Sheath for sealed access to vessel

Abstract

To provide a sheath that allows reliable production of a fully sealed access to an interior of a vessel at the same time as reduction of a danger of blood flow disturbances in the vessel.SOLUTION: A sheath (10) for producing a fully sealed access to an interior of a vessel of an animal or human body comprises a base sheath (20) having a tubular body defining a pass-through channel (22). The base sheath (20) is adapted to be inserted into the vessel through a vessel aperture. The sheath further comprises an expansion device (26) which is adapted to cooperate with the base sheath (20) such that an outer diameter (d; D) of the sheath (10) increases in a region of the vessel aperture with the sheath (10) in a stationary position in the vessel and upon actuation of the expansion device (26).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a sheath for creating well-sealed access to the interior of a blood vessel, such as an artery, in an animal or human body. [Background technology]

[0002] Sheaths are used in various forms during percutaneous interventions in the human body, for example when introducing a cardiac catheter through an artery or vein, for example the femoral artery. The various steps of such an intervention are described herein below in a brief and simplified form to serve the purpose of the present invention.

[0003] In a first step, the blood vessel is punctured for this purpose with the aid of a puncture needle. A first guidewire is then inserted into the blood vessel through this needle. The needle is removed and a first sheath is inserted into the blood vessel along the guidewire. The above steps are performed according to the well-known "Seldinger technique". This sheath usually comprises a base sheath, a removable dilator and a hemostatic valve at the proximal end of the sheath, i.e. at the end of the sheath facing the body of the practitioner. In the context of the present invention, the anatomical orientation terms are chosen in relation to the practitioner. The sheath has an outer diameter of about 2 mm. The dilator and the guidewire are successively removed so that only the base sheath of the first sheath remains partially inside the blood vessel.

[0004] In a second step, a now stiff guidewire is inserted through the remaining proximal sheath into the vessel, for example to a depth of up to 40 cm. The proximal sheath is then removed, leaving the guidewire partially in the vessel.

[0005] Optionally, this may be followed by further pre-dilatation, which will not be described here. Optionally or alternatively, instead of applying a small intermediate sheath, the puncture into the vessel can be further dilated by applying dilators of various sizes over the originally placed guidewire.

[0006] Here, the sheath is inserted into the blood vessel along with the guide wire remaining in the blood vessel, through which the heart pump is introduced. In the context of this application, an "introducer" or "introducing sheath" is a sheath having a hemostatic valve. This introducer sheath typically has an inner diameter of about 4.5-5 mm and an outer diameter of about 5-6 mm. The basic structure of the introducer sheath is the same as that of the first sheath described above, i.e., it consists of an outer base sheath, a dilator, and a hemostatic valve. The dilator and guide wire are again removed, leaving the base sheath of the introducer sheath in the blood vessel. Access to the heart pump is now created.

[0007] A guide catheter is usually placed through the base sheath and along the artery into the left ventricle. For this purpose, for example, so-called pigtail catheters can be used, which consist of a thin tube and a soft, pre-bent distal guide tip. A supporting guide wire may be already inserted extending into the guide catheter and supports the catheter. The soft supporting wire is then removed and a stiffer wire is inserted through the catheter into the heart. After removal of the pigtail catheter, a heart pump is inserted into the heart along the stiff guide wire. The inlet of the heart pump is then placed in the left ventricle and the outlet in the aorta, and the guide wire is withdrawn. The pump is connected to a supply catheter that extends along the artery used to place the pump and exits from the vascular opening (puncture side). Alternatively, the pump can be inserted directly into the base sheath and, if the pump is designed with the appropriate features necessary to atraumatically reverse the aortic valve, it can be delivered into the heart without the need for an additional guide catheter and guide wire.

[0008] The introducer sheath used for the heart pump insertion is now removed from the blood vessel, completely withdrawn and then finally removed, for example by tearing along a given separation line ("peel away" technique). A further sheath is now inserted into the blood vessel along the part of the heart pump supply catheter located outside the body, in order to close the blood vessel at the vessel opening, i.e. to close the gap between the circumference of the vessel hole and the outer diameter of the pump's supply catheter. The last-mentioned sheath is the subject of the present invention. It is also possible through this sheath to displace or reposition the heart pump, for example via the supply catheter, so that this sheath is also called a repositioning sheath (or "liposheath").

[0009] To avoid blood flow obstruction in the artery and possible thrombosis associated with low blood flow or foreign surfaces, the sheath should be inserted into the vessel only as deep as necessary and should have an outer diameter just large enough to provide an adequate seal to close the vessel, i.e., to stop bleeding or oozing that would otherwise occur.

