HK1199846B - Sheath device for inserting a catheter - Google Patents

Abstract

In a sheath device for inserting a catheter 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, wherein when used as intended the distal end of the first sheath is provided for arrangement in the patient's body and the proximal end of the first sheath is provided for arrangement outside the patient's body, and wherein the first sheath comprises a tubular section (11, 21, 21', 21", 41) and a sheath housing (13, 43), which is disposed at the proximal end of the section and comprises a receiving channel (46) for a catheter, according to the invention the tubular section (11, 21, 21', 21", 41) is detachably held in a clamping element (45, 48, 50, 62, 63, 64) of the sheath housing in a non-positive manner so as to be able to easily shorten the tubular section.

Description

Sheath device for inserting a catheter

Technical Field

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

Background

Generally, such sheath devices are known. They are used for insertion of various catheters, for example in the field of minimally invasive medicine. Such a sheath, for example, may be used for insertion of a blood pump for cardiac support, such unit comprising a distal pump unit, a hollow catheter and a drive shaft guided through the hollow catheter. In a miniaturized form, such pumps are often designed so that they can be radially compressed and inserted in the compressed state along with a catheter through a blood vessel of the body. The pump may then be deployed at the site of use, for example in a blood vessel or in the heart chamber. In the deployed state, such a pump can then achieve the desired pumping capacity upon activation of the delivery member.

In addition to such compressible heart pumps, other functional elements are also conceivable, such as stents or milling heads, which are introduced into the body lumen through the sheath of the invention for removing plaque from blood vessels.

Insertion of such functional elements and catheters through a sheath is very easy and has a lower medical risk than direct insertion.

The sheath itself may be inserted, for example, into the vascular system using the known Seldinger Technique (Seldinger Technique). To this end, the body vessel is first provided with an opening through the puncture needle, after which the guide wire is pushed in. The dilator is then optionally introduced over the guide wire, and the sheath itself is then advanced. Unless further guiding tasks are required, the guide wire may be removed and other elements may be introduced through the sheath.

Corresponding processes are disclosed, for example, in WO 02/43791. According to the present disclosure, the heart pump is advanced along the lead and into the left ventricle of the patient, and the pump unit is pushed out of the sheath, through the vascular system and into the ventricle.

Fluid pumps with high rotational speeds, which are provided in the form of blood pumps in order to achieve a corresponding pumping capacity, are likewise known from WO02/43791 a1 and EP 2047872. EP 2047872 a1 describes a pump comprising a distal pump unit to which a proximal shaft hollow conduit is adjoined. A drive shaft extending in the shaft conduit is connected to the drive unit to drive the rotor of the pump.

The insertion of a catheter using a convenient sheath, in particular a sheath comprising a drive shaft, has the advantage of subjecting the catheter, in particular the drive shaft, to less mechanical stress during insertion. This is particularly advantageous for drive shafts which are exposed to high mechanical stresses when the blood pump is in operation.

To facilitate use of a sheath inserted into a catheter, particularly a sheath comprising 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 to retract the sheath at least a certain distance. The unit to be introduced is thus moved the smallest possible distance in the vessel system or a cavity of the patient's body when positioned outside the sheath, in order to substantially reduce the tension of the vessel wall due to the insertion of a foreign object and the mechanical stress of the unit to be inserted.

On the other hand, such procedures require the sheath to have a corresponding excess length to typically protrude a certain distance from the patient's body after advancement and subsequent retraction.

Disclosure of Invention

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

This object is achieved by the features of a sheath device for inserting a catheter into a patient described herein, by the catheter system of the invention, and by using the method of inserting a catheter into a patient of the invention.

According to the invention, a sheath device for inserting a catheter into a patient comprises a first sheath having a proximal end and a distal end, wherein the distal end of the first sheath is placed inside the patient while the proximal end protrudes from the patient when used as desired. The first sheath additionally comprises a tubular section and a sheath housing which is located at the proximal end of the tubular section and comprises a receiving channel for the strand-like body, in particular for a catheter.

