[Late results of mitral valve replacement in 155 subjects under 16 years of age. Comparative study with 4 prosthesis]

We followed 155 children aged 6 to 16 years who underwent mitral valve replacement for rheumatic heart disease. Group I included 74 patients with Starr-Edwards prostheses and the mean follow-up period was 13 years. Group II was formed by 36 patients with Bjork-Shiley prostheses and a mean follow-up of 7.5 years. Group III consisted of 31 children with dura mater bioprostheses and a mean follow-up of 5.1 years. Finally, group IV included 14 patients followed a mean period of 4.9 years with Hancock xenografts. The four groups of patients were comparable before surgery. The criteria of the New York Heart Association (NYHA) were used to evaluate all patients before and 12 months after surgery. All patients with mechanical prostheses received anticoagulant therapy with acenocumarol from the first postoperative day. The incidence of complications such as thromboembolism, infective endocarditis, prosthetic dysfunction and death were determined at the end of the follow-up. The Fisher's exact test was used for nonparametric analysis and the two-tailed Student's T test for parametric results. All but two patients improved their NYHA clinical status after surgery (p less than 0.0001). Forty eight patients with mechanical prostheses were catheterized 1 to 7 years after the operation. The mean pulmonary arterial systolic pressure was reduced from 58 mmHg to 30 mmHg (p less than 0.001) and the mean pulmonary arterial wedge pressure decreased from 22 mmHg to 11 mmHg (p less than 0.001). There were no significant differences between the groups with mechanical and tissue prostheses in the incidence of thromboembolism and infective endocarditis.(ABSTRACT TRUNCATED AT 250 WORDS)