A less invasive heart test holds up—but not for everyone yet

A new way to measure coronary artery blockages without threading a catheter deep into the heart performed as well as the current gold standard in a rigorous, multicountry trial. The findings, presented at ACC.26 and published simultaneously in the New England Journal of Medicine, offer a potential alternative to fractional flow reserve (FFR), an invasive procedure that requires a pressure wire to be inserted into the artery. Researchers randomized 2,800 patients across 13 European countries, making this one of the largest studies of its kind for coronary physiology testing.

The novel technique—called quantitative flow ratio (QFR)—uses angiographic images and computational modeling to estimate blood flow restriction without additional hardware. In the trial, QFR matched FFR’s diagnostic accuracy in 92% of cases, a threshold that meets non-inferiority criteria. But the study’s design has limits: it excluded patients with complex lesions or prior stents, groups where real-world performance might differ.

Critically, this is still an evidence grade: randomized controlled trial (RCT)—the highest tier for clinical studies—but it’s not yet a regulatory green light. The U.S. FDA and European Medicines Agency have not approved QFR for routine use, and interventional cardiologists note that operator experience with the software could affect results outside trial conditions.

For patients, the immediate impact is negligible. Hospitals won’t adopt QFR until regulatory bodies weigh in, a process that could take years. Even then, the trial’s exclusion criteria mean the technique’s real-world reliability in high-risk cases—like those with calcified arteries or multiple blockages—remains untested. The study’s lead author, Dr. Nico Pijls of Catharina Hospital in the Netherlands, acknowledged that while QFR reduces procedural time and patient discomfort, it ‘should not be seen as a replacement for FFR in all scenarios.’

What the data don’t show is equally important. The trial didn’t track long-term outcomes—like heart attack rates or repeat procedures—so it’s unclear whether QFR-guided decisions improve patient survival. Cost-effectiveness analyses are also pending; while QFR avoids disposable pressure wires, it requires high-quality angiograms and proprietary software, which may limit access in lower-resource settings.

The cardiology community’s response has been cautiously optimistic. The European Society of Cardiology highlighted the study in its latest guidelines update but stopped short of a full endorsement, citing the need for ‘further validation in diverse populations.’