HK1251993B - Sheath device for inserting a catheter - Google Patents

Description

Sheath device for inserting a catheter

The present application is a divisional application of application number 201280060021.1 filed on December 21, 2012, and the invention name is sheath device for inserting a catheter.

Technical Field

The present invention belongs to the field of mechanics and can be advantageously used in medical engineering. The invention relates to a sheath device for inserting a catheter into a patient, wherein the sheath extends into the patient's body and a proximal end of the sheath protrudes from the patient's body. The sheath provides an inner lumen through which the catheter is inserted into the patient's body.

Background Art

Generally speaking, such sheath devices are known. They are used, for example, in the field of minimally invasive medicine for inserting various catheters. Such a sheath can be used, for example, to insert a blood pump for cardiac support, which unit comprises a distal pump unit, a hollow catheter and a drive shaft guided through the hollow catheter. In miniaturized form, such pumps are often designed so that they can be radially compressed and, in the compressed state, inserted through a blood vessel of the body together with the catheter. The pump can then be deployed at the place of use, for example in a blood vessel or in a heart chamber. In the deployed state, such a pump can then achieve the required pumping capacity upon activation of the transport element.

In addition to such a compressible heart pump, other functional elements are also conceivable, such as stents or milling heads, which are introduced into a body cavity via the sheath according to the invention for removing plaque from a blood vessel.

Inserting such functional elements and catheters through a sheath is much easier and carries lower medical risks than direct insertion.

The sheath itself can be inserted, for example, using the known Seldinger technique, into the vascular system. To do this, an opening is first made in the body vessel using a puncture needle, after which a guidewire is advanced. Optionally, a dilator is then introduced over the guidewire, followed by the sheath itself. Unless further guidance is required, the guidewire can be removed and other components can be introduced through the sheath.

A corresponding method is disclosed, for example, in WO 02/43791. According to this document, a heart pump is advanced along a guide wire into the patient's left ventricle, whereupon the pump unit is pushed out of a sheath through the vascular system into the ventricle.

Fluid pumps with high rotational speeds, such as blood pumps, to achieve corresponding pumping capacities are also disclosed in WO 02/43791 A1 and EP 2 047 872. EP 2 047 872 A1 describes a pump comprising a distal pump unit to which a proximal hollow shaft tube is connected. A drive shaft extending within the shaft tube is connected to the drive unit to drive the rotor of the pump.

Using a convenient sheath, especially a sheath that includes a drive shaft, to insert the catheter has the advantage that the catheter, especially the drive shaft, is subjected to less mechanical stress during insertion. This is particularly advantageous for the drive shaft, which is exposed to high mechanical stress when the blood pump is in operation.

In order to facilitate the use of a sheath for inserting a catheter, especially a sheath including a distal pump unit, it is necessary to advance the sheath together with the hollow catheter as close as possible to the point of use and then remove the shaft catheter or pump from the sheath, thereby retracting the sheath at least a certain distance. The unit to be introduced is thus moved the minimum possible distance in the vascular system or the lumen of the patient's body when it is located outside the sheath, thereby significantly reducing the tension on the vessel wall caused by the insertion of the foreign object and the mechanical stress on the unit to be inserted.

On the other hand, such a procedure requires that the sheath have a corresponding excess length, typically protruding a certain distance from the patient's body after advancement and subsequent retraction.

Summary of the Invention

The object of the present invention is to advantageously design a corresponding sheath device so that it is particularly easy to handle.

This object is achieved by the following features of the invention, by the following catheter system of the invention, and by using the following method of the invention.

The present invention provides a sheath device for inserting a catheter into a patient's body, comprising a first sheath having a proximal end and a distal end, wherein when used as needed, the distal end of the first sheath is for placement inside the patient's body and the proximal end of the first sheath is for placement outside the patient's body, and wherein the first sheath comprises a tubular segment and a sheath housing, wherein the sheath housing is located at the proximal end of the segment and comprises a receiving channel for a wire-shaped body, in particular for a catheter, and wherein the tubular segment is detachably retained in a non-active manner by a clamping element of the sheath housing.

The present invention provides a catheter system, comprising a catheter and a sheath device according to the aforementioned technical solution, characterized in that the sheath shell includes an additional clamping element proximal to the clamping element, wherein the additional clamping element is provided to radially clamp the catheter or radially clamp a second sheath surrounding the catheter and/or a functional element connected to the catheter.

The present invention provides a method, comprising a method for inserting a catheter having a functional element at its end into a patient's body, characterized in that the catheter is inserted into the sheath housing and the tubular section and then inserted until the tubular section enters the patient's body, the tubular section is then pulled out of the patient's body in the proximal direction for a certain distance, the clamping element is released and the tubular section is moved into the sheath housing.

According to the present invention, a sheath device for inserting a catheter into a patient includes a first sheath having a proximal end and a distal end, wherein, when used as desired, the distal end of the first sheath is positioned within the patient's body while the proximal end protrudes from the patient's body. The first sheath further includes a tubular section and a sheath housing, the sheath housing being located at the proximal end of the tubular section and including a receiving channel for a wire harness, particularly a catheter.

