Results after mitral valve replacement with mechanical prostheses in young children

Abstract

We examined outcomes after mitral valve replacement in children younger than 8 years. Medical records of patients who underwent mitral valve replacement from 1990 to 2006 were reviewed. Competing-risks methodology determined time-related prevalence and associated factors for death, repeated valve replacement, and survival without reoperation. In total, 79 patients, median age 24 months (40 days-8 years) underwent 91 mitral valve replacements (10 had repeated procedures). Underlying pathology was congenital heart disease in 95% of cases. Forty-six patients (58%) had undergone previous operations. Operative mortality was 18%, 30% for those 2-years old and younger and 6% for those older than 2 years. Competing-risks analysis showed that 10 years after initial mitral valve replacement, 40% of patients had died without repeated replacement, 20% had undergone a second replacement, and 40% remained alive without further replacement. Factors associated with death included higher prosthesis size/patient weight ratio (P < .0001) and longer crossclamp time (P < .0001). Second replacement 6 +/- 4 years after initial replacement was necessary for 10 survivors. At second replacement, larger prostheses were implanted (mean 24 mm vs 19 mm initially). Repeated MVR was associated with younger age at surgery (p = .006). Permanent pacemaker implantation was eventually needed by 11% of hospital survivors. Mortality and repeated valve replacement are common after mitral valve replacement in children younger than 8 years, especially younger patients with significantly oversized valves. At valve reoperation, larger prostheses could be implanted, suggesting continued annular growth.