Fractional Flow Reserve and Cardiac Events in Coronary Artery Disease Data From a Prospective IRIS-FFR Registry

Abstract

Background—We evaluated the prognosis of deferred and revascularized coronary stenoses after FFR measurement to assess its revascularization threshold in clinical practice.

Methods—The IRIS-FFR registry prospectively enrolled 5846 patients with at least one coronary lesion with FFR measurement. Revascularization was deferred in 6468 lesions and performed in 2165 lesions after FFR assessment. The primary endpoint was major adverse cardiac events (MACE; cardiac death, myocardial infarction, and repeat revascularization) at a median follow-up of 1.9 years and analyzed on a per-lesion basis. A marginal Cox model accounted for correlated data in patients with multiple lesions, and a model to predict per-lesion outcomes was adjusted for confounding factors.

Results—For deferred lesions, the risk of MACE demonstrated a significant, inverse relationship with FFR (adjusted hazard ratio [aHR], 1.06; 95% confidence interval [CI], 1.05-1.08; P < 0.001). However, this relationship was not observed in revascularized lesions (aHR, 1.00; 95% CI, 0.98-1.02; P = 0.70). For lesions with FFR ≥ 0.76, the risk of MACE was not significantly different between deferred and revascularized lesions. Conversely, in lesions with FFR ≤ 0.75, the risk of MACE was significantly lower in revascularized lesions than in deferred lesions (for FFR 0.71-0.75, aHR, 0.47; 95% CI, 0.24-0.89; P = 0.021, and for FFR ≤ 0.70, aHR 0.47; 95% CI, 0.26-0.84; P = 0.012).

Conclusions—This large, prospective registry showed that the FFR value was linearly associated with the risk of cardiac events in deferred lesions. In addition, revascularization for coronary artery stenosis with a low FFR (≤ 0.75) was associated with better outcomes than the deferral, while for a stenosis with a high FFR (≥ 0.76), medical treatment would be a reasonable and safe treatment strategy.