Since the tubular segment is detachably held in the clamping element of the sheath housing in a non-active manner, the sheath device can first be pushed a certain distance into the patient's body to insert the catheter into the patient, the catheter can then be deployed, and the sheath device can be pulled a certain distance out of the patient's body. The tubular segment can then be easily changed from being clamped to being unclamped, shortened, and re-clamped.

This allows the sheath device to be very easily cut to a suitable size after use so that no unnecessary length protrudes from the patient's body.

According to an advantageous embodiment of the invention, the tubular section can be moved into the sheath housing when the clamping element is loosened. The tubular section can thereby be accommodated in the sheath housing and removed therein or through the proximal opening of the sheath housing.

Particularly useful is that the tubular section extends into the sheath housing in a manner that directly extends from the catheter's receiving channel. This design greatly simplifies the insertion of the catheter into the tubular section, as the catheter is first inserted into the sheath housing, guided through its receiving channel, and thus reaches the opening of the tubular section directly and effortlessly. This ensures that insertion of the catheter into the proximal end of the sheath device is simplified and can be performed reliably.

This design also allows the proximal end of the tubular section of the sheath to be easily pushed into the receiving passage within the sheath housing, thereby being received or removed therefrom.

According to another advantageous embodiment of the present invention, the clamping element comprises an elastically deformable clamping ring that surrounds the tubular segment and can be compressed by an operating element so that the ring radially clamps the tubular segment. Such a clamping element has a very simple mechanical design, is reliable, saves space, and is easy to operate. It provides a passive fixation of the tubular segment and can be easily released.

For this reason, the clamping ring can be deformed radially by the axial pressure effect.For this reason, this ring can be designed as an elastic ring, or a slotted ring made of plastic material or metal.

As an elastic ring, for example, the clamping ring can be flattened by a pressure piece, wherein the ring expands radially inwards and outwards, thereby reducing the inner diameter of the ring. If the clamping ring is a plastic or metal slotted ring, it can be compressed radially inwards, for example, by the action of a wedge-shaped body on the radially outer side of the ring. For this purpose, for example, a ring with a wedge-shaped cross-section can be used, which is axially movable relative to the tubular element. The clamping ring can also have a conical cross-section. In a preferred embodiment, the clamping ring also ensures a liquid-tight connection between the sheath housing and the tubular section, which can be achieved, for example, in the form of the elastic ring described above. However, the sealing effect can also be achieved by another sealing element, for example when using a plastic or metal slotted ring.

The clamping element can comprise a threaded element, for example, for axially pressing the clamping ring. The threaded element can then be used, for example, to press the pressure piece axially onto the clamping ring.

To facilitate the cutting of the tubular segment to shorten it, the tubular segment may advantageously have at least one predetermined breaking point at least at the proximal end, which is used to sever the longitudinal section of the tubular segment. In certain areas, the tubular segment may include spherical notches or perforations or other circumferentially weakened areas of the material, which may be selectively predetermined, for example, by molecular structure.

The tubular segment may also have one or more predetermined breaking points or axially extending tear lines, which are referred to as peel-away inserts. In the case of such tear lines, the insert can be opened at one end by pulling the two or more outer shell parts apart and away. To this end, the tubular segment may also include an operating element at the proximal end, such as a loop or tab.

According to the present invention, the sheath device may further include a cutting element, by which a portion of the tubular segment can be severed, perforated, grooved, or scored to facilitate severing. For example, one or more blades may be inserted into the sheath housing so as to automatically groove the tubular segment as it is pushed through the sheath housing. For example, such perforations may occur longitudinally along the tubular segment. Blades may also be provided to create cuts or weakened areas circumferentially along the tubular segment during rotation of the sheath housing relative to the tubular segment.

Such a blade can be made of a very hard material, such as a ceramic material, so that even reinforced tubular sections, in particular tubular sections reinforced with metal fabric, can be cut. A substantially needle-shaped blade can also be provided which can cut during axial movement and circumferential rotation of the tubular section.

According to a particularly advantageous embodiment of the invention, the cutting element comprises at least one blade which is movably guided, in particular movably guided in the sheath housing and radially movably guided therefrom towards the catheter. Such a blade can be driven by a handle located on the outside of the sheath housing, so that when the tubular section is pushed out of the patient's body and moved relative to the sheath housing, a partial severing of the tubular section can be achieved with a simple manual action.

In addition to a sheath device of the form described above, the present invention also relates to a catheter system comprising a catheter and such a sheath device, wherein according to the invention, the sheath housing advantageously comprises a further clamping element proximal to the clamping element, wherein the further clamping element is provided in order to radially clamp the catheter or to radially clamp a second sheath around the catheter and/or a functional element connected to the catheter.

Generally speaking, the respective further clamping element can also comprise a clamping ring and can, for example, have the same design as the first clamping element for fixing the tubular section. However, the further clamping element can also have a different design from the first clamping element and, essentially, be designed according to the variants of the above-mentioned clamping elements.

