Electron microscopic evaluation of internal thoracic artery endothelial morphology in diabetic coronary bypass patients.

Background: Diabetes is a well- identified major risk factor for cardiovascular diseases. This study was performed to evaluate the effect of diabetes and impact of glycemic control on internal thoracic artery (ITA) morphology by electron microscopy.
Methods: Thirty patients scheduled for coronary artery bypass grafting were enrolled in this study. Samples of ITA were taken during the surgery for electron microscopic evaluation. Group I (n = 10) consisted of diabetics who have poor glycemic control (HbA1c > 7.5%), group II (n = 10) of well-regulated (HbA1c = 4.4% to 6.2%) diabetic patients, and group III (n = 10) of nondiabetic patients. Samples were prepared as ultrathin sections and an original semiquantitative method of scoring was applied to describe the morphologic changes of endothelium. Final scores were analyzed with analysis of variance and post hoc analysis.
Results: In group I large vacuoles, swollen mitochondria were seen in endothelial cells and subendothelial edema was prominent. Endothelia (2.5 ± 1.2), arterial wall (2.0 ± 0.0), and endothelial mitochondria (2.9 ± 1.3) scores of group I were significantly higher than the other 2 groups (p < 0.001). The samples of group II and group III did not show significant differences with each other. The correlation between HbA1c values and total endothelial scores statistically significant (r = 0.912; p < 0.001).
Conclusions: There is a correlation between HbA1c values and morphologic changes of ITA graft. Uncontrolled diabetes is an important predictor of morphologic changes evidenced by the ultrastructural findings. These ultrastructural changes were not as prominent in the diabetes mellitus patients with well controlled metabolic statuses and patients without diabetes.
(Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)