Assessment of the Coronary Sinus Diameter after Successful Coronary Artery Bypass Surgery: A Preliminary Echocardiographic Cardiac Perfusion Study

Background: There is a growing interest in noninvasive methods for the assessment of sufficient coronary flow after coronary artery bypass graft surgery (CABG) by transthoracic echocardiography (TTE). Methods: We performed this study to evaluate the coronary sinus diameter (CSD), as a confident marker of the coronary blood flow, by TTE among patients undergoing CABG. A total of 104 elective CABG patients with double, triple, or more coronary artery diseases were enrolled in this cross-sectional study. Four patients were lost to follow-up because of poor echocardiographic window or death. One day before and 7 days after CABG, all the patients underwent TTE. Results: The mean CSD was calculated by averaging the diameters of the middle and terminal segments of the coronary sinus. The left ventricular ejection fraction (LVEF) was calculated using the Simpson methods. The CSD in the middle (11.1%; P < 0.0001) and terminal (10.1%; P < 0.0001) segments was significantly increased after CABG among all the patients. Additionally, the diameter change was most prominent among those with triple vessel disease. Similarly, a significant increase was observed in the mean CSD after CABG (11.3%; P < 0.0001). Conclusions: No significant changes were observed after CABG with respect to the LVEF in the first postoperative week. The findings showed that the TTE-determined CSD could be a potential surrogate for sufficient coronary perfusion and graft patency after CABG.