Three NEJM Trials Challenge Routine Use of Advanced Imaging in Coronary Stent Procedures
Key Insights
The OPTIMAL trial found IVUS guidance did not reduce stroke, heart attack, repeat procedures, or death versus angiography alone in left main coronary artery PCI over three years.
The IVUS-CHIP study showed no significant reduction in target-vessel failure with routine IVUS guidance compared to angiography in complex, high-risk PCI after 19 months.
The FAST III trial demonstrated that wire-free vFFR was as safe and effective as standard pressure-wire FFR, with identical 7.5% event rates at one year.
Three major international trials presented at the American Cardiology Conference and published simultaneously in the New England Journal of Medicine have produced findings that may reshape how interventional cardiologists guide coronary revascularisation procedures. The studies, led by senior researchers from the Radcliffe Department of Medicine (RDM) and Oxford University Hospitals (search) (OUH), examined different imaging and physiological assessment techniques used during percutaneous coronary intervention (PCI), with results that challenge some prevailing assumptions about advanced guidance technologies.
OPTIMAL: IVUS in Left Main Coronary Artery PCI
The OPTIMAL study enrolled 806 patients with left main coronary artery disease (search) who had not previously undergone bypass surgery. Participants were randomly assigned to receive PCI guided either by intravascular ultrasound (IVUS) or by standard angiography alone. The left main coronary artery supplies blood to most of the heart muscle, making interventions in this vessel particularly consequential.
After approximately three years of follow-up, the composite outcome of stroke, heart attack, repeat revascularisation, or death occurred in 34% of patients in the IVUS-guided group and 31% of those in the angiography-guided group — a difference that was not statistically significant.
Professor Adrian Banning, Chief Investigator on the OPTIMAL trial and Professor of Interventional Cardiology at RDM, stated: "After nearly three years of the OPTIMAL study, we found that IVUS guidance did not reduce the risk of stroke, heart attack, further procedures or death compared with angiography alone. Our findings may challenge guidance that IVUS should always be used for complex PCI."
IVUS-CHIP: Complex, High-Risk Procedures Under Scrutiny
The IVUS-CHIP trial examined over 2,000 patients undergoing complex, high-risk PCI — procedures involving more difficult arterial narrowing. Investigators assessed whether routine IVUS guidance could reduce target-vessel failure, defined as serious problems affecting the treated artery.
After an average follow-up of 19 months, target-vessel failure occurred in 14% of patients in the IVUS group compared with 11% in the angiography group. The difference did not reach statistical significance, and complication rates were similar between both approaches.
Professor Banning, who also served as Principal Investigator in Oxford for the IVUS-CHIP trial, noted: "The IVUS CHIP trial, which was carried out in a number of busy hospitals across Europe, found that using IVUS imaging routinely during complex, high-risk coronary stent procedures offered limited extra benefit. It did not reduce the risk of target-vessel failure compared with standard angiography guidance."
FAST III: Wire-Free vFFR Proves Non-Inferior
The third study, FAST III, investigated fractional flow reserve (FFR) assessment — a technique that measures the extent to which an arterial narrowing actually limits blood flow. The trial compared standard FFR, which uses a small pressure wire passed through the blockage, with vessel fractional flow reserve (vFFR), a wire-free method that estimates the same information using standard X-ray imaging and computer modelling to create a three-dimensional reconstruction of the artery.
FAST III included more than 2,000 participants with moderate coronary lesions. At one year, the proportion of patients who had experienced death, heart attack, or any repeat revascularisation was identical at 7.5% in both the vFFR and FFR groups.
Dr Giovanni De Maria, OUH Consultant Interventional Cardiologist and Principal Investigator in Oxford for both FAST III and OPTIMAL, commented: "Within the parameters set by the trial, vFFR was found to be just as safe and effective as FFR when looking at our key outcomes; vFFR led to more patients having procedures, but outcomes were similar. This could potentially be significant because they suggest a wire-free method could offer similar outcomes to the established pressure-wire approach, potentially making assessment simpler and more comfortable for patients."
Implications for Clinical Practice
Collectively, these three trials provide robust, randomised evidence that may prompt guideline committees to reconsider recommendations around routine advanced imaging during PCI. While IVUS and FFR remain valuable tools in specific clinical scenarios, the data suggest that their universal application in complex PCI may not confer the outcome benefits previously anticipated. The non-inferiority of vFFR, meanwhile, opens the door to a less invasive, wire-free approach to physiological assessment that could streamline procedural workflows and improve patient comfort.
Professor Banning concluded: "These studies show how NHS teams can deliver cutting edge, practice changing research that ultimately improves the outcomes for our patients in Oxford. It demonstrates the powerful synergy of NHS researchers working closely with the University of Oxford and the NIHR Biomedical Research Centre: Oxford (search)."