Device for endovascular resection of septal myocardial tissue

Abstract

In a device (1) for endovascular resection of septal myocardial tissue, at least comprising an outer catheter (2), an inner catheter (3) guided movably in the outer catheter (2), a filter hose (5) and a cutting tool (9), the filter hose (5) bears sealingly, at its proximal end (5a), on the inner catheter (3) and, by extension of its distal end (5b) connected to a radially expandable holding structure (6), can be deployed from the outer catheter (2), wherein a plurality of valve flaps (10), held by the holding structure (6) and extending in the direction of the proximal end (5a) of the filter hose (5), are arranged with mutually contactable coaptation surfaces in order to form a temporary aortic valve, and wherein the cutting tool (9) can be deployed from the inner catheter (3) and is designed to extend through the aortic valve and project distally from the filter hose (5).

Description

[0001] Device for endovascular resection of septal myocardial tissue

[0002] The present invention relates to a device for endovascular resection of septal myocardial tissue.

[0003] Left ventricular obstruction is a frequently observed pathological change in the cardiac septum in which the septum is thickened at the expense of the outflow tract of the left ventricle. Two causes are currently known for the formation of this type of left ventricular obstruction. One is hypertrophic cardiomyopathy, and the other is interventricular septal hypertrophy in aortic valve stenosis. With a prevalence of 1:500 in the general population, hypertrophic cardiomyopathy is the most common genetic cardiomyopathy and the most frequent cause of sudden cardiac death in infants, adolescents, and young adults.

[0004] Currently, there is a surgical and an interventional approach to the surgical treatment of patients with left ventricular obstruction. Surgical resection of the interventricular septum requires opening the chest and a correspondingly longer postoperative recovery period, but it yields good results. Non-surgical approaches such as alcoholic ablation of the septum or embolization of the septal branches of the left coronary artery are inherently far less traumatic, but generally do not result in long-term, stable treatment success.In aortic valve replacement in patients with interventricular septal hypertrophy due to aortic valve stenosis, surgical resection of the septum is routinely performed. However, the narrowed excretory tract of the left ventricle poses a significant technical challenge for valve implantation in transcatheter aortic valve implantations and carries an increased surgical risk. However, septal resection in these transcatheter implantations has not been possible to date.

[0005] In the publications WO 2023200706 A1, WO 2023137497 A2, US 2023016149 A1, US 11759315 B1 and DE 102023112240 A1, surgical instruments for the minimally invasive correction of defects in the cardiac septum with reference to the subject matter of the present invention are disclosed.

[0006] It is therefore an object of the present invention to provide a device with which a septum resection, in particular of the excretory tract of the left ventricle, can be carried out without opening the chest and consequently endovascularly.

[0007] To achieve this object, a device of the type mentioned at the outset comprises at least one outer catheter, an inner catheter which is guided displaceably in the outer catheter, a filter tube and a cutting tool, the filter tube being connected in a sealing manner to the inner catheter at its proximal end and being able to be deployed from the outer catheter by extending its distal end which is connected to a radially expandable holding structure, a plurality of valve leaflets which extend in the direction of the proximal end of the filter tube and have coaptation surfaces which can be brought into contact with one another to form a temporary aortic valve being held by the holding structure, and the cutting tool being able to be moved out of the inner catheter and being designed to extend through the aortic valve and to project distally beyond the filter tube.

[0008] The material of the filter tube offers good protection against embolisms and does not significantly impede blood flow.

[0009] This device makes it possible to keep the aortic valve open for access to the left ventricle and also to introduce a cutting tool into the left ventricle and safely collect resected myocardial tissue in order to prevent embolism through the resected tissue.

[0010] For this purpose, the device according to the invention is inserted along a guide wire, through the femoral artery and the aortic arch up to the aortic valve. The inner catheter with the filter tube and the cutting tool is pulled into the outer catheter. The radially expandable holding structure and the filter tube are then unfolded by withdrawing the outer catheter from the distal end of the inner catheter, so that the native valve, i.e. the leaflets of the aortic valve, are held open by the radially expandable holding structure, the function of the native valve being replaced by the valve leaflets.The cutting tool is then extended from the inner catheter and introduced through the temporary aortic valve into the left ventricle. The cutting tool only displaces the leaflets of the temporary valve far enough for the cutting tool to pass through the valve plane, but the coaptation surfaces are also able to create a sealing connection to the cutting tool extending into the ventricle. In this way, cardiac function and coronary perfusion are ensured even when the device according to the invention is already in the working position displacing the native aortic valve, so that the septal tissue can be resectioned without difficulty.

