阅读说明：本技术 用于密封到血管的通路的护套 (Sheath for sealing a passageway to a blood vessel ) 是由 索斯藤·西斯 克里斯托夫·尼克斯 弗兰克·基尔霍夫 赫尔·奥卡罗尔 于 2015-07-06 设计创作，主要内容包括：一种用于产生对动物或人体的血管内部的完全密封通路的护套(10)包括具有管状主体的基部护套(20),管状主体限定通过通道(22)。基部护套(20)适于通过血管孔眼插入到血管中。护套进一步包括膨胀装置(26),所述膨胀装置(26)适于与基部护套(20)配合,使得当护套(10)在血管中的静止位置中的情况下并且当致动膨胀装置(26)时,护套(10)的外径(d；D)在血管孔眼的区域中增大。(A sheath (10) for creating a completely sealed passageway to the interior of a blood vessel of an animal or human body includes a base sheath (20) having a tubular body defining a through passage (22). The base sheath (20) is adapted to be inserted into a blood vessel through a blood vessel aperture. The sheath further comprises expansion means (26), said expansion means (26) being adapted to cooperate with the base sheath (20) such that the outer diameter (D; D) of the sheath (10) increases in the region of the vessel aperture with the sheath (10) in a rest position in the vessel and when the expansion means (26) is actuated.)

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

a base sheath (20) having a tubular body defining a through passage (22), wherein the base sheath (20) is adapted to be inserted into a blood vessel through a blood vessel aperture,

it is characterized in that the preparation method is characterized in that,

the sheath (10) for producing the fully sealed passage comprises expansion means (26), the expansion means (26) being adapted to cooperate with the base sheath (20) such that the outer diameter (D; D) of the sheath (10) for producing the fully sealed passage increases in the region of the vessel aperture with the sheath (10) for producing the fully sealed passage in a rest position in the vessel and when the expansion means (26) is actuated to close the vessel aperture in a fully sealed manner,

wherein the sheath (20) for producing the fully sealed passage further comprises a fixation element (60) for fixing the sheath (10) for producing the fully sealed passage to a patient, the fixation element (60) having a region (62) spanning the base sheath (20) for applying a sterile cap, the region (62) being inclined downwards in a ramp shape on both sides of the base sheath (20) transverse to a main direction of the base sheath.

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

a base sheath (20) having a tubular body defining a through passage (22), wherein the base sheath (20) is adapted to be inserted into a blood vessel through a blood vessel aperture,

it is characterized in that the preparation method is characterized in that,

the sheath (10) for producing the fully sealed passage comprises expansion means (26), the expansion means (26) being adapted to cooperate with the base sheath (20) such that the outer diameter (D; D) of the sheath (10) for producing the fully sealed passage increases in the region of the vessel aperture with the sheath (10) for producing the fully sealed passage in a rest position in the vessel and when the expansion means (26) is actuated to close the vessel aperture in a fully sealed manner,

wherein the sheath (20) for creating the fully sealed passageway further comprises a heart pump (70) having a supply conduit (40), the sheath (10) for creating the fully sealed passageway being adapted to be displaceably arranged on the supply conduit (40).

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

a base sheath (20), the base sheath (20) having a distal end (20a) and a proximal end (20b) and a tubular body defining a through passage (22), the base sheath (20) being adapted for insertion into a blood vessel through a blood vessel aperture,

it is characterized in that the preparation method is characterized in that,

the sheath (10) for producing the fully sealed passage comprises expansion means (26), the expansion means (26) being adapted to cooperate with the base sheath (20) such that the outer diameter (D; D) of the sheath (10) for producing the fully sealed passage increases in the region of the vessel aperture with the sheath (10) for producing the fully sealed passage in a rest position in the vessel and when the expansion means (26) is actuated to close the vessel aperture in a fully sealed manner,

wherein the sheath (10) for creating the fully sealed passageway further comprises a haemostatic valve (24) at the proximal end (20 b).

4. Sheath (10) for producing a completely sealed access according to any one of claims 1 to 3, wherein the expansion means (26) are configured as an expansion sheath (26) which is displaceable on the base sheath (20) in the direction (R) of the vessel aperture.

