Philips has announced the completion of patient enrollment in the DEFINE GPS (Distal Evaluation of Functional performance with Intravascular sensors to assess the Narrowing Effect – Guided Physiologic Stenting) trial, marking a significant milestone in interventional cardiology research. This large-scale clinical study aims to transform how physicians perform percutaneous coronary interventions (PCI) by incorporating physiologic confirmation through iFR co-registration technology.
Addressing Unmet Needs in Coronary Interventions
Despite advances in PCI techniques, a significant number of patients continue to experience chest pain following these procedures. According to findings from the earlier DEFINE PCI study, approximately 25% of patients leave the catheterization laboratory with residual ischemia even after treatment. More concerning is that in 80% of these cases, additional stenting or balloon dilation could have resolved the issue if properly identified.
The DEFINE GPS trial builds upon these insights by evaluating whether iFR co-registration technology can guide treatment more precisely and verify procedural success before patients leave the catheterization laboratory. This approach could potentially reduce unnecessary procedures and hospital readmissions while improving clinical outcomes.
"We always strive for better outcomes—lower mortality, fewer heart attacks, and less re-hospitalization," noted a trial investigator. "This trial could help us achieve that. There's also a cost element: by treating patients more precisely, we could reduce unnecessary procedures and hospital visits. It's about delivering better care for more people while potentially easing the economic burden on healthcare systems."
Bringing Objectivity to Interventional Decision-Making
One of the key challenges in PCI guided by angiography alone is the variability in interpretation between operators. What appears as a 70% blockage to one physician may look like only a 40% stenosis to another. The iFR co-registration technology aims to remove this subjectivity by providing objective physiological assessment of coronary lesions.
"It brings objectivity," explained a clinical expert involved in the trial. "Say a physician sees two or three blockages—one might appear severe; the others may appear borderline on the angiogram. iFR co-registration tells you which ones are actually significant and helps you map out your stenting strategy. And after treatment, it confirms successful treatment and helps ensure no key steps are missed."
This approach could be particularly valuable in complex cases involving borderline or multi-vessel disease, where treatment decisions are often challenging.
Trial Design and Endpoints
The DEFINE GPS trial is designed to measure several important clinical outcomes over a two-year follow-up period. The primary endpoint is the rate of major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction, and ischemia-driven revascularization, or hospitalization for progressive or unstable angina at two years.
Secondary endpoints include quality of life assessments, resource utilization, and cost-effectiveness analyses, all tracked at 30 days, one year, and two years post-procedure. This comprehensive approach will provide valuable insights into both the clinical and economic impact of iFR-guided PCI.
With enrollment now complete, the trial has entered the follow-up and analysis phase. Investigators are focused on thorough clinical follow-up, including reviewing medical records and capturing any endpoints such as myocardial infarction, revascularization, or death.
Potential Impact on Clinical Practice
If the results prove positive, the DEFINE GPS trial could represent a paradigm shift in how interventional cardiologists approach PCI procedures. Physicians may begin to routinely incorporate physiologic confirmation using iFR to verify treatment effectiveness before concluding procedures.
"This could represent a paradigm shift in how we approach PCI," a trial investigator stated. "We may begin to routinely incorporate physiologic confirmation, using iFR, to verify treatment effectiveness before concluding the procedure. If the data validates this strategy, it has the potential to influence international clinical guidelines."
The trial investigators note that iFR already has a Class 1A recommendation for invasive physiology in PCI—a distinction no other non-hyperemic index has achieved. Positive results from DEFINE GPS could strengthen the case for updating guidelines worldwide to include iFR co-registration as a standard component of PCI procedures.
Philips' Commitment to Evidence-Based Innovation
DEFINE GPS represents one of the largest clinical trials Philips has ever sponsored, reflecting the company's commitment to evidence-based innovation in healthcare. The trial underscores Philips' approach to developing technologies that address real clinical needs and improve patient outcomes.
"DEFINE GPS is one of the largest clinical trials that Philips has ever sponsored," noted a company representative. "It reflects our conviction that innovation must be evidence-based. Whether it's cardiology or other areas of care, our goal is to bring the best tools, practices, and technologies to clinicians—and provide better care for more people."
As the healthcare community awaits the results of this landmark trial, the potential implications for interventional cardiology practice and patient care remain significant. If successful, the DEFINE GPS trial could establish a new standard for PCI procedures that improves outcomes, reduces costs, and enhances the precision of coronary interventions.
