TCT 2016: COLOR trial finds PCI of lipid-rich plaque is safe

Percutaneous coronary intervention (PCI) on coronary artery lipid-rich plaque (LRP) is not associated with major adverse cardiac events, according to two-year results from the COLOR trial.

The study’s findings were presented Nov. 1 at the Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in Washington, D.C.

The primary objective of COLOR was to evaluate the association of coronary lipid rich plaque as imaged by near-infrared spectroscopy (NIRS) with peri-procedural and long-term events after PCI.

LRP’s clinical impact in patients with atherosclerosis undergoing PCI is poorly understood, according to Gloria Weisz, MD, chairman of the cardiology department at Shaare Zedek Medical Center in Jerusalem, Israel.

Autopsy-based studies have suggested that LRP may be associated with increased PCI risk and subsequent events. Catheter-based NIRS can identify the presence and extent of LRP in the coronary artery. Previous case reports suggest an association between LRP as assessed by NIRS and peri-procedural outcomes after PCI.

The COLOR registry was a prospective, multicenter, observational study designed to determine whether LRP detected by NIRS is associated with subsequent major adverse cardiac events. LRP was detected using an intracoronary NIRS imaging catheter that provides an assessment of coronary lipid distribution. Lipid core burden index (LCBI) was calculated as the fraction of yellow pixels within a scanned region multiplied by 1,000.

A total of 1,899 patients at 22 sites in the U.S. underwent NIRS during a clinically indicated catheterization procedure. The goal was to measure the composite of cardiac death, myocardial infarction, stent thrombosis, revascularization and hospitalization (MACE) at two years.

Events occurring within two years were adjudicated by an independent clinical events committee and further classified as to whether they arose from the originally treated coronary segments or untreated segments. The relationship between baseline LCBI and MACE at two years was also evaluated.

The overall rate of MACE at two years was 14 percent for all patients, 6 percent related to the culprit lesion, 8 percent related to the non-culprit lesion related and 2 percent indeterminate.

"In this large-scale registry, non-culprit lesion related events were a little more common than culprit lesion post-PCI related events during two-year follow-up," said Weisz. "The results also indicate that PCI of NIRS-defined lipid rich plaques was safe, and was not associated with increased peri-procedural or long-term adverse outcomes compared to PCI of non-LRPs. Additional studies are needed to determine the clinical significance of NIRS-defined non-culprit LPRs."