5. The sheath (10) for producing a fully sealed passageway according to any one of claims 1 to 3, wherein the inflation device (26') is configured as a gas-filled tube helically wound around the base sheath (20).

6. The sheath (10) for producing a fully sealed passageway according to any one of claims 1 to 3, wherein the expansion means (26a, 26b, 26c, 26d) comprises a flexible portion (26a) of the base sheath (20) between the proximal end (20b) and the distal end (20a), the flexible portion (26a) being configured to expand to increase the outer diameter of the sheath for producing the fully sealed passageway when the distal portion of the base sheath is pulled in the proximal direction with a pulling means (26b, 26c, 26 d).

7. The sheath (10) for creating a fully sealed access according to any of claims 1-3, wherein the expansion means (26 ") comprises a stretchable portion (26") of the base sheath (20) between the proximal end (20b) and the distal end (20a), the stretchable portion being configured to reach a first thickness in a stretched state and a second thickness greater than the first thickness in an unstretched state, such that an outer diameter of the sheath for creating the fully sealed access increases when a proximal end portion of the base sheath (20) is released from the stretched state to the unstretched state in a direction of the vessel aperture.

8. The sheath (10) for producing a fully sealed access according to any one of claims 1 to 3, comprising a sleeve (28), the sleeve (28) surrounding the base sheath (20) and the expansion means (26,26', 26a) such that in a rest position of the sheath (10) for producing the fully sealed access in a blood vessel, the sleeve (28) is in contact with the blood vessel aperture.

9. The sheath (10) for producing a fully sealed access according to claim 4, comprising a sleeve (28), the sleeve (28) surrounding the base sheath (20) and the expansion sheath such that in the rest position of the sheath (10) for producing the fully sealed access in a blood vessel, the sleeve (28) is in contact with the vessel aperture and such that an expansion sheath (26) is displaceable on the base sheath (20) between the base sheath (20) and the sleeve (28).

10. The sheath (10) for producing a fully sealed access according to any of claims 1 to 3, wherein the expansion means (26) is adapted to increase the outer diameter (d) of the sheath (10) for producing the fully sealed access in the region of the vessel aperture by an amount between 0.33mm and 1.00 mm.

11. A sheath (10) for creating a completely sealed passage according to any one of claims 1 to 3, wherein the wall (25) of the tubular body of the base sheath (20) has a through channel (27) extending in the wall (25) from the distal end (20a) towards the proximal end (20 b).

12. Sheath (10) for producing a completely sealed passage according to claim 11, wherein the channel (27) is adapted to conduct blood from a blood vessel to the proximal end (20b) of the sheath (10).

13. Sheath (10) for producing a completely sealed passage according to claim 12, comprising a blood pressure measuring device (30) connected to the channel (27).

14. The sheath (10) for producing a completely sealed passage according to claim 12, comprising a temperature measuring element inserted through the channel (27).

15. Sheath (10) for producing a completely sealed passage according to claim 11, comprising a guide wire (50) that can be introduced into a blood vessel from the proximal end (20b) of the sheath through the channel (27).

16. Sheath (10) for producing a completely sealed passage according to claim 1, wherein the fixation element (60) comprises a stop (64) for applying the sterile cover, said stop extending transversely to the main direction of the base sheath on a proximal end of the region (62).

17. The sheath (10) for producing a fully sealed access according to any one of claims 1 to 3, the expansion means (26) being adapted to increase the outer diameter (d) of the sheath (10) for producing the fully sealed access in the region of the vessel aperture by an amount between 0.33mm and 1.33 mm.

18. The sheath (10) for producing a fully sealed access according to any one of claims 1 to 3, the expansion means (26) being adapted to increase the outer diameter (d) of the sheath (10) for producing the fully sealed access in the region of the vessel aperture by an amount between 0.33mm and 1.66 mm.

Technical Field

The present invention relates to a sheath for producing a completely sealed access to the interior of a blood vessel, such as an artery, of an animal or human body.

Background

During percutaneous interventions in the human body, such as when introducing a cardiac catheter through an artery or vein (e.g. the femoral artery), sheaths are used in different forms. The different steps of such intervention will be set forth below in a simplified and simplified form in order to achieve the object of the invention.