The present invention also relates to a method for inserting a catheter, comprising inserting a functional element arranged at the end into a patient's body, wherein the catheter is inserted into a sheath housing and a tubular section and then inserted until the tubular section enters the patient's body, the tubular section is then pulled out of the patient's body in a proximal direction for a certain distance, and a clamping element is released and the tubular section is moved into the sheath housing.

After being moved into the sheath housing and/or pushed through the sheath housing, the tubular section can be shortened. Before or after shortening, the tubular section can be clamped again by the clamping element.

This clamping is advantageously carried out by tearing the tubular section in the longitudinal direction, in particular starting from the proximal end of the tubular section, and subsequently tearing it off.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the drawings and described below on the basis of exemplary embodiments.

FIG1 is a general schematic diagram of a vascular system including an inserted first sheath;

FIG2 is a detailed view of a section in FIG1 ;

FIG3 shows an embodiment of the present invention comprising a first sheath and a second sheath;

FIG4 shows an embodiment of a pump;

FIG5 shows a second sheath including a pump deployed therein;

Figures 6 and 7 show the pump being pulled into the second sheath;

Figures 8 and 9 show the transfer of the pump from the second housing to the first housing;

FIG10 is a longitudinal section through the sheath housing including the tubular section;

FIG11 is a longitudinal section through a portion of a sheath including a cutting element;

FIG12 is a longitudinal section through a jacket housing comprising a clamping element for a tubular section and further clamping elements; and

FIG. 13 is a longitudinal section through an alternative clamping ring comprising a conical pressure piece.

DETAILED DESCRIPTION

FIG1 shows a schematic diagram of a human vascular system 1. One of the femoral arteries 2 is located in the groin area and is connected to the aortic arch 3 via the aorta and subsequently leads to the ventricle 4. An introduction sheath 10 is first inserted into the femoral artery 2, for example using the Seldinger technique. To this end, the femoral artery or blood vessel is punctured, for example using a steel cannula with a cutting head. A guide wire 12 is pushed through the steel cannula, which is inserted into the puncture and inserted retrogradely through the aortic arch 3 into the left ventricle 4. After the puncture cannula is removed, a first sheath 10 designed as an introduction sheath is threaded over the guide wire and inserted into the vascular system through the puncture, the first sheath 10 comprising a tubular section 11 and an optional dilator (not shown here), wherein the sheath is inserted a short distance into the lumen of the vascular system or into the place of use of the element to be inserted. Subsequently, a fluid pump is inserted into the vascular system via the introduction sheath 10.

For example, the tubular section 11 of the first sheath 10 is inserted into the artery so that the proximal end of the first sheath 10 is located outside the femoral artery and can then be used to insert a pump. The pump can then be threaded onto the guidewire 12 to guide the pump into the left ventricle via the guidewire.

It is also possible to introduce the tubular section 11 of the first sheath 10 into the left ventricle over a guide wire and then remove the guide wire 12 from the first sheath. An optional pump unit is then introduced into the vicinity of or into the left ventricle 4 through the volume of the first sheath.

In this example, the method is described based on inserting a pump into the left ventricle to support cardiac function. However, it is readily apparent to those skilled in the art that the pump or other functional components can also be placed and introduced into other areas of the endogenous vascular system.

FIG2 shows the region of FIG1 , in which a first sheath 10 is introduced from the outside through endogenous tissue into the lumen _LG of the femoral artery 2. The first sheath comprises a tubular segment 11, which is connected at its proximal end to a sheath housing 13. The tubular segment 11 defines a lumen _L1 having an inner diameter _d11 . This inner diameter widens in a trumpet-like manner towards the proximal end of the tubular segment 11 in a region 14.

The sheath housing 13 includes a hemostatic valve known in the art that prevents the fluid in the lumen _LG from leaking out through the lumen _L1 .

3 , the first sheath 10 of FIG. 2 is coupled to a second sheath 20. Only the tubular section 21 of the second sheath 20 is shown, defining a lumen L ₂ having an inner diameter d _21. The outer diameter of the distal end of the second sheath 20 is such that it can be inserted into the sheath housing 13. However, the inner diameter d ₂₁ is greater than the inner diameter d ₁₁ .

A pump (not shown) located within lumen _L2 can be transferred from the second sheath lumen _L2 to the first sheath lumen _L1 by pressing. The pump is then delivered through the first sheath lumen _L1 to the location in the vascular system where it is effective. To this end, the pump can be guided over a guidewire or introduced through the first sheath lumen without a guidewire. Before the pump is pushed out, the first sheath can be advanced distally to the location where the pump is to be used to protect the pump, the vessel wall, and the shaft catheter.

A possible embodiment of the pump 30 will be described in detail based on FIG4 . The pump 30 includes a distal pump unit 31 and a shaft catheter 32, which is adjacent to the proximal end of the distal pump unit 31. At the proximal end, the shaft catheter 32 includes a coupler (not shown) for coupling the shaft catheter 32 to a drive element. The drive element can be placed outside the patient's body and causes a flexible shaft extending within the shaft catheter 32 to rotate, thereby driving the distal pump unit 31.

