Coronary arterial stenosis. An autopsy study

Hearts from 131 unselected medico-legal autopsies from 5 years to 80 years of age have been studied. Following injection with radio-opaque dye, the hearts were dissected, and angiograms taken were assessed for the presence of coronary artery narrowing. The arteries were then dissected off their beds, cut transversely at 3 mm intervals and studied both macro and microscopically for the degree of stenosis. Concentric and eccentric types of lesions were encountered. Former comprised chiefly of diffuse intimal thickening (DIT) which produced minimal luminal narrowing. The other concentric lesions consisted of fibrous plaques, calcified lesions and thrombosis. Concentric lesions constituted 40% of all stenotic lesions. Eccentric lesions were seen in 60% of all occlusions and were comprised by fibrous plaques, calcified lesions and thrombosis. Severe coronary arterial narrowing (Grades III and IV) observed microscopically, were detected radiologically. Microscopic examination followed by radiologic and gross examination in that order, seemed to be the best methods for the study of occlusive lesions. The left anterior descending artery (LAD) was narrowed in maximum number of cases followed by left circumflex and the right coronary artery (RCA). The average grade of narrowing was found, maximum in the LAD, followed by the left circumflex, left main artery, RCA, marginal and posterior descending (PDA) branches of the RCA respectively. The incidence and severity of occlusive lesions was maximum in the proximal segments of all the main arteries. This study suggests that in the local population, minimal narrowing is present resulting from the concentric intimal reaction to lipid accumulation in the form of DIT in a fair number of cases. The occlusive lesions in the various coronary artery segments lag 2-3 decades behind as compared to those observed in the western population.