In a first phase, the blood vessel is punctured with a puncture needle for this purpose. A first guidewire is then inserted through the needle and into the blood vessel. The needle is removed and the first sheath is inserted into the vessel along the guidewire. The above steps are performed according to the well-known "Seldinger technique". The sheath typically includes a base sheath, a removable dilator, and a hemostasis valve on the proximal end of the sheath, i.e., the end of the sheath facing the physician's body. With respect to the present invention, anatomical directional terms will be selected with reference to the practitioner. The jacket has an outer diameter of about 2 mm. The dilator and the guidewire are successively removed such that only the base sheath of the first sheath remains partially in the vessel.

In the second stage, the rigid guidewire is now inserted into the vessel through the remaining base sheath, for example up to a depth of 40 cm. Thereafter, the base sheath is removed. The guidewire is partially retained in the vessel.

Optionally, this may be followed by a further pre-expansion, which will not be described here. Optionally or alternatively, instead of applying a small intermediate sheath, the puncture into the vessel may be dilated upward by applying dilators of various sizes over the initially deployed guidewire.

Along the guide wire held in the vessel, the sheath is now inserted into the vessel into which the heart pump is to be introduced. In the context of the present application, an "introducer" or "introducer sheath" is a sheath with a hemostatic valve. The introducer sheath typically has an inner diameter of about 4.5mm to 5mm and an outer diameter of about 5mm to 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 guidewire are again removed, with the base sheath of the introducer sheath remaining in the vessel. A pathway for a heart pump has now been formed.

With the base sheath, the guide catheter is now placed into the left ventricle, usually along the artery. For this purpose, a so-called pigtail catheter, for example, can be used, which consists of a thin tube and a soft distal pre-bent guide tip. The support guidewire may already be inserted into the guide catheter extending therein, which supports the catheter. The soft support wire is then removed and a stiffer guide wire is inserted through the catheter into the heart. Following removal of the pigtail catheter along the hard guide wire, a heart pump was inserted into the heart. Thus, the inlet of the heart pump is located in the left ventricle, the outlet in the aorta, and the guidewire is withdrawn. The pump is connected to a supply conduit that runs along the artery for placement of the pump and exits at the vascular aperture (puncture side). Alternatively, the pump can be inserted directly into the base sheath and delivered into the heart without the need for additional guide catheters and guidewires, in cases where the pump has been designed with the appropriate features necessary to pass retrograde through the aortic valve in an atraumatic manner.

The introducer sheath, which has been used to insert the heart pump, is now removed from the vessel and pulled completely out, and then finally removed, for example by separation along a predetermined separation line ("peel-off" technique), to perform final removal. Now, to close the blood vessel again at the vessel aperture, i.e. to close the gap between the circumference of the hole in the blood vessel and the outer diameter of the supply catheter of the pump, a further sheath is inserted into the blood vessel along the portion of the heart pump supply catheter which is located outside the body. The last mentioned jacket is the subject of the present invention. Because the heart pump may also be displaced or repositioned through the sheath, e.g., via a supply catheter, the sheath is also referred to as a repositioning sheath (or "reflux sheath").

To avoid blood flow disturbances in the artery and potential low flow or outer surface related thrombosis, the sheath should be inserted only as deeply into the vessel as necessary and have an outer diameter just sufficient to close the vessel in a completely sealed manner, i.e. to prevent bleeding or oozing that would otherwise occur.

Typically, the vessel aperture, which is significantly widened by insertion of the introducer sheath, will be contracted again after removal of the introducer sheath, so that the outer diameter of the sheath, which is now subsequently inserted, can be reduced compared to the introducer sheath. However, in some cases, such contraction cannot be observed, or only partially or late. This has the consequence that a subsequently inserted sheath cannot completely prevent any bleeding because the outer diameter is too small.

In the prior art, it has therefore been proposed that the jacket has an increasing outer diameter in its longitudinal direction, for example stepped in the shape of a staircase. By advancing the sheath, the sheath diameter of the sheath can be enlarged as desired in the region of the vessel aperture. However, the use of such sheaths has proved disadvantageous, since in practice they are usually inserted unnecessarily deep, i.e. always with the largest outer diameter for closing the vessel aperture. This results in an unnecessary widening of the vessel aperture. Too deep insertion and/or large outer diameter can cause blood flow disturbances in the vessel, as described above.