The distal pump unit comprises a pump housing 33 made of crossed nickel-titanium alloy struts. One or more portions of the nickel-titanium alloy housing are provided with a covering 34 which extends distally and proximally to a rotor 35 placed in the housing 33. The rotor is connected to a shaft 36 which extends in the shaft catheter 32, thereby causing it to rotate. The housing and rotor are compressible, i.e. the pump is self-decompressible. After the distal pump unit is pushed out of the sheath at the distal end, the pump is deployed. In preparation for implantation, the pump is compressed and the distal pump unit is pulled into the distal end of the sheath lumen of the second sheath. The inner diameter of the sheath lumen is at least greater than the outer diameter of the shaft catheter.

The rotor is movable relative to the pump housing in the axial direction, in particular by an axial displacement of the drive shaft. However, the rotor can also be fixed relative to the pump housing in the axial direction.

The pump optionally comprises an outflow hose 37 defining a flow path for the pumped fluid proximal to the rotor 35. An outlet opening (not shown in detail) is located at the proximal end of the outflow hose 37.

Of course, the pump can also be switched from pumping operation to aspiration operation, so that the pump no longer conveys fluid from the distal end to the proximal end, but vice versa.

A detailed description of further suitable pumps can be found, for example, in document EP 2 047 872 A1.

The functionality of the system will now be described based on FIG. 5 to FIG. 9 .

FIG5 shows a pump 30', which generally corresponds to the pump 30 of FIG4. For simplicity, the pump details are not shown. Only the inflated housing and the "pigtail" at the distal end of the housing, which prevents the heart from pumping against the heart wall, are shown. A shaft catheter 32' extends toward the proximal end of a distal pump unit 31'. A second sheath 20' is provided, which surrounds a region 38' of the shaft catheter 32' and includes a lumen _L2 , which, when expanded, has an inner diameter _d21 that is smaller than the diameter of the distal pump unit 31'.

The pump 30' shown in FIG5 is a compressible pump. That is, for example, the distal pump unit 31', including the pump housing and the rotor located therein, is designed to be compressible, meaning its diameter can be reduced. For example, after a quality inspector or physician confirms the proper functioning of the pump 30', for example by observing the rotation of the rotor unit located therein during a test run, the distal pump unit 31' is pulled into the lumen _L2 of the second sheath 20' by pulling the shaft catheter 32' in a proximal direction. Pulling the pump into the second sheath 20' prevents bending or damage to the shaft catheter or the shaft extending therein. The pump 30' shown in FIG5 and the second sheath 20' surrounding the region 38' of the shaft catheter 32' form a system 200 that allows for testing the functionality of the pump 30' prior to surgery and before compressing the pump by pulling the distal pump unit 31' into the distal end of the sheath 20', thereby preventing damage to the shaft.

Although the system can be implemented with both actively decompressing and self-decompressing pumps, it is particularly suitable for self-decompressing pumps, ie pumps in which the distal pump element automatically returns to its original size outside the sheath.

Figure 6 shows an intermediate step when the distal pump unit 30' is pulled into the lumen of the second sheath 20'. Obviously, the distal pump unit 30' can be compressed and reduced to a very small diameter so that the distal pump unit 30' can be accommodated in the lumen of the second sheath 20'.

FIG6 further shows a coupler 39' adjacent to the shaft catheter 32', which allows the shaft extending in the shaft catheter to be coupled to the drive unit. Since the outer diameter of the coupler 39' is generally larger than the inner diameter of the inner cavity _L2 , the second sheath 20' is generally added from the proximal end of the shaft catheter 32' in a direction toward the distal end before the coupler 39' is installed so that the pump can be shipped as a system 200, that is, the pump includes a second sheath 20' located at the proximal end of the distal pump unit 31' and a sub-assembled coupler 39'. FIG6 also shows a slightly trumpet-shaped expansion at the distal end of the second sheath 20'. The trumpet-shaped expansion 24' allows the distal pump unit 31' to be more easily pulled into the inner cavity _L2 of the second sheath 20'.

In Figure 7, the distal pump unit 31' is finally placed as a whole in the inner cavity _L2 of the second sheath 20". The second sheath 20" includes two partially assembled clamping units 22". When the distal pump unit 31' is pulled into the inner cavity _L2 or subsequently torn, the partially assembled clamping units enable the second sheath 20" to be better clamped or removed. If there is a "coil", it is also advantageously pulled into the inner cavity _L2 so that the distal pump unit 31' together with the pump components located at the distal end of the distal pump unit 31' are located in the inner cavity _L2 .

From FIG. 8 it can be seen how the system 200 comprising the pump 30 ′ and the second sheath 20 ″ is effectively connected to the first sheath 10 to form the system 100 . First, the distal end of the second sheath 20 ″ is inserted into the sheath housing of the first sheath 10 . When the distal tip of the second sheath 20 ″ contacts and aligns with the mouth of the tubular section of the first sheath 10 , the pump is immediately transferred from the second sheath 20 ′ to the first sheath 10 ′ by pushing in the distal direction, which is generated by pushing the shaft catheter 32 ′. The diameter of the distal pump unit 31 ′ is thereby further reduced to the inner diameter d ₁₁ of the lumen L ₁ .

