Deferred vs. performed revascularization for coronary stenosis with grey-zone fractional flow reserve values: data from the IRIS-FFR registry.

Aims: The optimal fractional flow reserve (FFR) cut-off value for revascularization is debated. We evaluated the prognosis for deferred and performed revascularization in coronary stenosis with FFR values in the grey zone (0.75-0.80). Methods and results: This study included 1334 native coronary stenosis with grey-zone FFR values in 1334 patients from the prospective multicentre Interventional Cardiology Research In-cooperation Society Fractional Flow Reserve registry. Revascularization was deferred for 683 patients (deferred group) and performed for 651 (performed group). The primary outcome, a composite of death, target-vessel myocardial infarction (MI), and target vessel revascularization (TVR) occurred in 55 (8.1%) patients in the deferred group and 55 (8.4%) in the performed group [adjusted hazard ratio (aHR) 1.05, 95% confidence interval (CI) 0.67-1.66; P = 0.79] during a median follow-up of 2.9 years (interquartile range 1.5-4.1 years). Overall mortality and spontaneous MI did not differ between the groups (mortality 2.5% vs. 2.0%; aHR 0.82, 95% CI 0.34-2.00; P = 0.66; spontaneous MI 0.7% vs. 0.5%; aHR 1.85, 95% CI 0.35-9.75; P = 0.47). Myocardial infarction was significantly higher in the performed group (0.7% vs. 3.2%; aHR 0.27, 95% CI 0.09-0.80; P = 0.02) mainly because of a higher risk of periprocedural MI. Target vessel revascularization was significantly higher in the deferred group (5.7% vs. 3.7%; aHR 2.17, 95% CI 1.17-4.02; P = 0.01). Conclusion: For coronary stenosis with grey-zone FFR, revascularization was not associated with better clinical outcomes. The higher likelihood of periprocedural MI with revascularization was offset by the higher likelihood of TVR with deferral. Trial registration: Clinicaltrials.gov identifier: NCT01366404.