EP3852836A1

EP3852836A1 - Modular cannula device

Info

Publication number: EP3852836A1
Application number: EP19773009.6A
Authority: EP
Inventors: Philipp Lepper
Original assignee: Universitaet des Saarlandes
Current assignee: Universitaet des Saarlandes
Priority date: 2018-09-17
Filing date: 2019-09-16
Publication date: 2021-07-28
Also published as: DE102018122616A1; WO2020058147A1; US20220047853A1

Abstract

The invention relates to a modular cannula device in various embodiments, which cannula device comprises an external tubular cannula, a first tubular guide part, which has a narrowing distal end and can be inserted into the cannula such that the outer wall of the first guide part lies tightly against the inner wall of the cannula, and a second tubular guide part, which has a narrowing, tapered distal end and can be inserted into the first guide part such that the outer wall of the second guide part lies tightly against the inner wall of the first guide part.

Description

Modular cannula device

The invention relates to a modular cannula device which is particularly suitable for use as a right heart replacement.

Right heart failure is a common problem in patients with severe lung failure, in patients with an implanted left ventricular assist device (LVAD), and in general in intensive care patients. The disadvantage of surgically implanted systems is that they require two sternotomy procedures - one procedure for the implantation and one procedure for the removal of the system. In the already seriously ill patients, these complex and lengthy interventions contribute significantly to morbidity and mortality. So far, there are only a few percutaneous systems for hemodynamic relief of the heart, especially the right heart. These are usually not very powerful and the implantation is complex.

For the insertion of a percutaneous system, which is supposed to support the cardiac function, the patient does not have to undergo an inpatient operation, since these systems are introduced into the patient's body by inserting a catheter. This intervention, which is usually carried out using Seldinger technology, requires little effort. The insertion of the catheter begins by puncturing a large blood vessel with a hollow needle using customary methods. For percutaneous cardiac support systems, the upper jugular vein is usually used for this, since it allows a fairly short and predominantly rectilinear access to the heart. Then a guidewire is inserted into the jugular vein via a hollow needle and advanced until just before the right atrium. A lock is then introduced along the guide wire and the guide wire is removed again. A balloon catheter can be advanced through the sluice to its destination, the pulmonary artery. A second, relatively thin wire is then pushed through the single-lumen balloon catheter. The balloon catheter, which is used to lay the second wire "around the curve", i.e. from the atrium into the pulmonary artery, is then removed and a change is made to a so-called pigtail catheter over the second wire. A stiffer, third wire is then placed through the pigtail catheter. The sheath can then be removed again in order to finally push the cannula finally used along the wire into the heart and the pulmonary artery. Here, the stiffer, third wire serves as a guide rail, which forces the finally inserted cannula into a U-shaped path within the right ventricle.

In the event of an error, for example when the balloon catheter or guide wire slips, the procedure has to be practically started again since the Balloon catheter, which in the initial phase generated the necessary buoyancy to provide the U-shaped curvature required to pass the ventricle, is no longer in place. Slipping of the balloon catheter and / or the guide wire is favored in that the balloon catheter, which usually has a length of 1.50 m, relative to the guide wire, which is significantly longer with a length of up to 2.60 m , is movable.

Based on the above description of the usual procedural steps when inserting a catheter, it can be seen that the entire procedure involves numerous insertion and removal procedures for objects (guidewire, catheter) into and out of the vein used, each of which takes a certain amount of time and can lead to ablation of tissue on the inner wall of the affected vessel. In addition, each insertion of an object, such as the wire or a catheter, into the corresponding blood vessel carries the risk of perforation of the vessel wall, particularly in the case of elderly patients or those whose blood vessels are weakened due to the disease. In addition, the numerous changes in the catheters and wires favor incorrect positions, which in the worst case scenario mean that the procedure must be started again. Although the procedure is now well mastered by medical specialists, it can be seen that overall it still poses a certain risk to the patient.

In light of these problems, the present invention provides a modular cannula device which can simplify the handling of the process of inserting a cannula with the tip into the pulmonary artery, in particular the placement of an arterial ECMO cannula (ECMO: extracorporeal membrane oxygenation) the intervention time can be significantly reduced.

