Abstract 3552: Abnormal Glucose Regulation is Associated with Lipid-Rich Plaque: Involvement of Insulin Resistance
Background: Abnormal glucose tolerance (AGT) has emerged an important determinant of cardiovascular risk. We hypothesized that AGT would be associated with coronary plaque instability.
Methods: Conventional and integrated backscatter intravascular ultrasound (IB-IVUS) using 40-MHz (motorized pullback 0.5mm/s) intravascular catheter was performed to 153 consecutive patients with 358 coronary lesions. The percentage of fibrous area (% FA) and the percentage of lipid area (% LA) were automatically calculated by IB-IVUS system. Following the WHO criteria, the subjects were classified into the diabetic group, the impaired glucose tolerance (IGT) group, and the normal glucose tolerance group. We defined the cut-off point for the lipid-rich plaque as % LA>44 % or % FA<53 %, which were the 75th percentile of % LA or the 25th percentile of % FA in this study population. Insulin resistance (IR) was defined as the homeostasis model assessment of IR (HOMA-IR).
Results: There were no significant differences in the baseline characteristics except for HOMA-IR, and in the conventional IVUS parameters among the three groups. In the IB-IVUS analysis, as compared with the normal glucose tolerance group, the diabetic group and the IGT group showed a significant increase in % LA (35 ± 16 %, p=0.005 and 36 ± 19 %, p=0.006 vs. 29 ± 16 %) and a significant decrease in % FA (60 ± 14 %, p=0.003 and 59 ± 15 %, p=0.004 vs. 65 ± 12 %). The lipid-rich plaque rate was significantly associated with an increasing HOMA-IR in the tertile (p ANOVA=0.008). On logistic regression analysis after adjusting for confounding and coronary risk factors, HOMA-IR (>3.4) was significantly associated with the lipid-rich plaque (OR 1.79, 95% CI 1.03–3.13, p=0.04).
Conclusions: Coronary lesions in patients with AGT are associated with lipid-rich plaque, which might be on the basis of the increased IR in these patients.