Data from trials such as DEFER, FAME, and FAME 2 suggest that fractional flow reserve (FFR) is useful in guiding coronary revascularization in patients referred for a PCI procedure who have at least one ambiguous lesion. There is, however, currently no large report regarding the impact of FFR on the selection of revascularization—or not—in a broad population of patients referred for diagnostic angiography.

The Registre Français de la FFR (or R3F) study enrolled 1,075 consecutive patients undergoing diagnostic FFR-guided angiography at 20 French centers.¹ It is the largest nationwide clinical FFR registry including patients with at least one ambiguous coronary lesion.

Take-aways Investigators sought to determine the rate of reclassification of patients and change in subsequent management based on fractional flow reserve (FFR) assessment at the time of diagnostic angiography. Performing FFR during diagnostic angiography is associated with reclassification of the revascularization decision in about half of the patients. The proportion of patients who ended up being managed by medical therapy, PCI, or CABG did not change much, but many patients (43%) had their individual case management change based on FFR results.

Investigators first recorded their expected revascularization approach —or "a priori" strategy—based on angiography before performing FFR, then recorded their final revascularization strategy after assessing FFR. Patients in whom the final strategy differed from the a priori strategy were defined as "reclassified" by FFR. Clinical follow-up was conducted and obtained in all patients at a median of 379 days.

The a priori strategy, based on angiography, was medical therapy for 55% and revascularization for 45% (of which PCI was expected to be used in 38% and coronary artery bypass graft [CABG] surgery in 7%). The FFR information was used for the medical decision of revascularization in 95% of cases.

The proportion of patients treated in the different categories looked very similar after FFR: the applied strategy after FFR was medical therapy in 58% and revascularization in 42% (PCI in 32% and CABG in 10%). That's good to know, because there had been some evidence suggesting that fewer patients will be treated with PCI if FFR results are available.

The big difference was seen in the nearly half (43%) of patients overall who had shifts in their management strategy based on the FFR results: in other words, the final strategy applied differed from the originally expected approach in 33% of a priori medical patients, in 56% of patients expected to undergo PCI based on a priori selection, and in 51% of patients anticipated to undergo a priori CABG surgery.

So, while the overall proportion of patients changed very little, the FFR results led to big swings in terms of individual cases being shifted from one strategy to the other.

Clinical Implications
The authors said that the results provide important information on the clinical use of FFR in patients referred for coronary angiography. In this population, use of FFR is associated with reclassification of the revascularization decision in about half of the patients.

Importantly, the R3F investigators found that it is safe to pursue a revascularization strategy divergent from that suggested by angiography alone. In reclassified patients treated based on FFR and in disagreement with the angiography-based a priori decision (n = 464), the 1-year outcome (major cardiac event, 11.2%) was as good as for patients in whom the final applied strategy concurred with the angiography-based a priori decision (n = 611; major cardiac event, 11.9%; p = 0.78). At 1 year, more than 93% of patients were asymptomatic without difference between reclassified and nonreclassified patients (p = 0.75). Reclassification safety was preserved in high-risk patients.

This is also one of the first studies to look at borderline lesions with FFR rather than using FFR to determine borderline lesions. Additionally, the data support the concept of physiology-guided coronary revascularization and provide an important basis for future studies.

Attractive alternatives to FFR, such as FFR-computed tomography or instant wave-free ratio, have recently been developed. While initial reports have been promising, the R3F investigators stated that their use in tailoring the decision of coronary revascularization remains to be demonstrated.

Reference

1. Van Belle E, Rioufol G, Pouillot C, et al. Circulation. 2014;129:173-85.

To listen to an interview with Eric Van Belle, MD, PhD, about fractional flow reserve, visit youtube.cswnews.org. The interview was conducted by Douglas P. Zipes, MD.

Keywords: Registries, Follow-Up Studies, Coronary Angiography, Tomography, X-Ray Computed, Coronary Artery Bypass

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