In various exemplary embodiments, a modular cannula device is provided which has an external tubular cannula. Furthermore, the modular cannula device has a first tubular guide part, which has a tapering distal end and can be inserted into the outer cannula, so that its outer wall lies tightly against the inner wall of the cannula. Furthermore, the modular cannula device has a second tubular guide part which has a tapering tapering distal end and can be inserted into the first guide part, so that its outer wall lies tightly against the inner wall of the first guide part. The outer cannula can be designed as a tube or hose with a length in the range of, for example, 50 cm to 3 m. Likewise, the guide parts can be of tubular or tubular design with a corresponding dimension to the dimension of the cannula, so that in each case an internal module of the modular cannula device is inserted into the correspondingly external module can be. Neglecting the distal areas of the two guide parts, their lengths can at least correspond to the length of the cannula or can also be longer. Side holes can be provided in the jacket or in the side wall of the distal end region of the cannula.

The outer cannula of the cannula device according to the invention is preferably the final cannula to be used, for example an arterial ECMO cannula. A two-part guide part adapted to this can be inserted into this final cannula. The two-part guide part ensures, on the one hand, that the cavity in the outer cannula remains closed while the modular cannula device is in place and thus no blood can pass through to avoid blood loss in the patient. On the other hand, the two-part guide part can be stiffer than the outer cannula and can serve as a support part stiffening the cannula in order to insert cannulas made of soft / flexible material into the body. Consequently, by attaching the outer cannula to the two-part guide part, cannulas can be introduced into the body which would otherwise buckle or twist during the insertion process and therefore could not be guided through body vessels at all or only with great difficulty.

The first guide part which can be inserted into the outer cannula can correspond to an outer guide of a two-layer stylet and the second guide part which can be inserted into this can correspond to an inner guide of the two-layer mandrel. The tapered end of the first and the second guide part can be tapered or tapered. In the assembled state (i.e. in a state in which the second guide part is inserted in the first guide part), the ends of the two guide parts can merge continuously into one another and form an overall tapered or tapered or tapered distal end of the (two-part) guide part.

In the assembled state of the modular cannula device according to the invention, the outer wall of each of the modules located inside another module lies close to the inner wall of the module located outside relative to it.

According to further embodiments of the cannula device, the opening angle of the tapering distal end of the first guide part can be greater than the opening angle of the tapering distal end of the second guide part. The distal end of the second guide part can thus taper more sharply than the distal end of the first guide part. Overall, the specific configuration of the opening angle and the outer shape of the two distal ends can be adapted as required, the adaptation of these parameters and the sizes of the cannula and the guide parts thereof Can have adaptation to the size of the patient. The distal end or end region of the cannula device according to the invention (or one of its modules) is understood to mean the end or the end region with which the cannula device is inserted into the patient. The proximal end or end region of the cannula device according to the invention (or one of its modules) is accordingly understood to mean the opposite end or end region.

According to further embodiments of the cannula device, the first tubular guide part can have an enlarged area at the proximal end or in the proximal end area with an outer diameter which is larger than the inner diameter of the tubular cannula. The inside diameter of the first guide part can remain the same regardless of the outside diameter. The expanded area at the proximal end of the first guide part can be arranged on the outside or on the outer wall of the first guide part. The expanded area can have, for example, a partial or full thickening of the wall of the first guide part to the outside. Likewise, the expanded area can have material webs or other structures which are, for example, formed integrally with the outer wall of the first guide part. By providing the enlarged area at the proximal end of the first guide part, it can be prevented that the first guide part slips too deep into the cannula. The expanded area can thus act as a type of stopper, which limits or defines the maximum immersion depth of the first guide part into the cannula when the first guide part is inserted into the cannula.

According to further embodiments of the cannula device, the first and second guide part can each have a part of a fixing device at the proximal end, by means of which the second guide part can be fastened to the first guide part relative to the latter. A relative movement of the two guide parts to one another can be prevented by means of the fixing device. The position in which the two guide parts can be fixed relative to one another by means of the fixing device can define a desired position of the two guide parts with respect to one another. The desired position can correspond to the position in which the second guide part is arranged in the first guide part in such a way that the distal ends of the two guide parts form a tapered distal end which can be essentially free of steps.

