Royal Philips, a global leader in health technology, has announced the one-year results of the DEFINE PCI  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.”