Imaging-Based FFR on Par With Wire for PCI Outcomes

NEW ORLEANS — Revascularization treatment guided by fractional flow reserve calculated from an angiogram yielded similar outcomes as that guided by direct pressure wire measurement in randomized trials of two different software programs.

In the ALL-RISE trial, the primary endpoint of 1-year all-cause mortality, myocardial infarction (MI), or unplanned clinically indicated revascularization occurred in 6.9% of patients treated using the CathWorks FFRangio system compared with 7.1% in the pressure wire-guided group (HR 0.98, 95% CI 0.70-1.39, P=0.0008 for non-inferiority), said Ajay Kirtane, MD, of Columbia University Irving Medical Center/NewYork-Presbyterian Hospital in New York City.

In the FAST III trial, Pie Medical Imaging’s vessel fractional flow reserve (vFFR) system resulted in an identical 7.5% 1-year Kaplan-Meier estimated rate of all-cause mortality, MI, or any revascularization as seen in the pressure wire-guided controls (P=0.004 for non-inferiority).

Adverse events and subgroup analyses were also similar between groups, reported Joost Daemen, MD, PhD, of Erasmus University Medical Center in Rotterdam in the Netherlands.

Both ALL-RISE and FAST III were presented at the American College of Cardiology (ACC) annual meeting and online in the New England Journal of Medicine.

“Abundant Class 1A evidence has established the clinical utility and economic value of coronary physiologic testing to guide revascularization in the cath lab. And yet, like many other guideline-endorsed practices, coronary physiology is underutilized,” said Kirtane.

One reason has been a lack of data proving impact on clinical outcomes.

“This is what we’ve been looking for — the clinical impact of what it is to use FFRangio or other angio-based FFR modalities,” said David Moliterno, MD, of the University of Kentucky Medical Center in Lexington and a discussant at the late-breaking clinical trial session where both trials were presented.

Panelist William F. Fearon, MD, of Stanford University School of Medicine in California and co-author on the ALL-RISE study, said that with the two trials, “We can conclude FFR angiography is here to stay,” pointing to the concordant results between the two trials and improved workflow, “which I think will translate to further uptake of physiology in the cath lab and will translate into improved patient care and outcomes.”

Anna Bortnick, MD, PhD, of Montefiore Medical Center and Albert Einstein College of Medicine in New York City, called it “a glimpse of the future of the cath lab, where we’re going to see more AI [artificial intelligence] and computational tools integrated into our workstations and our workflow. … And right now, while we have to interact a lot with the program and maybe point out where the lesions are, eventually the program is going to learn and it may become even more automated and even faster.”

But while these two trials were positive, Kirtane warned that the same might not be the case for other software.

“I would caution folks from attributing a class effect to all of these devices. The actual algorithms differ and actually the requirement for a number of angiograms substantially differs,” he said, noting that the FFRangio in his trial required three views unlike some of the 2D models. “If it’s garbage in, it’s going to be garbage out.”

FFRangio uses those routine angiographic images together with AI and computational science to trace coronary vessels. After contour confirmation by the physician, the program applies a resistance flow algorithm to derive FFR values all along the coronary tree in multiple vessels.

Pie Medical Imaging’s vFFR likewise uses 3D quantitative coronary angiography, using physical laws applicable to coronary flow behavior, including viscous resistance and effects of separation loss, to calculate the FFR.

If angiography image quality is poor or vessels overlap significantly or are foreshortened, wire-based physiology will still be needed, Daemen said.

“We hope that this increases the adoption. It all depends on the cost,” said ACC press conference moderator Roxana Mehran, MD, of the Mount Sinai School of Medicine in New York City.

A dedicated cost-effective analysis will be done for ALL-RISE, Kirtane responded, although suggesting that the cost is similar to wire-based analysis. Daemen said there’s no clear pricing yet, at least in Europe, for Pie Medical Imaging’s system.

ALL-RISE included 1,930 patients (25.0% women, mean age 68.4) undergoing coronary angiography who were found to have at least one intermediate coronary stenosis. They were randomly assigned to physiological assessment with FFRangio or a pressure wire-based approach. Most were stable coronary syndromes.

FAST III included 2,235 patients at 37 European centers with intermediate coronary artery lesions (30-80% diameter stenosis) who presented with chronic or acute coronary syndromes (81% and 19%, respectively). They were randomly assigned open-label to undergo either vessel FFR-guided or pressure wire-based FFR-guided revascularization of the intermediate coronary artery lesions.

Both trials showed shorter procedural time but more revascularization with the angiography-based FFR calculations (about 45% vs about 35% in both trials).

“Even though the efficiency gains were modest, such workflow advantages may influence real-world adoption,” wrote Yiannis S. Chatzizisis, MD, PhD, of the University of Miami, in an editorial accompanying the FAST III paper.

The higher rate of percutaneous coronary intervention (PCI) in lesions assessed with the newer technology wasn’t surprising, according to an editorial accompanying the ALL-RISE trial by Gianluca Campo, MD, of Azienda Ospedaliero Universitaria di Ferrara in Cona, Italy.

“Decisions near the treatment threshold have long been recognized as gray zones, and modest differences in measured values or their interpretation may alter procedural rates without affecting clinical outcomes at 1 year,” he wrote. “Rather than implying overtreatment, the observation underscores the rationale for an integrated strategy: angiography-derived indexes can expand physiological assessment, whereas pressure-wire confirmation remains available when decisions hinge on a narrow margin.”