Correlation Between Glycated Hemoglobin (HbA1c) and Post-Systolic Index Measured by Speckle-Tracking Echocardiography in Patients with Non-apparent Coronary Artery Disease

Glycated hemoglobin (HbA1c) is a useful biomarker for the diagnosis of diabetes and also for determination of individuals with an increased risk of a severe disease. Some subtle changes in myocardial contractile function is measurable by post-systolic index (PSI) which is defined as late systolic shortening after aortic valve closure. The aim of our study was to determine the relationship between HbA1c and PSI in patients with non-apparent coronary artery disease (CAD) on angiograms. This study was a historical cohort study on 85 consecutive patients with a left ventricular ejection fraction ≥ 50% and non-apparent CAD on angiogram. Patients were divided into two groups based on their HbA1c levels, regardless of the diagnosis of diabetes in these patients, to patients with an HbA1c level of equal or higher than 5.7% and those with an HbA1c of less than 5.7%. A speckle-tracking echocardiography was performed for all patients and global longitudinal strain, PSI, left ventricular diameters, left atrial volume, pulsed-Doppler-derived transmitral early (E wave) and late (A wave) diastolic velocities, and tissue-Doppler-derived mitral annular early diastolic (eʹ) and peak systolic (sʹ) velocities were determined. PSI, E/eʹ ratio, and A wave were higher and eʹ velocity was lower in patients with HbA1c ≥ 5.7% than those with a level of < 5.7% (P value = 0.04, 0.001, 0.014, and 0.004, respectively). Other echocardiographic variables were not different between two groups. Multiple linear regression analysis showed the association between HbA1c and PSI was independent of other demographic, biochemical, and echocardiographic variables (B = 35.674, 95% CI 10.741–60.606, P value = 0.006). Our study showed PSI is more pronounced in individuals with an HbA1c > 5.7% than those with a lower value in the absence of CAD. Because PSI is an important indicator of adverse outcome and increased mortality, these data can underline the importance of an abnormal HbA1c level and its association with subtle cardiac dysfunction, irrespective of the diagnosis of diabetes in patients with non-apparent CAD.