9 shows a subsequent step in which the distal pump unit 31' is entirely located within the lumen _L1 of the first sheath 10. The fact that the distal pump unit 31' is entirely located within the lumen _L1 of the first sheath can be indicated, for example, by using colored markings 50 applied to the exterior of the shaft catheter 32'.

Subsequently, the second sheath 20 ″ designed as a “peel-off” sheath is removed from the shaft catheter 32 ′ by tearing the peel-off sheath from the proximal end to the distal end and tearing it off the shaft catheter 32 ′. This direct tearing from the proximal end to the distal end can be supported by the grooves A, which are mainly based on the direction of the molecular chains of the plastic material used from the proximal direction to the distal direction.

After the peel-off sheath is removed, the pump 30 ′ is further guided to a suitable position in the lumen L ₁ of the first sheath 10 .

Optionally, the first sheath is advanced to the immediate vicinity of the site of use before or after the pump is inserted using the distal sheath port.

The second sheath 20" does not need to be reinforced, especially when the distal pump unit 31' is pulled into the distal end of the second sheath lumen _L2 , because the risk of shaft twisting during the pulling action is greatly reduced.

As shown in Figures 7 to 9, when the pump is transferred from the second sheath to the first sheath, the second sheath may include a reinforcement structure in the form of a lead-in wire, or the tubular section 21" of the sheath 20" may be made of non-deformable plastic material or metal instead of flexible plastic material.

Another option for stabilizing the pump and the second sheath is to clamp the second sheath 20 ″ by means of a supporting element 40 in the form of a stabilizing outer sleeve when the pump 30 ′ is advanced in the distal direction, ie in particular when transferring the pump 30 ′ from the second sheath to the first sheath.

Next, another possible variation of the method for inserting the pump into the left ventricle will be described. As a preparatory measure, the pump is first filled with sterile saline solution, thereby completely isolating it from air. Subsequently, a peel-away sheath located proximal to the distal pump unit is advanced into the optional outflow hose. For example, the peel-away sheath may have a diameter of 10 French (Fr). Once the peel-away sheath is advanced into the outflow hose, it is surrounded by a sleeve-like element to secure the secondary sheath. The distal pump unit is then pulled into the peel-away sheath, optionally by slightly rotating it proximally on the shaft catheter. The pump is then advanced into the secondary sheath, securing the optional coiled tubing within the peel-away sheath. These steps make it possible to check the pump's functionality even before the procedure and subsequently insert the pump into the catheter without time pressure. For example, the vascular system is only then punctured to insert the primary sheath. However, to save time, an assistant can also prepare the pump while the user completes the puncture.

For example, after a 9 Fr introducer sheath has been introduced into the left ventricle, the optional dilator is pulled out of the introducer sheath and removed.

The pump, which is initially enclosed in a peel-away sheath, for example, which is enclosed by a sleeve to hold the second sheath, is pushed into the sheath housing until the tip of the peel-away sheath hits a mechanical stop. The pump is then transferred from the peel-away sheath into the tubular segment by pushing the shaft catheter. When the distal pump unit has been fully transferred into the introduction sheath, which can be verified, for example, based on optical markings on the catheter shaft, the peel-away sheath can be torn open and removed from the shaft catheter. The pump is then advanced into the first sheath and into the left ventricle. The first sheath is then pulled out of the left ventricle to the starting point of the descending aorta.

For example, the positioning of the distal pump unit in the left ventricle can be controlled by radiofluoroscopy. To this end, radiographically visible markers are located on or near the pump housing, for example, on the catheter, or the pump housing itself is radiographically visible. The pump's discharge area, that is, the outlet opening of the outflow hose, is also located in the region of the ascending aorta. This, too, can be checked using radiographically visible markers. The tip of the optional coiled catheter should contact the apex of the left ventricle.

To remove the pump from the ventricle, the pump is retracted from the introduction sheath by applying tension to the shaft catheter and removed from the arterial vascular system in a compressed state. If the primary sheath has already been shortened, the pump can also be first retracted a certain distance into the shaft catheter to compress it. To this end, the shaft catheter can include a retraction funnel through which the pump can be pulled by pulling on the drive shaft. The primary sheath and any remaining components are then removed from the vascular system.

The present invention offers particular advantages when using a long sheath for pump implantation and placement. The long sheath not only serves to insert the pump into the endogenous lumen, as in the prior art, but also guides the pump through the sheath lumen into the vicinity of the site of action. To this end, a sheath length of between 40 and 120 centimeters is advantageous in the medical field. This length is determined by the intended site of action of the pump and the patient's size.

If the pump, along with the long sheath, is pulled out of the endogenous lumen, the femoral artery bleeding can be stopped by applying a pressure bandage. Alternatively, the pump can be pulled out of the sheath lumen of the long sheath. An additional guidewire can be placed in the sheath lumen, and the elements for suturing the puncture site can be guided over this guidewire after the sheath is removed. This improves hemostasis.

10 to 13 show a particular embodiment of a first sheath according to the invention, comprising one or more clamping units for fixing the tubular section 41 in the sheath housing 43 .

