[0015] Figure 11 Schematic view of the catheter pump of the second embodiment being introduced into the subject. DETAILED DESCRIPTION

[0016] The terms "proximal" and "distal" are relative to the physician manipulating the catheter pump 100. "Proximal" refers to the portion that is relatively closer to the physician, and "distal" refers to the portion that is relatively further away from the physician. For example, the catheter 110 is located at the proximal end of the pump assembly 120, and the pump assembly 120 is located at the distal end of the catheter 110. It should be understood that these orientation terms are defined for the convenience of description and are not limiting and absolute.

[0017] As Figures 1 to 3As shown, the catheter pump 100 comprises a catheter 110 and a pump assembly 120, the pump assembly 120 comprising a motor 140 connected to a distal end of the catheter 110, a blood flow passage connected to a distal end of the motor 140, and an impeller located in the blood flow passage and driven to rotate by the motor 140 to pump blood. A proximal end of the blood flow passage is provided with a first opening 120a, and a distal end of the blood flow passage is provided with a second opening 120b. The blood flow passage comprises a curved cannula 121, a first blood window 122 connected to a proximal end of the cannula 121, and a second blood window 123 connected to a distal end of the cannula 121, the impeller being located in the first blood window 122. The first opening 120a is formed in a side wall of the first blood window 122, and a side wall of the second blood window 123 is provided with a third opening 120c for blood to pass through. The first blood window 122 is connected between the cannula 121 and the motor 140, and a distal end of the second blood window 123 is connected to a protection structure 124 for preventing damage to a blood vessel and tissue of an inner wall of the left ventricle LV.

[0018] As shown in the drawings, in one embodiment, the protection structure 124 is a flexible hollow pigtail in a natural state with an arc-shaped or coiled end portion (the pigtail is partially straightened when the guide wire 130 is arranged in the pigtail), and the second opening 120b is a distal end opening of the pigtail. Alternatively, as shown in the drawings, in another embodiment, the distal end of the second blood window 123 is not provided with a pigtail, and the protection structure 124 is replaced by a round head structure with a smooth outer surface, and the second opening 120b is formed in a side wall of the second blood window 123, i.e., the third opening 120c constitutes the second opening 120b. Figures 1 to 2 Figure 3 As shown in the drawings, in one embodiment, the protection structure 124 is a flexible hollow pigtail in a natural state with an arc-shaped or coiled end portion (the pigtail is partially straightened when the guide wire 130 is arranged in the pigtail), and the second opening 120b is a distal end opening of the pigtail. Alternatively, as shown in the drawings, in another embodiment, the distal end of the second blood window 123 is not provided with a pigtail, and the protection structure 124 is replaced by a round head structure with a smooth outer surface, and the second opening 120b is formed in a side wall of the second blood window 123, i.e., the third opening 120c constitutes the second opening 120b.

[0019] One of the first opening 120a and the third opening 120c constitutes an inlet, and the other constitutes an outlet, depending on the application scenario of the catheter pump 100. When the catheter pump 100 is used for left ventricular assistance, the first opening 120a is the outlet, and the third opening 120c is the inlet. When the catheter pump 100 is used for right ventricular assistance, the first opening 120a is the inlet, and the third opening 120c is the outlet.

[0020] ​For example, in the case of using the catheter pump 100 for left ventricular assist, the guide wire 130 can be inserted into the subject through a puncture opening formed on the skin of the subject, and the distal end of the guide wire 130 can pass through the aortic valve AV into the left ventricle LV. At this time, the distal end of the guide wire 130 is located in the subject, and the proximal end of the guide wire 130 is exposed to the outside of the subject. The physician guides the pump assembly 120 to the guide wire 130, and the guide wire 130 passes into the pump assembly 120 from the second opening 120b, and then passes out of the pump assembly 120 from the first opening 120a. Then, the catheter 110 is pushed forward, and the pump assembly 120 is moved forward in the subject under the guidance of the guide wire 130, until the distal end of the pump assembly 120 passes through the aortic valve AV into the left ventricle LV, the cannula 121 is located across the aortic valve AV, the third opening 120c is located in the left ventricle LV, and the first opening 120a is located in the aorta AO. The rotation of the impeller sucks the blood in the left ventricle LV into the cannula 121 through the third opening 120c, and pumps the blood from the first opening 120a to the aorta AO, so as to assist the pumping function of the heart and reduce the burden on the heart.

