Statin treatment markedly reduces the incidence of acute coronary events in patients with coronary atherosclerosis. Although imaging studies have indirectly shown the beneficial effects of statins on plaque morphology, there has to our knowledge been no reported histologic comparison of the morphology of coronary plaque in statin-treated versus untreated patients who had substantial coronary artery atherosclerosis. We retrospectively studied arterial sections from the native hearts of patients who had experienced end-stage ischemic heart disease and subsequent cardiac transplantation. Of 44 qualified patients, 33 study patients had received pre-transplantation statin therapy, and 11 control patients had not. Pathologic examination of each explanted heart confirmed coronary artery disease and previous myocardial infarction in all patients. Diabetes mellitus was more prevalent in the study group. The groups were similar in levels of total and low-density lipoprotein cholesterol, and in the available number of arterial cross-sections per patient. All patients had plaques. High-grade lesions were found in 66.3% of cross-sections in the control group, and in 34.6% in the study group (P=0.011). Conversely, the degree of inflammation was markedly lower in the study group: low-grade fibrous plaques occurred in 45.7% of cross-sections in the study group, versus 11.3% in the control group (P=0.006). The study group had significantly fewer high-grade plaques and more fibrous plaques than did the control group at the time of transplantation. Our findings show that statin therapy substantially enhances plaque stabilization. We further suggest that reduction of plaque inflammation is an important aspect of this stabilization. © 2008 by the Texas Heart ® Institute.