Long-term follow-up after mitral valve replacement in childhood: poor event-free survival in the young child.

OBJECTIVE In children, mechanical mitral valve replacement may be the only option if the failing mitral valve cannot be repaired. Mandatory anticoagulation and the fixed size prosthesis are of concern in the growing child, but long-term follow-up results are lacking. METHODS Single centre, extended retrospective study of 54 patients who underwent first mitral valve replacement between June 1982 and December 1997. Median age at operation was 3.0 years (range 2 days-18.1 years), 21 patients were15 years (maximum 22 years) in nine patients. RESULTS Thirty-day mortality was 42% in patients<or=2-year-old, and 6% in older patients. There were 10 late deaths. Estimated survival at 10 and 15 years follow-up was 33%+/-19% and 33+/-27% in patients<or=2-year-old, and 81%+/-8% and 75%+/-16% in older patients, respectively. High operative mortality in the younger age group was the most important contributor to poor long-term survival. Fifteen patients underwent redo-mitral valve replacement with one operative death. A larger valve was always implanted. Freedom from redo-mitral valve replacement at 10 and 15 years was 25%+/-22% and 0% in patients with prostheses<23 mm, and 83%+/-13% and 83%+/-27% in patients with larger prostheses. Significant bleeding events occurred in eight patients and were often associated with operative interventions. Estimated freedom from bleeding was 75.7%+/-9% and 70.6%+/-16% at 10 and 15 years, respectively. Thromboembolism and endocarditis were rare. There was no structural valve failure. Estimated freedom from all adverse events at 10 years follow-up was 17%+/-13%. CONCLUSIONS At 10 years follow-up after mechanical mitral valve replacement, most children had suffered an adverse event. At 15 years, all children with a prosthesis<23 mm had outgrown their valve, but redo-mitral valve replacement with a larger size prosthesis was always possible, and carried low operative risk. Long-term anticoagulation was well tolerated. In children every effort should be made to preserve the native valve.