[0021] That is, the catheter pump 100 of the present embodiment and the scheme of using the guide wire 130 to assist the insertion of the pump assembly 120 into the subject described below are not only suitable for the scenario of using the catheter pump 100 for left ventricular assist, but also suitable for the scenario of right ventricular assist. Of course, it can also be suitable for assisting the kidney as a kidney pump. The following mainly describes the scenario of using the catheter pump 100 for left ventricular assist, but based on the description above, it can be known that the protection scope of the present embodiment is not limited in this way.

[0022] As shown in Figures 4 to 11 , the sheath assembly includes a first sheath 210 and a second sheath 220. The first sheath 210 can guide the pump assembly 120 into the first sheath 210 outside the subject, including a first sheath seat 211, a first sheath tube 212 connected to the distal end of the first sheath seat 211, and a first repeatable sealing member 213 arranged in the first sheath seat 211 (specifically, in the proximal end). The second sheath 220 can be partially inserted into the subject through the puncture opening, including a second sheath seat 221, a second sheath tube 222 connected to the distal end of the second sheath seat 221, and a second repeatable sealing member 223 arranged in the second sheath seat 221 (specifically, in the proximal end).

[0023] As shown in Figures 4 to 5 , the first sheath tube 212 includes a first section 212a located at the distal end of the first repeatable sealing member 213. The inner diameter of the first section 212a is greater than the outer diameter of the part of the pump assembly 120 corresponding to the first opening 120a (i.e., the first blood window 122), so that a gap is formed between the inner wall of the first section 212a and the outer wall of the first blood window 122 for the guide wire 130 to pass through.

[0024] When the pump assembly 120 is introduced into the first sheath 210, the first blood window 122 is located within the first segment 212a and distal to the first reusable seal 213. The first sheath 210 can be inserted through the second reusable seal 223 into the second sheath 220, with at least a portion of the first segment 212a located distal to the second reusable seal 223. The pump assembly 120 moves from the first sheath 210 into the second sheath 220 as the catheter 110 is advanced, and moves from the second sheath 220 into the subject as the catheter 110 continues to be advanced.

[0025] Because a gap is formed between the first section 212a and the first blood window 122 with the first opening 120a, allowing the guide wire 130 to pass through, the guide wire 130 will not be squeezed and scraped against the wall of the first opening 120a during the process of the pump assembly 120 being introduced into the second sheath 220. Therefore, the larger inner diameter of the first section 212a separates the guide wire 130 from the second sheath 220, preventing the radial extrusion force from the second sheath 220 from pressing the guide wire 130 tightly against the first opening 120a. This allows the guide wire 130 to freely pass through the first opening 120a during the forward movement of the pump assembly 120 along the guide wire 130, reducing or even preventing the coating of the guide wire 130 from being scraped off, thereby reducing the risk of coating particles entering the human body.

[0026] In addition, such as Figure 9 As shown, after the first sheath 210 is inserted into the second sheath 220 and the pump assembly 110 is put into the exhaust position (described below), since the first blood window 122 with the first opening 120a is located at the distal end of the first reusable seal 213, the blood flowing out from the first opening 120a is trapped in the first sheath 210 by the first reusable seal 213 and will not spill onto the operating table, thereby avoiding blood contamination.

