Clinical and morphological features of human hypertensive-diabetic cardiomyopathy

Abstract

The existence of a specific cardiomyopathy secondary to diabetes mellitus is controversial. During a 2-year period, we had the opportunity to examine nine diabetic patients at autopsy who had clinically severe congestive heart failure and minimal extramural coronary artery atherosclerosis. Unexpectedly, all nine patients were found to be hypertensive. Accordingly, we initiated a detailed study of the clinical and morphological features of this group, and compared the findings to age-matched autopsied subjects with either isolated hypertension, isolated diabetes mellitus, or no heart disease. The study of the hypertensive-diabetic hearts revealed severe interstitial fibrosis, focal or confluent scars, and extensive myocytolytic activity. Comparison with the diabetic, hypertensive, and normal groups showed statistically significant differences in regard to the degree of interstitial and focal scarring, and the presence of myocytolysis. Only the hypertensive group had minimal interstitial scarring. There were no statistical differences in the small vessel changes between the four groups, although subjectively the hypertensive and hypertensive-diabetic patients had more severe disease. It is concluded that the association of diabetes mellitus and hypertension in the absence of significant coronary artery atherosclerosis may lead to a severe cardiomyopathy. Although the etiology of myocardial failure in this syndrome is uncertain, the degree of myocardial fibrosis and the frequency of myocytolytic lesions possibly related to catecholamine hypersensitivity, are potential explanations. Several studies suggesting that hypertension has adverse consequences in diabetes, as well as an animal model of hypertensive-diabetic cardiomyopathy, support our conclusion that cardiomyopathy associated with diabetes mellitus is a specific entity which may be secondary to the combined effects of diabetes and hypertension on the myocardium.