FIG10 shows a longitudinal cross-section of a sheath housing 43, which generally has the shape of a cylindrical sleeve that can be closed at least at its distal end 44, facing the patient's body, by a pressure screw 45. The sheath housing 43 has a continuous receiving channel 46 for the tubular segment 41 of the first sheath. In the depiction of FIG10 , the tubular segment 41 is shown extending from the direction of the patient's body into the flushing space 47 of the receiving channel 46 and then into a dotted pattern in the proximal direction. This indicates that the tubular segment 41 is axially displaceable relative to the sheath housing 43 within the receiving channel 46, or, in other words, that the sheath housing 43 is displaceable on the tubular segment 41.

To insert a functional element, such as a pump, into the first sheath, the tubular section 41 is typically pulled out of the sheath housing 43, or during the production of the first sheath, so that its end is approximately at the first stop 48. As described above, the second sheath, including the retracted pump, can be pushed to this point to subsequently move the pump from the second sheath into the first sheath.

The first clamping element includes elements such as a first pressure screw 45 , a first clamping ring 50 made of elastic material, and a first stopper 48 .

The pressure screw is tightened onto the sheath housing via external threads in an area overlapping the distal end 44 of the sheath housing 43. Manual rotation of the pressure screw 45 causes the pressure screw to move axially, resulting in axial compression or expansion of the clamping ring 50. During axial compression, due to resistance encountered proximal to the first stop 48, the clamping ring 50 tends to deform radially inward or outward to maintain its volume, thereby clamping the tubular section 41.

The tubular section 41 is thus axially fixed relative to the jacket housing 43. This fixation can be released by loosening the pressure screw 45, so that the tubular section 41 can then be easily moved axially in the jacket housing 43. To this end, when loosened, the clamping ring can have an inner diameter that is equal to or greater than the first jacket diameter.

Thus, if tubular segment 41 is first advanced as far as possible into the patient's body to allow insertion of the sheath-protected pump to its point of use, such as the heart chamber, after the pump is removed, tubular segment 41 is pulled out, with the sheath as a whole protruding slightly relative to the patient's body. Clamping elements 48, 45, 50 can then be loosened and sheath housing 43 can be advanced over tubular segment 41 close to the patient's body. Tubular segment 41 then extends completely within sheath housing 43 and optionally protrudes proximally therefrom. Using a method described in greater detail below, tubular segment 41 can then be cut at certain locations to remove excess length.

A combined hemostatic valve is provided in the sheath housing 43 to provide a better seal, consisting of a dome valve 51 and a valve leaf 52. If no tubular segment 41 or shaft catheter is extending in the receiving passage 46 at this point, the valve leaf closes the sheath housing 43, while the dome valve 51 is optimized to provide a tight seal around a wire-like body, such as a tubular segment or catheter.

A further pressure screw 54 is provided at the proximal end 53 of the sheath housing 43. This pressure screw operates in essentially the same manner as the first pressure screw 45 and, via the pressure element 55, effects compression of a second clamping ring 56 relative to a second mechanical stop 57. A particular feature of note is that the distal end of the second clamping ring 56 has a conical shape, which facilitates radially inward deformation when axial pressure is applied by the pressure screw 54. The second stop 57 has an oppositely directed conical design. However, a non-conical clamping ring 56 may also be used, and may instead have a rectangular or circular cross-section.

The flushing space between the clamping elements 48 , 45 , 50 and the flushing inlet 58 can then additionally be provided with one or more further valves in order to ensure a fluid-tight connection between the tubular section 41 and the sheath housing 43 even when the clamping elements 48 , 45 , 50 are loosened.

10 schematically shows a flushing element 58, which allows the flushing space 47 to be flushed with liquid to prevent bacteria from penetrating the patient's body through the first sheath. This flushing is particularly effective if the tubular section 41 ends in the flushing space 47 or distally thereto, so that the flushing liquid can reach both the outside and the inside of the tubular section 41.

FIG. 11 shows by way of example the arrangement and operating principle of the cutting element of the present invention.

If predetermined breakpoints are not pre-cut or otherwise predetermined, for example by providing a regional weakening of the wall thickness of the tubular segment 21 due to a predetermined molecular structure or thickness, these breakpoints can be introduced in a suitable manner by a cutting element during use of the first sheath. In the region of the flushing space 47 of the sheath housing 43 in FIG. 11 , a cutting element comprising blades 59, 60 is provided, which, for example, cuts the tubular segment in a circumferential cross-section during rotation of the sheath housing relative to the tubular segment. Cutting can also be performed in the axial direction.

To this end, the blades 59, 60 may also be arranged so that they cut longitudinally during the axial movement of the tubular section 41, as indicated by arrows 61. Blades may be provided for cutting in both circumferential and longitudinal directions.

FIG11 also shows that the blades 59, 60 can be moved radially toward the tubular segment 41 by actuation from outside the sheath housing 43. There, one or more blade holders, corresponding seals, and radial guide extensions of the suspension can be provided to prevent bacterial penetration through the moving elements of the blades, and when not actuated, the blades are positioned radially at a distance from the tubular segment 41. After the first sheath is used, pressure can be manually applied to the blades, and the undesired portion of the tubular segment 41 can be cut away. A stopper, not shown here, prevents the cutting depth from exceeding a critical dimension, thereby preventing damage to the catheter that may be located inside the sheath.

