Preliminary outcomes of quantitative flow ratio-guided coronary bypass grafting in primary valve surgery: A propensity score weighted analysis.

Objectives: The guidelines recommend fractional flow reserve-guided coronary artery bypass grafting (CABG) during primary valve surgery without evidence. Quantitative flow ratio (QFR) is a novel coronary angiography (CAG)-based fractional flow reserve measurement. We aimed to compare the early clinical outcomes between QFR-guided and CAG-guided CABG in these patients.

Methods: This observational study screened all 2081 patients admitted to our institution for elective primary mitral and/or aortic valve surgery from January 2017 to September 2020. Of them, all 188 patients with comorbid coronary artery lesions (visual estimated stenosis ≥50%) were included. Sixty-nine patients with QFR analysis received bypasses only for lesions with QFR ≤0.80 (QFR-guided group). The remaining 119 patients without QFR analysis received bypasses for all stenosis ≥50% (CAG-guided group). Propensity overlap weighting was used to neutralize the intergroup imbalance. The primary end point was major adverse cardiovascular events.

Results: After propensity score weighting, the baseline characteristics were comparable. Concomitant coronary artery bypass grafting was performed 58.1% versus 100% in the QFR-guided and CAG-guided groups, respectively. The mean number of grafts was significantly lower in QFR-guided group than in the CAG-guided group (0.9 ± 0.7 vs 1.6 ± 0.5 [ < .001]). The weighted 30-day incidence of major adverse cardiovascular events was numerically lower in the QFR-guided group than in the CAG-guided group, but not statistically significant (6.3% vs 11.8% [ = .429]). After a median follow-up of 31.6 months, the weighted risk of major adverse cardiovascular events and mortality were significantly lower in the QFR-guided group than in the CAG-guided group (major adverse cardiovascular events: hazard ratio, 0.45; 95% CI, 0.24-0.84;  = .012; mortality: hazard ratio, 0.38; 95% CI, 0.16-0.93;  = .029).

Conclusions: Compared with CAG-guided coronary artery bypass grafting, QFR-guided CABG is associated with less grafting and better clinical outcome in primary valve surgery with comorbid coronary artery disease. To confirm this finding, the Quantitative Flow Ratio Guided Revascularization Strategy for Patients Undergoing Primary Valve Surgery With Comorbid Coronary Artery Disease trial (NCT03977129) is ongoing.