Interatrial septal thickness as a marker of atherosclerosis and its correlation with the presence and severity of coronary artery disease

Background: Coronary artery disease (CAD) is a leading cause of global morbidity and mortality. There is a need for noninvasive markers of subclinical atherosclerosis to improve early detection. Interatrial septal (IAS) thickness, a surrogate for epicardial adipose tissue, is a potential but less-studied marker. This study aimed to assess the utility of IAS thickness as a marker of atherosclerosis and in predicting the presence and severity of CAD. Materials and Methods: This cross-sectional study included 115 patients with no prior history of CAD, scheduled for noncoronary cardiac surgery, who underwent a preoperative coronary angiogram (CAG). IAS thickness was measured using two-dimensional echocardiography. The presence of atherosclerosis was confirmed by CAG, and the severity of CAD was quantified using the Gensini score. Data on traditional risk factors were collected. Statistical analysis included correlation, Chi-square tests, receiver operating characteristic (ROC) curve analysis, and binary logistic regression. Results: The mean age of the study population was 56.8 ± 9.9 years, and 63.5% had evidence of atherosclerosis on CAG. The mean IAS thickness was 6.9 ± 2.1 mm. A strong, significant correlation was observed between IAS thickness and the Gensini score ( r = 0.823, P < 0.001). ROC curve analysis demonstrated that IAS thickness was an excellent predictor of atherosclerosis, with an area under the curve of 0.975. An optimal cutoff value of > 6 mm for IAS thickness yielded a sensitivity of 93.15% and a specificity of 97.62%. In a multivariate logistic regression model, after adjusting for age, diabetes, dyslipidemia, and low-density lipoprotein levels, IAS thickness remained the main significant independent predictor of atherosclerosis, with an odds ratio of 339.9 ( P < 0.001). Conclusion: IAS thickness is a powerful, noninvasive, and independent marker for the presence and severity of CAD. An IAS thickness > 6 mm is a highly sensitive and specific indicator of underlying atherosclerosis. The routine measurement of IAS thickness through echocardiography can serve as a simple and valuable tool for cardiovascular risk stratification.