Since the tubular section is detachably held in the clamping element of the sheath housing in a non-active manner, the sheath device can first be pushed into the patient over a certain distance in order to insert the catheter into the patient, the catheter can then be deployed and the sheath device can be pulled out of the patient over a certain distance. The tubular section can then be very easily changed from clamped to unclamped and can be shortened and reclamped.

This allows the sheath device to be cut very easily to a suitable size after use so that it does not protrude from the patient body by an unnecessary length.

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

It is particularly useful for the tubular section to project into the sheath housing in such a way that the receiving channel of the catheter extends directly. This design makes the insertion of the catheter into the tubular section very simple, since the catheter is first inserted into the sheath housing, guided in its receiving channel and thus reaches the mouth of the tubular section directly and without difficulty. It is thus ensured that the 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 channel in the sheath housing to be received or removed therein.

According to a further advantageous embodiment of the invention, the clamping element comprises an elastically deformable clamping ring which surrounds the tubular section and can be compressed by the actuating element in order to cause the ring to radially clamp the tubular section. Such a clamping element has a very simple mechanical design, is reliable, saves space and is easy to operate. It produces a non-active fixing effect of the tubular section and can also be easily released.

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

As an elastic ring, for example, the clamping ring can be flattened by means of a pressure piece, wherein the ring expands radially inwards and outwards, so that the inner diameter of the ring is reduced. If the clamp ring is a plastic or metal slotted ring, for example, it may be compressed radially inward by wedges 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 may also have a conical cross-section. In a preferred embodiment, the clamping ring also ensures a fluid-tight connection between the jacket housing and the tubular section, which can be realized, for example, in the form of the above-mentioned elastic ring. However, the sealing action can also be achieved by means of further sealing elements, for example when using a slotted plastic or metal ring.

The clamping element may 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 to the clamping ring.

In order to facilitate cutting of the tubular segment portion for shortening thereof, the tubular segment may advantageously have at least one predetermined breaking point at least at the proximal end, the predetermined breaking point being adapted to sever a longitudinal segment of the tubular segment. In certain areas, the tubular section may include spherical indentations or perforations or other weakened areas of material in the circumferential direction, which may optionally be predetermined by molecular structure, for example.

The tubular section may likewise have one or more predetermined breakpoints or axially extending tear lines, which are referred to as peel-away introducer sheaths. In the case of such a tear line, the sheath may be opened at one end by pulling two or more of the sheath portions apart and down. To this end, the tubular section may also comprise an operating element at the proximal end, such as a loop (loop) or a tab (tab).

According to the invention, the sheath device may further comprise a cutting element by means of which a portion of the tubular section may be cut, or perforated, scored or scored for ease of cutting. For example, one or more blades may be inserted into the sheath housing so that the tubular segment is automatically scored as it is pushed through the sheath housing. Such perforations may occur, for example, in the longitudinal direction of the tubular section. A blade may also be provided to create a cut or weakened region in the circumferential direction to the tubular section during rotation of the sheath housing relative to the tubular section.

Such a blade can be made of a very hard material, for example a ceramic material, for example so that even a reinforced tubular section, in particular a tubular section reinforced with a metal fabric, can be severed. It is also possible to provide a substantially needle-shaped blade which can cut during axial as well as 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 is guided radially movably therefrom towards the catheter. Such a blade may be driven by a handle located outside the sheath housing so that when the tubular section is pushed out of the patient's body and moved relative to the sheath housing, the severing of the tubular section portion may be achieved using a simple manual action.

In addition to a sheath device of the type described above, the 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 on the proximal side of the clamping element, wherein the further clamping element is provided in order to radially clamp the catheter or a second sheath surrounding the catheter and/or functional elements connected to the catheter.

In general, the respective further clamping element may likewise comprise a clamping ring and may, for example, have the same design as the first clamping element for fixing the tubular section. However, the further clamping element may also have a different design than the first clamping element and be designed substantially in accordance with the above-described variants of the clamping elements.

The invention also relates to a method of inserting a catheter, comprising inserting an end-placed functional element into a patient, wherein the catheter is inserted into a sheath housing and a tubular segment and subsequently inserted into the tubular segment into the patient, the tubular segment is subsequently pulled out of the patient in a proximal direction over a certain distance, and releasing the clamping element and the tubular segment is moved into the sheath housing.