The blade shown may also form a cutting element for the second sheath.

FIG12 illustrates the advantageous use of a second clamping element, which, after the tubular section has been shortened, is located proximal to the jacket housing 43, and the shaft conduit 61 is guided out of the proximal end of the tubular section 41 and subsequently onto a coupling element for the pump drive shaft (not shown here), and then out of the jacket housing 43. The shaft conduit is sealed in the aforementioned dome seal 51, and the clamping element, which is axially compressed by the pressure piece 55 against the second stop 57, together with the elements of the second pressure screw 54 and the second clamping ring 56, provides sufficient radial space inward for the shaft conduit 61 to be clamped and, in particular, to be additionally sealed. The shaft conduit 61 has an outer diameter that is substantially smaller than the outer diameter of the tubular section 41 or the second jacket. The tubular section 41 and the shaft conduit 61 protrude therefrom and can thus be fixed in the jacket housing 43.

The second clamping element is also adapted to secure the second sheath with the second clamping ring 56 when the second sheath is inserted into the sheath housing 43 so that the second sheath is sufficiently fixed relative to the sheath housing and in particular to the tubular section 43 to allow the shaft catheter 61 to be advanced.

The first and second clamping rings 50,56 can be made of an elastomer, such as a rubber or silicone elastomer, and thus can be fully elastic, but can be deformable and not compressible. In this regard, it is also possible to use an elastic foam material, the partial volume of which can be compressed.

FIG13 is a schematic diagram of another type of clamping ring 62, which may be made of, for example, a plastic material or metal and may include slots to allow radial compression. The slotted clamping ring 62 has a conical outer profile. When axial pressure is applied to a pressure piece 63 in the direction indicated by arrow 65, the conical profile of the pressure piece 63 pushes against the clamping ring 62, for example, by the pressure screw shown above, to radially compress the clamping ring. The slotted clamping ring 62 is axially secured by a stop 64.

A first aspect of the invention relates to a sheath device for inserting a catheter into an inner cavity, in particular into a patient's body, comprising a first sheath (10, 11, 13, 21, 21', 21", 41, 43) having a proximal end and a distal end, in particular located on the patient's body side, wherein the first sheath comprises a sheath housing (13, 43) having a receiving channel, which is hereinafter indicated as the first receiving channel, and a further receiving channel for receiving a tubular section, which extends distally from the sheath housing and coaxially with respect to the first receiving channel, and the tubular section is axially displaceable and fixable.

The first and the further receiving channel are in particular arranged coaxially with respect to one another and axially behind one another, and the tubular section can also extend in both receiving channels.

A second aspect of the present invention relates to a sheath device according to the first aspect, wherein the diameter of the first receiving channel is different from the diameter of the further receiving channel.

The diameter of the first receiving channel can be smaller or larger than the diameter of the further receiving channel. However, it is also possible that the diameter of the first receiving channel substantially corresponds to the diameter of the further receiving channel.

According to a third aspect of the invention, clamping elements (54, 54', 55, 56, 56', 57, 57') can be provided in the first receiving channel (46) and/or the further receiving channel according to the first or second aspect of the invention for fixing the tubular section (11, 21, 21', 21", 41) by clamping in the further receiving channel.

For example, at least one of the clamping elements (54, 54', 55, 56, 56', 57, 57') can be designed such that it selectively allows clamping of a wire-shaped body having a first diameter or a wire-shaped body having a second diameter, wherein the first diameter is different from the second diameter.

For this purpose, for example, a clamping mechanism comprising a clamping screw can be provided, which has several preferred clamping positions. For example, these can be achieved by a variety of positions of the clamping screw.

According to a fourth aspect of the invention, a sheath device according to the first, second or third aspect is provided, wherein radial expansion of the first or further receiving channel including a flushing element can be additionally provided in the first receiving channel and/or the further receiving channel in the sheath housing (13, 43).

For example, the flushing element may comprise one or more radial fluid connections for supplying and removing fluid.

For example, in the radial expansion region, at one axial end, a valve may be additionally provided for closing the radial expansion in a fluid-tight manner.

The valve may include a flap and/or a dome valve.

A fifth aspect of the invention relates to a sheath device according to any of the preceding aspects, wherein a cutting device is provided comprising at least one blade having at least one possible position in which it protrudes radially into the first receiving channel or into the further receiving channel or into the deployment area and in particular into the flushing space.

For example, at least one blade can be provided for cutting in the circumferential direction of the receiving channel or for cutting in the axial direction. Each blade can be displaced in the radial direction relative to the receiving channel or the expansion area between at least one cutting position and a non-cutting position, in particular a position in which it does not protrude into the receiving channel. This displacement can occur against the reaction force of a spring, thereby cooperating with the knife or knife holder.

Additionally, a liquid-tight guide channel may be provided for each knife.

A sixth aspect of the present invention relates to a sheath device according to any of the preceding aspects, comprising a tubular section located in the further receiving channel.