According to further embodiments of the cannula device, the fixing device can comprise an internal thread arranged in the first guide part and a matching external thread arranged on the second guide part. To fix the two guide parts relative to one another, the two guide parts can be screwed together, wherein in the screwed together position, the two guide parts can be arranged relative to each other in the target position.

According to further embodiments of the cannula device, in the assembled state of the modular cannula device, the cannula device as a whole can have a tapered distal end which is formed at least by the tapered ends of the first and second guide parts. The diameter of the tapered end can decrease continuously from its largest circumference to its smallest circumference, so that the tapered end of the cannula device is essentially stepless. The tubular cannula itself can have a blunt end, and the edge region can be beveled, so that there is an almost continuous transition between the outer wall of the cannula and the outer wall of the first guide part.

According to further embodiments of the cannula device, a radiopaque marking can be arranged in the region of the distal end of the tubular cannula, which is preferably designed as a full circumferential ring in the lateral surface of the cannula. A radiopaque material is understood to mean one that does not allow X-rays to pass unhindered and is therefore recognizable in the X-ray image. The radiopaque marking can also comprise more than one full circumferential ring or instead or additionally have additional structures made of radiopaque material. The use of more than one structure made of radiopaque material can make it easier to determine the position of the cannula in the patient during an intervention from recorded X-ray images. The radiopaque marking at the distal end of the cannula can be used, for example, to show the position of the end or the exit opening of the cannula at its destination (e.g. in the pulmonary trunk) over time after implantation in the patient. In particular, a radiopaque marking can be provided on the distal edge of the cannula, for example in the form of a ring made of radiopaque material.

According to further embodiments of the cannula device, the distal end region of the cannula, which can preferably be at least 2 cm long and can for example comprise the distal 4 cm of the length of the cannula, can be made from a softer material than the rest of the cannula, for example from silicone. This can reduce the risk of injury from perforation of blood vessels or excessive ablation of tissue from the vessel walls. In general, the cannula body can be made of polyethylene, Teflon, polyurethane or nylon, for example.

According to further embodiments of the cannula device, the cannula can be wire-reinforced. For this purpose, the cannula can have a wire reinforcement, which on the outer wall of the Cannula is attached or embedded in its wall and strengthens / stabilizes the cannula body. The distal end region, which can be made softer, can be excluded from this. An area at the proximal end of the cannula may have a 3/8 inch (0.95 cm) connector. This area at the proximal end of the cannula can also be excluded from the wire reinforcement.

According to further embodiments of the cannula device, the cannula can be made of a softer material than the first guide part. This can ensure that the cannula device has the necessary rigidity when inserted into the patient. After the cannula device has been brought into its target position and the two-part guide part stiffening it is then removed at the end of the procedure, only the soft cannula remains in the patient.

According to further embodiments of the cannula device, at least one part in the distal region of the cannula can be impressed with a pretension on the material side, so that the corresponding part of the cannula has / assumes an arch shape without external force. According to this embodiment, the cannula can be formed at least in part from a suitable shape memory polymer. The shape memory polymer is able to take on its original shape, despite the fact that it has undergone major reshaping in the meantime. In the present case, the outer cannula is reshaped by the guide part inserted therein, which is made of a stiffer material. Particularly preferably, the cannula can be embossed with an arch shape so that in the final state it adapts optimally to the shape of the right or left ventricle and does not cause the patient any discomfort while remaining in his body. The position of the area formed from the shape memory material within the cannula can be varied in order to optimally adapt the position of the arch shape within the cannula to the anatomy of the patient, which can depend on age, gender and size. By means of an arcuate shape of the cannula, the anatomy of the right ventricle and the right outflow tract of the heart can be taken into account, for example.