The tubular section may shorten after being moved into and/or pushed through the sheath housing. Before or after shortening, the tubular section can be reclamped by the clamping element.

Such clamping is advantageously achieved by tearing the tubular section longitudinally, in particular starting from the proximal end of the tubular section, and subsequently tearing it off.

Drawings

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

FIG. 1 is a general schematic view of a vascular system including insertion of a first sheath;

FIG. 2 is a detailed view of a section of FIG. 1;

FIG. 3 shows an embodiment of the invention comprising a first sheath and a second sheath;

FIG. 4 illustrates an embodiment of a pump;

FIG. 5 shows a second sheath including a pump deployed therein;

figures 6,7 show the pump being pulled into the second sheath;

figures 8,9 show the transfer of the pump from the second sheath to the first sheath;

FIG. 10 is a longitudinal cross-section through a sheath housing comprising a tubular section;

FIG. 11 is a longitudinal cross-section through a portion of a sheath including a cutting element;

FIG. 12 is a longitudinal section through a sheath housing including a gripping element for a tubular segment and a further gripping element; and

figure 13 is a longitudinal section through an alternative clamp ring comprising a conical pressure member.

Detailed Description

Fig. 1 shows a schematic 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 then leads to the ventricle 4. The introducer sheath 10 is first inserted into the femoral artery 2, for example using the seldinger technique. For this purpose, the femoral artery or vessel is punctured, for example, using a steel cannula with a cutting head. The guide wire 12 is pushed through a steel cannula which is inserted into the puncture and backwards through the aortic arch 3 into the left ventricle 4. After removal of the puncture cannula, a first sheath 10 designed as an introducer 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 optionally a dilator (not shown here), wherein the sheath is inserted a short distance into the lumen of the vascular system or to the application of the element to be inserted. Subsequently, a fluid pump is inserted into the vascular system through the introducer sheath 10.

For example, the tubular section 11 of the first sheath 10 is inserted into an artery such that the proximal end of the first sheath 10 is outside the femoral artery and can then be used, for example, to insert a pump. The pump may thus be threaded over the guide wire 12 to guide the pump through the guide wire into the left ventricle.

It is also possible to guide the tubular section 11 of the first sheath 10 into the left ventricle by means of a guide wire and subsequently remove the guide wire 12 from the first sheath. The optional pump unit is then guided by the volume of the first sheath to the vicinity of the left ventricle 4 or into the left ventricle 4.

In this example, the method is described based only on inserting a pump into the left ventricle to support cardiac function. However, it will be readily apparent to those skilled in the art that the pump or other functional element may be placed and introduced into other regions of the endogenous vasculature.

Fig. 2 shows the region of fig. 1, in which the first sheath 10 is introduced from the outside through the endogenous tissue into the lumen L of the femoral artery 2_G. The first sheath comprises a tubular section 11, the tubular section 11 being connected at a proximal end to a sheath housing 13. The tubular section 11 defines an inner diameter d₁₁Inner chamber L of₁. The inner diameter widens in a flared shape in the region 14 towards the proximal end of the tubular section 11.

The sheath housing 13 contains a hemostatic valve as is known in the art. The valve prevents lumen L_GThrough the lumen L₁And (4) leakage.

In the depiction of fig. 3, the first sheath 10 in fig. 2 is coupled to the second sheath 20. Only the tubular section 21 of the second sheath 20 is shown, the tubular section 21 defining a tubular section having an inner diameter d₂₁Inner chamber L of₂. The distal end of the second sheath 20 has an outer diameter such that it can be inserted into the sheath housing 13. However, the inner diameter d₂₁Greater than the inner diameter d₁₁。

Is located in the inner cavity L₂Can be pressed from the second sheath lumen L₂Transferred to the first sheath lumen L₁. The pump then passes through the first sheath lumen L₁Is delivered to the site in the vascular system where the pump is acting. To this end, the pump may be guided over a guide wire, or may be introduced through the first sheath lumen without the need for a guide wire. Is pushed out of the pumpPreviously, the first sheath could be advanced distally to the site of use of the pump to protect the pump and the vessel wall and shaft catheter.

