Chronic rheumatic heart disease in India: a reappraisal of pathologic changes.

Rheumatic heart disease contributes to significant cardiac morbidity and mortality in India. The disease predominantly affects the valvular endocardium culminating in crippling valvular deformities, preferentially involving the mitral valve which may be severely affected in children and young adults. This appears to be unique to India and has been termed juvenile mitral stenosis. It is characterized by cardiomegaly, refractory congestive heart failure, and marked by elevated pulmonary vascular pressures and a progressive, fulminant clinical course. Autopsies of patients dying of rheumatic heart disease revealed that the mitral valve was most commonly afflicted either alone or in combination with the aortic and tricuspid valves in 31.6% and 52.8%, respectively. Organic involvement of the tricuspid valve was documented in 38.4% of cases. The extent and severity of the disease process was most marked in the mitral valve, followed by the aortic and tricuspid valves. Mitral valves showed various degrees of calcification, moderate or severe calcification being observed in 36.4%. Chronic inflammatory cell infiltration was observed in both calcified and non-calcified valves. The phenotypic profile of the inflammatory cells by immunohistochemical staining revealed a significant number to be T-helper/inducer lymphocytes. Lungs from cases of mitral stenosis exhibited prominent vascular and parenchymal changes. Pulmonary vessels revealed moderate to marked medial hypertrophy of the medium sized branches of the pulmonary artery. Dilatation lesions were also seen in a few cases. The most striking parenchymal change was the prominent smooth muscle in the bronchoalveolar walls. The extent and severity of the vascular and parenchymal changes were more marked in juvenile patients. The presence of inflammatory cells in cases of chronic heart disease reflects a possible ongoing insult/injury to some persistent antigenic stimulus by beta hemolytic streptococcal antigens that have primed the various target tissues. Further study of surface characteristics of various mesenchymal cells may help in understanding the nature and pathogenesis of this serious cardiac problem.