Abstract 5503: Association of Hyperglycemia with VCAM-1 and Baseline and Minimal Coronary Vascular Resistance in Patients with Abnormal Glucose Tolerance
Background: It has been reported that hyperglycemia in patients with acute myocardial infarction (AMI) is associated with increased mortality after AMI. However its underlying mechanism of these adverse effects of hyperglycemia remains unknown. We presume that impaired epicardial flow is associated with increased coronary vascular resistance, and investigate whether poor glycemic control (hyperglycemia and high HbA1c) is associated with increased coronary vascular resistance and adhesion molecules.
Methods: Consecutive 105 patients (mean age, 64±12 years) without coronary artery disease underwent Doppler flow study of the left anterior descending coronary artery. Vascular reactivity was examined by intra-coronary administration of papaverine, acetylcholine (Ach), and nitroglycerin using a Doppler guidewire. Coronary vascular resistance (CVR) was calculated as the mean arterial pressure divided by coronary blood flow (CBF). Baseline CVR was shown as CVR at control and minimal CVR was shown as CVR with papaverine administration. Fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), and adhesion molecules (ICAM-1 and VCAM-1) were measured. The patients were divided into two groups: Abnormal group 1 (n=35), patients with abnormal glucose tolerance; Normal group (n=70), patients with normal glucose tolerance.
Results: When only subjects in Abnormal group were considered, both the baseline CVR and the minimal CVR had positive correlations with HBA1c (r=0.54, p<0.001; r=0.41, p<0.05, respectively), but not with FPG. Both the baseline CVR and the minimal CVR were also positively correlated with VCAM-1 (r=0.55, p<0.05; r=0.54, p<0.05, respectively). Furthermore, a positive correlation existed between HbA1c and VCAM-1 (r=0.49, p<0.05). These correlations were not found in Normal group. HbA1c had no significant correlation with CBF response to Ach or papaverine.
Conclusion: These data demonstrate that the increases in both the baseline and minimal coronary vascular resistance are associated with elevated glucose levels and VCAM-1, which may contribute to unfavorable results in coronary hemodynamics in hyperglycemic patients without coronary heart disease.