Evaluation of Mitral Annuloplasty for Mitral Regurgitation

Abstract

Eleven patients seriously disabled by mitral regurgitation were re-evaluated 4 to 41 months following mitral annuloplasty (average 19.4 months). Preoperative and postoperative comparative data are presented. One patient was unimproved or worse. The rest were subjectively better. Mean changes were transverse cardiac diameter -17.8 mm. (median 15 mm.) ( p < .005); resting stroke index +9 ml./beat/M. 2 (median 9 ml./beat/M. 2 , p < .05); resting cardiac index +0.5 L./min./M. 2 ( p = .20); mean pulmonary artery pressure -7.2 mm. Hg, or 29 per cent (median 8 mm. Hg, p < .03); and arteriovenous oxygen difference -12 ml./L. (median 13 ml./L., p < .005). Abnormally prolonged mixing, as shown by indicator-dilution curves, was decreased in all patients ( p < .05). Exercise testing showed varying degrees of improvement in six of the nine so studied. In six patients mitral regurgitation by angiocardiographic measurements postoperatively represented 0, 0, 21, 24, 35, and 46 per cent of the total left ventricular stroke volume. Two patients had increased end-systolic left ventricular volume as evidence for postoperative left ventricular failure. The other four were probably normal. Ten of the 11 patients showed postoperative improvement that was felt to be significant in two or more of the above objective measures. Striking x-ray improvement in heart size occurred in two patients, eight others showed decreases in transverse diameter of up to 17 mm. One developed an increase in heart size. Although probably improved over their preoperative status, two patients had significant mitral stenosis at the time of re-evaluation. Another showed evidences of progressive mitral regurgitation after an initial period of improvement. Mitral annuloplasty is a palliative procedure with considerable potential for effecting a reduction in regurgitant volume and improving the clinical status of carefully selected patients.