Association Between Adherence to Fractional Flow Reserve Treatment Thresholds and Major Adverse Cardiac Events in Patients With Coronary Artery Disease

Key PointsQuestionIn patients with coronary artery disease, is adherence to recommended fractional flow reserve (FFR) thresholds for percutaneous coronary intervention (PCI) associated with better outcomes in clinical practice? FindingsIn this retrospective cohort study that used inverse probability of treatment weighting and included 9106 patients, PCI, as compared with no PCI, was significantly associated with a lower rate of major adverse cardiac events at 5 years among patients with ischemic FFR measurements (31.5% vs 39.1%; hazard ratio [HR], 0.77) and a higher rate of major adverse cardiac events at 5 years among patients with nonischemic FFR measurements (33.3% vs 24.4%; HR, 1.37). MeaningPerforming PCI procedures in accordance to evidenced-based FFR thresholds was associated with better outcomes. ImportanceFractional flow reserve (FFR) is an invasive measurement used to assess the potential of a coronary stenosis to induce myocardial ischemia and guide decisions for percutaneous coronary intervention (PCI). It is not known whether established FFR thresholds for PCI are adhered to in routine interventional practice and whether adherence to these thresholds is associated with better clinical outcomes. ObjectiveTo assess the adherence to evidence-based FFR thresholds for PCI and its association with clinical outcomes. Design, Setting, and ParticipantsA retrospective, multicenter, population-based cohort study of adults with coronary artery disease undergoing single-vessel FFR assessment (excluding ST-segment elevation myocardial infarction) from April 1, 2013, to March 31, 2018, in Ontario, Canada, and followed up until March 31, 2019, was conducted. Two separate cohorts were created based on FFR thresholds (<= 0.80 as ischemic and >0.80 as nonischemic). Inverse probability of treatment weighting was used to account for treatment selection bias. ExposuresPCI vs no PCI. Main Outcomes and MeasuresThe primary outcome was major adverse cardiac events (MACE) defined by death, myocardial infarction, unstable angina, or urgent coronary revascularization. ResultsThere were 9106 patients (mean [SD] age, 65 [10.6] years; 35.3% female) who underwent single-vessel FFR measurement. Among 2693 patients with an ischemic FFR, 75.3% received PCI and 24.7% were treated only with medical therapy. In the ischemic FFR cohort, PCI was associated with a significantly lower rate and hazard of MACE at 5 years compared with no PCI (31.5% vs 39.1%; hazard ratio, 0.77 [95% CI, 0.63-0.94]). Among 6413 patients with a nonischemic FFR, 12.6% received PCI and 87.4% were treated with medical therapy only. PCI was associated with a significantly higher rate and hazard of MACE at 5 years compared with no PCI (33.3% vs 24.4%; HR, 1.37 [95% CI, 1.14-1.65]) in this cohort. Conclusions and RelevanceAmong patients with coronary artery disease who underwent single-vessel FFR measurement in routine clinical practice, performing PCI, compared with not performing PCI, was significantly associated with a lower rate of MACE for ischemic lesions and a higher rate of MACE for nonischemic lesions. These findings support the performance of PCI procedures according to evidence-based FFR thresholds. This cohort study assesses adherence to evidence-based fractional flow reserve (FFR) thresholds for percutaneous coronary intervention in Canada between 2013 and 2018, and associations of percutaneous coronary intervention with major adverse clinical outcomes for patients with FFR measures above and beneath ischemic thresholds.