[0027] The first sheath 212 also includes a second section 212b located at the distal end of the first section 212a, with its inner diameter gradually decreasing from near to far. The second section 212b is a tapering section, with its inner diameter slightly smaller than the outer diameter of the pump assembly 120 (specifically, the insertion tube 121). When the pump assembly 120 is in the position of... Figure 9In the venting position shown, the second section 212b seals the outer wall of the pump assembly 120, clamping the pump assembly 120, and the third opening 120c is located within the second sheath 220, and the first opening 120a is located within the first sheath 210. Thus, the third opening 120c within the second sheath 220 is in communication with the blood vessel, and under the action of the internal and external pressure difference, the blood enters the pump assembly 120 through the third opening 120c, and the pump assembly 120 is vented, until the blood flows out of the first opening 120a, that is, the pump assembly 120 is considered to be completely vented. Therefore, the second section 212b seals the outer wall of the pump assembly 120 in the venting position, and establishes a unique channel for the blood to flow through the third opening 120c→the pump assembly 120→the first opening 120a, and the establishment of the unique channel enables the pump assembly 120 to be fully pre-charged and vented.

[0028] The side wall of the first sheath 210 is provided with a through hole 215, and the through hole 215 is provided with a waterproof and breathable material 216. Figure 4 As shown, in one embodiment, the waterproof and breathable material 216 can be a waterproof and breathable film in the form of a strip, which is wound around the outer wall of the first sheath 210 and covers the through hole 215. Alternatively, as shown, Figure 5 In another embodiment, the waterproof and breathable material 216 can be a water gel film provided in US2004 / 0052689, which is filled in the through hole 215. The waterproof and breathable material 216 allows the air discharged from the pump assembly 120 to pass through the first sheath 210 and overflow, so as to balance the pressure inside and outside the first sheath 210, avoid the pressure inside the first sheath 210 being too high to inhibit the venting of the pump assembly 110, and ensure that the pump assembly 110 is completely and fully vented. The waterproof and breathable material 216 further prevents the blood from passing through, so as to prevent the blood from overflowing and spilling on the operating table when the blood displaces the air in the pump assembly 110, and avoid blood pollution.

[0029] The through hole 215 can be provided with at least a plurality of through holes for improving the venting efficiency. Furthermore, the through hole 215 is arranged on the first sheath seat 211. Since the first sheath seat 211 has a larger inner diameter than the first sheath tube 212, and the first opening 120a is closer to the first sheath seat 211 when the pump assembly 120 is in the venting position shown, Figure 9 Therefore, the gas discharged from the pump assembly 120 is more likely to first gather in the first sheath seat 211 with a larger space, and the through hole 215 arranged on the first sheath seat 211 will facilitate the efficient discharge of the gas. In addition, since the stopper exists (described below), the first sheath seat 211 is always located outside the second sheath seat 221, that is, outside the proximal end of the second resealable member 223. The through hole 215 arranged on the first sheath seat 211 can always be located outside the second sheath seat 221 and not be blocked or sealed by the second resealable member 223, so as to ensure smooth venting.

[0030] AsFigure 6 As shown, the distance between the distal end face of the first resealable member 213 and the distal end face of the first sheath 212 is L1, and the farthest distance between the first opening 120a and the third opening 120c is L2, L1>L2. In this way, the first sheath 210 forms an inner lumen of sufficient length to completely receive the pump assembly 120 therein at least between the first opening 120a and the third opening 120c. At this time, the first opening 120a for blood outflow during exhaust is located within the distal end of the first resealable member 213, so that the blood flowing out of the first opening 120a during exhaust of the pump assembly 120 is trapped within the first sheath 210.

[0031] Further, the farthest distance between the first opening 120a and the second opening 120b is L3, L1>L3. In this way, the inner lumen of the first sheath 210 completely receives the pump assembly 120 therein, and when the first sheath 210 is inserted into the second sheath 220, the second section 212b which is closed at the distal end of the first sheath 210 penetrates the second resealable member 223 which is harder, and the penetration task does not have to be borne by the protection structure 124, which is conducive to smooth insertion of the first sheath 210 into the second sheath 220, improves the coupling efficiency of the two, and protects the protection structure 124 (especially when a flexible hollow pigtail is used) from being damaged.

