Coronary composition and macrophage infiltration in atherectomy specimens from patients with diabetes mellitus

Background-Lipid-rich, inflamed atherosclerotic lesions are associated with plaque rupture and thrombosis,; which are the most important causes of dea th in patients with diabetes mellitus. This study was designed to quantify Lipid composition and macrophage infiltration in the coronary lesions of pa tients with diabetes mellitus, Methods and Results-A total of 47 coronary atherectomy specimens from patie nts with diabetes mellitus were examined and compared with 48 atherectomy s pecimens from patients without diabetes. Plaque composition was characteriz ed by trichrome staining. Macrophage infiltration was characterized by immu nostaining. Clinical and demographic data were similar in both groups. The percentage of total area occupied by lipid-rich atheroma was larger; in spe cimens from patients with diabetes (7+/-2%) than in specimens from patients without diabetes (2+/-1%; P=0.01); and the percentage of total area occupi ed by macrophages was larger in specimens from patients with diabetes (22+/ -3%) than in specimens from patients without diabetes (12+/-1%; P=0.003). T he incidence of thrombus was also higher in specimens from patients with di abetes than in specimens from patients without diabetes (62% versus 40%; P= 0.04). Plaque composition, macrophage infiltration, and thrombus were simil ar in lesions from diabetic patients treated with insulin compared with les ions from patients treated with sulfonylureas or diet. Conclusions-Coronary tissue from patients with diabetes exhibits a larger c ontent of lipid-rich atheroma, macrophage infiltration, and subsequent thro mbosis than tissue from patients without diabetes. These differences sugges t an increased vulnerability for coronary thrombosis in patients with diabe tes mellitus.