Disclosure of Invention

It is therefore an object of the present invention to propose a sheath and a method of using the sheath that allow a completely sealed access to the interior of a blood vessel to be reliably created while reducing the risk of blood flow disturbances in the blood vessel.

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

A sheath for creating a completely sealed passageway to the interior of a blood vessel of an animal or human body in accordance with the present invention includes a base sheath having a tubular body defining a passageway therethrough. Typically, the sheath includes a conventional hemostatic valve at the proximal end. The base sheath is adapted to be inserted into a blood vessel through a vessel aperture, i.e. to be mounted in a blood vessel through a vessel aperture. According to the invention, the sheath comprises an expansion means. The latter is adapted to cooperate with the base sheath such that the outer diameter of the sheath increases in the region of the vessel aperture with the sheath in a rest position in the vessel and upon actuation of the expansion means.

In order to create a completely sealed access to the vessel by means of the sheath according to the invention, the sheath is therefore inserted into the vessel through the vessel aperture. Thereafter, the outer diameter of the sheath is increased in the region of the vessel aperture by actuating the expansion means of the sheath as required. To determine a sufficient degree of increase in the outer diameter of the sheath, the pressure applied to the vessel aperture can be determined. This pressure may be measured indirectly, for example by measuring the inflation pressure of a balloon used as the inflation device. In general, any force feedback signal of the inflation device can be used in order to determine the pressure applied to the orifice.

Said disadvantages of the prior art can be avoided since the outer diameter of the sheath can be increased in the region of the vessel aperture by actuating the expansion means in the case of a sheath arranged in a resting position in the vessel. In order to increase the outer diameter of the sheath if necessary, it is not necessary in particular to insert the sheath deeper into the vessel, since the outer diameter of the sheath can be increased in the region of the vessel aperture with the sheath in the rest position. Since the sheath has a relatively small outer diameter in its initial state, i.e. without actuation of the expansion means, unnecessary widening of the vessel aperture and disturbance of the blood flow in the vessel due to a large outer diameter or a long penetration depth can be avoided.

It is intended that the repositioning sheath be designed such that its initial size is too small, for example the initial outer diameter of the sheath may be as high as 4F (═ 1.33mm) compared to the initial puncture diameter produced by the introducer sheath for the pump. The reason for this undersized outer diameter is that if the initially larger sheath is placed for only a short time (<60 minutes), the vessel itself may have the ability to resiliently spring back to the smaller aperture. It will be appreciated that a minimal obstruction to achieve hemostasis is the most preferred embodiment, with a minimal amount of impurities in the vessel, and with a minimal likelihood of vessel occlusion and discontinuous distal perfusion. Only in the absence or limited vessel recoil will the expanded portion of the repositioning sheath gradually expand to achieve hemostasis. In a preferred embodiment, the expansion device is configured such that the expanded portion of the sheath is confined to a target area around the vascular puncture to allow for the proximal sheath, which extends through the skin to the exterior of the body, to be recessed. In this way, bleeding is still visible at the skin level, and further expansion of the expanded portion is required. Thereafter, it is unlikely that the perforation will be plugged at the skin level and there will be continuous bleeding into the adjacent tissue at the vascular perforation, which then appears as a circular hematoma.

According to a preferred embodiment, the expansion means is configured as an expansion sheath which is displaceable on the sheath in the direction of the vessel aperture. Such an expansion sheath may, for example, surround the base sheath in a tubular manner. By displacing the expanding sheath over the base sheath in the direction of the vessel aperture, it is possible to increase the sheath outer diameter in the region of the site of entry into the vessel without inserting the entire sheath deeper into the vessel.

A number of embodiments of the expansion device according to the invention other than those described above are also possible. For example, the expansion device can be provided not to be displaced on the base sheath in the direction of the vessel aperture, but to be arranged in the passage channel of the base sheath or around the base sheath. Such an expansion device can be configured substantially similar to a dilator and, for example, widen the base sheath from the inside like a balloon dilator or a sleeve arranged on the base sheath (described in more detail below). The balloon dilator may also be disposed outside of the sheath. According to a preferred embodiment, an expansion device in the form of a helical inflation tube is provided, preferably arranged between the base sheath and the sleeve. The inflation tube is helically wrapped around the base sheath. During inflation of the tube, the sheath expands while still being flexible, i.e., bendable, in the expanded region.

