Physiological impact of coronary artery bypass surgery on chronic total occlusion: a functional evaluation using coronary flow reserve

AIMS: This study evaluated the physiological impact of CABG for left anterior descending (LAD) artery chronic total occlusion (CTO) using postoperative coronary flow reserve (CFR). METHODS: We retrospectively analyzed 1,149 patients undergoing isolated CABG, comparing LAD-CTO (n = 164) and non-CTO (n = 985) groups. Postoperative CFR was measured in 685 patients. The CTO group was stratified by preoperative Rentrop collateral classification. RESULTS: In the entire cohort (n = 1,149), early mortality (3.7% vs. 1.7%, p = 0.1018) and LAD graft patency (97.8% vs. 98.6%, p = 0.4595) were comparable between groups. In the CFR cohort (n = 685), the CTO group showed lower CFR values than the non-CTO group (2.76 ± 0.90 vs. 3.04 ± 0.88, p = 0.0012). However, mean CFR exceeded 2.0 across all CTO subgroups, regardless of collateral status (Poor: 2.66 ± 0.7; Moderate: 2.76 ±0.94; Good: 2.78 ± 1.00; p = 0.763). CONCLUSIONS: CABG achieves reliable physiological improvement (CFR > 2.0) and favorable outcomes for LAD-CTO revascularization, independent of preoperative Rentrop collateral grade.