By using the modular cannula device according to the invention, the placement of a cannula can be simplified and shortened. This applies in particular to the percutaneous installation of a cannula (for example in the pulmonary artery) using the Seldinger technique. The cannula placed by means of the cannula device described here can be connected to a centrifugal pump with or without an oxygenator (ECMO). With a suitably selected diameter of the cannula, significantly higher flow rates than with conventional systems can be achieved. For example, the standard outer diameter of the cannula may be 21 French (F) (7 mm), but the inside diameter may be Cannulas used within the scope of the invention are readily provided in other dimensions (e.g., for children or very tall adults) so that the cannula outer diameter ranges from about 15 F (5 mm) to about 27 F (9 mm), for example in 2 F (0.66 mm) steps can have. The length of the cannula can also be adapted to the patient's anatomy. For an adult, the length of the cannula in the range of 1.5 m can be assumed. The cannula of the cannula device according to the invention can have a standard connection at the proximal end, which can have a size of 3/8 inch (0.95 cm) or 1/4 inch (0.64 cm).

The modular and fluid-tight construction of the cannula device according to the invention in relation to the relative position of the modules (i.e. cannula and guide parts) provides the basis for simplifying and accelerating the process of inserting a cannula, for example through the superior vena cava as an access vein. However, it should be understood that any vein can serve as the access vein, the invention is not limited in the choice of the access vein.

During passage through an access vein, e.g. the superior vena cava, during implantation, the external cannula is kept stiff / straight by the guide parts. The first and second guide parts form a two-part stylet. As already described, both the first and the second guide part (ie the inner stylet) are open at the end, so that the cannula device as a whole is guided along a guide wire, for example a j-wire with a diameter of 0.035 inches (0.89 mm) can be. If, after insertion of the cannula device, for example into the upper vena cava or into another large body vessel, the second guide part is removed from the first guide part, the through opening inside the cannula device is actually enlarged. Then, for example, a 0.09 inch (2.3 mm) balloon catheter can be inserted into the cannula device and the cannula device according to the invention (with the second guide part removed) can be guided by means of this. Here, the cannula can simultaneously take on the role of a sluice and the first guide part that remains in the cannula, the role of a vascular dilator.

In a further embodiment of the cannula device, the second guide part can be set up as a balloon catheter. As a result, the step of removing the second guide part and then inserting the balloon catheter can be omitted, which saves additional time and eliminates a further manual process as part of the overall intervention. In an exemplary course of the procedure, the cannula device according to the invention can be introduced into the pulmonary artery by means of a guide wire (J-wire) and the balloon catheter subsequently inserted, via the internal jugular vein and the superior vena cava. The balloon catheter can be designed similar to a conventional Swan-Ganz catheter in terms of its wall thickness and its surface. Distinctions result from the fact that the balloon catheter used in the context of the invention can be structurally connected to a guide module. This can be done, for example, with a short Luer lock thread. The balloon catheter and the cannula of the cannula device according to the invention are matched to one another in terms of length and diameter by printed markings and, moreover, can each have radiopaque and / or echogenic markings at suitable locations in order to facilitate the implantation and correct positioning with the aid of X-rays and / or control ultrasound.

Particularly preferably, a single-lumen balloon catheter can be used in connection with the cannula device according to the invention, which enables contrast agent application, which can likewise indicate the end of the cannula by using length-coordinated modules of the cannula device. It is therefore possible to determine the position of the distal tip of the outer cannula at any time during the implantation process and in relation to the anatomical structures, in particular the bifurcation of the pulmonary arteries. Overall, this represents a significant improvement over previous systems.

The invention is based on the approach that the external cannula, which from the point of view of the intervention represents the target object for the implantation, is part of the modular cannula device which is inserted into the patient at the beginning of the intervention. Consequently, when the invention is used, the final cannula is placed immediately during the first insertion process. In particular, no operations precede the insertion of the cannula, in which provisional cannulas or wires are inserted into the target blood vessel and removed again. To place the cannula by means of the cannula device according to the invention, it is brought into contact only once with the vessel walls of the target vessel and advanced to its end position. As a result, the present invention enables a considerably faster and safer implantation of a cannula compared to the previously known systems.