[0010] Usually, the vessel opening, which is considerably enlarged by the insertion of the introducer sheath, shrinks again after the introducer sheath is removed, so that the later-inserted sheath may have a smaller outer diameter compared to the introducer sheath. However, in some cases, such shrinkage cannot be observed or may be observed only partially or with a delay. As a result, the later-inserted sheath cannot stop bleeding completely because its outer diameter is too small.

[0011] Therefore, in the prior art, sheaths have been proposed whose outer diameter increases along the longitudinal direction, for example in the form of a step. By advancing this sheath, the sheath diameter of the sheath can be enlarged as required in the region of the vascular opening. However, the placement of such a sheath has been found to be disadvantageous in practice in many cases, since its insertion is unnecessarily too deep, i.e. the maximum outer diameter is always utilized to close the vascular opening. This leads to an unnecessary enlargement of the vascular opening. An excessively deep insertion and / or a large outer diameter can cause blood flow disorders in the blood vessel, as mentioned above. Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention is therefore to propose a sheath and a method for its use, which makes it possible to reliably create access to a well-sealed interior of a vessel, while at the same time reducing the risk of blood flow disturbances in the vessel. [Means for solving the problem]

[0013] This object is achieved by a sheath and a method having the features of the independent claims. Advantageous embodiments and developments are set out in the dependent claims.

[0014] A sheath for creating a well-sealed access to the interior of a blood vessel of an animal or human body according to the present invention comprises a base sheath having a tubular body defining a passage channel. Typically, the sheath comprises a conventional hemostatic valve at the proximal end. The base sheath is configured to be inserted into the blood vessel through a vascular opening, i.e. to be placed in the blood vessel through the vascular opening. According to the present invention, the sheath comprises a dilation device. The dilation device is configured to cooperate with the base sheath such that the sheath is in a rest position in the blood vessel and, upon activation of the dilation device, the outer diameter of the sheath increases in the region of the vascular opening.

[0015] Thus, to create a sufficiently sealed access to a blood vessel by means of a sheath according to the invention, the sheath is inserted into the blood vessel through the vascular opening. The outer diameter of the sheath is then increased as required in the region of the vascular opening by actuation of the sheath's expansion device. To determine a sufficient degree of increase in the outer diameter of the sheath, the pressure applied to the vascular opening can be measured. This pressure can be measured indirectly, for example, by measuring the inflation pressure of a balloon used as the expansion device. In general, any force feedback signal of the expansion device can be used to measure the pressure applied to the opening.

[0016] The described drawbacks of the prior art can be avoided, since the outer diameter of the sheath can be increased in the region of the vascular opening by activation of the expansion device while the sheath is located in a rest position in the blood vessel. In particular, it is unnecessary to insert the sheath deeper into the blood vessel, since an increase in the outer diameter of the sheath in the region of the vascular opening is possible with the sheath in a rest position, in order to increase the outer diameter of the sheath when necessary. Since the sheath has a relatively small outer diameter in its initial state, i.e. the expansion device is not activated, unnecessary widening of the vascular opening and blood flow disorders in the blood vessel due to a large outer diameter or a long penetration depth can be avoided.

[0017] The repositioning sheath is intended to be initially small, i.e., the initial outer diameter of the sheath is designed to be up to 4F (=1.33 mm) smaller in diameter than the initial puncture diameter made by the introducer sheath for the pump. The reason for such a small outer diameter is that the vessel itself may have the ability to elastically return to the smaller hole even if the initial larger sheath is deployed for a short period of time (<60 minutes). It will be appreciated that the smallest occluder to achieve hemostasis is the most preferred embodiment with the least amount of foreign material in the vessel and the least chance of complete vessel occlusion and interruption of distal perfusion. Only when there is no or limited vessel return is the expanded portion of the repositioning sheath gradually expanded to achieve hemostasis. In a preferred embodiment, the expansion device is configured such that the expanded portion of the sheath is limited to the target area around the vessel puncture, thereby retracting the proximal sheath extending through the skin to the outside of the body. In this way, bleeding is visible even at the skin level requiring further expansion of the expanded portion. Thus, it is less likely that the puncture will close at skin level and that there will be continuous bleeding at the vascular puncture site into adjacent tissue, which will later appear as a ring hematoma.

[0018] According to a preferred embodiment, the expansion device is configured as an expansion sheath displaceable on the sheath in the direction of the vascular opening. Such an expansion sheath can, for example, tubularly surround the base sheath. By displacing the expansion sheath on the base sheath in the direction of the vascular opening, the outer diameter of the sheath in the region of the entry point into the vessel can be increased without inserting the entire sheath deeper into the vessel.

