Clinical Decision-Making for the Hemodynamic "Gray Zone" (FFR 0.75-0.80) and Long-Term Outcomes

Background: Fractional flow reserve (FFR) value between 0.75 and 0.80 is considered the "gray zone" and outcomes data relative to treatment strategy (revascularization vs medical therapy alone [deferral]) are limited for this group.

Methods And Results: A total of 238 patients (64.3 ± 8.6 years; 97% male; 45% diabetic) with gray-zone FFR were followed for the primary endpoint of major adverse cardiovascular event (MACE), defined as a composite of death, myocardial infarction (MI), and target-vessel revascularization. Mean follow-up duration was 30 ± 17 months. Deferred patients (n = 48 [20%]) had a higher prevalence of smoking and chronic kidney disease compared with the percutaneous coronary intervention (PCI) group (n = 190 [80%]; P<.05). Patients who underwent PCI had significantly lower MACE compared with the deferred patients (16% vs 40%; log rank P<.01). While there was a trend toward a decrease in all-cause mortality (8% vs 19%; log rank P=.06), the composite of death or MI was significantly lower in the PCI group (9% vs 27%; P<.01). On multivariate Cox proportional hazards regression analysis, PCI was associated with lower MACE (hazard ratio, 0.5; 95% confidence interval, 0.27-0.95; P=.03).

Conclusion: Revascularization for patients with gray-zone FFR was associated with a significantly reduced risk of MACE compared with medical therapy alone.