Association of Cardiomegaly with Coronary Artery Histopathology and its Relationship to Atheroma

Abstract

Aims: Hypertrophied hearts at autopsy often display excessive coronary artery atherosclerosis, but the histopathology of coronary arteries in hearts with and without cardiomegaly has rarely been compared.
Methods: In this study, forensic autopsies provided hearts with unexplained enlargement plus comparison specimens. Right coronary artery was opened longitudinally and flattened for formalin fixation and H&E-stained paraffin sections were cut perpendicular to the endothelial surface. The micro-scopically observed presence or absence of a necrotic atheroma in the specimen was recorded. At multiple sites far removed from any form of atherosclerosis, measurements were taken of intimal thickness, numbers of smooth muscle cells (SMC) and their ratio, the thickness per SMC, averaged over the entire nonatheromatous arterial length. When the mean thickness per SMC exceeded a certain cutoff point, the artery was declared likely to contain a necrotic atheroma.
Results: The prevalence of specimens with necrotic atheromas increased stepwise with increasing heart weight, equally with fatal or with incidental cardiomegaly, and equally with hypertension- or obesity-related hypertrophy, rejecting further inclusion of appreciable age, race, or gender effects. The prevalence of specimens with thickness per SMC exceeding the cutoff point was almost always nearly identical to the prevalence of observed necrotic atheroma, showing the two variables to be tightly linked to each other with quantitative consistency across group comparisons of every form.
Conclusions: In summary, cardiomegaly, irrespective of the specific cause, seems to accelerate the risk of atheromas, and to do so by first altering the arterial architecture, especially by increasing intimal thickness per SMC.