Late left ventricular function after surgery for children with chronic symptomatic mitral regurgitation

Abstract

Background: The use of quantitative echocardiography has been emphasized in optimizing timing of surgery in adult patients with mitral regurgitation to avoid irreversible left ventricular dysfunction. In contrast, surgery for infants and children is often delayed until the appearance of severe symptoms because of the patient's size and anticoagulation requirements and the possible need for early reoperation. The purpose of this study was to determine long-term ventricular function after mitral valve surgery in symptomatic children and to analyze risk factors for adverse outcome.

Methods and results: Thirty-three patients (0.5 to 19 years old) operated on for mitral regurgitation as a single hemodynamically significant lesion were studied. All but 3 had medically refractory symptoms. One patient died during surgery, and 32 were followed for 0.3 to 17.1 years (mean, 4.5 years). The mean preoperative left ventricular shortening fraction was 0.38+/-0.09. Successful mitral valvuloplasty or replacement was documented by long-term normalization of end-diastolic dimensions. Early postoperative shortening fraction was significantly reduced (0.28+/-0.1, P<.01), but it improved to 0.40+/-0.07 (P<.01) on late follow-up, at which time only 1 patient had ventricular dysfunction. Preoperative shortening fractions did not correlate well with early or late postoperative values (r=.18 and r=.31, respectively). Seven of 32 surviving patients had preoperative shortening fractions <0.33 (mean, 0.26+/-0.05) and 25 >0.33 (mean, 0.39+/-0.08). Analysis of these subgroups showed no significant differences between the groups in early or late postoperative function. Duration of mitral insufficiency appeared to be associated with the development of atrial arrhythmias.

Conclusions: Late left ventricular function normalizes in children after surgical correction of mitral insufficiency. In contrast to adults, delay of surgery in children with significant mitral regurgitation until the onset of severe symptoms does not increase the risk for long-term ventricular dysfunction, although late atrial arrhythmias are more likely to be encountered.