A possible embodiment of the pump 30 will be described in detail on the basis of fig. 4. The pump 30 comprises a distal pump unit 31 and a shaft conduit 32, the shaft conduit 32 abutting a 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 may be placed outside the patient's body and cause a flexible shaft extending in the shaft conduit 32 to rotate, thereby driving the distal pump unit 31.

The distal pump unit includes a pump housing 33 made of intersecting nitinol struts. One or more portions of the nitinol shell are provided with a covering layer 34 that extends distally and proximally of a rotor 35 disposed in the shell 33. The rotor is connected to a shaft 36 extending in the shaft conduit 32, thus causing it to rotate. The shell and rotor may be compressible, that is to say the pump is a self-compressible (self-compressible) pump. After the distal pump unit is pushed out of the distal end of the sheath, the pump is deployed. The pump is compressed in preparation for implantation 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 axially movable relative to the pump housing, in particular by axial displacement of the drive shaft. However, the rotor may also be fixed axially relative to the pump housing.

The pump optionally includes an outflow hose 37, the outflow hose 37 defining a flow path for the pumped fluid at the proximal end of the rotor 35. A discharge opening, not shown in detail, is located at the proximal end of the outflow hose 37.

Of course, the pump may also be switched from pumping to aspirating such that the pump no longer delivers 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 2047872 a 1.

The function of the system will now be described based on fig. 5 to 9.

Fig. 5 shows a pump 30' which generally corresponds to the pump 30 in fig. 4. Details of the pump are not shown to simplify the problem. Only the inflated shell and the "coiled tubing" (pigtail) at the distal end of the shell are shown, the coiled tubing preventing the heart from pumping against the heart wall. The shaft catheter 32 'extends towards the proximal end of the distal pump unit 31'. A second sheath 20' is provided which surrounds a region 38' of the shaft catheter 32' and includes a lumen L₂At the time of deployment, its inner diameter d₂₁Smaller than the diameter of the distal pump unit 31'.

The pump 30 'shown in fig. 5 is a compressible pump, that is to say, for example, a distal pump unit 31' comprising a pump housing and a rotor located therein is designed to be compressible, that is to say its diameter can be reduced. For example, after a quality inspector or physician confirms proper operation of the pump 30', the distal pump unit 31' is pulled into the lumen L of the second sheath 20', for example by pulling the shaft catheter 32' in the proximal direction, for example by observing rotation of a rotor unit located in the distal pump unit during a test run₂. By pulling the pump into the second sheath 20', bending or damage to the shaft conduit or to the shaft extending therein is prevented. The pump 30' and the second sheath 20' surrounding the region 38' of the shaft catheter 32' shown in fig. 5 constitute a system 200, the system 200 allowing for timely testing of the function of the pump 30' prior to surgery and prior to compressing the pump by pulling the distal pump unit 31' into the distal end of the sheath 20', thus preventing damage to the shaft.

Although the system can be implemented with both active and self-relieving pumps, it is particularly applicable to self-relieving pumps, i.e. the pump's distal pump unit automatically returns to its original size outside the sheath.

Fig. 6 shows an intermediate step in pulling the distal pump unit 30 'into the lumen of the second sheath 20'. It is apparent that the distal pump unit 30' can be compressed and reduced to a small diameter so that the distal pump unit 30' can be accommodated within the lumen of the second sheath 20 '.

Fig. 6 further shows a coupler 39 'adjacent to the shaft guide 32', which coupler allows a shaft extending in the shaft guide to be coupled to the driveAnd a moving unit. Since the outer diameter of the coupler 39' is generally larger than the inner cavity L₂The second sheath 20 'is typically added in a distal direction from the proximal end of the shaft catheter 32' prior to installation of the coupler 39 'so that the pump is delivered as a system 200, that is, the pump includes the second sheath 20' at the proximal end of the distal pump unit 31 'and the sub-assembled coupler 39'. Fig. 6 also shows a slight flare deployment of the distal end of the second sheath 20'. Flared deployment 24 'allows distal pump unit 31' to be more easily pulled into lumen L of second sheath 20₂。

In fig. 7, the distal pump unit 31' is finally placed entirely in the lumen L of the second sheath 20 ″₂In (1). The second sheath 20 "comprises a two-part assembled gripping unit 22" when the distal pump unit 31' is pulled into the lumen L₂Or subsequently torn, the partially assembled gripping unit allows better gripping or removal of the second sheath 20 ". If there is a "coil", it is also advantageously pulled into the lumen L₂So that the distal pump unit 31' is located in the lumen L together with the components of the pump located at the distal end of the distal pump unit 31₂In (1).