[0011] Therefore, the use of a heart-lung machine is not necessary. The septal tissue resected with the cutting tool is flushed from the ventricle by the heart's work and safely collected in the filter tube, which seals proximally with the internal catheter.

[0012] Overall, this method achieves a minimally invasive resection of the septum that is comparable in effectiveness to the above-mentioned surgical treatment, so that correspondingly positive long-term results can be achieved and prolonged rehabilitation after the operation is not necessary. If necessary, the minimally invasive procedure can be performed several times using the device according to the invention if satisfactory results are not achieved immediately.

[0013] In order to ensure that the temporary aortic valve provided by the device according to the invention functions as closely as possible to the physiological function of the native aortic valve, a preferred embodiment of the present invention provides for three congruent valve leaflets to be arranged at positions offset from one another in the circumferential direction by 120°. According to a preferred embodiment of the present invention, the cutting tool is formed by a cutting loop. Cutting loops are known in the art and have been tried and tested for the resection of muscle tissue and therefore represent an optimal cutting tool for use in connection with the present invention.

[0014] In a proven manner, the cutting tool is connected to a surgical coagulator via an insulated electrical conductor, which further increases the cutting performance and, above all, the precision of the cutting.

[0015] According to a preferred embodiment of the present invention, the radially expandable holding structure has or is formed by an expandable stent. Expandable stents are known in the art in many different forms and are used in the present invention for the controlled application of the filter tube and the temporary aortic valve to the end of the filter tube in order to keep the native aortic valve open and to protect it from injury by the cutting tool. The stent is preferably made of metal or plastic. In keeping with the usual dimensions of a native aortic valve, the distal end of the filter tube and, in this preferred case, consequently the expandable stent, has a diameter of 20 mm to 35 mm. In connection with the present invention, the filter tube can, for example, have a length of approximately 90 mm.

[0016] According to a preferred embodiment, the present invention is further developed in that the cutting tool is guided proximally from the valve leaflets in a guide ring and is guided centrally through the radially expanded support structure by the guide ring. The guide ring serves to hold the cutting tool centrally with respect to the valve ring directly before it passes through the temporary aortic valve, so that the cutting tool passes through the temporary aortic valve as centrally as possible. This achieves a more or less complete seal of the temporary aortic valve, which minimizes the strain on the patient's circulatory system during the procedure.

[0017] According to a preferred embodiment of the present invention, the guide ring is held by a plurality of holding wires which are connected to a corresponding plurality of guide wires extending from the inner catheter to the stent and each firmly connected to the latter, wherein preferably three holding wires are arranged at positions offset from one another in the circumferential direction by 120°, and three guide wires are arranged at positions offset from one another in the circumferential direction by 120°. In this way, a compact holder for the guide ring is created which can be easily folded up inside the outer catheter and unfolded from the outer catheter when the inner catheter is extended.

[0018] The cutting tool can have a bending region with low rigidity and control elements for bending the bending region, as corresponds to a preferred embodiment of the present invention. The control elements can be formed by pull wires, as is known in the prior art in the field of endovascular catheters and other endoscopic systems. The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing. In this drawing: Figure 1 shows a perspective view of the device according to the invention, Figure 2 shows a plan view of the filter tube and the guide ring without the cutting tool, and Figure 3 shows a perspective view of a cutting tool of the device according to the invention.

[0019] In Figure 1, the device according to the invention for the endovascular resection of septal heart muscle tissue is designated by the reference numeral 1. The device 1 essentially comprises an outer catheter 2 and an inner catheter 3, the inner catheter 3 being guided displaceably in the outer catheter 2 in the direction of the double arrow 4. The reference numeral 5 designates a filter tube which, at its proximal end 5a, is sealingly connected to the inner catheter 3 and, in the position shown in Figure 1, extended from the outer catheter 2, is unfolded to form an open distal end 5b. An expandable holding structure 6 is fixed to the open distal end 5b, which in the present case is formed by a stent 7, for example made of metal or plastic, the stent 7 being covered by the filter tube 5.The stent 7 consists, in a manner known per se, of a deformable metal mesh that can be compressed into the outer catheter 2 when the inner catheter 3 is retracted. For this purpose, for example, the outer catheter has a diameter of 19 Fr, the inner catheter a diameter of 17 Fr, and the stent 7 has a diameter of 20 mm to 35 mm, corresponding to a native aortic valve.

[0020] Reference numeral 8 denotes a guide ring through which the cutting tool 9 is guided. The guide ring 8 is arranged proximally of the valve leaflets 10 of the temporary aortic valve provided by the device according to the invention. In this way, the cutting tool 9 is centrally aligned before passing through the artificial, temporary aortic valve, so that optimal coaptation of the valve leaflets 10 can take place. Furthermore, holding wires 11 and guide wires 12 for the guide ring 8 can be seen in Figure 1.