[0032] In the present embodiment, the farthest distance L2 is the distance between the proximal end of the first opening 120a and the distal end of the third opening 120c when the cannula 121 is straightened. The farthest distance L3 varies depending on the protection structure 124. When the protection structure 124 is a round head structure as shown in Figure 3 , the L3 is the distance between the proximal end of the first opening 120a and the distal end of the second opening 120b / third opening 120c when the cannula 121 is straightened; when the protection structure 124 is a pigtail as shown in Figure 1 or 2, the L3 is the distance between the proximal end of the first opening 120a and the distal end of the pigtail when the cannula 121 and the pigtail are straightened at the same time.

[0033] As shown in Figure 4 , Figure 5 , Figures 8-10 , the outer diameter of the first sheath seat 211 is larger than the outer diameter of the first sheath tube 212 to form a first outer stop 214 at the transition connection therebetween. The inner diameter of the second sheath seat 221 is larger than the inner diameter of the second sheath tube 222 to form an inner stop 224 at the transition connection therebetween. The first outer stop 214 and the inner stop 224 are used to limit the depth of insertion of the first sheath 210 into the second sheath 220, so that the first sheath tube 212 is located outside the puncture port, and the first sheath seat 211 is naturally located outside the second sheath seat 221.

[0034] As the prior art CN112867531B discloses a solution to minimize leakage during pump insertion, a sleeve is arranged outside the pump, and the bleeding port of the pump is located in the sleeve to receive blood exuded from the bleeding port when the distal pump inlet enters the body during pump intervention, thereby reducing blood leakage during pump intervention. However, the distal end of the sleeve needs to be inserted into the blood vessel of the patient through a hemostatic valve. Although this can increase the rigidity of the cannula and make it easier for the pump to enter the patient's blood vessel, it will increase the outer diameter of the intervention sheath, resulting in an increase in the size of the intervention.

[0035] In contrast, the first sheath tube 212 is limited outside the puncture port by the above-mentioned limiting design, avoiding the insertion of the first sheath tube 212 into the second sheath tube 222. Since the second sheath tube 222 is arranged in the puncture port, the first sheath tube 212 is limited outside the second sheath tube 222, which can avoid the radial expansion of the second sheath tube 222 caused by the introduction of the first sheath tube 212, which can maintain the small size of the puncture port without being enlarged, thereby reducing the risk of bleeding and infection of the puncture port.

[0036] As shown in Figure 8 , for the same purpose of avoiding the expansion of the puncture port, the outer diameter of the second sheath seat 221 is larger than that of the second sheath tube 222 to form a second outer stop 225 at the transition connection between the two, which can be used to limit the insertion depth of the second sheath 220 into the subject, so that the second sheath seat 221 with a relatively larger outer diameter is located outside the puncture port.

[0037] The transition connection mentioned above is generally arranged as a gradual slope or arc surface to avoid forming a clear step structure. For the same purpose, a stop structure can also be arranged on the proximal outer wall of the first sheath tube 212 and the second sheath tube 222 to limit the insertion depth of the first sheath 210 and the second sheath 220, respectively.

[0038] The repeatable seals 213, 223 are made of silicone material and are fixed in the sheath seats 211, 221 by interference and / or compression fitting. The repeatable seals 213, 223 are provided with a cut-through in the central position (as shown by the dashed line in Figures 4-8 ), which passes through the front and back surfaces thereof, for the pump or sheath to pass through. After the pump or sheath is removed, the cut-through is closed by the elastic recovery of the material itself to the original state, achieving sealing.

[0039] Since the first resealable seal 213 generally only functions as a seal when the above-described deflation operation of the pump assembly 120 is required, the sealing pressure and sealing time that the first resealable seal 213 needs to bear are relatively small and short (as described below, the first sheath 210 will be peeled off in time). Therefore, the first resealable seal 213 is made softer, which can reduce the resistance of the pump assembly 120 to the introduction of the first sheath 210 while meeting the requirements, which is important for protecting the non-rigid and bendable and deformable cannula 121. The second resealable seal 223 needs to function as a seal during the entire intervention process of the pump assembly 120 and the entire working process of the pump assembly 120 after the intervention is completed, and a harder second resealable seal 223 is needed to bear a greater sealing pressure and a longer sealing time. In addition, the second resealable seal 223 is used for the sheath tube 211 of the first sheath 210, which is harder than the cannula 121, to penetrate into, and the first sheath 210 is a tearable sheath, so it has a lower damage protection level than the cannula 121. The greater hardness design of the second resealable seal 223 can less consider the damage protection for the harder and less flexible first sheath 210, which can also provide better and longer sealing.