Further advantages and refinements of the invention result from the following detailed description and the accompanying drawings. Exemplary embodiments of the invention are shown schematically therein, which are described below with reference to the drawings. They show schematically:

1 is a side perspective view of an embodiment of the distal end of the outer cannula,

2 is a side perspective view of an embodiment of the distal end of the first guide member,

3 shows a perspective side view of an exemplary embodiment of the distal end of the second guide part,

4 shows a perspective side view of the distal end of the cannula device in the assembled state,

5 is a side view showing the proximal end portion of the outer cannula into which the first guide member is inserted,

6 is a perspective side view of the proximal end of the second guide part of the cannula device,

7 shows an illustration of an exemplary position of the cannula device in a ventricle of the heart,

8 is a diagram illustrating the prestressing of the cannula,

FIG. 9 is a diagram illustrating an exemplary position of the cannula device with the balloon catheter carried out during the implantation.

1 shows a perspective side view of an exemplary embodiment of the distal end of the outer cannula 10 of the cannula device. In the example shown, the cannula 10 has a cylindrical or tube-like basic shape 11 and has an opening 15 at the distal end. The circular cross section of the cannula 10 can generally have a different geometric shape and, for example, be round or oval or correspond to a regular polygon (e.g. pentagon, hexagon, octagon, etc.). Rings 12 made of radiopaque material are arranged in the wall of the cannula 10. One of the rings is arranged directly at the distal end of the cannula 10, so that it defines the opening 15 of the cannula 10. The other ring 12 is arranged at a distance from the opening 15. In the wall of the cannula 10, side holes 14 are provided, the position, number and size of which can be selected depending on the intended use of the cannula device according to the invention. Furthermore, a spiral 13 is provided around the outer wall of the cannula 10, which serves as a reinforcement or

Stiffening structure takes over. The material from which the spiral 13 is made can preferably be stiffer than the material from which the wall of the cannula 10 is made. A distal area of the cannula 10, which extends between the distal end of the spiral 13 and the distal opening 15 of the cannula 10, is not reinforced / stiffened and is therefore more flexible / flexible than the part of the cannula 10 reinforced by the spiral 13 A distal area of the cannula 10 is also provided with a flow sensor 16, by means of which a fluid flow present on the outer wall of the cannula can be examined. Data transmission and power supply to the flow sensor 16 take place by means of (at least) one line 17 running on the outer wall (or else in the outer wall).

FIG. 2 shows a perspective side view of an exemplary embodiment of the distal end of the first guide part 20. The first guide part 20 essentially has a cylindrical basic shape which tapers in the distal region 21 towards the distal end 22 or tapers. Just as in the case of the external cannula (see FIG. 1), an opening is also provided at the distal end 22. In other words, the first guide part 20 (just like the outer cannula 10 shown in FIG. 1) is hollow on the inside. The first guide part 20 is dimensioned such that it can be inserted into the cannula 10 shown in FIG. 1. By adapting the dimensions of the two modules to one another, the contact area between the two modules is tight, so that no fluid (in particular blood) can pass through them. The inside diameter of the cannula 10 and the geometrical shape of its cross section therefore correspond to the outside diameter or the geometrical shape of the cross section of the first guide part 20. A top view of the distal region 21 of the first guide part 20 is additionally illustrated at the top right in FIG.

