Mitral valve replacement in severe pulmonary arterial hypertension.

The immediate postoperative hemodynamics in 43 patients with severe pulmonary arterial hypertension who underwent mitral valve replacement between January 2000 and September 2001 were studied prospectively. The mean age was 30.6 years. There was mitral stenosis in 19 (44.1%), mitral regurgitation in 9 (20.9%), and mixed lesions in 15 (34.9%). In 36 patients (83.7%, group 1) pulmonary arterial pressure was sub-systemic, with a mean of 58.1 mm Hg and pulmonary vascular resistance of 743.4 dyne x s x cm(-5). Seven patients (16.3%, group 2) had supra-systemic pulmonary arterial pressure of 83.2 mm Hg and pulmonary vascular resistance of 1,529 dyne x s x cm(-5). Lung biopsies were taken from the right lower lobe in 24 patients. Operative mortality was 5.5% in group 1 and 28.5% in group 2. After mitral valve replacement, the pulmonary arterial pressure and vascular resistance decreased significantly in group 1. In group 2, pulmonary arterial pressure decreased significantly but pulmonary vascular resistance remained elevated. Pulmonary vascular changes did not progress beyond grade III (Heath-Edwards' classification). Mitral valve replacement is safe even in the presence of severe pulmonary arterial hypertension as long as pulmonary arterial pressures are below systemic pressures. Lung biopsy did not help in identifying patients with irreversible pulmonary arterial changes.