Instead of balloon dilators or the like, it is also possible to provide mechanical expansion elements, such as wire mesh stents. Such a stent element can be brought from a contracted position to an expanded position, for example by rotation or displacement of an actuating element arranged at the proximal end of the sheath and coupled with the stent element, thereby increasing the sheath outer diameter in the region of the stent element. According to a preferred embodiment, the sheath comprises a flexible portion in the area to be expanded. The flexible portion forms a portion of the base sheath and is disposed between the proximal end and the distal end. The flexible portion is expandable by operation of a pulling device connected at a distal end to the base sheath.

According to another preferred embodiment, the sheath comprises a stretchable portion in the area to be expanded as the expansion means. The stretchable portion forms a portion of the base sheath and is disposed between the proximal end and the distal end. The stretchable portion is configured to reach a first thickness in a stretched state and a second thickness greater than the first thickness in an unstretched state to increase the sheath outer diameter when the proximal end portion of the base sheath is released from the stretched state to the unstretched state in a direction of the vessel aperture. In other words, the sheath with the stretchable portion provides the smallest outer diameter in the stretched state. By releasing the stretch from the proximal end of the sheath in the direction of the vessel aperture, the stretchable portion reaches an unstretched state, which results in a sheath having a larger outer diameter in the region of the vessel aperture. This embodiment is advantageous in case the sheath has a minimum wall thickness which hinders an even compression by axial displacement.

Any other form of similar expansion, expansion or widening mechanism may be provided as an expansion device for the purposes of the present invention. In another embodiment, the expansion can be automated by swelling the material (e.g. hydrophilic gel) with the surrounding blood, and by appropriate choice of the swelling modulus, the material expands only slightly to the "correct size" with minimal stress on the vessel.

According to another preferred embodiment, the sheath comprises a housing as already indicated. The sleeve encases the base sheath and the expansion means such that the sleeve is in contact with the vessel aperture when the sheath has been inserted into the vessel, i.e. when the sheath is in a resting position in the vessel. This can prevent traumatic effects of the expansion device on the vessel when the expansion device is actuated, in particular advanced, to increase the outer diameter of the sheath. This sleeve also serves as a sterile barrier and allows the insertion of a non-sterile dilator from the proximal end of the repositioning sheath.

In the case of an expansion device configured in the form of an expansion sheath displaceable over the base sheath as described above, the sleeve encloses the base sheath and the expansion sheath such that the expansion sheath is displaceable over the base sheath between the base sheath and the sleeve.

Preferably, the base sheath has a through channel with an inner diameter allowing a catheter, preferably a supply catheter of a heart pump, to be guided through the through channel. For this purpose, an inner diameter of about 3mm is sufficient. It will be appreciated that the inner diameter of the sheath may be adjusted depending on the intended application, and may also be paired and operated with any other indwelling device.

Preferably, the outer diameter of the sheath is chosen to be large enough so that the vessel aperture created when the heart pump is inserted into the vessel is closed in a completely sealed manner, ideally without the need to actuate the expansion means. An outer diameter of about 3.33 to 5mm is sufficient for this purpose, taking into account the heart pumps currently used and the introducer sheaths used for introducing the pumps. It should be understood that the outer diameter of the sheath may also be adjusted, i.e., decreased or increased, depending on the application. It should be mentioned, however, that above 5mm the incidence of vascular complications increases exponentially, which is why the preferred target size should be in order to achieve the smallest possible diameter of hemostasis.

The expansion means of the sheath is preferably adapted to increase the sheath outer diameter by about 1F to 3F (0.33mm to 1.00mm), preferably about 1F to 4F (0.33mm to 1.33mm), particularly preferably about 1F to 5F (0.33mm to 1.66mm) in the region of the vessel aperture. In this way, it can be ensured that a completely sealed access to the interior of the blood vessel is produced under different circumstances, in particular taking into account different patients with different possibilities of recoil of the blood vessel and blood vessel sizes.

