Efficacy of aortic balloon valvoplasty: direct measurement of orificial area in a model with pulsatile flow.
The efficacy of balloon valvoplasty of calcific aortic stenosis remains controversial. We studied, therefore, 5 human aortic valves obtained at necropsy in a positive-displacement pulse duplicator which delivered stroke volumes of 40-100 ml with a quasiphysiological waveform of flow. All valves had three leaflets without commissural fusion and were preserved in antibiotic solution before study. Orificial area was planimetered from videotape of opening of the valve and varied with flow in all cases. Valvoplasty with a 20 mm diameter balloon had no effect on the orifice of the normal valve but increased the orifice of 2 mildly calcified valves from 0.70-1.77 cm2 (range) at baseline to 1.06-1.95 cm2. In 2 valves with severe calcification of the leaflets, the orifice was increased from 0.31-0.82 cm2 to 0.73-1.07 cm2. Dual balloon valvoplasty achieved a variable but small further increase in orificial area. No valve showed tears of the leaflets or fracture of calcific deposits after valvoplasty. We conclude that balloon valvoplasty can acutely increase orificial area, independently of any change in stroke volume. In valves without commissural fusion, its mechanism appears to be an increase in the pliability of the leaflets which does not require macroscopic fracture of calcific deposits.
Cardiac Department, King's College Hospital, London, U.K.
D C
DC
Sprigings
J B
JB
Chambers
T
T
Cochrane
J
J
Allen
M M
MM
Black
G
G
Jackson
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000473:pathology; D001024:Aortic Valve Stenosis / Q000473:pathology / Q000628:therapy*; D001783:Blood Flow Velocity; D002404:Catheterization; D005260:Female; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D011379:Prognosis; D013318:Stroke Volume