Insulin resistance and angiographical characteristics of coronary atherosclerosis

Insulin resistance (IR) is frequently observed in patients with coronary he art disease (CHD). The relationship between IR and the angiographical chara cteristics of coronary atherosclerosis were investigated in 66 patients wit h coronary artery lesions. Insulin resistance was assessed by a 75-g oral g lucose tolerance test and homeostasis model assessment (HOMA). The angiogra phical characteristics of coronary atherosclerosis (ie, the severity of CHD ) were defined by both Gensini's score (GS) (a higher degree of coronary ar tery stenosis or a proximal lesion was assigned a higher score than a dista l lesion) and the number of significantly stenosed vessels. When GS was exa mined as a categorical variable classified by tertile values (Group A, n=22 : 1 less than or equal to GS less than or equal to 14; Group B, n=22: 15 le ss than or equal to GS less than or equal to 32; and Group C, n=22: 33 less than or equal to CS), patients with a high GS (Group C) had significantly (p<0.05) higher values of fasting plasma insulin, insulin response, and HOM A IR than patients with a low GS (Group A) (12.6+/-1.2 mu U/ml vs 6.9+/-1.2 mu U/ml, 122.2+/-11.9 mu U ml(-1) h(-1) vs 72.9+/-12.9 mu U ml(-1) h(-1), and 2.9+0.3 vs 1.5+/-0.3, respectively). The values in Group B patients (9. 4+/-1.2 mu U/ml, 108.5+/-12.5 mu U ml(-1) h(-1), and 2.1+/-0.3, respectivel y) were intermediate between those in Groups A and C. The area of insulin/a rea of glucose ratio was significantly (p<0.05) higher in Groups B and C th an in Group A (0.54+/-0.06 mu U/mg, 0.54+/-0.06 mu U/mg, and 0.32+/-0.06 mu U/mg, respectively). However, no significant differences were observed in variables of glucose tolerance, serum lipid, lipoproteins, fibrinogen, uric acid, and blood pressure among the 3 groups. Significant (p<0.05) positive associations were found between GS, the number of diseased coronary arteri es, and Fasting immunoreactive insulin, insulin response, the area of insul in/area of glucose ratio and HOMA IR by logistic regression analysis. After adjusting for the number of diseased coronary arteries, the association be tween GS and IR was not significant, suggesting that IR contributed to the severity of coronary atherosclerosis but not to the distribution of lesions . In conclusion, IR was associated with the severity of CHD as measured by both Gensini's score and the number of diseased coronary arteries, and incr eased the risk of CHD regardless of the location of the lesions.