An important complication of Hancock mitral valve replacement in children.

Nine children ages 2--15 years have undergone mitral valve replacement (MVR) with Hancock porcine heterograft valves for severe mitral insufficiency. The etiology of the mitral valve disease was rheumatic in two patients, and congenital in seven. Porcine valve sizes ranged from 19--31 mm. Follow-up has been from 1.6 to 6.1 years (mean, 4.3 years). All nine children have had marked postoperative improvement, no thromboembolic complications despite no long-term anticoagulations, and no episodes of endocarditis. There have been no early or late deaths. Although six of the nine patients remain asymptomatic, three others developed severe fibrocalcific obstruction of the heterograft, requiring valve re-replacement at 3.5, 3.6, and 4.8 years following the initial valve replacement. This complication has not been previously reported in children. It is a factor that must be considered when deciding on MVR for children and their postoperative management.