High Rate of Residual Ischemia After PCI Despite Excellent Angiographic Outcomes: DEFINE-PCI Trial

The use of iFR could identify other focal lesions, thereby reducing residual ischemia and potentially cutting recurrent events after PCI, say experts.

· Presenting the main results of DEFINE-PCI on March 17, 2019, at ACC. 2019 Scientific Session, investigators said that recurrent angina after PCI is quite prevalent in most PCI trials, ranging from 20% to 30% at 1 year.

· Despite successful PCI and optimal angiographic outcomes, nearly one in four patients leave the catheterization lab with some degree of residual ischemia, according to the results of DEFINE-PCI study.

· With a better assessment of coronary physiology post-PCI, however, physicians could reduce the number of significant lesions left behind after stenting and potentially trim the risk of recurrent ischemic events, say researchers.  

· “Even though we think we do a good job based on the angiogram, the angiogram isn’t totally reliable,” lead investigator Allen Jeremias, MD.

·  Investigators believe that DEFINE-PCI is unique as it shows how the instantaneous free-wave ratio (IFR) and iFR “pullback,” which is a pressure map of the entire coronary vessel, could be clinically meaningful.

· “It’s striking that the 24% residual ischemia is similar to the numbers of recurrent angina in a large number of PCI studies, including COURAGE, FAME, FAME 2, and SYNTAX.”

iFR Pullback and Residual Ischemia

· The purpose of DEFINE-PCI was to determine how often patients leave the cardiac catheterization laboratory with significant residual ischemia despite operators achieving excellent angiographic outcomes. In total, 500 stable and unstable angina patients with a baseline iFR value of less than 0.89, indicative of physiological impairment, underwent PCI.

· Mean iFR increased from 0.69 at baseline to 0.93 after the completion of PCI (average change 0.24). Of the 467 patients who had successful PCI—defined as operator-assessed residual diameter stenosis less than 50% in any treated lesion—24% had an iFR ≤ 0.89, which is hemodynamically significant.

· The good news, is that the vast majority (81.6%) of physiologically significant lesions left behind were focal stenoses rather than diffuse diseases

· Of the 93 vessels with residual focal disease, the “physiologic miss” was observed equally in segments distal and proximal to the implanted stent.

·  It was estimated that if all residual focal lesions could be treated with additional PCI, which is obviously somewhat speculative, the rate of significant ischemia would be reduced from 24% to 5%.” 

No Correlation Between Angiogram and Post-PCI Physiology

· The investigators observed no significant correlation between angiographic diameter stenosis and post-PCI physiologic measures. Nearly 30% of patients with a residual diameter stenosis ≥ 50% on angiography had an iFR ≤ 0.89. For those with a residual diameter stenosis less than 50%, more than 21% had an iFR ≤ 0.89 (P = 0.24).

Source :, , By: Michael O"Riordan

March 21, 2019

Download the study summary slides made by American College of Cardiology here : Download