Balloon catheter for generating vibrations for breaking up vascular calcifications

Abstract

A balloon catheter (1), comprising a shank (2) extending in an axial direction (x) and connected at a distal end to an inflatable balloon (3) surrounding a balloon interior (30), wherein the balloon interior (30) can be pressurised with a fluid medium via a lumen of the shank (2) to inflate the balloon (3), characterized in that the balloon catheter (1) comprises a vibration exciter (4) arranged at least partially in the balloon interior (30), which vibration exciter is configured to set the balloon (3) to vibrate in a radial direction (R) extending perpendicular to the axial direction (x).

Description

[0001] BALLOON CATHETER FOR GENERATING VIBRATIONS FOR BREAKING UP VASCULAR CALCIFICATIONS

[0002] The present invention relates to a balloon catheter for breaking up vascular calcifications.

[0003] Such catheters are used for example for dilating stenoses in vessels. Furthermore, the generation of shock waves is known to be effective for breaking up vascular calcifications.

[0004] The aim of such technologies is to provide energy inside the balloon in order to generate shock waves. Such a shock wave is a high intensity mechanical wave which is characterised by an initial, high-intensity, pulse-like wave front followed by a rapidly descending wave.

[0005] Due to the increased effectiveness in preventing or managing the need for percutaneous coronary interventions (PCIs) the age of patients to be treated is increasing. As the treatment is used for an increasingly aging patient population, PCI procedures are being used more and more on calcified lesions. It is currently estimated that approximately 25% of the lesions treated include calcifications. When treating calcified lesions, the procedure is not only more high risk for the physician but the treatment is generally expected to be less effective. Several techniques are known which can be used to dissolve calcifications and avoid treatment risks. One of the most successful, but also more expensive, solutions for pre-treating lesions is the use of a vascular lithotripsy procedure. The success of lesion preparation is often assessed by the amount of fractures created in the calcified structure, as observed in studies using intravascular imaging, IVUS or OCT.

[0006] The present invention is based on the problem of superposing the balloon dilatation force with a mechanical vibrational energy in a simple and efficient manner. This problem is solved by a balloon catheter having the features of claim 1. Advantageous embodiments of the invention are described in the following.

[0007] According to claim 1 a balloon catheter is disclosed, comprising a shank extending in an axial direction, which is connected at a distal end to an inflatable balloon that surrounds a balloon interior, wherein the balloon interior can be filled with a fluid medium via a lumen of the shank for inflating the balloon.

[0008] According to the invention, it is provided that the balloon catheter has a vibration exciter arranged at least partially in the balloon interior, which vibration exciter is configured to cause the balloon to vibrate in a radial direction extending perpendicular to the axial direction and / or in an axial direction.

[0009] According to a particularly preferred embodiment of the invention, it is provided that the vibration exciter is configured to use a rotational movement within the balloon interior filled with the fluid medium to generate a vibrational movement of the balloon in radial and / or axial direction. The balloon filled at least partially with the fluid medium causes a (pre)tensioning of the balloon, in particular a balloon skin, which is excited to vibrate by the rotational movement of the vibration exciter.

[0010] Vibration waves can thus be generated in the balloon interior which can be used to break up calcified tissue structures. The radially and / or axially vibrating balloon can introduce vibrational energy, e.g. indirectly (e.g. via tissue, such as e.g. blood) or directly (by contact), into the calcified tissue structure.

[0011] The invention makes it possible in an advantageous manner to combine a vibrational movement of the balloon with impact on the calcified vascular site by the inflated balloon.

[0012] According to a preferred embodiment of the invention, it is provided that the vibration exciter has a longitudinally extended rotatable shaft, which has an imbalance, in particular in the form of an eccentric section. The vibration of the balloon is induced by rotation of the imbalance. The imbalance or the eccentric section is preferably arranged in the balloon interior. According to a further preferred embodiment of the invention, the shaft can extend in a lumen of the shank to a handle of the balloon catheter at a proximal end of the shank or balloon catheter. Preferably, according to one embodiment of the invention an actuator is arranged in the handle, e.g. in the form of an electric motor, which is configured to generate a rotational movement of the shaft about its longitudinal axis in order to rotate the imbalance to generate vibrations.

[0013] In the following embodiments of the invention as well as further features and advantages of the invention are explained with reference to the Figure.

[0014] Fig. 1 shows a schematic cross-sectional view of an embodiment of a balloon catheter according to the invention.