[0019] Different embodiments of the expansion device according to the invention are possible. For example, an expansion device can be provided which is not displaced on the base sheath in the direction of the vascular opening, but is arranged in the passage channel of the base sheath or around the base sheath. Such an expansion device can be constructed essentially like a dilator, for example expanding the base sheath or a sleeve arranged on the base sheath (described more precisely later) from the inside, for example like a balloon dilator. The balloon dilator can also be arranged outside the sheath. According to a preferred embodiment, an expansion device is provided in the form of a spiral expansion tube, which is preferably arranged between the base sheath and the sleeve. The expansion tube is wound around the base sheath in a spiral manner. During expansion of the tube, the sheath is expanded in the expansion area while remaining flexible, i.e. bendable.

[0020] Instead of a balloon dilator or the like, a mechanical deployment element, for example a wire mesh stent, can also be provided. Such a deployment element can be moved from a contracted position to an expanded position, for example by rotation or displacement of an actuation element arranged at the proximal end of the sheath and connected to the deployment element, so that the outer diameter of the sheath increases in the region of the deployment element. According to a preferred embodiment, the sheath comprises a flexible portion in the expansion area, which forms part of the base sheath and is arranged between the proximal and distal ends. The flexible portion can be expanded by operating a tensioning means connected at the distal end to the base sheath.

[0021] According to a further preferred embodiment, the sheath comprises an elastic part as an expansion device in the area to be expanded. This elastic part forms part of the base sheath and is arranged between the proximal and distal ends. The elastic part is configured to achieve a first thickness in the expanded state and a second thickness in the unstretched state, which is greater than the first thickness, so as to increase the outer diameter of the sheath when the proximal end part of the base sheath is released from the expanded state in the direction of the vascular opening to the unstretched state. In other words, a sheath with an elastic part has a minimum outer diameter in the expanded state. By releasing the stretch - from the proximal end of the sheath in the direction of the vascular opening - the elastic part goes into the unstretched state, which results in an increase in the outer diameter of the sheath in the area of ​​the vascular opening. This embodiment is advantageous when the sheath has a minimum wall thickness that prevents a uniform compression by axial displacement.

[0022] Any other form of similar unfolding, expanding, or enlarging apparatus may be provided as an expansion device for the purposes of the present invention. In another embodiment, expansion may be automated by allowing the surrounding blood (e.g., a hydrophilic gel) to swell the material, which simply expands gently to the "right size" while minimizing stress on the blood vessels by appropriate selection of the swelling ratio.

[0023] According to a further preferred embodiment, the sheath comprises a case as already shown. The sleeve encases the base sheath and the expansion device such that when the sheath is inserted into the vessel, i.e. when the sheath is in a resting position in the vessel, the sleeve is in contact with the vessel opening. This makes it possible to prevent a traumatic effect of the expansion device on the vessel when the expansion device is actuated, especially when advanced, to increase the outer diameter of the sheath. This sleeve also serves as a sterile barrier, allowing the insertion of a non-sterile expander from the proximal end of the repositioning sheath.

[0024] Should the expansion device be configured in the form of the expander sheath described above that is displaceable over the base sheath, the sleeve encases the base sheath and the expander sheath such that the expander sheath is displaceable over the base sheath between the base sheath and the sleeve.

[0025] Preferably, the base sheath has a passage channel with an inner diameter capable of guiding a cardiac pump catheter, preferably a delivery catheter. An inner diameter of about 3 mm will be sufficient for this purpose. It will be appreciated that the inner diameter of the sheath can be adjusted according to the intended application and can also be paired or operated with any other indwelling device.

[0026] Preferably, the outer diameter of the sheath is selected to be large enough so that the vascular opening that occurs upon insertion of the heart pump through the blood vessel is closed in a sufficiently sealed manner, ideally without activating the dilatation device. An outer diameter of about 3.33 to 5 mm is sufficient for this purpose, taking into account currently used heart pumps and introducer sheaths for pump introduction. It will be recognized that the outer diameter of the sheath can also be adjusted, i.e., made smaller or larger, taking into account the application. However, it should be mentioned that the vascular complication rate increases exponentially above 5 mm, since the preferred target size should aim for the minimum diameter that achieves hemostasis.

[0027] The sheath expansion device is preferably configured to increase the outer diameter of the sheath in the region of the vascular opening by about 1F-3F (0.33mm-1.00mm), preferably by about 1F-4F (0.33mm-1.33mm), particularly preferably by about 1F-5F (0.33mm-1.66mm). In this way it can be ensured that a well-sealed access to the interior of the vessel is created in various scenarios, in particular taking into account various patients with different vascular returns and vessel sizes.