It can be seen from fig. 8 how a system 200 comprising a pump 30' and a second sheath 20 "can be operatively connected to a first sheath 10 to form a 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 is aligned with the mouth of the tubular section of the first sheath 10, it is immediately transferred from the second sheath 20' to the first sheath 10' by pushing the pump in the distal direction, which pushing is generated by the pushing of the shaft catheter 32 '. The diameter of the distal pump unit 31' is thus further reduced to the lumen L₁Inner diameter d of₁₁。

Fig. 9 shows the subsequent step, in which the distal pump unit 31' is entirely located in the lumen L of the first sheath 10₁In (1). The distal pump unit 31' is located entirely within the lumen L of the first sheath₁The fact(s) in (b) can be indicated, for example, by the use of a colored marking 50, which colored marking 50 is applied to the exterior of the shaft catheter 32'.

Subsequently, the second sheath 20 ", which is 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 may be supported by the groove a, which is mainly based on the orientation of the molecular chains of the plastic material used from the proximal direction to the distal direction.

After the peel-away sheath is removed, the pump 30' is further directed to the lumen L of the first sheath 10₁In the appropriate location.

Optionally, the first sheath is advanced to be immediately adjacent to the use, either before or after insertion of the pump using the distal sheath port. As such, the first sheath needs to have a desired length.

The second sheath 20 "does not require reinforcement, particularly in pulling the distal pump unit 31' into the second sheath lumen L₂Because the risk of shaft twisting during the pulling action is substantially reduced.

As shown in fig. 7 to 9, the second sheath may comprise a reinforcing structure in the form of a lead-in wire when the pump is transferred from the second sheath to the first sheath, or the tubular section 21 "of the sheath 20" is not made of a flexible plastic material, but of a non-deformable plastic material or metal.

Another option for stabilizing the pump and the second sheath is to grip the second sheath 20 "by means of a support element 40 in the form of a stable outer sleeve when advancing the pump 30 'in the distal direction, that is to say in particular when transferring the pump 30' from the second sheath to the first sheath.

Next, another possible variant 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 solvent and is thus completely isolated from air. The peel-away sheath, located proximal to the distal pump unit, is then advanced into the optional outflow hose. For example, the diameter of the release sheath is 10 Fr. After the peel-off sheath has been advanced to the outflow hose, the peel-off hose is surrounded by the sleeve-like element to seize the second sheath. The distal pump unit is then pulled into the peel-away sheath, optionally by slight rotation, by pulling in a proximal direction on the shaft catheter. The pump is advanced into the second sheath so that the optional coiled tubing is also secured in the stripping sheath. These steps make it possible to check the functional capacity of the pump even before surgery and then to insert the pump only into the catheter without time pressure. For example, only then the vascular system is punctured for insertion of the first sheath. However, in order to save time, the pump may also be prepared by an assistant, while the user has finished piercing.

For example, after the 9Fr 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 stuck in the peel-off sheath, in its initial state, e.g. wrapped by a sleeve to stick a second sheath, is pushed into the sheath housing until the tip of the peel-off sheath hits the mechanical stop. The pump is then transferred from the peel-away sheath into the tubular section by pushing the shaft catheter. When the distal pump unit is completely transferred into the introducer sheath, the peel-away sheath may be torn away and torn away from the shaft catheter, e.g., as may be verified based on optical markings on the catheter shaft. The pump is then advanced to the first sheath into the left ventricle. The first sheath is then pulled out of the left ventricle to the beginning of the descending aorta.

