Method and system for treating valve stenosis
View Patent ↗A valvuloplasty catheter comprises a balloon or other expansible shell which carries a plurality of scoring elements, typically formed in an elastic, self-closing metal cage. The expansible shell and scoring elements are positioned inside an aortic or other cardiac valve, and the shell expanded to engage the scoring elements against stenotic material which covers the valve leaflets and valve annulus. The scoring elements uniformly distributed force to break up the stenotic material, and the cage further contributes to rapid balloon deflation allowing shortening of the treatment time.
1. A device for treating cardiac valve stenoses, said device comprising:
a shaft having proximal and distal ends;
an expansible shell carried on a distal region of the shaft;
a plurality of nondeployable scoring elements coupled to said shaft but not attached to the expansible shell;
wherein the expansible shell has a length and expanded diameter selected to fully occupy an adult human cardiac valve annulus and said scoring elements have flat radially outward surfaces;
wherein the shaft is a catheter shaft adapted to be introduced over the aortic arch to position the expansible shell in the cardiac valve annulus;
wherein the expansible shell is a nondistensible inflatable balloon having an inflated diameter in the range from 20 mm to 30 mm;
wherein the inflatable balloon has a length in the range from 2 cm to 4 cm;
wherein from 5 to 20 scoring elements extend from a proximal end to a distal end of the balloon and are evenly circumferentially spaced apart over an exterior balloon surface;
wherein the scoring elements are struts in an elastic metal cage structure and parallel to its axis, wherein the cage structure is coupled to the catheter shaft but not attached to the balloon, wherein the cage is elastically biased to contract when the balloon is not inflated;
wherein the elastic metal cage structure comprises circumferentially arranged elongated hexagonal cells which are parallel to the axis, wherein each cell has a proximal connection point to a proximal ring and a distal connection point to a distal ring and where the struts extend between said connection points;
wherein the cage further comprises distal connector links which extend between the distal connection point and the catheter shaft to secure the cage to the catheter shaft; and
further comprising a compliance tube having a distal end coupled to proximal connector links of the cage and a proximal end attached to the catheter shaft, wherein the compliance tube is adapted to accommodate axial elongation and circumferential rotation of the cage structure.
2. A device as in claim 1 , wherein the scoring elements have a rectangular cross-section with a height in the radial direction in the range from 0.1 mm to 0.4 mm and a width in the circumferential direction in the range from 0.25 mm to 0.5 mm.
3. A device as in claim 1 , wherein the elastically biased cage is capable of improving balloon deflation characteristics by causing the balloon to deflate more rapidly and more uniformly.
4. A device as in claim 1 , wherein the elastically biased cage is capable of contracting to a diameter in the range of from 3 mm to 7 mm.
5. A device according to claim 1 , wherein at least one of said rings has a zig zag shape.