Vessel-Oriented Analysis on the Relationship Between Quantitative-Flow Ratio and Mortality in Patients With Severe Aortic Stenosis and Intermediate Coronary Lesions

Background: Quantitative flow ratio (QFR) is effective in predicting mortality in patients undergoing transcatheter aortic valve replacement (TAVR). How QFR reclassifies coronary artery disease (CAD) at vessel-level compared to angiography and how this influences the risk of death, remains undetermined. Methods: We calculated QFR from consecutive 280 TAVR patients with bystander coronary stenoses. All lesions were managed conservatively. Angiographic CAD was defined by a diameter stenosis ≥ 50%, functional CAD by a QFR ≤ 0.80. The outcome was mortality at 3 years. Results: Overall, 635 lesions were included. Angiographic CAD was evident in 165 (26.0%), functional CAD in 17 (11.2%) (reclassification: p < 0.001). Angiography/QFR mismatch occurred in 22.5%, mostly in large vessels and lesions located in the proximal left anterior descending (LAD). QFR ≤ 0.80 was an independent predictor of death (HR 2.91, 95% CI 1.94−4.36; p < 0.001). The risk was progressively increased for lower QFR values and positive QFR at LAD site (vs. QFR > 0.80 HR: 3.92, 95% CI 2.78−5.53; p < 0.001; vs. QFR ≤ 0.80 at non-LAD site: HR 2.65, 95% CI 1.07−6.59; p = 0.034). Conclusions: QFR leads to a significant reclassification of CAD rates at vessel-level and shows a significant prognostic value in patients undergoing TAVR.