Evolution of Mitral Valve Replacement in Children: A 40-Year Experience

Abstract

This report reviews our 40-year experience with pediatric mitral valve replacement (MVR) with respect to mortality, valve-related morbidity, and reoperation risk factors. From 1970 to 2010, 97 patients have undergone a total of 136 MVRs. Median age was 8 years (2 weeks to 18 years), 41 patients (42%) were less than 5 years, and 16 were infants (17%). Etiology was congenital in 65 patients (67%), rheumatic in 27 (28%), and endocarditis in 5 (5%). Regurgitation was the predominant lesion in 67 patients (69%), stenosis in 23 (24%), and mixed in 7 (7%) patients. Mechanical valves (ball, n=11; or bileaflet disc, n=66) and xenografts (porcine, n=14; bovine, n=2) were used in 93 initial MVR patients. Since 2002, 5 children have undergone Ross MVR with a pulmonary autograft in 3 and an aortic homograft in 2. Hospital mortality was 6% (6 of 97). There were 23 late deaths and 5 patients have required cardiac transplantation. Thirty-five year actuarial survival was 71%. Age less than 2 years, MVR prior to 1980, atrioventricular septal defect, univentricular heart, and additional left side obstructions were significant predictors of death. Mean follow-up was 12.8±10.1 years (range, 2 months to 38 years). Seventeen patients with mechanical valves experienced systemic emboli in 9 (10%), valve thrombosis in 5 (6%), and bleeding requiring transfusion in 3 (3%) patients. Thirty-two patients required reoperations (35%) from 3 months to 14 years (mean, 6.5±4.4 years) after initial MVR. Actuarial freedom from reoperation at 35 years was 63%. Variables associated with mitral re-replacement were younger age, small weight, valve diameter less than 23 mm, MVR prior to 1980, and type of implanted valves (xenograft, single-leaflet disk, ball-caged, or human valves). Pediatric MVR can be performed with low initial mortality but should be reserved for medical and reconstruction failure because reoperation, valve-related complications, and late mortality are high. Bileaflet prostheses larger than 23 mm have the lowest reoperation risk. Ross MVR may offer select patients a durable tissue valve without lifelong anticoagulation and its associated complications.