Moving Beyond Coronary Stenosis
Has the Time Arrived to Address Important Physiological Questions Not Answered by Fractional Flow Reserve Alone?
Make everything as simple as possible, but not simpler.
Fractional flow reserve (FFR) is an intracoronary pressure-derived index that circumvents many of the limitations of angiography in assessing stenosis severity.1 From a broad perspective, the greatest achievement of the investigators from Aalst, Eindhoven, and Houston who developed FFR was incorporating intracoronary physiology to routine clinical practice. Key elements in FFR success were (1) the simplicity of the technique, (2) the use of a well-defined cutoff (initially 0.75; since the FAME study, 0.80) that facilitated interpretation of the results, and (3) the gathering of evidence in properly designed trials.2 But, above all, the key aspect was the relevance of the question answered by FFR: Does this stenosis requires revascularization?
Article see p 301
The latter is an important issue, which largely explains why physiology indices used in the pre-FFR era did not reach clinical application. Leaving aside a few exceptions, the most important studies using Doppler-derived coronary flow reserve (CFR) in the 1990s, such as Doppler Endpoints Balloon Angioplasty Trial Europe (DEBATE), DEBATE II, French Randomized Optimal Stenting Trial (FROST), and Doppler Endpoint STenting INternational Investigation (DESTINI) (including in total 1734 patients), explored whether optimization of the results of balloon angioplasty with CFR could reduce restenosis or avoid the use of coronary stenting (the so-called provisional stenting strategy).3,4 A posteriori, it is easy to understand why, despite the positive results of several of these studies, the Doppler guidewire never became indicated for this purpose not a part of the interventionalists toolbox.
On the contrary, the robustness of the question behind FFR (focused on revascularization appropriateness) increased over time, becoming maximal in current scenario, dominated by major doubts on the overall benefit of percutaneous coronary intervention, concerns on percutaneous coronary intervention overindication, and urge for …