In addition to having the correct sealing diameter, it is also important that the expanded portion of the sheath is "radially soft". In this context, radially soft means that the portion does not have to function as a rigid portion, which may deform and/or traumatize the vessel, but which may still limit the curvature/radius at which the repositioning sheath enters the vessel. This requires a low durometer polymer material and/or a special design of the inflation device, such as a helically wound inflation tube (as already mentioned above). The latter can expand radially but not exceed any tangential force causing longitudinal stretching or extension of the pre-bent section.

The degree of expansion of the sheath outer diameter is guided by the inflation pressure of the balloon or any other force feedback device that can be used to limit the expansion to a diameter sufficient to provide hemostasis. An expansion force slightly above the maximum blood pressure is considered sufficient. If the balloon material is highly flexible, the inflation force may be considered to be equal to the inflation pressure of the balloon.

It is desirable to be able to reliably identify if and when the sheath has been inserted sufficiently deep into the vessel. This may vary depending on the thickness of the subcutaneous adipose tissue to be penetrated and/or the angle of the passage, and is therefore difficult to determine. Conventional sheaths provide no solution in this regard.

To remedy this problem, the wall of the tubular body of the base sheath can have a through passage. The through passage extends proximally in the wall from the distal end. This through passage may exit the wall of the tubular body to the outside of the sheath at the proximal end of the sheath or earlier, i.e. between the distal and proximal ends of the sheath. The through channel can be present separately from the through channel of the base sheath. According to an alternative embodiment, the through channel can be formed as a lateral extension of the through channel at least at the distal end, i.e. it does not have to be separated from the through channel over its entire length. Such a through-passage is adapted to guide blood from the vessel to the proximal end of the sheath when the sheath has been inserted into the vessel. In this way, the sheath can be reliably seen once it has been inserted through the tissue and into the vessel to a sufficient depth. In other words, the channel enables to obtain an insertion depth indicator, simply by the fact that: once blood from the vessel can be identified at the proximal end of the channel, it can be concluded that the sheath is inserted deep enough into the vessel. In particular, there is no risk of the sheath being inserted further into the vessel than is necessary, which would otherwise again cause a disturbance in the blood flow.

Advantageously, blood can also be collected in a suitable manner through the channel for diagnostic purposes. Important diagnostic methods here are, in particular, the measurement of the blood pressure of the patient and the determination of the cardiac output. For measuring the blood pressure, the sheath may further comprise a blood pressure measuring device connected to the channel. Cardiac output can be determined, for example, by thermodilution. To this end, the sheath can comprise a temperature measuring element, such as a thermistor, inserted through the channel.

The sheath may also include a guide wire, which is preferably mountable through the channel. In other words, the channel is thereby adapted for inserting the guidewire into the vessel from the proximal end of the sheath via the channel. Via such a guidewire, vascular access is maintained even after the pump is withdrawn.

According to another preferred embodiment, the sheath comprises a fixation element at the proximal end. The fixation element is used to fix the sheath to the patient after insertion of the sheath into the patient's blood vessel. For example, the fixation element can thereby be sutured to the skin of the patient. The fixation element includes an area spanning the base sheath for application of the sterile cover. This region slopes downward in a ramp shape on both sides of the base sheath transverse to the main direction of the base sheath.

Such an embodiment of the fixation element allows for a simple and safe application of the sterile cover, thereby minimizing the entry site of bacteria and pathogens at the vascular aperture.

The fixation element may additionally comprise a fixation area which in the fixed state abuts against the skin of the patient. The fixing area is thus located opposite the area for applying the sterile cover.

Preferably, the fixing element further comprises a guiding element. The guide element serves as a stop for applying the sterile cap. Preferably, the guide element extends transversely to the main direction of the base sheath and substantially perpendicularly to the region on the proximal end of the region, but at least protrudes from the region such that a stop function can be provided. By applying the sterile cover on the guide element and by the configuration of the smooth area for wrinkle-free application of the sterile cover, a particularly safe and sterile covering of the wound can be obtained. The guide element also helps prevent inadvertent fixation of any elements of the repositioning sheath that are proximal to the fixation element, such as a contamination-resistant sleeve for protecting the proximal portion of the catheter from contamination.

