Long-term follow-up after mitral valve reconstruction: incidence of postoperative left ventricular outflow obstruction.

Reconstructive surgery of the mitral valve has been an alternative to mitral valve replacement in patients with mitral regurgitation. Previously, we reported on postoperative left ventricular outflow tract obstruction associated with systolic anterior motion of the anterior mitral leaflet. The current study was designed to evaluate the incidence of this complication and the long-term results of mitral valve reconstructive surgery. Sixty-five patients, aged 19 to 78 years, had mitral valve reconstructive surgery. Two patients died perioperatively, and three died late after surgery. The 60 surviving patients were studied by M mode, two-dimensional, and Doppler echocardiography 1 to 55 months postoperatively (mean 21). Fifty patients had no evidence of postoperative mitral regurgitation, two patients had moderate mitral regurgitation, three patients had mild mitral regurgitation, and five patients had trace mitral regurgitation. No significant mitral stenosis was detected in any patient postoperatively. After surgery, the diameter of the left ventricular outflow tract was significantly smaller than that before surgery. The echocardiograms of six patients showed abnormal systolic anterior motion of the anterior mitral leaflet that was not observed preoperatively. Doppler echocardiography demonstrated pressure gradients across the left ventricular outflow tract between 10 and 64 mm Hg. Inhalation of amyl nitrite increased these gradients. An additional patient who had systolic anterior motion but no gradient developed a 36 mm Hg gradient after inhalation of amyl nitrite. The remaining patients had no gradient induced by amyl nitrite. Abnormal systolic anterior motion of the anterior mitral leaflet may be surgically induced by changes in left ventricular geometry and the size of the left ventricular outflow tract during systole.(ABSTRACT TRUNCATED AT 250 WORDS)