Mechanical valve replacement in children and teenagers.

A previous study from this unit showed that only 19% of children with mitral bioprostheses were free from complications after 7 years and prompted us to review the performance of new-generation mechanical prostheses implanted in the same population group. In a 5-year period (1980-1985), 352 patients 20 years old and younger (mean age 15.3 +/- 4 years) with rheumatic valvular disease had 177 mitral, 62 aortic and 113 double (mitral + aortic) valve replacements with Medtronic-Hall or St. Jude prostheses. The overall early mortality was 6.3%. All survivors, followed up for a total of 1171 patient-years, received oral anticoagulation. The late mortality for mitral, aortic and double valve replacement was 4.1% per patient-year, 4.3% per patient-year and 8.0% per patient-year, respectively (P less than 0.05), and was valve-related in 46% of the cases. Twenty-nine patients, all but 2 in the mitral and double valve replacement groups, were reoperated upon (2.5% per patient-year), mainly for infective endocarditis (34%), for prosthetic thrombosis (33%) and for bland periprosthetic leak (31%). The incidence of thrombotic obstruction was 1.1% per patient-year: mitral valve replacement, 1.0% per patient-year; aortic valve replacement 0.5% per patient-year; and double valve replacement, 1.7% per patient-year; P less than 0.05) and was fatal in 33% of the cases. Major systemic thromboembolism occurred at the rate of 1.4% per patient-year, similar in the three groups. The incidence of prosthetic endocarditis was 0.9% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)