Mitral valve replacement in children with rheumatic heart disease.

We followed 110 children, ages 6-15 years, who had undergone mitral valve replacement for rheumatic heart disease.Group 1 consisted of 74 patients with mechanical prostheses and a mean follow-up of 6.3 years.Group 2 consisted of 13 patients with porcine xenografts followed for 3.3 years.Group 3 included 23 children with dura mater bioprostheses and a mean follow-up of 1.9 years.The clinical evolution of each group was assessed according to the New York Heart Association criteria.The incidence of complications also was determined.Ninety-five percent confidence limits were calculated for all proportions from binomial distri- bution; lack of superposition was adopted as the criterion of significance.In group 1, thromboembolic complications occurred in 1.7% per patient/year, infective endocarditis in 0.85% per patient/year, valvular dysfunction in 0.85% per patient/year, and death in 1.3% per patient/year.Group 2 patients had no thromboembolic complications; infective endocarditis occurred in 2.3% per patient/year, dysfunction in 16.3% per patient/year, and death in 14% per patient/year.Seven patients with Hancock porcine xenografts presented valve obstruction, and four cases that were studied anatomically showed fibrocalcific obstruction of the prosthesis.In group 3, thromboembolic episodes occurred in 2.3% per patient/year, dysfunction in 6.8% per patient/year, and death in 2.3% per patient/year.Calcific obstruction of the prosthesis was observed in one patient at necropsy.We conclude that mechanical prostheses offer the best results in children.With adequate anticoagulation, thromboembolism is of little significance, the incidence of infective endocarditis is comparable to that reported for bioprostheses, dysfunction is less frequent, and the long-term mortality rate is lower.