[0021] The cutting tool 9 can be completely retracted into the inner catheter 3 and then reinserted into the inner catheter 3 from the proximal end. For example, it is possible to remove the cutting tool 9 before retrieving the filter tube 5 by retracting the inner catheter 3 into the outer catheter 2. This also allows different cutting tools 9 to be inserted into the inner catheter 5, or, with the cutting tool 9 completely removed, large resected specimens to be removed from the surgical field through the lumen of the inner catheter 3.

[0022] The distal end 5b of the filter tube 5 or the distal end of the holding structure 6 is covered by a liquid-tight coating which extends in an arc as far as the bases of the valve leaflets 10. The minimum extension of the coating in the proximal direction is approximately 3 mm and this ensures that, on the one hand, the entire blood flow from the left ventricle is directed through the temporary aortic valve and, on the other hand, no blood from the aorta can pass past the temporary aortic valve and back into the left ventricle. In Figure 2, the guide wires 12 and the holding wires 11 are now more clearly visible and it can be seen that the guide wires 12 extend from the inner catheter 3 to the stent 7 and are firmly connected to it.In this way, the guide ring 8 is centrally aligned when the stent 7 and thus the filter tube 5 are deployed, so that the cutting tool 9 (not shown in Figure 2) can pass centrally through the mutual contact surfaces or coaptation surfaces of the valve leaflets 10. The holding structure 6 at the distal end 5b of the filter tube 5 has an extension in the proximal-distal direction shown by the double arrow 4 of approximately 3 mm, and the filter tube 5 has an extension in this direction of approximately 70 to 90 mm.

[0023] In Figure 3, the cutting tool 9 is shown enlarged and it can be seen that the cutting tool 9 is in the form of a cutting loop, wherein the cutting edge 9a is formed on the proximal edge of a recess 13 of the cutting tool 9. The resection of septal tissue is thus carried out with this cutting tool when the cutting tool 9 is retracted in the proximal direction symbolized by the arrow 14. The cutting tool 9 has a bending region 15 which has reduced rigidity compared to the rest of the cutting tool 9. The bending region 15 can therefore be deformed in a manner known in the art by actuating the pull wires 16, for which purpose the pull wires 16 are anchored distal to the bending region 15 in anchors 17 in the cutting tool 9. A guide wire is designated by the reference numeral 18.

Claims

Patent claims:

1. Device for the endovascular resection of septal heart muscle tissue, at least comprising an outer catheter (2), an inner catheter (3) displaceably guided in the outer catheter (2), a filter tube (5) and a cutting tool (9), wherein the filter tube (5) is sealingly connected to the inner catheter (3) at its proximal end (5a) and can be deployed from the outer catheter (2) by extending its distal end (5b) connected to a radially expandable holding structure (6), wherein a plurality of valve leaflets (10) extending in the direction of the proximal end (5a) of the filter tube (5) are arranged, with coaptation surfaces that can be brought into contact with one another, to form a temporary aortic valve, and wherein the cutting tool (9) extendable from the inner catheter (3) and designed to extend through the aortic valve and project distally beyond the filter tube (5).

2. Device according to claim 1, characterized in that three congruent flap leaflets (10) are arranged at positions offset from one another in the circumferential direction by 120° each.

3. Device according to claim 1 or 2, characterized in that the cutting tool (9) is formed by a cutting loop.

4. Device according to claim 1, 2 or 3, characterized in that the cutting tool (9) is connected to a surgical coagulator via an insulated electrical conductor.

5. Device according to one of claims 1 to 4, characterized in that the radially expandable holding structure (6) has an expandable stent (7) or is formed by it.

6. Device according to claim 5, characterized in that the stent (7) is made of metal or plastic.

7. Device according to one of claims 1 to 6, characterized in that the cutting tool (9) is guided proximally from the valve leaflets (10) in a guide ring (8) and is guided centrally through the radially expanded holding structure (6) by the guide ring (8).

8. Device according to claim 7, characterized in that the guide ring (8) is held on a plurality of holding wires (12) which are connected to a corresponding plurality of guide wires (11) extending from the inner catheter (3) to the holding structure (6) and are each firmly connected thereto.

9. Device according to claim 8, characterized in that three holding wires (12) are arranged at positions offset from one another in the circumferential direction by 120° each and three guide wires (11) are arranged at positions offset from one another in the circumferential direction by 120° each.

10. Device according to one of claims 1 to 9, characterized in that the cutting tool (9) has a Bending area (15) with low rigidity and control elements for bending the bending area (15).

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