Prognostic Value of QFR Measured Immediately After Successful Stent Implantation: The International Multicenter Prospective HAWKEYE Study

OBJECTIVES: The aim of this study was to investigate the potential role of post-percutaneous coronary intervention (PCI) quantitative flow ratio (QFR) measurements to predict clinical outcomes in patients with successful PCI. BACKGROUND: The prognostic value of QFR measured immediately after PCI has not been prospectively investigated. METHODS: Patients undergoing complete revascularization with successful PCI and stent implantation were eligible for acquisition of projections for QFR computation. At the end of the procedure, 2 angiographic projections for each vessel treated with PCI were acquired. Computation of QFR was performed offline by an independent core laboratory. The primary outcome was the vessel-oriented composite endpoint, defined as vessel-related cardiovascular death, vessel-related myocardial infarction, and ischemia-driven target vessel revascularization. RESULTS: Seven hundred fifty-one vessels in 602 patients were analyzed. The median value of post-PCI QFR was 0.97 (interquartile range: 0.92 to 0.99). Lesion location in the left anterior descending coronary artery, baseline SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score, lesion length, and post-PCI diameter stenosis were found to be predictors of lower post-PCI QFR. Altogether, 77 events were detected in 53 treated vessels (7%). Post-PCI QFR was significantly lower in vessels with the vessel-oriented composite endpoint during follow-up, compared with those without it (0.88 [interquartile range: 0.81 to 0.99] vs. 0.97 [interquartile range: 0.93 to 0.99], respectively; p < 0.001). Receiver-operating characteristic curve analysis identified a post-PCI QFR best cutoff of ≤0.89 (area under the curve 0.77; 95% confidence interval: 0.74 to 0.80; p < 0.001). After correction for potential confounding factors, post-PCI QFR ≤0.89 was associated with a 3-fold increase in risk for the vessel-oriented composite endpoint (hazard ratio: 2.91; 95% confidence interval: 1.63 to 5.19; p < 0.001). CONCLUSIONS: Lower values of QFR after complete and successful revascularization predict subsequent adverse events (Angio-Based Fractional Flow Reserve to Predict Adverse Events After Stent Implantation [HAWKEYE]; NCT02811796).