The distal end region of the second guide part 30 is illustrated in FIG. The second guide part 30 has a structure which is basically similar to that of the first guide part 10 (if one initially disregards the smaller diameter). That is to say that the second guide part 30 likewise has essentially a cylindrical basic shape which tapers or tapers in the distal region 31 toward the distal end 32. The distal end 32 terminates with an opening which is arranged at the distal end of the hollow channel running through the interior of the second guide part 30. In analogy to the design of the first guide part 20 with respect to the cannula 10, the second guide part 30 is dimensioned such that it can be inserted into the first guide part 20 shown in FIG. The contact area between these two modules is also tight, so that no fluid (in particular blood) can pass through it. The opening at the distal end 32 of the second guide part can be pushed onto a guide wire. FIG. 4 shows a perspective side view of an exemplary embodiment of the distal end of the modular cannula device 40. In the assembled state, which corresponds to the implantation state, the second guide part 30 is arranged in the first guide part 20 and the first guide part 20 is in turn arranged in the cannula 10 as an extreme module of the cannula arrangement 40. In the assembled, ready-to-use state, the modules are arranged relative to one another such that the distal end region 21 of the first guide part protrudes from the opening 15 at the distal end of the cannula 10 and at the same time the distal end region 31 of the second guide part protrudes from the opening at the distal end of the first guide part 20 protrudes. Such a configuration of the modules of the cannula arrangement 40 can be fixed by means of corresponding fixing or locking mechanisms so that it exists automatically, ie without a doctor having to hold the modules relative to one another. That is, the modules in contact with each other can be connected to each other in pairs, so that this configuration is maintained during an intervention and the entire cannula device 40 can be moved as a unit. A fixing or locking mechanism that is independent of the other mechanism can be provided between two of the three components. In particular, the modules can be positioned relative to one another in the assembled state in such a way that the distal end regions 21, 31 of the first and second guide parts 20, 30 merge into one another continuously and “smoothly”, in particular without steps or edges. In other words, a continuously continuous surface can result from the edge of the opening 15 at the distal end of the cannula 10 to the opening at the distal end of the second guide part 30. As shown in FIG. 4, the slopes of the lateral surfaces of the tapered distal end regions 21, 31 of the guide parts 20, 30 can be different. In particular, these manufacturing parameters can be optimized / adapted for the respective type of intervention in which the cannula device according to the invention is to be used. Also, a connecting line between a first point 41 at the edge of the opening 15 and a second point 42 at the opening at the distal end of the second guide part 30 does not necessarily have to be straight when the cannula device 40 is viewed in longitudinal cross section, but can be a curvature / curvature exhibit. For example, the connecting line between the two points 41, 42 can have a concave or convex curvature.

FIG. 5 shows a side view in which the proximal end region of the outer cannula 10 is shown with a first guide part 20 inserted therein. The first guide part 20 has at its proximal end a thickened region 23 with an outer diameter which is larger than the diameter of the Hollow channel inside the cannula 10. The thickened area 23 is designed as a radial projection 24 which can protrude completely or only in segments from the outer wall of the first guide part 20. The projection 24, which rests on the edge of the proximal end of the cannula 10, prevents the first guide part 20 from being inserted too deeply into the cannula 10. In the present case, the projection 24 has an indentation 25 at its distal end (or the segments which are arranged along the circumference of the first guide part 20 have corresponding indentations) which accommodate the edge region of the proximal end of the cannula 10. The length of the first guide part 20 can be selected such that when the edge region of the proximal end of the cannula 10 engages in the indentation 25, the first guide part 20 assumes a position with respect to the cannula 10 as shown in FIG. In addition, the first guide part 20 has an internal thread 26 which is arranged at the proximal end of the first guide part 20.

FIG. 6 shows a perspective side view of the proximal end region of the second guide part 30 of the cannula device 40. At the proximal end, a grip area 34 is provided, which is located in front of an external thread 33. The external thread 33 is designed such that the second guide part 30, when it is pushed into the first guide part 20, can be screwed to the internal thread 26 of the first guide part 20. The external thread 33 and the internal thread 26 provide two parts of a fixing device, by means of which the two guide parts can be connected to one another. At the same time, the maximum immersion depth of the second guide part 30 in the first guide part 20 can be defined. A bottom view of the proximal end of the second guide part 30 is additionally shown in the lower right corner of FIG. The proximal end has an opening 35, which preferably has the same diameter as the opening at the distal end 31 of the second guide part 30.

The fixing device designed as an example of a screwing device represents only one of many possibilities of how the two guide parts 20, 30 can be connected to one another. For example, a snap-turn lock can also be used. In general, the fixing device is an optional feature, which can also be omitted entirely. Instead, the grip area, which is a thickened area in relation to the remaining part of the second guide part 30, can act as a limitation for the depth of immersion of the second guide part 10 in the first guide part 20. At maximum depth of insertion or insertion of the second guide part 30 into the first guide part 20, the guide parts 20, 30 can assume the position shown in FIG. 4 relative to one another.