According to another preferred embodiment, the sheath comprises a heart pump with a supply conduit. The sheath is here adapted to be movably arranged on the supply conduit. In other words, the heart pump, the supply catheter and the sheath form a cohesive system according to this embodiment.

Drawings

In the following, the invention will be described by way of example with reference to the accompanying drawings. In which it is shown that:

FIG. 1 is a plan view of a preferred embodiment of a sheath according to the present invention;

figure 2 is a transverse cross-sectional view of the sheath of figure 1,

figures 3, 4 and 5a, 5b are transverse cross-sectional views of another preferred embodiment of a sheath according to the invention, an

Fig. 6 is a perspective view of the sheath of fig. 1 and additional optional sheath elements.

Detailed Description

The illustration of the sheath 10 in fig. 1 to 6 is not to scale, but merely schematic. The actual dimensions are therefore sometimes incorrect in order to better show some elements of the sheath 10. For example, the tapered portion is exaggerated and appears more like a sloped step rather than a flat and smooth transition from a small diameter to a large diameter.

As shown in fig. 1 and 2, the sheath 10 for creating a completely sealed passageway to the interior of a blood vessel of an animal or human body includes a base sheath 20 having a tubular body defining a through passage 22. A hemostasis valve 24 (see fig. 6) terminates the proximal end 20b of the sheath.

The through passage 22 has an inner diameter d' and an outer diameter d. The inner diameter d' is dimensioned such that the sheath 10 is adapted to be pushed through the supply conduit 40 of the heart pump 70 (compare fig. 6), and is preferably about 3 mm. The outer diameter d is preferably about 3.33mm to 5mm, so that the sheath 10 is suitable for closing in a completely sealed manner the vessel aperture created when the introducer of the heart pump 70 is inserted into a vessel. The outer diameter d may need to be greater than 3.33mm based on, for example, the minimum wall thickness of the sheath 10, the size of the through passage 27 (see fig. 2) in the wall of the tubular body, or the size of the supply conduit 40 (see fig. 6).

The sheath 10 comprises expansion means in the form of an expansion sheath 26, the expansion sheath 26 being displaceable on the base sleeve 20 in the direction R of the vessel aperture. In the present example, the expansion sheath 26 is configured as an expansion sheath 26 that tubularly surrounds the base sheath 20. The expansion sheath 26 is adapted to be displaced over the base sheath 20 in the direction R in order to increase the sheath outer diameter d in the region of the entry location G of the vessel when the sheath 10 has been inserted into the vessel. Thereafter, the outer diameter D present in the region of the vessel aperture exceeds the initial outer diameter D by an amount 2x, wherein 2x may be as large as 0.75 x D.

The sheath 10 includes a sleeve 28. The latter is preferably fastened at its distal end to the base sheath 20 and can furthermore be fastened at its proximal end to the fixation element 60. The sleeve 28 surrounds 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 expanded sheath 26 on the vessel can be prevented and sterility is maintained as the expanded sheath 26 is moved along the base sheath 20 into the vessel aperture to increase the outer diameter of the sheath 10 in the vessel aperture.

The wall 25 of the tubular body of the base sheath 20 has a through passage 27. The latter extends in the wall 25 from the proximal end 20b to the distal end 20a of the base sheath 20 and is separated from the through passage 22 of the base sheath 20, and preferably extends parallel to the through passage 22. According to another embodiment (not shown), the through channel 27 is not separated from the through channel 22 over its entire length, but only at the proximal end, for example. On the distal end, the through channel 27 can form a lateral extension through the channel 22. The through-passage 27 is adapted to guide blood from the vessel (e.g. an artery) to the proximal end of the sheath 10 once the sheath 10 has been inserted sufficiently deep into the vessel. In this way, a sufficient penetration depth into the blood vessel can be determined in a simple manner by the channel 27.

Furthermore, the sheath 10 may comprise externally readable marking areas in the region of the sheath, which marking areas are intended in operation to be located in the region of the vessel puncture site. External readability can be achieved, for example, by providing radiopaque markers in the area. In addition, fluorescent or echogenic substances can be used to form the labels. According to a first embodiment, as shown in fig. 2 and 3, this area can be defined by two limit marks 29a and 29 b. These markings also guide the inflation and help locate the correct position of the sheath relative to the distal opening of the through passage 27 and its vascular puncture site. The respective markings can be provided, for example, on the sleeve 28 covering the base sheath 20 and on the base sheath 20. Alternatively, the entire region may be marked substantially uniformly by adding a suitable externally readable substance to the jacket material in that region. According to such embodiments, at least a portion of the expandable portion, such as the above-described flexible portion and/or stretchable portion of the sheath, can be marked.

