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 method for treating cardiac valve stenoses, said method comprising:
providing a 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 carried by the shaft;
wherein the expansible shell has a length and expanded diameter selected to fully occupy an adult human cardiac valve annulus and the 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;
wherein the scoring elements extend from a proximal end to a distal end of the balloon and are circumferentially spaced 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 carried by the catheter shaft, 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 the connection points;
wherein the cage further comprises distal connector links which extend between the distal connection point and the catheter shaft, the distal links being fixed relative to the distal end of the shaft; and
further comprising a compliance tube having a distal end coupled to proximal connector links of the cage, the distal end of the compliance tube being movable relative to the shaft, and the compliance tube further having a proximal end fixed to the catheter shaft, wherein the compliance tube is adapted to accommodate axial elongation and circumferential rotation of the cage structure;
positioning the balloon inside a stenosed cardiac valve annulus;
expanding the balloon to engage the scoring elements against the annulus;
maintaining the balloon expansion for a time sufficient for the scoring elements to disrupt the stenoses; and
contracting the balloon.
2. A method as in claim 1 , wherein positioning comprises advancing the shaft over the aortic arch into the aortic valve annulus.
3. A method as in claim 1 , wherein the balloon expansion is maintained for a time in the range from 1 second to 12 seconds.
4. A method as in claim 3 , wherein expanding the balloon comprises inflating the balloon.
5. A method as in claim 4 , wherein the balloon is inflated to a pressure in the range from 1 atm to 12 atm.
6. A method as in claim 5 , wherein the balloon is inflated to a diameter in the range from 20 mm to 30 mm.