[0028] In addition to having the correct sealing diameter, it is equally important that the expansion portion of the sheath is "radially soft". In this context, radially soft means that this portion must not act like a hard portion that may deform and / or injure the vessel, but that this portion can be limited to the curvature / radius where the repositioning sheath enters the vessel. This calls for low durometer polymeric materials and / or special designs of the expansion device, e.g., helically wound expansion devices (already mentioned above). The expansion device can expand radially but without exceeding any tangential forces that would longitudinally stretch or unfold the pre-bent portion.

[0029] The degree of expansion of the outer diameter of the sheath is guided by the inflation pressure of the balloon, or any other force feedback means that can be used to limit the expansion to a diameter sufficient to provide hemostasis. An expansion force just above the systolic blood pressure is considered sufficient. The expansion force can be considered equal to the inflation pressure of the balloon if the balloon material is very flexible.

[0030] It is desirable to know with certainty whether and when the sheath has been inserted deep enough into the vessel. This can be difficult to determine as it can vary depending on the thickness of the subcutaneous adipose tissue being penetrated and / or the angle of access. Conventional sheaths do not provide any solution in this regard.

[0031] To alleviate this problem, the wall of the tubular body of the base sheath can have a through-channel. This through-channel extends into the wall from the distal end towards the proximal end. The through-channel can exit the wall of the tubular body at or before the proximal end of the sheath, i.e. between the distal and proximal ends of the sheath, to the outside of the sheath. The through-channel can be separate from the passing channel of the base sheath. According to an alternative embodiment, the through-channel can be formed as a lateral extension of the passing channel at least at the distal end, i.e. it does not have to be independent of the passing channel for its entire length. Such a through-channel is configured to direct blood from the blood vessel to the proximal end of the sheath as soon as the sheath is inserted into the vessel. In this way, it can be reliably recognized as soon as the sheath has been inserted through the tissue into the vessel to a sufficient depth. In other words, the channel allows a kind of insertion depth indicator to be obtained, by simply estimating a sufficient insertion depth of the sheath into the vessel as soon as blood from the vessel becomes visible at the proximal end of the channel. In particular, there is no risk of inserting the sheath further into the blood vessel than necessary, which could also cause blood flow disturbance.

[0032] Advantageously, blood can also be withdrawn through the channel in a suitable manner for diagnostic purposes. Important diagnostic methods here are in particular the measurement of the patient's blood pressure and the measurement of cardiac output. To measure blood pressure, the sheath can furthermore comprise a blood pressure measuring device connected to the channel. Cardiac output can be measured, for example, by thermodilution. For this purpose, the sheath can comprise a temperature measuring element, for example a thermistor, which is inserted through the channel.

[0033] The sheath may further preferably comprise a guidewire that can be placed through the channel, in other words the channel is then configured to insert a guidewire from the proximal end of the sheath through the channel and into the blood vessel, via which vascular access is maintained even after removal of the pump.

[0034] According to a further preferred embodiment, the sheath comprises a fixing element at the proximal end, which serves to fix the sheath to the patient after the sheath has been inserted into the patient's blood vessel. The fixing element can thus be sutured, for example, to the patient's skin. The fixing element comprises an area spanning the base sheath for applying a sterile cover, which area is inclined downwards on both sides of the base sheath transversely to the main direction of the base sheath in the form of a bevel.

[0035] Such an embodiment of the fixation element allows for easy and safe application of a sterile covering, thus minimizing entry points for bacteria and pathogens at the vascular opening.

[0036] The fastening element may further comprise fastening areas for bearing against the patient's skin in a fastening state, said fastening areas then being located on either side of said area for applying the sterile cover.

[0037] Preferably, the fixing element further comprises a guide element, which acts as a stop for applying a sterile cover. Preferably, the guide element extends at the proximal end of the region transversely to the main direction of the base sheath and approximately perpendicular to the region, but at least protruding from the region so that the stop function can be provided. Through the application of the sterile cover to the guide element and through the configuration of the region smooth for a wrinkle-free application of the sterile cover, a particularly safe sterile covering of the wound can be obtained. The guide element also serves to prevent inadvertent fixation of any element of the repositioning sheath proximal to the fixing element, for example a contamination protection sleeve used to protect against contamination the proximal parts of the catheter.

[0038] According to a further preferred embodiment, the sheath comprises a cardiac pump with a delivery catheter, wherein the sheath is adapted to be displaceably positioned on the delivery catheter, in other words the cardiac pump, the delivery catheter and the sheath form a combined system according to this embodiment.

