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Mitral valve replacement in the first 5 years of life
T N Zweng1, M K Bluett, R Mosca
1Division of Thoracic Surgery, University of Michigan Medical Center, Ann Arbor 48109.
Insights
Mitral valve replacement in young children has high mortality, but mechanical valves offer better long-term results than bioprosthetic valves. Reoperation rates were lower with mechanical valves, suggesting superior durability.
Area of Science:
- Cardiovascular Surgery
- Pediatric Cardiology
- Biomaterials Science
Background:
- Congenital heart defects often necessitate interventions in early childhood.
- Mitral valve replacement in infants and young children presents unique surgical challenges and risks.
- Previous studies on pediatric mitral valve replacement outcomes are limited.
Purpose of the Study:
- To evaluate the outcomes of mitral valve replacement in children aged 1 month to 5 years.
- To compare the long-term efficacy and safety of mechanical versus bioprosthetic mitral valves in pediatric patients.
- To identify risk factors associated with mortality and reoperation after mitral valve replacement in this age group.
Main Methods:
- Retrospective analysis of 19 children (1 month to 5 years) who underwent mitral valve replacement between 1976 and 1986.
- Review of indications for initial replacement and reoperations, including congenital mitral stenosis, valve dysfunction, and failed valvuloplasty.
- Comparison of outcomes between mechanical and bioprosthetic valve recipients, including mortality, thromboembolic events, bleeding, and reoperation rates.
Main Results:
- High operative mortality (32%) with 6 hospital deaths.
- Three late deaths occurred among survivors, unrelated to valve malfunction.
- Thromboembolic events occurred in 2 mechanical valve recipients; one bleeding complication in a patient on Coumadin.
- Five patients with bioprostheses required reoperation due to regurgitation or calcific stenosis; no deaths occurred after second replacement.
- Overall survival was 51% +/- 12% at 112 months.
- Mechanical valves showed a lower reoperation rate than bioprostheses.
Conclusions:
- Mitral valve replacement in children under 5 years is associated with significant early and late mortality.
- Mechanical mitral valves demonstrate superior long-term results and lower reoperation rates compared to bioprosthetic valves in this pediatric population.
- Despite high risks, mitral valve replacement can provide long-term palliation for selected children with mitral valve disease.
Abstract:
Between 1976 and 1986, 19 children aged 1 month to 5 years underwent replacement of the mitral (systemic atrioventricular) valve. Indications for valve replacement included isolated congenital mitral stenosis (n = 2), valve dysfunction associated with a more complex procedure (n = 15), and failed valvuloplasty (n = 2). Seven different valve types were used; nine were mechanical valves and ten were bioprosthetic valves. There were 6 hospital deaths (32%; 70% confidence limits, 20% to 47%). Among the 13 survivors there were 3 late deaths at a mean of 14 months after operation. The late deaths were unrelated to valve malfunction. Thromboembolic events occurred in 2 patients, both with mechanical valves. One minor bleeding complication occurred among 10 patients on a regimen of Coumadin (crystalline warfarin sodium). Five patients, all with bioprostheses, required a second valve replacement. Indications for reoperation included prosthetic valve regurgitation (n = 1) and calcific stenosis (n = 4). No early or late deaths occurred after second valve replacement. Survival was 51% +/- 12% (standard error) at 112 months after valve replacement. Analysis failed to identify age, weight, sex, previous operation, underlying cardiac lesion, or prosthesis size and type as significant risk factors for mortality. Mechanical valves had a lower reoperation rate compared with bioprostheses. These data suggest that although mitral valve replacement within the first 5 years of life is associated with a high operative and late mortality, satisfactory long-term palliation for many patients can be achieved. Mechanical valves are superior to bioprosthetic valves, and offer the best long-term results.