Technical Field

The invention relates to a catheter system comprising a steerable and/or deflectable catheter having a distal end and a proximal end, the proximal end furthermore comprising a manipulator for bending the distal end area of the catheter.

Background of the invention

Steerable or deflectable catheters are well known in the state of the art and are typically used to reach into body areas or lumens of a patient that are difficult to access. A typical field of application that is preferably addresses in this specification is heart surgery in which it is intended to place an implant into the heart that at least reduces or preferably eliminates a heart valve insufficiency, i.e. regurgitation.

In the typical terminology the steerability of a catheter refer to the ability to turn or rotate the distal end of the catheter with like-for-like movement of the proximal end of the catheter to which typically a manipulator, preferably a handle is attached. Such catheters may provide strong torque transfer along the length of the catheter.

Deflection refers to the ability to move the catheter tip or preferably a distal end area of the catheter independent of the remaining part of the catheter. In order to provide such function, it is known to transfer a movement at a manipulator situated at the proximal end of the catheter by means of at least one transfer means into a

movement of the catheter tip or end area. Such transfer means may be formed of pull wires or pull fibers that extend along the catheter length and are fixed at the distal end area of the catheter. This invention refers to both types of catheters and preferably to the ones providing deflection.

In order to treat a diseased heart, the necessary implant comprises a closure element and at least one anchoring element, being connected to each other. In preferred embodiments the anchoring element is only connected to the atrial side of the closure element and serves to fix the position of the closure element with the mitral valve annulus. The anchoring element is in such a case preferably formed of an

expandable cage and the exterior surface of the expanded cage is intended to contact the internal surface of the atrial myocard, preferably without puncturing the myocard. Accordingly, the cross section of the expanded cage is typically bigger that the cross section of the atrium of the heart and the cage is resilient and provides at least in a radial direction a force against the myocard that provides fixation of the implant.

The closure element is also expandable and typically self-expanding or expanded by inflating a balloon of the closure element. The exterior surface of the expanded closure element is intended to get in contact with the closing leaflets of the mitral valve and to close a remaining gap between the leaflets.

Such an implant, particularly if it is self-expanding, needs to be carefully positioned in the heart prior to expansion in order to avoid to harm the leaflets or the myocard. Particularly the anchoring element needs to be placed in the atrium and must not expand prior to be correctly placed.

It is generally known in the state of the art to set a catheter having its distal end positioned in the ventricle and the proximal end outside the body of a patient. A surgeon may move the collapsed implant, particularly by pushing it, through the catheter until it is release from the distal catheter end into the heart.

It is known to use steerable or most preferred deflectable catheters particularly if the catheter is fed in the heart though the aortic valve into the ventricle. Using such a type of catheter it is possible to deflect it in such a way that the distal end is aiming through the mitral valve. Accordingly, an implant will be release form the catheter in a direction towards the mitral valve. Unfortunately, it is not possible to move the catheter end through the mitral valve in order to place at least a part of the implant, preferably the anchoring element, directly into the atrium.

Accordingly, it is an object of the invention to provide a catheter system that facilitates to place the implant into the correct position and that in addition reduces the risk of trauma. Furthermore, it is an object of the invention to provide an improved method of treatment in connection with such a catheter system.

Any direction mentioned in this application text is to be understood in relation to the heart of a treated patient or to the implant correctly implanted in the heart, preferably if the closure element is positioned in the valve annulus, preferably of the mitral valve.

Even though the application of this invention is preferred in regard to humans the invention may be also applied to animals, particularly mammalian animals.

Summary of the invention

The object is solved by a catheter system comprising a steerable / deflectable catheter having a distal end and a proximal end, the proximal end furthermore comprising a manipulator for bending the distal end area of the catheter and comprising an elongation sheath coaxially surrounding the steerable / deflectable catheter at least in its distal end area, the elongation sheath being slidingly movable on the exterior surface of the catheter and along the extension of at least the distal end area of the catheter into a position in which the distal tip of the elongation sheath is projecting beyond the distal tip of the catheter.

