Correlation of HbA1c with coronary flow velocity and disease severity in chronic stable angina

Abstract

Introduction: Increasing hemoglobin A1c (HbA1c) levels in individuals with and without diabetes mellitus are risk factors for cardiovascular events and atherosclerosis. Aims and Objectives: The aim and objective was to study the association of HbA1c with coronary flow velocity (CFV). Materials and Methods: This was a single-center, hospital-based, nonrandomized, prospective observational study. All consecutive patients admitted in the department of cardiology with the diagnosis of chronic stable angina who underwent coronary angiography from April 1, 2017, to October 31, 2018, were subjected to the eligibility criteria. The patients were divided into the four HbA1c quartiles based on the HbA1c at hospital admission: Group A (HbA1c < 5.2%), Group B (HbA1c: 5.2–5.6), Group C (HbA1c: 5.7–6.4), and Group D (HbA1c: ≥6.5%). Corrected TIMI frame count (TFC) was used to assess the CFV. The severity of coronary artery disease (CAD) was studied by Gensini score. Results: A total of 263 consecutive patients with a mean age of 56.71 ± 10.59 years were included. Nearly 70% (n = 184) of the patients were males. The mean HbA1c was statistically significantly higher in obstructive CAD versus nonobstructive versus no CAD (6.06 vs. 5.63 vs. 5.23) (P < 0.001). Increasing HbA1c among all quartiles was statistically significantly associated with increasing TFC in all coronary arteries (left anterior descending artery [LAD] 30.32 vs. 34.05 vs. 36.72 vs. 36.94; left circumflex artery [LCX] 19.89 vs. 22.41 vs. 24.05 vs. 23.76; right coronary artery [RCA] 19.42 vs. 22.02 vs. 23.24 vs. 23.50, respectively, for the four HbA1c quartiles; P < 0.001). HbA1c had a significant linear correlation with TFC of LAD, LCX, and RCA (r = 0.6, 0.54, and 0.51, respectively). Among the various quartiles of HbA1c, CAD was significantly more common in patients with higher HbA1c values (P < 0.0001) (1.03% vs. 33.89% vs. 73.33% vs. 82.35%, respectively). The mean Gensini score increased with increasing HbA1c quartiles (0.40 vs. 4.68 vs. 21.63 vs. 30.52, respectively, P < 0.001). Conclusion: HbA1c has a significant association with CFV even in subdiabetic range. However, the therapeutic strategies and benefit of lower HbA1c in nondiabetic patients are still uncertain. Large randomized trials are needed to address this issue.