A device for fracturing calcifications in heart valves includes a stabilizer assembly (20) for use with an impactor assembly (10). Relative motion between the impactor assembly (10) and the stabilizer assembly (20) with sufficient energy fractures a calcification located in tissue which is sandwiched between the stabilizer assembly (20) and the impactor assembly (10). The stabilizer assembly (20) includes a plurality of distal stabilizer struts (28) connected by stabilizer loops (30) which extend proximally backwards.