According to the invention it is possible to elongate the catheter by the length that the elongation sheath extends beyond the distal catheter tip. Such elongation may be performed without movement of the catheter that is already set into place. The elongation of the catheter may be done in such a way that the distal end of the elongation sheath is positioned in the valve annulus or preferably slightly positioned beyond the annulus when regarded from the ventricle in atrial direction. According to a preferred embodiment the elongation sheath may be movable between two positions, in the first position the distal tip of the sheath being positioned on the proximal side of the distal catheter tip and in the second position the distal tip of the sheath being positioned on the distal side of the distal catheter tip. Accordingly, in the first position there is no elongation of the catheter at all even though the sheath is positioned around the catheter near the tip. In the second position the catheter is elongated as mentioned before.

In a first possible embodiment the proximal end of the elongation sheath may comprise an operating means, particularly a handle, preferably near the manipulator of the catheter, the operating means being adapted to be moved by a surgeon in order to move the distal end of the sheath. Preferably in this embodiment the operating means and the sheath are directly connected.

The elongation sheath may have a length so that during surgery the proximal end of the sheath or the operating means at the proximal end of the sheath is positioned outside a treated patient. This preferably means that the distance of the proximal end of the sheath to the proximal end of the catheter is smaller than the distance of the proximal end of the sheath to the distal end of the catheter.

In this embodiment and also in the embodiments mentioned later the mechanical properties, particularly the stiffness in axial and/or radial direction of the sheath may vary along the longitudinal extension of the sheath. Accordingly, in a proximal part the sheath may have a bigger axial stiffness compared to the distal part in order to provide like-for-like movement in axial direction if the surgeon moves the operations means in order to advance the elongation sheath.

In the distal part the sheath may have a smaller axial stiffness but a bigger radial stiffness in order to withstand the radial forces of self-expanding implant.

In this and the following embodiments the elongation sheath may comprises an exterior wall and an interior wall, having coiled or braided wires/fibers being

positioned between the walls. The mechanical properties may be varying for example by providing different means, like the coiled or braided wires / fibers between the exterior and interior wall of the sheath in dependence of axial position. According to another preferred embodiment the proximal end of the catheter, particularly the manipulator of the catheter may comprise an operating means for moving the elongation sheath, the operating means and the elongation sheath being separate, spaced and connected along the distance of separation by at least one transfer means, the transfer means extending between the operating means and the sheath, preferably the transfer means being guided through the catheter, particularly through a hollow catheter wall. According to this embodiment there is no need to feed the elongation sheath through the patient's skin. The elongation sheath of the catheter system may be totally positioned inside a patient if he is treated.

The distance of the proximal end of the sheath to the proximal end of the catheter is in this case preferably bigger than the distance of the proximal end of the sheath to the distal end of the catheter. Furthermore, the distance between the proximal end of the sheath and the proximal end of the catheter, particularly the length of the at least one transfer means is bigger than the length of the sheath in its longitudinal direction.

A catheter system of one of the aforementioned embodiments and even of non- mentioned but comprised embodiments may provide a novel technique of treatment, particularly of placing an implant into the heart.

According to the invention it is possible to treat mitral heart valve insufficiency of a diseased heart valve having a remaining gap between closed valve leaflets, by implanting an implant into the heart using the said catheter system.

The method of treatment and the different embodiments will be furthermore

described in connection with the figures.

Description of the figures

Figure 1A, B, C, D illustrate the different stages of the method to place and implant into the heart using a first embodiment of the catheter system

Figure 2 illustrates this first embodiment of the system

Figure 3 illustrates a second embodiment of the catheter system Detailed description of the invention

According to Figure 1 A the system is used to forward the distal end area 1 of a steerable / deflectable catheter 2, particularly through the aortic valve 3, into the ventricle 4 below the mitral valve 5. Afterwards by steering / deflecting the distal end area 1 of the catheter 2 the catheter tip 6 may be positioned to have the frontal area of the catheter tip 6 facing the opening in the mitral valve annulus, particularly the distal end of the catheter 1 aiming through the mitral valve annulus. Preferably the distal end area 1 of the catheter 2 may have a straight end portion 1a ending in the catheter tip 6, the imaginary middle axis 7 of this portion being positioned in the vale annulus and surrounded by it.

The elongation sheath 8 that is coaxially surrounding at least the distal end area 1 of the catheter 2 may now be advanced, i.e. moved towards the atrium 9 into a position projecting beyond the distal tip 6 of the catheter 1 , particularly starting from a position not projecting beyond the distal tip of the catheter. If the distal end 1 of the catheter 2 has a straight portion 1a the elongation sheath 8 will follow the extension of this portion along the axis / line 7.