[0039] The technology related to the present invention features a sheath (10) for creating a substantially sealed access to the interior of a blood vessel of an animal or human body, the sheath (10) comprising a base sheath (20) having a tubular body defining a passage channel (22) and configured to be inserted into the blood vessel through a vascular opening, and an expansion device (26) configured to cooperate with the base sheath (20) such that, when the sheath (10) is in a resting position within the blood vessel, an outer diameter (d; D) of the sheath (10) increases in the area of ​​the vascular opening upon actuation of the expansion device (26).

[0040] Desirably, the expansion device (26) is configured as an expansion sheath (26) displaceable on the base sheath (20) in the direction (R) of the vascular opening.

[0041] Desirably, the expansion device (26') is configured as an inflation tube that is spirally wound around the base sheath (20).

[0042] Desirably, the expansion device (26a, 26b, 26c, 26d) comprises a flexible portion (26a) of the base sheath between the proximal end (20b) and the distal end (20a), the flexible portion being configured to expand to increase the outer diameter of the sheath when the distal end portion of the base sheath is pulled towards the proximal end by a tensioning means (26b, 26c, 26d).

[0043] Desirably, the expansion device (26") comprises a stretchable portion (26") of the base sheath between the proximal end (20b) and the distal end (20a), the stretchable portion configured to achieve a first thickness in the stretched state and a second thickness, greater than the first thickness, in the unstretched state such that the outer diameter of the sheath increases when the proximal end portion of the base sheath is released from an extended state toward the vascular opening to an unstretched state.

[0044] Desirably, the sleeve (28) encases the base sheath (20) and the expansion device (26, 26', 26a) such that the sleeve (28) contacts the vascular opening when the sheath (10) is in a resting position within the blood vessel.

[0045] Desirably, the sheath (10) includes a sleeve (28) that encases the base sheath (20) and the expansion device (26) such that the sleeve (28) contacts the vascular opening when the sheath (10) is in a resting position within the blood vessel, and the expansion sheath (26) is displaceable over the base sheath (20) between the base sheath (20) and the sleeve (28).

[0046] Desirably, the expansion device (26) is configured to increase the outer diameter (d) of the sheath (10) in the region of the vascular opening by 0.33 mm to 1.00 mm, preferably by 0.33 mm to 1.33 mm, particularly preferably by 0.33 mm to 1.66 mm.

[0047] Desirably, the wall (25) of the tubular body of the proximal sheath (20) has a through channel (27) extending into the wall (25) from the distal end (20a) toward the proximal end (20b).

[0048] Desirably, the through channel (27) is configured to conduct blood from the blood vessel to the proximal end (20b) of the sheath (10).

[0049] Desirably, there is a blood pressure measuring device (30) connected to said channel (27).

[0050] Desirably, there is provided a temperature measuring element inserted through said channel (27).

[0051] Desirably, a guidewire (50) is introduceable through the channel (27) from the proximal end (20b) of the sheath (10) and into the blood vessel.

[0052] Desirably, the sheath (10) includes a fixation element (60) for fixing the sheath (10) to a patient, the fixation element (60) having an area (62) spanning the base sheath (20) for applying a sterile cover, the area (62) sloping downward in the form of an inclined surface transverse to the main direction of the base sheath on both sides of the base sheath (20).

[0053] Desirably, the fixing element (60) comprises a stop (64) for applying a sterile cover, the stop extending transversely to the main direction of the base sheath at the proximal end of the region (62).

[0054] Desirably, a cardiac pump (70) is provided having a delivery catheter (40), the sheath (10) being adapted to be displaceably positioned over the delivery catheter (40).

[0055] Also related to the present invention is a method for creating a sufficiently sealed access to the interior of a blood vessel of an animal or human body by means of the sheath (10), comprising the steps of inserting the sheath (10) into a vascular opening of the blood vessel and increasing the outer diameter (d;D) of the sheath (10) in the area of ​​the vascular opening by actuating the expansion device (26) of the sheath (10).

[0056] Desirably, the method includes the further step of measuring the pressure applied to the opening to determine a sufficient increase in the outer diameter (d;D) of the sheath (10).

[0057] Also, a related technique according to the present invention is a sheath (10) for creating a sufficiently sealed access to the interior of a blood vessel of an animal or human body, comprising a base sheath (20) having a tubular body with a distal end (20a) and a proximal end (20b), the tubular body defining a passage channel (22) opening at the distal end (20a) and the proximal end (20b), the base sheath (20) configured to be inserted into the blood vessel through a blood vessel opening, the sheath (10) having an outer diameter of about 3.33 to 5 mm, the sheath (10) being in a rest position within the blood vessel, and the expansion device (26) configured to cooperate with the base sheath (20) such that upon actuation of the expansion device (26) an outer diameter (d; D) of the sheath (10) increases in the region of the blood vessel opening to close the blood vessel opening in a sufficiently sealed manner.