For example, the positioning of the distal pump unit in the left ventricle may be controlled by fluoroscopy. For this purpose, the X-ray visible markings are located at or near the pump housing, for example on the catheter, or the pump housing itself is X-ray visible. The discharge region of the pump, that is to say the discharge opening of the outflow hose, is likewise located in the ascending aorta region. This can also be checked using X-ray visible markers. The optional coil catheter tip should be in contact with the tip of the left ventricle.

To remove the pump from the ventricle, the pump retracts the introducer sheath by pulling on the shaft catheter and is removed from the arterial vasculature in a compressed state. If the first sheath has been shortened, the pump may also first be retracted a distance into the shaft conduit to compress the pump. To this end, the shaft conduit may comprise a pull-in funnel, by which the pump may be pulled by pulling the drive shaft. The first sheath and the further remaining elements are subsequently removed from the vascular system.

The present invention provides particular advantages when long sheaths are used in the implantation and description of the pump. The long sheath is not only used to insert the pump into the endogenous lumen as in the prior art, but also to guide the pump through the sheath lumen into proximity of the site of action. For this purpose, the sheath has a length of between 40 and 120 centimeters, which is advantageous in the medical field. The length is determined by the subsequent action of the pump and the size of the patient.

If the pump is pulled out of the intrinsic lumen along with the long sheath, femoral artery bleeding is stopped by a compression dressing method. Alternatively, the pump may be pulled out of the sheath lumen of the long sheath. An additional guide wire may be placed within the lumen of the sheath and the element for suturing the puncture may be guided over the guide wire after the sheath is removed. This achieves improved hemostasis.

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

Fig. 10 shows a longitudinal section through a sheath housing 43, which has substantially the shape of a cylindrical sleeve which can be closed at least at a distal end 44 facing the body of the patient by means of a pressure screw 45. The sheath housing 43 has a continuous receiving channel 46 for the tubular section 41 of the first sheath. In the description of fig. 10, the tubular section 41 is shown from the direction of the patient's body and continuing to the irrigation space 47 of the receiving channel 46 and then in a punctiform fashion in the proximal direction. This means that the tubular section 41 is axially displaceable in the receiving channel 46 relative to the sheath housing 43, or, in other words, the sheath housing 43 is displaceable over the tubular section 41.

For inserting a functional element, for example a pump, into the first sheath, the tubular section 41 is usually 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 retraction pump, may be pushed to this point to subsequently move the pump from the second sheath into the first sheath.

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

The pressure screw is screwed to the sheath housing by means of an external thread in the region of the overlap with the distal end 44 of the sheath housing 43. The pressure screw 45 is manually rotated to cause axial movement of the pressure screw, causing compression or expansion of the clamp ring 50 in the axial direction. During axial compression, the clamping ring 50 tends to deform radially inwardly or outwardly to hold volume and thus clamp the tubular section 41 due to the resistance experienced proximal to the first stop 48.

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

Thus, if the tubular section 41 is first pushed as far into the patient as possible to allow insertion of the pump, which is protected by the sheath, to the site of use, for example the ventricle, after removal of the pump, the tubular section 41 is pulled out, the sheath as a whole slightly protruding with respect to the patient's body. The clamping elements 48,45,50 may then be released and the sheath housing 43 may be pushed over the tubular section 41 into proximity with the patient's body. The tubular section 41 then extends completely within the sheath housing 43 and optionally protrudes there in the proximal direction. The tubular section 41 may then be cut in some areas to remove excess length, using methods that will be described in more detail below.

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 flap 52. If at this point no tubular section 41 or shaft catheter extends in the receiving channel 46, the valve flap closes the sheath housing 43 while the dome valve 51 is optimized to provide a tight seal around the bundle, e.g., the tubular section or catheter.

At the proximal end 53 of the sheath housing 43 a further pressure screw 54 is provided, which operates essentially in the same way as the first pressure screw 45 and which effects a compression of the second clamping ring 56 relative to the second mechanical stop 57 by means of a pressure member 55. A particular feature to be mentioned here is that the distal end of the second clamping ring 56 has a conical shape which facilitates a radially inward deformation when axial pressure is applied by the pressure screw 54. The second stop 57 has a concave conical design in the opposite direction. However, non-conical clamp ring 56 may also be used at this point and instead have a rectangular or circular cross-section.

