Original Title: Significance of Intermediate Values of Fractional Flow Reserve in Patients with Coronary Artery Disease. Reference: Julien Adjedj et al. Circulation. 2016 Jan 5. Epub ahead of print.

The fractional flow reserve (FFR) value of 0.75 has been validated against tests for inducible ischemia, whereas the value 0.80 has been widely accepted to guide the clinical practice. All the same, there is a “grey zone” between 0.76 and 0.85 where deciding for one of the two treatment strategies over the other remains arguable.

The study included all patients with single segment disease and an FFR value within the grey area (0.70 – 0.75 and 0.81 – 0.85) between 1997 and 2013. Primary end point was major adverse cardiovascular events (MACE: death, infarction, and any revascularization) within a 5 year follow up.
During this period, 17380 FFR measurements were carried out; 1459 were found in this grey zone and were analyzed. 449 of these were treated with revascularization and 1010 with medical treatment.

In the grey zone, MACE rate was similar between the medical treatment and revascularization groups (13.9% vs. 11.2% respectively; p=0.3). There was a strong trend towards higher death and infarction rates (9.4 vs. 4.8; p=0.06) and higher all cause death rate (7.5 vs. 3.2; p=0.059) in the medical treatment group.

In patients receiving medical treatment, there was a progressive increase in MACE as FFR decreased (de 0.85 a 0.70) especially for proximal lesions; however, patients receiving revascularization did not show this gradient, but a similar MACE rate in all value strata.

Conclusion
FFR in the “grey zone” still has great prognosis value, especially when it comes to proximal lesions. These data confirm the FFR cutoff value ≤ 0.80 is valid to guide our clinical practice.