[0058] Also, a related technique according to the present invention is a method for creating a sufficiently sealed access to the interior of a blood vessel of an animal or human body by means of the sheath (10), comprising the steps of inserting the sheath (10) into a vascular opening of the blood vessel and increasing the outer diameter (d;D) of the sheath (10) in the area of ​​the vascular opening by actuating the expansion device (26) of the sheath (10) so as to close the vascular opening in a sufficiently sealed manner.

[0059] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0060] [Figure 1] FIG. 1 is a plan view of a preferred embodiment of an embodiment in accordance with the present invention. [Diagram 2] FIG. 2 is a side cross-sectional view of the sheath of FIG. 1. [Diagram 3] 1 is a side cross-sectional view of a further preferred embodiment of a sheath according to the present invention. [Figure 4] 1 is a side cross-sectional view of a further preferred embodiment of a sheath according to the present invention. [Figure 5a]1 is a side cross-sectional view of a further preferred embodiment of a sheath according to the present invention. [Figure 5b] 1 is a side cross-sectional view of a further preferred embodiment of a sheath according to the present invention. [Figure 6] FIG. 2 is a perspective view of the sheath of FIG. 1 with additional optional sheath elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] The sheath 10 in Figures 1-6 is not drawn to scale and is merely schematic, and therefore may not represent exact dimensional relationships in order to better illustrate certain elements of the sheath 10. For example, the taper has been exaggerated and appears more like an angled step rather than a gradual, smooth transition from a smaller diameter to a larger diameter.

[0062] 1 and 2, a sheath 10 useful for creating well-sealed access to the interior of a blood vessel of an animal or human body includes a base sheath 20 having a tubular body defining a passage channel 22. A hemostatic valve 24 (see FIG. 6) terminates at the proximal end 20b of the sheath.

[0063] The passage channel 22 has an inner diameter d' and an outer diameter d. The inner diameter d' is suitable for the sheath 10 to be pushed up over the supply catheter 40 of the heart pump 70 (compare FIG. 6) and is preferably dimensioned to reach about 3 mm. The outer diameter d preferably reaches about 3.33-5 mm, so that the sheath 10 is suitable to close the vascular opening that occurs upon insertion of the introducer of the heart pump 70 through the blood vessel in a sufficiently hermetic manner. The outer diameter d may need to be increased beyond 3.33 mm, depending on the minimum wall thickness of the sheath 10, the size of the through channel 27 in the wall of the tubular body (see FIG. 2), or the size of the supply catheter 40 (see FIG. 6), etc.

[0064] The sheath 10 comprises an expansion device in the form of an expansion sheath 26 displaceable on the base sheath 20 in the direction R of the vascular opening. In this embodiment, the expansion sheath 26 is configured as an expansion sheath 26 tubularly surrounding the base sheath 20. When the sheath 10 is inserted into the blood vessel, the expansion sheath 26 is configured to be displaced on the base sheath 20 in the direction R in order to increase the outer diameter d of the sheath in the region of the entry point G into the blood vessel. The outer diameter D then present in the region of the vascular opening exceeds the original outer diameter d by a factor of two, whereby the factor of two may be as large as 0.75*d.

[0065] The sheath 10 comprises a sleeve 28. The sleeve 28 is preferably fixed at its distal end to the base sheath 20 and may further be fixed at its proximal end to a fixation element 60. The sleeve 28 encases the base sheath 20 and the expansion sheath 26 such that the expansion sheath 26 is displaceable on the base sheath 20 between the base sheath 20 and the sleeve 28. In this way, traumatic effects of the expansion sheath 26 on the blood vessel can be prevented and sterility is maintained when the expansion sheath 26 is displaced along the base sheath 20 into the blood vessel opening to increase the outer diameter of the sheath 10 at the blood vessel opening.

[0066] The wall 25 of the tubular body of the base sheath 20 has a through channel 27. The through channel 27 extends in the wall 25 from the proximal end 20b towards the distal end 20a of the base sheath 20, independent of and preferably parallel to the passing channel 22 of the base sheath 20. According to another embodiment (not shown), the through channel 27 is not independent of the passing channel 22 over its entire length, for example except for the proximal end only. At the distal end, the through channel 27 can form a lateral extension of the passing channel 22. The through channel 27 is configured to guide blood from a blood vessel (e.g. an artery) to the proximal end of the sheath 10 as soon as the sheath 10 has been inserted deep enough into the vessel. In this way, a sufficient penetration depth into the vessel can be ascertained by the channel 27 in a simple manner.

