[The effect of electromagnetically produced shock waves on calcified, stenosed aortic valves]

To determine if electromagnetically generated shock-wave lithotripsy has potential application for treatment of stenotic, calcified aortic valves, 38 cusps of surgically excised human aortic valves were studied. Valves were weighed, photographed, and calcium deposition was determined by x-ray. Stiffness was determined by palpation and by measuring the pressure gradient generated in a perfusion system. Valves were exposed to shock waves at 16 or 18 kV with 200 or 400 impulses each. Twenty valves reacted to exposure to shock waves with a reduction in pressure gradient of 1.9 +/- 2 cm H2O. Calcified valve area was reduced by 3.5 +/- 1.3 mm2. Valves without changes in pressure gradient showed a reduction of 7.1 +/- 2 mm2 of calcified valve area. There was no significant difference in weight loss. Using a small focus (4 mm) there was a significant reduction in pressure gradient and calcified valve area, but not in weight; with a large focus (8 mm) reduction in calcified valve area, gradient, and weight was significant (p less than 0.05). Changes in valve stiffness were independent of weight loss and reduction in calcified valve area. In conclusion, shock-wave lithotripsy is capable of reducing stiffness of calcified aortic valves, presumably by fragmentation of tissue calcium deposits.