A seventh aspect of the invention relates to a catheter device comprising a sheath device according to any of the preceding aspects and comprising a catheter, which extends in the receiving channel together with a second tubular sheath, wherein the second sheath is fixed in the first receiving channel, in particular in a clamping element (54, 54', 55, 56, 56', 57, 57') of the first receiving channel.

An eighth aspect of the invention relates to a method for inserting a catheter (32, 66) into a patient's body, by using a sheath device according to any of the preceding aspects of the invention and by using a second sheath (20, 20', 20", 20'", wherein the second sheath together with the catheter is first inserted into the first sheath (10, 11, 13, 21, 21', 21", 41', 43), in particular up to the end of the tubular section and adjacent thereto, the second sheath being subsequently fixed by a clamping element (54, 54', 55, 56, 56', 57, 57'), after which the catheter is transferred from the second sheath into the first sheath.

A ninth aspect of the present invention relates to a method according to the eighth aspect, wherein after the catheter is inserted into the first sheath, the second sheath (20, 20', 20", 20'") is removed, in particular by tearing it open or tearing it off.

A tenth aspect of the invention relates to a method according to the eighth or ninth aspect of the invention, wherein the catheter is fixed in a clamping element (54, 54', 55, 56, 56', 57, 57') after the second sheath (20, 20', 20", 20'") is removed.

An eleventh aspect of the present invention relates to a method for inserting a catheter into a patient's body, by using a sheath device according to any of the preceding aspects of the invention, wherein a tubular segment (11, 21, 21', 21", 41) is introduced into the sheath housing (13, 43) and likewise into the inner cavity of the patient's body, wherein a functional element is then introduced into the inner cavity of the patient's body by means of the sheath device, wherein the tubular segment is then pulled at least a certain distance out of the inner cavity of the patient's body, wherein the sheath housing is displaced relative to the tubular segment, and wherein the tubular segment is then fixed to the sheath housing by means of a clamping element and/or cut out in the sheath housing.

Claims (14)

1. A sheath device for inserting a catheter into a patient, comprising a first sheath (10, 11, 13, 21, 21', 21”, 41, 43) having a proximal end and a distal end, wherein, when used as needed, the distal end of the first sheath is used for placement within the patient and the proximal end of the first sheath is used for placement outside the patient, and wherein the first sheath comprises a tubular segment (11, 21, 21', 21”, 41) and a sheath housing (13, 43), the sheath housing being located at the proximal end of the tubular segment and including a receiving channel (46) for a wire bundle (41, 66), and wherein the tubular segment (11, 21, 21', 21”, 41) is removably held in a non-active manner in clamping elements (45, 48, 50, 62, 63, 64) of the sheath housing. The sheath housing (43) is provided with a combined hemostatic valve, which consists of a dome valve (51) and a valve plate (52). 2. The sheath device according to claim 1, characterized in that, when the clamping elements (45, 48, 50, 62, 63, 64) are released, the tubular segment (11, 21, 21', 21”, 41) can be moved into the sheath housing. 3. The sheath device according to claim 1 or 2, characterized in that the tubular segment (11,21,21',21”,41) extends into the sheath housing in such a way that the receiving channel (46) extends directly into the sheath housing. 4. The sheath device according to claim 1 or 2, characterized in that the clamping element comprises an elastically deformable clamping ring (50, 62) surrounding the tubular segment (11, 21, 21', 21”, 41) and compressible by an actuating element to radially clamp the tubular segment. 5. The sheath device according to claim 4, wherein the clamping ring (50, 62) can be radially deformed by axial pressure. 6. The sheath device according to claim 4, wherein the clamping ring (50) is made of an elastomer or a slotted ring (62), the slotted ring (62) being made of plastic or metal. 7. The sheathing device according to claim 4, wherein the clamping element includes threaded elements (43, 45) for axially pressing the clamping ring (50, 62). 8. The sheath device according to claim 1 or 2, characterized in that the tubular segment (11,21,21',21”,41) has at least one predetermined break point at the proximal end of the tubular segment, the predetermined break point being used to cut off the longitudinal segment of the tubular segment. 9. The sheath device according to claim 1 or 2, characterized in that the sheath housing (13, 43) includes cutting elements (59, 60) through which a portion of the tubular segment (11, 21, 21', 21”, 41) can be cut, perforated, grooved, or scored to facilitate cutting. 10. The sheathing device according to claim 9, wherein the cutting element comprises at least one blade (59, 60) that is movably guided. 11. The sheath device according to claim 10, wherein the blade is movably guided within the sheath housing (13, 43). 12. The sheath device according to claim 10, wherein the blade is radially movable toward the conduit. 13. The sheath device according to claim 1, wherein the wire bundle is a conduit. 14. A catheter system comprising a catheter and a sheath device according to any one of the preceding claims, characterized in that the sheath housing (13, 43) includes additional clamping elements (54, 55, 56, 57) proximal to the clamping elements (45, 48, 50, 62, 63, 64), wherein the additional clamping elements are provided to radially clamp the catheter (66) or radially clamp a second sheath surrounding the catheter and/or connected to functional elements of the catheter.