The distal tip 10 of the elongation sheath 8 may now be furthermore moved through the mitral valve annulus. Now the catheter system is elongated and serves to put the implant 11 into place, that is positioned in the interior free space of the catheter 1. This situation is depicted in Figure 1A by means of the dashed lines.

According to Figure 1 B the implant 11 may now be moved out of the steerable / deflectable catheter 1 into the elongation sheath 8 and through the elongation sheath 8. The implant 11 will be released from the elongation sheath 8, particularly at least the anchoring element 11a, preferably the self-expanding anchoring element 11a of the implant 11 into the atrium of the heart, as shown in Figure 1 C. The sheath 8 protects to valve annulus from the expanding anchoring cage and accordingly placing the implant is totally atraumatic.

One of the major advantages of this system is that the elongation sleeve does not at all restrict the diameter of the implant. Since the inner diameter of the sheath 8 is bigger than the outer diameter of the catheter 1 and the diameter of the implant 11 is smaller than the inner diameter of the catheter. Any implant that may be fed through the catheter will automatically also pass through the elongation sheath 8.

Figure 1C shows that the anchoring cage 11a of the implant is expanded and fixes the position of the implant by contacting the myocard in the atrium.

Now the elongation sheath that still surrounds the closure element 11 b of the implant 11 may be retracted, particularly by doing so the closure element 11 b of the implant 11 is released from the elongation sheath 8 into the mitral valve annulus and may be now expanded for example by inflating with a fluid if it is not self-expanding. This is shown in Figure 1 D.

Now the blood regurgitation will be eliminated or at least reduced by filling the remaining gap between the closed valve leaflets with the closure element.

The catheter 1 may now be retracted together with the surrounding sheath 8.

According to a different method the catheter system may be also used explanting an implant situated in the heart at least in part. The method just comprises the steps shown in Figure 1C and 1 D in opposite direction.

The method comprises forwarding the distal end area of the steerable / deflectable catheter, particularly through the aortic valve, into the ventricle below the mitral valve, steering / deflecting the distal end area of the catheter to have the frontal area of the catheter tip facing the mitral valve annulus, particularly the distal end of the catheter aiming through the mitral valve annulus and advancing an elongation sheath that is coaxially surrounding at least the distal end area of the catheter into a position projecting beyond the distal tip of the catheter, particularly starting from a position not projecting, furthermore collapsing an expanded closure element of the expanded implant, particularly by releasing a fluid out of the inflated closure element and moving the distal tip or distal end area of the elongation sheath over the collapsed / deflated closure element and through the mitral valve annulus by furthermore advancing the elongation sheath, furthermore comprising pulling the closure element of the implant into the elongation sheath and the catheter after separating the closure element from the anchoring element or pulling the entire implant into the elongation sheath and the catheter, particularly wherein the anchoring element gets

simultaneously collapsed. According to this method a retracted separated closure element may now be replaced by a new closure element that gets connected to the remaining anchoring element.

Figure 2 shows the embodiment of the system used in connection with figures 1. The system comprises the steerable or deflectable catheter 1 surrounded by the elongation sheath 8. First the sheath 8 has a position POS.1 in which the distal tip of the sheath does not project beyond the tip 6 of the catheter 1.

The manipulator 12 at the proximal end of the catheter 1 is used to steer / deflect the catheter in the desired way and the operation means 13 at the proximal end of the sheath 8 is used to move the sheath along the catheter 1. Moving to operations means 13 towards the distal end of the catheter / sheath the tip 10 of the sheath 8 may be advance into position POS.2, in which the tip 10 is moved beyond the catheter tip 6. In this embodiment the sheath has a length so that the proximal end of the sheath 8 is situated outside the patient and the sheath is fed through the skin of the patient. The body boundary of the patient is depicted by 14.

Figure 3 depicts the same situation with a slightly different embodiment of the system. Here the sheath 8 is situated totally within the body of the patient and separated from the operation means 13 that may be integrated into the manipulator 12 of the catheter.

The distance between the proximal end of the sheath 8 and the operation means 13 is bridged by a transfer means 15. Any movement of the operations means 13 will be transferred by the transfer means to the sheath 8.