[0040] The first sheath 210 is a peelable sheath, and an outwardly protruding handle is formed at the proximal end of the first sheath seat 211 to facilitate the tearing operation of the operator. As shown in Figure 9 and Figure 10 After the pump assembly 110 is completely transferred into the second sheath 220 by the first sheath 210, the first sheath 210 can be peeled off. The peeling of the first sheath 210 can reduce the resistance of the pump assembly 120 to forward pushing and reduce the operation interference to the pushing catheter 110, so that the pump assembly 120 can be quickly inserted and the surgical deployment efficiency can be improved.

[0041] The pump assembly 120 can be introduced into the first sheath 210 from the proximal end or the distal end, depending on the arrangement of the first sheath 210 and the pump assembly 120. As shown in Figure 6 In one embodiment, the first sheath 210 and the pump assembly 120 are independent and separable from each other, and the pump assembly 120 can be introduced into the first sheath 210 from the proximal end thereof through the first resealable seal 213. Alternatively, as shown in Figure 7 In another embodiment, the first sheath 210 is movably sleeved on the catheter 110, and the pump assembly 120 is introduced into the first sheath 210 from the distal end thereof by pushing the first sheath 210 forward and / or pulling the catheter 110 backward. These two embodiments provide higher flexibility for the introduction of the pump assembly 120 into the first sheath 210.

[0042] The process of introducing the catheter pump 100 into the subject in the sheath assembly of the present embodiment is generally as follows:

[0043] As shown in Figure 6 or Figure 7In any of the manners shown, the pump assembly 120 is introduced into the first sheath 210 outside the subject, such that the pump assembly 120 is fully received within the first sheath 210 at least in the section between the first opening 120a and the third opening 120c (as shown in FIG. 2A). Subsequently, as shown in FIG. 2B, the first sheath 210 is inserted into the second sheath 220 together with the pump assembly 120, and the catheter 110 is pushed forward to move the pump assembly 120 from the first sheath 210 to the second sheath 220. After sufficient air is exhausted at the air exhaust position, the catheter 110 is continuously pushed forward, and the pump assembly 120 is pushed out of the first sheath 210 into the second sheath 220. Subsequently, the first sheath 210 is peeled off, and the catheter 110 is continuously pushed forward, and the pump assembly 120 is pushed out of the second sheath 220 into the blood vessel of the subject (as shown in FIG. 2C). Then, the catheter 110 is continuously pushed forward, and the pump assembly 120 is moved forward in the blood vessel of the subject until it is inserted into the heart. Figure 8 Figure 9 Figure 10 Figure 11

[0044] The above merely provides the preferred embodiments of the present application, and is not intended to limit the scope of the present application. Any equivalent structure variations made under the concept of the present application, or directly / indirectly applied in other related technical fields, are included in the protection scope of the present application.​​​​

