Objectives To study the relationship between insulin resistance and coronary collateral vessel formation in patients with impaired glucose tolerance.
Methods This study enrolled 122 patients with impaired glucose tolerance, who underwent coronary angiography. We prospectively selected all patients who had at least one total occlusion of a major coronary. The homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were used to quantify insulin resistance (HOMA2-IR). The severity scale of coronary artery stenosis was quantitatively assessed according to coronary angiography by Gensini scoring system. The collateral scoring system developed by Rentrop and Cohen was used. Patients were then classified according to their collateral grades as either poor (grade 0 or grade 1 collateral circulation) or good (grade 2 or grade 3 collateral circulation). All statistic work was carried out with software of SPSS 13.0.
Results Compared with good collateral group, Fasting insulin and HOMA2-IR were significantly higher in poor collateral group (P < 0.05). In order to further assess the relationship between coronary collateral grade and insulin resistance, multivariable analyses were performed. The stepwise multivariable regression analysis shown that Fasting insulin (R = 0.502, P < 0.05) and HOMA2-IR (R = 1.883, P < 0.05), was a statistically significant independent predictor for the severity scale of coronary artery stenosis. The binary regression analysis shown, Fasting insulin and HOMA2-IR enter the coronary collateral grade regression equation. The odds ratio were 1.226 and 1.629 respectively (P < 0.05), adjusted for potential confounding factors, HOMA2-IR was the only significantly independent predictor for poor coronary collateral.
Conclusions The presence of coronary collaterals may have beneficial effects during myocardial ischaemia and may improve cardiovascular outcome in patients with coronary artery disease. Impaired collateral formation could be one of the reasons for the increased cardiovascular risk in patients with diabetes mellitus. We hypothesised that in impaired glucose tolerance patients, in the event of a coronary occlusion, might exhibit a less developed collateral circulation. So we investigated the association between HOMA2-IR and coronary angiography data in 122 patients with impaired glucose tolerance. This study shows that in patients with coronary occlusion, collateral circulation is impaired in patients with impaired glucose tolerance. This association is partly related to insulin resistance.