Impactor for fracturing calcifications in heart valves

Abstract

A device for fracturing calcifications in heart valves includes a tube formed with at least two longitudinal slits that form at least two struts (4). Each of the struts includes two or more pairs of notches (3) formed on opposite sides of the strut. The struts have a contracted orientation in which the struts are not expanded outwards from the tube and an outwardly expanded orientation in which the struts are expanded outwards from the tube and have sufficient strength and rigidity to impact and fracture a calcification in a heart valve.

Claims

1. A device for fracturing calcifications in heart valves comprising: a tube formed with at least two longitudinal slits that form at least two struts, each of said struts comprising two or more pairs of notches formed on opposite sides of the strut, said struts having a contracted orientation in which said struts are not expanded outwards from said tube and an outwardly expanded orientation in which said struts are expanded outwards from said tube and have sufficient strength and rigidity to impact and fracture a calcification in a heart valve; and wherein the tube comprises a curved waist portion extending between two longitudinally-spaced pairs of said notches, wherein in the outwardly expanded orientation, said waist portion is curved radially inwards and wherein said waist portion is shaped to conform to a ventricular side of a valve leaflet.

2. The device according to claim 1, wherein said waist portion is made from a scored or weakened portion of said struts.

3. The device according to claim 1, wherein pairs of said notches are formed at different locations along a longitudinal length of said strut.

4. The device according to claim 1, wherein said struts are symmetrically separated from each other.

5. The device according to claim 1, wherein said struts are non-symmetrically separated from each other.

6. The device according to claim 1, wherein a distal end and a proximal end of said tube are affixed to an inner tube and an outer tube, respectively, of an actuator for expanding or contracting said struts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

(2) FIG. 1 is a simplified illustration of an impactor, in a completely contracted orientation, in accordance with a non-limiting embodiment of the invention;

(3) FIGS. 2 and 3 are simplified illustrations of the impactor, in two different expanding orientations, in accordance with a non-limiting embodiment of the invention;

(4) FIG. 4 is a simplified partially sectional illustration of the impactor assembled on an actuator for expanding or contracting the impactor, in accordance with a non-limiting embodiment of the invention; and

(5) FIGS. 5-7 are simplified illustrations of introducing the impactor to the site of a valve and valve leaflets, respectively, with the impactor contracted, partially expanded and fully expanded at the valve site.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) Reference is now made to FIG. 1, which illustrates an impactor device 7, in accordance with a non-limiting embodiment of the invention.

(7) The device 7 includes a tube 1 formed with at least two longitudinal slits 2, cut or otherwise formed through a thickness of the tube 1 for most, but not all, of the tube length. The material left between adjacent slits forms a strut 4. One or more transverse cuts 3 extend circumferentially from each slit 2 so as to form one or more notches 3 in the struts 4. In the non-limiting illustrated embodiment, there are three struts 4 (which may be symmetrically separated from each other by 120 or may be non-symmetrically separated from each other by different angular spacings). Each strut has two or more pairs of notches 3 on opposite sides of the strut at different locations along the longitudinal length of the strut. Each strut can be split along its longitudinal length (either at the center or off-center) to form two struts and thus increase contact locations with the cardiac tissue.

(8) The assembly can be made from nitinol or stainless steel or any other suitable material. The struts may include a curved waist portion 5, made from a scored or weakened portion of the strut. The waist 5 may be shaped to conform to the ventricular side of a valve leaflet 21 (seen in FIGS. 5-7). The waist 5 extends between two longitudinally-spaced pairs of notches 3.

(9) FIGS. 2 and 3 show device 7 with the struts 4 deployed outwards at varying amounts of outward expansion. It is seen that when struts 4 are in the outwardly expanded orientation, waists portions 5 are curved radially inwards.

(10) Reference is now made to FIG. 4. A distal end 50 and a proximal end 51 of the tube 1 of device 7 are affixed to an inner tube 10 and an outer tube 11, respectively, of an actuator 13 for expanding or contractioning the struts 4. Moving the inner tube 10 proximally with respect to the outer tube 11 causes the struts 4 to expand outwards; conversely, moving the inner tube 10 distally with respect to the outer tube 11 causes the struts 4 to contract inwards. Alternatively, moving the outer tube 11 distally with respect to the inner tube 10 causes the struts 4 to expand outwards; conversely, moving the outer tube 11 proximally with respect to the inner tube 10 causes the struts 4 to contract inwards.

(11) Reference is now made to FIGS. 5-7, which illustrate introducing the impactor to the site of a valve 20 (e.g., the aortic valve) and valve leaflets 21.

(12) The impactor device 7 is initially contracted and may be placed in a catheter with a protective sheath or any other delivery device (not shown). The delivery device may be used to deliver the contracted impactor device 7 through the vasculature, such as the peripheral artery through the aortic arch and into the ascending aorta, through the aortic valve and finally into the left ventricle. The actuator 13 (not shown here) is then manipulated to partially expand (FIG. 6) and then fully expand (FIG. 7) the struts 4 of the impactor 7 at the valve site. The operator can control the amount of outward expansion by manipulating the actuator 13. Varying the degree of expansion modifies the impact force the impactor 7 can apply to calcifications. The struts 4 can be optionally vibrated as they expand to increase the efficiency of the impacts to break calcifications. As in PCT Patent Applications PCT/US2010/058810 and PCT/US2012/067812, a stabilizer (not shown) can be used on the other side of the leaflets for bearing the force of the impacts.

(13) In the expanded orientation, the struts have sufficient strength and rigidity to impact and fracture calcifications. For example, without limitation, a material with an elastic modulus of at least 20 GPa and/or yield strength of at least 70 MPa will have sufficient strength and rigidity to impact and fracture calcifications.