Claims

1. A sheath assembly for introducing a catheter pump into a subject, the catheter pump including a catheter, a pump assembly connected to a distal end of the catheter and deliverable into the subject under the guidance of a guidewire, the pump assembly having a first opening and a second opening located distal to the first opening; the guidewire removably enters the pump assembly through the second opening and exits outward through the first opening; the sheath assembly includes: The first sheath, configured to allow the pump assembly to be introduced therein from outside the subject, includes a first sheath seat, a first sheath tube connected to the distal end of the first sheath seat, and a first repeatable seal disposed within the first sheath seat; The second sheath, configured to be partially inserted into the subject through a puncture port, includes a second sheath seat, a second sheath tube connected to the distal end of the second sheath seat, and a second repeatable seal disposed within the second sheath seat; The first sheath includes a first section, the inner diameter of which is larger than the outer diameter of the pump assembly at the location corresponding to the first opening, so that a gap is formed between the inner wall of the first section and the outer wall of the pump assembly at the location corresponding to the first opening for the guide wire to pass through. When the pump assembly is introduced into the first sheath, at least the portion of the pump assembly corresponding to the first opening is located within the first section and at the distal end of the first repeatable seal; the first sheath is operably inserted into the second sheath through the second repeatable seal, such that at least a portion of the first section is located at the distal end of the second repeatable seal.

2. The sheath assembly as claimed in claim 1, wherein the outer diameter of the first sheath seat is greater than the outer diameter of the first sheath tube to form a first outer stop at the transition connection between the two; and / or, the inner diameter of the second sheath seat is greater than the inner diameter of the second sheath tube to form an inner stop at the transition connection between the two; the first outer stop and the inner stop are used to limit the depth of insertion of the first sheath into the second sheath so that the first sheath tube is located outside the puncture site.

3. The sheath assembly of claim 1, wherein the outer diameter of the second sheath seat is greater than the outer diameter of the second sheath tube to form a second outer stop at the transition connection between the two, the second outer stop being used to limit the depth of insertion of the second sheath into the subject's body so that the second sheath seat is located outside the puncture site.

4. The sheath assembly as claimed in claim 1, wherein the distal end of the pump assembly is further provided with a third opening, the third opening and the first opening for blood flow; the distance between the distal end face of the first reusable seal and the distal end face of the first sheath is L1, the farthest distance between the first opening and the third opening is L2, and L1 > L2.

5. The sheath assembly as claimed in claim 1, wherein the pump assembly further includes a cannula, a first blood window connected to the proximal end of the cannula, and a second blood window connected to the distal end of the cannula; a first opening is provided on the first blood window, and a third opening is provided on the second blood window; The distal end of the second blood window is provided with a hollow pig tail tube, and the second opening is the distal opening of the pig tail tube; or, the distal end of the second blood window is not provided with a pig tail tube, and the third opening constitutes the second opening.

6. The sheath assembly as described in claim 1, wherein when the catheter pump is used for left ventricular assist, the first opening is the bleeding port and the third opening is the blood inlet port; when the catheter pump is used for right ventricular assist, the first opening is the blood inlet port and the third opening is the bleeding port.

7. The sheath assembly as claimed in claim 1, wherein the farthest distance from the first opening to the second opening is L3, and L1 > L3.

8. The sheath assembly of claim 1, wherein the first repeatable seal is more flexible than the second repeatable seal.

9. The sheath assembly as claimed in claim 1, wherein the first sheath and the catheter pump are separately and independently disposed, and the pump assembly is operatively introduced into the first sheath from its proximal end through a first repeatable seal; or, The first sheath is movably fitted radially outside the catheter, and the pump assembly is introduced into the distal end of the first sheath by pushing the first sheath forward and / or pulling the catheter backward.

10. The sheath assembly as described in claim 1, wherein the side wall of the first sheath has a through hole, and the through hole is provided with a waterproof and breathable material.

11. The sheath assembly as claimed in claim 10, wherein the through hole is provided on the first sheath seat.

12. The sheath assembly as claimed in claim 1, wherein the first sheath further comprises a second section located at the distal end of the first section and having an inner diameter that gradually decreases from proximal to distal; the distal end of the pump assembly is further provided with a third opening, the third opening and the first opening being for blood flow. During the process of the pump assembly moving from the first sheath to the second sheath, there is a position suitable for venting the pump assembly: the second section seals and wraps the outer wall of the pump assembly, the third opening is located inside the second sheath, and the first opening is located inside the first sheath.

13. The sheath assembly of claim 1, wherein the first sheath is configured as a peelable sheath and is peeled off after the pump assembly moves into the second sheath.

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