SYNTAX score affects LIMA graft flow dynamics in coronary artery bypass surgery.

Background: Intraoperative transit time flow (TTF) measurement provides quantitative information regarding graft patency and anastomotic quality. However, limited data exist on the relationship between SYNTAX scores and intraoperative graft flow dynamics during coronary artery bypass grafting (CABG). This study aimed to evaluate the predictive value of SYNTAX scores for intraoperative graft flow parameters, as assessed by TTF measurements of the left internal mammary artery (LIMA) grafted to the left anterior descending (LAD) artery. Methods: Patients with critical LAD disease who underwent CABG at a single tertiary referral center between February and October 2019 were prospectively evaluated. For each patient, the SYNTAX score, SYNTAX II score, and the LAD-specific contribution to the SYNTAX score (LAD-SYNTAX) were calculated. Correlations between these scores and TTF parameters-including mean graft flow (MGF), diastolic flow (DF), and pulsatility index (PI)-were analyzed. Results: The SYNTAX score demonstrated a negative correlation with MGF (r =-0.118, p=0.313) and DF (r =-0.026, p=0.828), and a positive correlation with PI (r =0.131, p=0.264). Similarly, the SYNTAX II score showed negative correlations with MGF (r=-0.040, p=0.735) and DF (r=-0.246, p=0.037), and a positive correlation with PI (r=0.168, p=0.149). Consistent trends were observed with LAD-SYNTAX, with MGF and DF showing negative correlations and PI showing a positive correlation; notably, the correlation between LAD-SYNTAX and MGF was statistically significant (r=-0.288, p=0.012). Conclusion: SYNTAX scores are associated with intraoperative TTF measurements of the LIMA-LAD graft. These findings suggest that both the atherosclerotic burden of the target vessel and patient-specific factors may influence LIMA graft flow dynamics during CABG.