Late results of mitral valve replacement with the Björk-Shiley prosthesis in children under 16 years of age.

The late results of isolated mitral valve replacement were evaluated in 37 children under 16 years of age receiving a Björk-Shiley prosthesis for the treatment of rheumatic mitral lesions. Three patients died, one during the operation and the others 2 months postoperatively. Of the latter two, one had a cerebral hemorrhage and the second had septicemia. The survivors were followed up for a mean of 4.7 years (range 2.8 to 8.9 years). After the operation, all patients were placed on a strict anticoagulant regimen with acenocoumarol. The actuarial survival rate was 92% at the end of the follow-up period. Before valve replacement two patients were in New York Heart Association Class I, 15 in Class II, 18 in Class III, and two in Class IV. After treatment 33 were in Class I and one in Class II. No instances of thromboembolism or infective endocarditis were observed in the survivors. Twenty-one patients underwent cardiac catheterization 2 to 7 years after the operation for evaluation of surgical results. The mean pulmonary artery systolic pressure decreased significantly after operation (p = 0.001), and the mean pulmonary artery wedge pressure decreased to normal values (p = 0.001). A mild mean diastolic gradient across the mitral valve at rest was found after the operation (4.9 +/- 2.4 mm Hg). During isometric exercise this gradient increased to 6.5 +/- 4.6 mm Hg. In two patients a discrete paravalvular leak was demonstrated by cineangiography, but the pulmonary wedge pressure was normal in both. The overall results with the Björk-Shiley prosthesis are encouraging in patients in whom reconstructive operations cannot be performed.