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Oct 15, 2020

DEFINE PCI study one-year data show potential of treating residual ischemia to improve clinical outcomes for coronary stent patients

New data suggest that PCI guided by iFR co-registered on the angiogram can improve outcomes and reduce angina for patients more effectively than treatment guided by angiography alone

Amsterdam, the NetherlandsRoyal Philips (NYSE: PHG, AEX: PHIA), a global leader in health technology, today announced the one-year results of the DEFINE PCI [1] study at the Cardiology Research Foundation’s TCT Connect 2020 virtual conference. The DEFINE PCI study assessed the level of residual ischemia, or reduced blood flow to the heart muscle, found in patients after a percutaneous coronary intervention (PCI), an image-guided, minimally invasive treatment to open coronary artery blockages. The assessment was carried out using a blinded instant wave-Free Ratio (iFR) pullback measurement, a physiologic guidance technology unique to Philips. 


The exciting promise of this data is that by using iFR co-registration physicians can identify precise locations causing ischemia, plan stent length and even place a virtual stent to predict physiologic improvement before the intervention is performed. The blinded acute data of DEFINE PCI revealed that 24% of patients with angiographically successful PCI still had residual ischemia. In approximately 82% of these patients, the residual ischemia was the result of a focal, potentially treatable lesion. The data suggests patients could have benefited from planning tools like iFR co-registration to find potentially treatable lesions that are often not identified by angiography alone.


The DEFINE PCI one-year data release shows that patients whose baseline ischemia was more effectively treated (post-PCI iFR ≥0.95) had improved outcomes and less recurrent angina (chest pain) at one year. The one-year data showed an optimal post-PCI iFR of ≥0.95 was associated with improved event-free survival. In fact, patients with a post-PCI iFR of ≥0.95 had 68% fewer clinical events than patients with less than optimal post-PCI iFR values (1.8% vs 5.7%, p=0.04).

“In DEFINE PCI we noted that if all lesions causing focal ischemia had been treated up-front, the rate of significant ischemia could theoretically be reduced from 24% to 5%,” said Allen Jeremias MD, principal investigator of the DEFINE PCI study. “Now with the one-year data, we find that patients with more complete resolution of ischemia do better clinically. To some that may not be a surprising finding, but we are conducting the science because, today, most interventionalists are only using physiology as a “who-to-treat” tool. Beyond who we should treat, tools like iFR can guide “how” and “where” to treat within a vessel and then confirm results after stent placement. It’s difficult to know which lesions will produce a significant physiological gradient and which won’t. If you don’t measure, really there’s no way of telling.” 

We now have technology such as iFR co-registration to determine the risk-benefit of revascularization as well as when, how, and where we should treat – and that should lead to better outcomes for patients.

Manesh Patel, MD

co-author of the DEFINE PCI study

“The goal is to get patients as close to normal, physiologically, as possible,” said Manesh Patel, MD, co-author of the DEFINE PCI study. “We’ve known this for a while, but we haven’t had the mature technology to deliver on this. We now have technology such as iFR co-registration to determine the risk-benefit of revascularization as well as when, how, and where we should treat – and that should lead to better outcomes for patients.”


The DEFINE PCI one-year data release follows the 500 patients who participated in the DEFINE PCI study announced last year at the American College of Cardiology (ACC) annual conference. The initial study results showed that 1 in 4 patients treated with standard of care PCI left the cath lab with residual ischemia (iFR < 0.90) [1].


“The one-year data from DEFINE PCI are the latest evidence that iFR contributes to reduced costs, enhanced patient experience and improved outcomes for PCI procedures [2, 3, 4],” said Chris Landon, Senior Vice President and General Manager Image Guided Therapy Devices at Philips. “With the recent introduction of OmniWire, the world’s first solid core pressure guide wire for coronary artery interventional procedures, as well as the next generation of our Azurion platform, we are advancing image-guided therapy with innovative, procedure-focused solutions.”

DEFINE GPS: evaluating whether iFR co-registration guidance improves patient outcomes in a large, prospective, randomized trial

In February, Philips announced DEFINE GPS, a randomized, controlled prospective trial which represents the next step in the DEFINE series of physiology studies. DEFINE GPS will assess the clinical effectiveness of iFR co-registration guidance to minimize post-PCI ischemia in patients. The study, which will include up to 3,000 participants at approximately 100 sites globally, will help determine whether a physiology-based PCI approach results in superior patient outcomes compared to standard angioplasty. Enrolment is expected to begin in Q1 2021. 


The DEFINE PCI and DEFINE GPS studies are sponsored by Philips with the Cardiovascular Research Foundation overseeing core lab and clinical event committee activities. 


[1] Jeremias A et al. The DEFINE PCI Trial: Blinded Physiological Assessment of Residual Ischemia after Successful Angiographic Percutaneous Coronary Intervention, presented at ACC 2019.

[2] Davies JE, et al. Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI. N Engl J Med. 2017 May 11;376(19):1824-1834.

[3] Gotberg M, et al. iFR Swedeheart Investigators. Instantaneous Wave-free Ratio versus Fractional Flow Reserve to Guide PCI. N Engl J Med. 2017 May 11;376(19):1813-1823.

[4] Manesh R. Patel. Cost-effectiveness of iFR compared with FFR to guide coronary revascularization decision-making-Analysis from DEFINE FLAIR. The American College of Cardiology (ACC) annual meeting in Orlando, Florida, March 10–12, 2018. 

About Royal Philips

Royal Philips (NYSE: PHG, AEX: PHIA) is a leading health technology company focused on improving people's health and enabling better outcomes across the health continuum from healthy living and prevention, to diagnosis, treatment and home care. Philips leverages advanced technology and deep clinical and consumer insights to deliver integrated solutions. Headquartered in the Netherlands, the company is a leader in diagnostic imaging, image-guided therapy, patient monitoring and health informatics, as well as in consumer health and home care. Philips generated 2019 sales of EUR 19.5 billion and employs approximately 81,000 employees with sales and services in more than 100 countries. News about Philips can be found at

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Mark Groves

Mark Groves

Philips Global Press Office

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Fabienne van der Feer

Fabienne van der Feer

Philips Image Guided Therapy

Tel: + 31 622 698 001

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