The illustration in FIG. 7 shows an exemplary position of the cannula device 40 during a percutaneous implantation process through the right heart ventricle 70 illustrated. As shown, the cannula device 40 is arcuate between the tricuspid valve 71 and the pulmonary valve 72. During the procedure in which the cannula device 40 is advanced through the corresponding veins and through the two heart valves 71, 72 of the right ventricle 70 into the right ventricular outflow tract the inserted guide wire or the balloon catheter predefine the shape of the cannula device 40 according to the invention. In other words, when the cannula device 40 is advanced along the guidewire or balloon catheter, its shape follows the course of the guidewire. After the cannula device 40 has assumed its final position at which the outer cannula 40 is to remain, the two-part guide part 20, 30 (or only the first guide part 20 still remaining in the cannula 10) is pulled out of the cannula 10. Here, the cannula 10 can take up its native shape and, for example, as shown in FIG. 8, bend in an arc to adapt to the anatomy of the right ventricle 70. The angle 18 between the legs of the arch or round V-shape can be in the range from approximately 10 ° to approximately 25 °, preferably in a range from approximately 10 ° to approximately 15 °. The arch shape can be generated by a material prestress introduced during manufacture, in that the cannula 10 is made of a shape memory polymer at least in the relevant partial area. As a result, the solitary cannula 10 independently assumes the arch shape imprinted on it and exerts no or only minimal pressure on the inner wall of the heart. The patient's discomfort while the cannula 10 is being worn can thus be prevented or at least greatly reduced.

FIG. 9 shows a representation in which an exemplary position of the cannula device 40 with the balloon catheter 42 carried out during the implantation is illustrated. In the example scenario shown, the second guide part 30 has been removed from the cannula device 40 and instead a balloon catheter 42 has been inserted, with which a guide path can be laid upwards from the right ventricle 70 to and through the pulmonary valve 72 into the right ventricular outflow tract 73 . The cannula device 40 can then be pushed out of the right ventricle 70 along this guide path into the right ventricular outflow tract 73.

In conclusion, it should be pointed out that the present description has been written only by way of example in the light of the right heart replacement as a primary example of use for the cannula device according to the invention. This application example in no way represents a restriction for the intended use of the cannula device according to the invention. Rather, the use of the modular cannula device according to the invention is advantageously possible in all interventions in which a cannula is to be placed in a patient's vessel and / or organ.

Claims

Expectations

1. Modular cannula device, comprising an external tubular cannula; a first tubular guide member which has a tapered distal end and can be inserted into the cannula, so that its outer wall lies tightly against the inner wall of the cannula; and; a second tubular guide part which has a tapering distal end and can be inserted into the first guide part, so that its outer wall lies tightly against the inner wall of the first guide part.

2. The modular cannula device according to claim 1, wherein the opening angle of the tapered distal end of the first guide part is greater than the opening angle of the tapered distal end of the second guide part.

3. Modular cannula device according to claim 1 or 2, wherein the first tubular guide part at the proximal end has an enlarged area with an outer diameter which is larger than the inner diameter of the tubular cannula.

4. Modular cannula device according to one of claims 1 to 3, wherein the first and second guide part at the proximal end each have a part of a fixing device, by means of which the second guide part can be attached to the first guide part relative to the latter.

5 _.. Modular cannula device according to claim 4, wherein the fixing device comprises an internal thread arranged on the first guide part and a matching external thread arranged on the second guide part.

6. Modular cannula device according to one of claims 1 to 5, wherein in the assembled state of the modular cannula device it has a tapered distal end which is formed by the tapered ends of the first and second guide parts.

7. Modular cannula device according to one of claims 1 to 6, wherein in the region of the distal end of the tubular cannula a radiopaque marking is arranged, which is preferably designed as a full circumferential ring in the lateral surface of the cannula.

8. Modular cannula device according to one of claims 1 to 7, wherein the distal end region of the cannula, which is preferably at least 2 cm long, is made of a softer material than the rest of the cannula.

9. Modular cannula device according to one of claims 1 to 8, wherein the cannula is made of a softer material than the first guide part.

10. Modular cannula device according to one of claims 1 to 9, wherein at least a part in the distal region of the cannula is pre-stressed on the material side, so that the corresponding part of the cannula has an arch shape without external force.