Impact of Diabetes Mellitus on Coronary Atherosclerosis and Plaque Composition Under Statin Therapy

BACKGROUND: Patients with diabetes mellitus (DM) have a markedly increased incidence of adverse cardiovascular events, but the mechanisms have not been well-characterized. METHODS AND RESULTS: The TRUTH study evaluated the effects of 8-month statin therapy on coronary artery plaque composition using virtual histology intravascular ultrasound (IVUS). Analyzable IVUS data were obtained from 119 patients, including 50 DM patients. The pattern of arterial remodeling, extent of coronary atherosclerosis, and plaque composition were compared in subjects with and without DM. Significant decreases in atheroma volume (-2.3%, P=0.02) and external elastic membrane volume (-1.7%, P=0.02) were observed only in the non-DM group. Although statin therapy significantly decreased the fibro-fatty component in both groups, this component at follow-up was significantly greater in the DM group (0.99 mm(3)/mm vs. 0.70 mm(3)/mm, P=0.03). Multivariate regression analysis showed that the presence of DM was associated with greater atheroma volume (β=0.203, P=0.02), particularly fibro-fatty plaque volume at follow-up (β=0.215, P=0.01). CONCLUSIONS: DM attenuated the degree of regression of coronary atherosclerosis under statin therapy. A large amount of fibro-fatty plaque volume under statin therapy may affect the development of coronary events in patients with DM.