One or more further valves may then additionally be placed in the irrigation space between the clamping elements 48,45,50 and the irrigation inlet 58 to ensure a fluid-tight connection between the tubular section 41 and the sheath housing 43, even if the clamping elements 48,45,50 are released.

Fig. 10 schematically shows an irrigation element 58 which allows the irrigation space 47 to be flushed with a liquid to prevent bacteria from penetrating into the patient through the first sheath. Such flushing is particularly effective if the tubular section 41 terminates distally in or at the flushing space 47, so that flushing liquid can reach the outside and inside of the tubular section 41.

Fig. 11 illustrates by way of example the arrangement and operating principle of the cutting element of the present invention.

If the predetermined breaking point is not pre-cut or is otherwise pre-set, for example providing a regional weakening through a predetermined molecular structure or wall thickness of the tubular section 21, these breaking points may be introduced in a suitable manner by the cutting element when the first sheath is used. In the area of the flushing space 47 of the sheath housing 43 in fig. 11, a cutting element comprising blades 59,60 is provided, for example to cut the tubular section in circumferential section during rotation of the sheath housing relative to the tubular section. The cutting may 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 the arrow 61. Blades may be provided for cutting in both the circumferential and longitudinal directions.

Fig. 11 also shows that the blades 59,60 can be moved radially towards the tubular section 41 by actuation outside the sheath housing 43. There, one or more blade clamps, respective seals and radial guide extensions of the suspension members may be provided to prevent penetration of bacteria through the moving element for the blade, and the blade has a radial distance with respect to the tubular section 41 when not driven. After use of the first sheath, pressure may be manually applied to the blade and the unwanted portion of the tubular section 41 may be cut away. A stop, not shown here, prevents the cutting depth from exceeding the critical dimension and thus from causing damage to the catheter which may be inside the sheath.

The illustrated blades may also form a cutting element for the second sheath.

Fig. 12 shows an advantageous use of a second clamping element, which is located on the proximal side of the sheath housing 43 after the shortening of the tubular section, and the shaft catheter 61 is guided out of the proximal end of the tubular section 41 and then onto a coupling element (not shown here) for the drive shaft of the pump and then out of the sheath housing 43. The shaft conduit is sealed in the above-mentioned dome seal 51 and, by means of the clamping element of the pressure piece 55 axially compressed against the second stop 57, together with the elements of the second pressure screw 54 and the second clamping ring 56, a space is provided radially inwards far enough to be clamped and in particular additionally sealed for the shaft conduit 61, which shaft conduit 61 has an outer diameter substantially smaller than the outer diameter of the tubular section 41 or the second sheath. From there, the tubular section 41 and the shaft catheter 61 protrude and can thus be fixed in the sheath housing 43.

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

The first and second clamping rings 50,56 may be made of an elastomer, such as rubber or silicone elastomer, and thus may be fully elastic, but deformable without compressing in volume. In this connection, it is also conceivable to use a resilient foam-like material, part of the volume of which can be compressed.

Fig. 13 is a schematic view of another form of clamping ring 62, which may be made of plastic material or metal, for example, and which may have slots and thus be radially compressible. The grooved clamping ring 62 has a conical outer profile, and when axial pressure is applied on the pressure member 63 in the direction indicated by arrow 65, the conical profile of the pressure member 63 pushes against the clamping ring 62 to radially compress the clamping ring, for example by means of the pressure screw shown above. The slotted clamp ring 62 is axially secured by a stop 64.

The invention relates in a first aspect to a sheath device for inserting a catheter into a lumen, in particular into a patient, comprising a first sheath (10,11,13,21,21', 41,43) having a proximal end and a distal end, in particular on the patient's body side, wherein the first sheath comprises a sheath housing (13,43) having a receiving channel, hereinafter denoted as 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 which is axially displaceable and fixed.

The first and further receiving channels are in particular arranged coaxially with respect to each other and axially behind each other, and the tubular section may also extend in both receiving channels.

A second aspect of the 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 may 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') may 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) in the further receiving channel by clamping.

For example, at least one of the clamping elements (54,54',55,56,56',57,57') may be designed such that it selectively allows clamping of a beam-like body having a first diameter or a beam-like 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. This can be achieved, for example, by various positions of the clamping screw.