[0067] In addition, the sheath 10 may be provided with an externally readable marking area in a region of the sheath intended to be placed in the region of the vascular puncture site during operation. External readability may be achieved, for example, by providing a radiopaque marked area. Also, fluorescent or echogenic substances may be used to form the markers. According to a first embodiment shown in Figs. 2 and 3, this region may be defined by two limiting markers 29a and 29b. These markers further guide the expansion and aid in the positioning of the sheath and its vascular puncture site in relation to the distal opening of the through-channel 27. Respective markers may be provided, for example, on the sleeve 28 covering the base sheath 20 and on the base sheath 20. Alternatively, it is possible to mark the entire region essentially uniformly by adding a suitable externally readable substance to the sheath material in that region. According to such an embodiment, the expanded portion of the sheath may be marked, for example at least a part of the above-mentioned flexible portion and / or elastic portion.

[0068] 3 shows another embodiment of the sheath 10 according to the present invention. According to this embodiment, the expansion device 26' is configured as an inflation tube that is spirally wound around the base sheath 20. By inflating this tube, the outer diameter of the sheath is increased without substantially affecting the bending flexibility of the device.

[0069] The embodiment according to Fig. 4 shows a further type of expansion device 26. Here, the base sheath 20 comprises a flexible portion 26a between the proximal end 20b and the distal end 20a. The flexible portion 26a is configured to expand so as to increase the outer diameter of the sheath when the distal end portion of the base sheath 20 is pulled in the direction R of the proximal end by the pulling means 26b, 26c, 26d. Such a pulling means can comprise, for example, a slider 26d arranged at the proximal end of the sheath. The slider 26d can be connected, for example, via a wire, to a pulling ring 26b. This pulling ring 26b is fixed at the distal end of the base sheath 20 adjacent to the distal end of the flexible portion 26a. By pulling the pulling ring in the direction R of the proximal end by the slider 26d, the flexible portion 26a of the sheath gradually expands in the desired manner so as to increase the outer diameter of the sheath 10. A ruler (not shown) may be provided on the base sheath 20, for example adjacent to the slider 26d, so that the degree of expansion of the flexible portion 26a can be easily observed by the sliding distance or position of the slider 26d. The same result can essentially be achieved by pushing the proximal end 20b towards the distal end 20a. In this case, if necessary, a tensioning means can be used to maintain the position of the proximal end of the sheath relative to the vascular opening.

[0070] The embodiment according to Figs. 5a, 5b shows a further type of dilation device 26" in which the base sheath 20 comprises an elastic portion 26" between the proximal end 20b and the distal end 20a. The elastic portion is configured to achieve a first thickness in a stretched state (see Fig. 5a) and a second thickness in a non-stretched state (see Fig. 5b), the second thickness being greater than the first thickness. By releasing the proximal end portion of the base sheath in the direction R' of the vascular opening from the stretched state to the non-stretched state (see Figs. 5a, 5b), the outer diameter of the sheath can be increased. Again, the tensioning means described in connection with Fig. 4 can be used, if necessary, to maintain the position of the proximal end of the sheath relative to the vascular opening.

[0071] Further components of the sheath 10 are described below in conjunction with FIG. 6, which shows a perspective view of the sheath 10 of FIG.

[0072] Channel 27 can be connected via suitable connections 32, 55 to various measurement devices, e.g., blood pressure measuring device 30. Alternatively or in addition, a temperature measuring device, e.g., a thermistor (not shown), can be connected to or inserted through channel 27, e.g., to obtain information for measuring the patient's cardiac output.

[0073] Guidewire 50 may further be inserted into the blood vessel via channel 27. Access to channel 27 may be created via a luer connector 55, for example.

[0074] As described above, the sheath 10 is suitable to be pushed up over the delivery catheter 40 of the heart pump 70. The heart pump 70 with catheter 40 and the sheath 10 may be provided as a combined unit. The heart pump 70 is preferably introduced into the patient's vascular system in the manner described above by means of an introducer sheath which is either removed using a peel-away technique or replaced by advancing the sheath 10.

[0075] The above-mentioned fixation element 60 serves to fix, for example, suture, the sheath 10 to the patient after the sheath has been inserted into the patient's blood vessel. For this purpose, an opening 66 can be provided. The fixation element 60 has an area 62 spanning the base sheath 20 for applying a sterile cover (not shown). The area 62 of the fixation element 60 slopes downwards in the form of a bevel, transversely to the main direction of the base sheath on both sides of the base sheath 20. Furthermore, the fixation element 60 comprises a guide element 64 which serves as a stop for applying a sterile cover.

[0076] The fixation element 60 may further include circulation openings 67 and / or circulation opening slots (not shown) to allow air circulation under the sterile cover, the openings or slots running through the fixation element, preferably in the direction that the sheath runs through.

