ACC 2017: Study compares use of fractional flow reserve with instantaneous wave-free ratio in PCI

March 18, 2017 – Compared with angiography alone, FFR-guided revascularization improves patient outcomes after PCI.

A new study involving a DCRI researcher found similar clinical outcomes in coronary revascularization guided by instantaneous wave-free ratio (iFR) and by fractional flow reserve (FFR), based on major adverse cardiac events at one year.

The study results were presented on Saturday at the 66th annual Scientific Sessions of the American College of Cardiology (ACC), in Washington, D.C., and published simultaneously in the New England Journal of Medicine.

Compared with angiography alone, FFR-guided revascularization improves patient outcomes after percutaneous coronary intervention (PCI). FFR helps assess whether narrowing in coronary arteries – which can interfere with blood flow and cause chest pain – require treatment.  However, this approach requires the administration of a drug, adenosine, which adds cost and time to the procedure, and may be unavailable in some countries. As a result, despite the clear health and healthcare costs benefits of FFR, this approach is currently used in fewer than 10 percent of revascularization procedures. As a new technique that does not require adenosine, iFR holds promise in delivering improved outcomes to a much larger patient population.

“This represents a substantial advance for the management of patients with coronary disease using an invasive technique that will better allow us to ensure that the right patient gets the right treatment,” said the DCRI’s Manesh R. Patel, MD, associate professor of medicine and chief of the Division of Cardiology (pictured). “The study was an international collaboration that showed our ability to rapidly enroll patients in clinical trial to compare iFR with FFR.”

In the Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation (DEFINE-FLAIR) study, 2,492 patients with coronary artery disease were randomized 1:1 to either iFR-guided or FFR-guided coronary revascularization. The primary end point was the composite of major adverse cardiac events, defined as the composite of all-cause mortality, non-fatal myocardial infarction or unplanned revascularization, at one year. The trial was designed to demonstrate non-inferiority of iFR to FFR.

At one year, the primary end point occurred in 78 patients (6.79 percent) in the iFR group and 84 patients (7.02 percent) in the FFR group. There were no statistically significant differences between groups for the components of the primary end point or for cardiovascular or noncardiovascular death. Rates of adverse procedural symptoms and clinical signs and procedural time were significantly lower in the iFR arm than the FFR arm, showing potential for improved efficiency with iFR.