Percutaneous mitral balloon dilatation by a new sequential single- and double-balloon technique.

Percutaneous balloon valvotomy by means of a new sequential single- and and double-balloon dilatation procedure was performed in 23 patients (aged 13 to 53 years) with severe rheumatic mitral stenosis. The dilatation procedure was initially performed with a small balloon to primarily dilate the stenotic valve for easier passage of a second balloon catheter and to make the procedure tolerable for severely ill patients; the procedure was then followed by two balloons to further increase the mitral valve area (MVA) for effective dilatation of the stenotic mitral orifice. The dilatation was successful in all patients; the mitral valve pressure gradient decreased from 19 +/ 6 to 5 +/ 2 mm Hg, the cardiac output increased from 4.0 +/ 0.5 to 5.2 +/ 0.6 L/min, and the MVA increased from 0.8 +/ 0.2 to 1.9 +/ 0.4 cm2 (p less than 0.01 each). The MVA after dilatation was relative to the effective balloon dilatation diameter selected (r = 0.57; p less 0.01). A small atrial septal defect was observed in 3 of 23 patients immediately after the dilatation procedure. Mild mitral regurgitation was produced in 3 of 23 patients by the dilatation. We conclude that the sequential single- and double-balloon dilatation procedure can effectively increase the MVA and improve hemodynamics in severe mitral stenosis and that the larger effective balloon diameter of 24.8 mm or more (12 +/ 18 mm of two balloons) is necessary for effective dilatation.