According to a fourth aspect of the invention, which relates to a sheath device according to the first, second or third aspect, a radial expansion of the first or further receiving channel comprising an irrigation element may additionally be 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 liquid connections for supplying and removing liquid.

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

The valve may comprise a valve membrane 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 comprising at least one blade is provided, which has at least one possible position in which it projects radially into the first receiving channel or into a further receiving channel or into the deployment region and in particular into the irrigation space.

For example, at least one blade can be provided for this purpose for cutting in the circumferential direction of the receiving channel, or in the axial direction. Each blade is displaceable in a radial direction relative to the receiving channel or the deployment region between at least one cutting position and a non-cutting position, in particular a position not protruding into the receiving channel. This displacement may occur against the reaction force of a spring to engage the knife or knife holder.

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

A sixth aspect of the invention relates to a sheath device according to any of the preceding aspects, comprising a tubular section 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 extending in said receiving channel together with a second sleeve-like sheath, wherein said second sheath is fixed in said first receiving channel, in particular in a clamping element (54,54',55,56,56',57,57') of said first receiving channel.

An eighth aspect of the invention relates to a method for inserting a catheter (32,66) into a patient, 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 into abutment, the second sheath is then fixed by means of 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 invention relates to a method according to the eighth aspect, wherein the second sheath (20,20',20 ", 20"') is removed after insertion of the catheter into the first sheath, in particular by tearing it open or 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" ') has been removed.

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

Claims (12)

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 the distal end of the first sheath is for arrangement in the patient and the proximal end of the first sheath is for arrangement outside the patient when used as required, and wherein the first sheath comprises a tubular section (11,21,21', 21", 41) and a sheath housing (13,43) located at the proximal end of the tubular section and comprising a receiving channel (46) for a strand-like body (41,66), and wherein the tubular section (11,21,21',21 ", 41) is detachably held in a clamping element (45,48,50,62,63,64) of the sheath housing in a non-active manner;

wherein the sheath housing (13,43) comprises a cutting element (59,60) by means of which a portion of the tubular section (11,21,21',21 ", 41) can be cut off, or perforated, scored or scored for ease of cutting off;

wherein the cutting element comprises at least one blade (59,60) which is movably guided.

2. The sheath apparatus of claim 1, wherein the strand-like body is a catheter.

3. Sheath device according to claim 1, characterized in that the at least one blade (59,60) is guided displaceably in the sheath housing (13, 43).

4. A sheath device according to claim 3, characterized in that the at least one blade (59,60) is radially movably guided towards the catheter.

5. Sheath device according to claim 1, characterized in that the tubular section (11,21,21',21 ", 41) can be moved into the sheath housing when the clamping element (45,48,50,62,63,64) is released.

6. Sheath device according to claim 1 or 5, characterized in that the tubular section (11,21,21',21 ", 41) projects into the sheath housing in such a way that the receiving channel (46) extends directly.

7. A sheath device according to claim 1 or 5, characterized in that the clamping element comprises an elastically deformable clamping ring (50,62) which surrounds the tubular section (11,21,21',21 ", 41) and which is compressible by means of an operating element to cause the clamping ring to radially clamp the tubular section.

8. Sheath device according to claim 7, characterized in that the clamping ring (50,62) is radially deformable by the action of axial pressure.

9. Sheath device according to claim 7, characterized in that the clamping ring (50) is made of an elastomer or of a slotted ring (62), the slotted ring (62) being made of a plastic material or of metal.

10. Sheath device according to claim 7, characterized in that the clamping element comprises a thread element (43,45) for axially pressing the clamping ring (50, 62).

11. Sheath device according to claim 1 or 5, characterized in that the tubular section (11,21,21',21 ", 41) has at least one predetermined breaking point at least at the proximal end of the tubular section, which predetermined breaking point is intended to cut off a longitudinal section of the tubular section.

12. 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) comprises a further clamping element (54,55,56,57) proximal to the clamping element (45,48,50,62,63,64), wherein the further clamping element is provided for radially clamping the catheter (66) or for radially clamping a second sheath surrounding the catheter and/or a functional element connected to the catheter.