Pulmonary arteriolar muscularization in coal workers' pneumoconiosis and its correlation with right ventricular hypertrophy.

The relationship between the thickness of the walls of small pulmonary arteries (the medial wall thickness as a percentage of external diameter, percentage of medial thickness) in coal miners and control subjects were studied using morphometric techniques and correlated with the degree of right ventricular hypertrophy, severity of coal workers' pneumoconiosis, emphysema, and other chronic lung diseases. Pulmonary arteries less than 100 microns in external diameter were identified and the external diameter, medial thickness, and intimal thickness were quantitatively measured in the lung tissues of 57 coal miners and 15 control subjects with and without other chronic lung diseases. Coal workers' pneumoconiosis, emphysema, and right ventricular hypertrophy were assessed uniformly in all cases. The arterial wall thickness correlated with right ventricular hypertrophy, progressive massive fibrosis, and other chronic lung diseases. Severity of emphysema also showed a weak correlation. Although the functional significance of these findings is not known, we conclude that the muscularization of pulmonary arterioles provides a structural basis for the development of right ventricular hypertrophy in coal miners.