Claims

1. A sheath (10) for creating a substantially sealed access to the interior of a blood vessel of an animal or human body, comprising:

1. A sheath (10) comprising a base sheath (20) having a tubular body having a distal end (20a) and a proximal end (20b), the tubular body defining a passage channel (22) opening at the distal end (20a) and the proximal end (20b), the base sheath (20) being configured to be inserted into a blood vessel through a blood vessel opening, A sheath (10), comprising an expansion device (26) configured to cooperate with the base sheath (20) and configured to increase an outer diameter (d; D) of the sheath (10) in the region of the vascular opening when the sheath (10) is in a rest position within the blood vessel, thereby sealingly closing the vascular opening.

2. 2. The sheath (10) of claim 1, wherein the expansion device (26) is configured as an expansion sheath (26) displaceable on the base sheath (20) in the direction (R) of the vascular opening.

3. 2. The sheath (10) of claim 1, wherein the expansion device (26') is configured as an inflation tube that is spirally wound around the base sheath (20).

4. 2. The sheath (10) of claim 1, wherein the expansion device (26a, 26b, 26c, 26d) comprises a flexible portion (26a) of the base sheath between the proximal end (20b) and the distal end (20a), the flexible portion being configured to expand to increase the outer diameter of the sheath when a distal end portion of the base sheath is pulled by a tensioning means (26b, 26c, 26d) toward the proximal end.

5. 2. The sheath of claim 1, wherein the expansion device comprises a stretchable portion of the base sheath between the proximal end and the distal end, the stretchable portion configured to achieve a first thickness in the stretched state and a second thickness greater than the first thickness in the unstretched state such that the outer diameter of the sheath increases when the proximal end portion of the base sheath is released from an extended state toward the vascular opening to an unstretched state.

6. 6. The sheath (10) of claim 1, further comprising a sleeve (28) that encases the base sheath (20) and the expansion device (26, 26', 26a) such that the sleeve (28) contacts the vascular opening when the sheath (10) is in a resting position within the blood vessel.

7. 3. The sheath (10) of claim 2, comprising a sleeve (28) encasing the base sheath (20) and the expansion device (26) such that the sleeve (28) contacts the vascular opening when the sheath (10) is in a resting position within the blood vessel, and the expansion sheath (26) is displaceable on the base sheath (20) between the base sheath (20) and the sleeve (28).

8. 8. The sheath (10) according to any one of claims 1 to 7, wherein the expansion device (26) is configured to increase the outer diameter (d) of the sheath (10) in the region of the vascular opening by 0.33 mm to 1.00 mm.

9. 8. The sheath (10) according to any one of claims 1 to 7, wherein the expansion device (26) is configured to increase the outer diameter (d) of the sheath (10) in the area of ​​the vascular opening by 0.33 mm to 1.33 mm.

10. 8. The sheath (10) according to any one of claims 1 to 7, wherein the expansion device (26) is configured to increase the outer diameter (d) of the sheath (10) in the area of ​​the vascular opening by between 0.33 mm and 1.66 mm.

11. 11. The sheath (10) of claim 1, wherein a wall (25) of the tubular body of the base sheath (20) has a through channel (27) extending therethrough from the distal end (20a) toward the proximal end (20b).

12. 12. The sheath (10) of claim 11, wherein the through channel (27) is configured to conduct blood from the blood vessel to the proximal end (20b) of the sheath (10).

13. 13. The sheath (10) according to claim 12, further comprising a blood pressure measuring device (30) connected to the channel (27).

14. A sheath (10) according to claim 12 or 13, characterized in that it comprises a temperature measuring element inserted through said channel (27).

15. The sheath (10) according to any one of claims 9 to 14, characterized in that it comprises a guidewire (50) that can be introduced into the blood vessel through the channel (27) from the proximal end (20b) of the sheath (10).

16. 16. A sheath (10) according to any one of claims 1 to 15, comprising a fixation element (60) for fixing the sheath (10) to a patient, the fixation element (60) having an area (62) spanning the base sheath (20) for applying a sterile cover, the area (62) being inclined downwards in the form of an inclined surface on both sides of the base sheath (20) transversely to a main direction of the base sheath.

17. 17. The sheath (10) of claim 16, wherein the fixing element (60) comprises a stop (64) for applying a sterile cover, the stop extending transversely to a main direction of the base sheath at a proximal end of the region (62).

18. 18. A sheath (10) according to any one of claims 1 to 17, comprising a cardiac pump (70) having a delivery catheter (40), the sheath (10) being configured to be displaceably positioned over the delivery catheter (40).

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