[0015] Figure 1 shows an embodiment of a balloon catheter 1 according to the invention, comprising a shank 2 extending in an axial direction x, which is connected at a distal end to an inflatable balloon 3 surrounding a balloon interior 30, wherein the balloon interior 30 can be filled with a fluid medium via a lumen of the shank 2 to inflate the balloon 3. The balloon catheter 1 comprises a vibration exciter 4 arranged at least partially in the balloon interior 30, which vibration exciter is configured to set the balloon 3 to vibrate in a radial direction R extending perpendicular to the axial direction x.

[0016] The vibration exciter 4 preferably has a rotating element or a rotating shaft 40 for transferring rotational energy inside a catheter body to the balloon 3. The balloon 3 distal to the catheter shank 2 is used to apply a hydraulic radial force to the narrowed vessel. The shaft 40 has an imbalance, e.g. in the form of an eccentric section or element 41 at the position of the balloon 3. In addition to the balloon 3, the rotation can also set a catheter tip 5, arranged distal to the balloon 3, into a vibrational state.

[0017] Optionally, the shaft 40 can be flushed internally to prevent overheating caused by frictional forces. In order to use a defined hydraulic pressure for inflating the balloon 3 and flushing the rotational structure 4, according to one embodiment of the invention a pressure supply is provided by means of a fluid 6 through an external device 7. This external device 7 can be connected to the shaft 40 by a mechanical and pressure-tight coupling 8 and generate (e.g. by means of an actuator 60) the rotation of the shaft 40 and thus of the imbalance 41.

[0018] In the simplest case where there is no flushing of the shaft 40, the device 7 can provide a fluid pressurisation 6 of the balloon 3 by introducing a fluid 6 via the shank 2 into the balloon interior 30. In the event that overheating of the shaft 40 needs to be prevented by flushing, the shaft 40 is pressurised with a fluid 6 by means of the device 7, wherein however the pressure for inflating the balloon 3 is controlled by a return flow of the fluid 6. According to Figure 1 the rotating structure or shaft 40 can be a tubular metal structure capable of directing the hydraulic fluid or medium 6 back to the device 7 to enable the flushing and pressurisation.

[0019] Knowledge of the systematic pressure losses and the known dependence of the pressure in the balloon interior on the flow rate of the fluid make it possible to precisely control the balloon pressure by means of the flow rate of the fluid 6. The fluid 6 can be a typical contrast agent or also an automated choice between a contrast agent and a more effective (also less expensive) sterile flushing fluid. The fluid 6 can also be a contrast agent which passes through a cooling and cleaning system outside the catheter 1.

[0020] Furthermore, the eccentric element 41 or the imbalance 41 in the balloon interior 30 can be provided with an independent, rotating cover element to protect the balloon 3 from abrasive effects or the rotating structure 41 when inflated or bent. This independent rotating cover can be a low friction metal or polymer tube which is placed over the rotating eccentric element 41 to allow rotation of the eccentric element 41 without direct balloon contact.

[0021] By using this element, the rotating structure 41 can also be used in situations with extremely low pressure in the balloon 3. In this case, the tip 5 will vibrate and axial bending forces will also be generated in the transitional area from the tip 5 to the balloon section 3. This effect can be useful for opening narrow stenoses and can be used as a way of passing a stenosis and allowing the final dilation operation at the intended position. Furthermore, the torques - which can be determined e.g. from the rotation-dependent instantaneous excitation of the catheter - can be used to determine whether the balloon has been twisted or to detect mechanical faults in general. Furthermore, the catheter tip 5 can be configured for receiving a guide wire extending laterally out of the catheter tip 5 and can have a corresponding guide wire lumen 50 for this purpose which opens laterally to the environment distal to the balloon 3.

[0022] The shaft 40 is preferably rotatably mounted proximally and distally in bearings 9, 10, e.g. plain bearings.

[0023] The present invention advantageously represents a technically simple and cost-effective alternative to a lithotripsy catheter system. Since, apart from the balloon, the catheter tip also vibrates, the mechanical properties of the balloon catheter can also be used for opening and passing narrow stenotic lesions.

Claims

Claims1. A balloon catheter (1), comprising a shank (2) extending in an axial direction (x) and connected at a distal end to an inflatable balloon (3) surrounding a balloon interior (30), wherein the balloon interior (30) can be pressurised with a fluid medium via a lumen of the shank (2) to inflate the balloon (3), characterized in that the balloon catheter (1) comprises a vibration exciter (4) arranged at least partially in the balloon interior (30), which vibration exciter is configured to set the balloon (3) to vibrate in a radial direction (R) extending perpendicular to the axial direction (x).

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