Fig. 3 shows another embodiment of a sheath 10 according to the invention. According to this embodiment, the inflation device 26' is configured as an inflation tube that is helically wrapped around the base sheath 20. By inflating the tube, the outer diameter of the sheath is increased without substantially affecting the bending flexibility of the device.

The embodiment according to fig. 4 shows another type of expansion device 26. Here, the base sheath 20 includes a flexible portion 26a between the proximal end 20b and the distal end 20 a. When the distal end portion of the base sheath 20 is pulled in the proximal direction R with the pulling means 26b, 26c, 26d, the flexible portion 26a is configured to expand so as to increase the outer diameter of the sheath. Such traction means can for example comprise a slider 26d at the proximal end of the sheath. The slider 26d can be connected to the pull ring 26b, for example, via a wire. This pull ring 26b is in turn secured to the base sheath 20 at a distal end, adjacent the distal end of the flexible portion 26 a. By pulling the pull ring in the proximal direction R by means of the slider 26d, the flexible portion 26a of the sheath gradually expands in a desired manner, thereby increasing the outer diameter of the sheath 10. A scale may be provided on the base sheath 20, for example, proximate the slider 26d, such that the extent of the flexible portion 26a may be readily viewed through the sliding distance or position of the slider 26 d. Essentially the same result can be achieved by pushing the proximal end 20b towards the distal end 20 a. In this case, if desired, a pulling device may be used in order to maintain the position of the proximal end of the sheath relative to the vessel aperture.

The embodiment according to fig. 5a, 5b shows another type of expansion device 26 ". Here, the base sheath 20 includes a stretchable portion 26 "between the proximal end 20b and the distal end 20 a. The stretchable portion is configured to reach a first thickness in a stretched state (see fig. 5a) and to reach a second thickness greater than the first thickness in an unstretched state (see fig. 5 b). The outer diameter of the sheath can be increased by releasing the proximal end of the base sheath in the direction R' of the vessel aperture from the stretched state towards the unstretched state (see fig. 5a, 5 b). Also, if desired, the traction device described with reference to FIG. 4 may be used to maintain the position of the proximal end of the sheath relative to the vessel aperture.

Other components of the sheath 10 will be described below with reference to fig. 6, which fig. 6 illustrates the sheath 10 of fig. 1 in perspective view.

The channel 27 may be connected to different measuring devices, such as a blood pressure measuring device 30, by suitable connectors 32, 55. Alternatively or additionally, a temperature measuring device, such as a thermistor (not shown), can be connected to or inserted into the channel 27, for example to obtain information for measuring the cardiac output of the patient.

Via channel 27, guidewire 50 may be further inserted into the blood vessel. For example, access to channel 27 can be made via luer connector 55.

As mentioned above, the sheath 10 is adapted to be pushed through the supply conduit 40 of the heart pump 70. The heart pump 70 with the catheter 40 and the sheath 10 may be provided as a cohesive unit. The heart pump 70 is preferably introduced into the vascular system of the patient in the manner described above by introducing a sheath, which is removed with a peeling technique and replaced by advancing the sheath 10.

The above-described securing element 60 is used to secure (e.g., suture) the sheath 10 to the patient after insertion of the sheath into the patient's blood vessel. For this purpose, openings 66 may be provided. The fixation element 60 has a region 62 across the base sheath 20 for application of a sterile cover (not shown). The regions 62 of the fixing element 60 slope downwards in a ramp shape on both sides of the base sheath 20 transversely to the main direction of the base sheath. Furthermore, the fixing element 60 comprises a guide element 64, the guide element 64 serving as a stop for applying the sterile cover.

The fixation element 60 may also include circulation openings 67 and/or circulation open slots (not shown) to allow air to circulate under the sterile cover. These openings or slots preferably pass through the fixing element in the direction in which the sheath passes.