ORIFICE VARIABILITY OF THE STENOTIC AORTIC-VALVE - EVALUATION BEFORE AND AFTER BALLOON AORTIC VALVULOPLASTY

The effects of balloon aortic valvuloplasty on orifice variability of the stenotic sclerocalcific aortic valve were evaluated by hemodynamic measurements of aortic valve function in 14 patients before balloon aortic valvuloplasty, during nitroprusside infusion before valvuloplasty, 48 h after valvuloplasty and during nitroprusside infusion 48 h after valvuloplasty. Aortic valve function was assessed by aortic valve area calculations with use of the Gorlin and Cannon formulas. Nitroprusside infusion before balloon aortic valvuloplasty caused no change in mean aortic valve gradient but a significant increase in mean aortic transvalvular flow from 186 +/- 46 to 202 +/- 61 ml/s (p < 0.05), in Gorlin aortic valve area from 0.49 +/- 0.17 to 0.53 +/- 0.21 cm2 (p < 0.05) and in Cannon aortic valve area from 0.45 +/- 0.18 to 0.49 +/- 0.22 cm2 (p < 0.05). Nitroprusside infusion 48 h after valvuloplasty induced no change in mean aortic valve gradient but a significant increase in mean aortic transvalvular flow from 214 +/- 61 to 254 +/- 78 ml/s (p < 0.005), in Gorlin aortic valve area from 0.71 +/- 0.25 to 0.83 +/- 0.32 cm2 (p < 0.01) and in Cannon aortic valve area from 0.78 +/- 0.33 to 0.88 +/- 0.40 cm2 (p < 0.05). Forty-eight hours after valvuloplasty, nitroprusside infusion induced a larger increase (40 +/- 40 ml/s) in mean transvalvular flow than before valvuloplasty (16 +/- 27 ml/s; p < 0.05) and a larger increase (0.12 +/- 0.14 cm2) in Gorlin aortic valve area than before valvuloplasty (0.05 +/- 0.07 cm2; p < 0.05). Balloon aortic valvuloplasty, which causes splitting of fused commissures and fracturing of calcific deposits within the valve leaflets, reduces the inertia of the leaflets during their opening motion. This explains the larger increment after balloon aortic valvuloplasty of effective valve orifice, when transvalvular flow is increased during nitroprusside infusion.