Usefulness of enhanced insulin secretion during an oral glucose tolerance test as a predictor of restenosis after direct percutaneous transluminal coronary angioplasty during acute myocardial infarction in patients without diabetes mellitus.

To determine predictive factors of the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA), 25 nondiabetic nonobese patients aged <80 years old and 57 consecutive patients with successful direct PTCA with acute myocardial infarction were subjected to a 75-g oral glucose tolerance test (OGTT) and underwent follow-up coronary angiography 4 months later. The relation between the development of restenosis (late loss index: the decrease in the absolute minimal lumen diameter [MLD] at follow-up coronary angiography divided by MLD measured 1 day after PTCA) and the results of OGTT together with basic patient characteristics like age, body mass index, plasma levels of cholesterol, triglycerides, and high-density lipoprotein cholesterol were analyzed. Spearman's rank correlation analysis revealed that neither age, body mass index, nor plasma lipids correlated with late loss index, but only insulin area (p = 0.041) and insulin area/glucose area (p = 0.038) significantly correlated with the development of restenosis; a stepwise multiple regression analysis revealed that the insulin area was the only independent predictor of restenosis (p = 0.019). These results suggest that enhanced insulin secretion in response to glucose plays an important role in the development of restenosis after direct PTCA in non-diabetic patients, which may be through the direct action of insulin on smooth muscle cells of the coronary artery. This study also suggests the importance of performing OGTT for patients undergoing PTCA for the prediction of the development of restenosis.