The incidence and impact of stent thrombosis in patients undergoing percutaneous coronary intervention (PCI) has been examined in a new angiographic analysis of the CHAMPION PHOENIX trial. Results of the study were released today and will be presented March 30 at the American College of Cardiology 63rd Annual Scientific Session.
CHAMPION PHOENIX was a prospective, double-blind, active-controlled trial which randomized 11,145 patients to receive intravenous cangrelor or oral clopidogrel administered at the time of PCI. In a previous analysis presented at TCT 2013 and published in the Journal of the American College of Cardiology, cangrelor significantly reduced periprocedural and 30-day ischemic events in patients undergoing PCI.
In this new analysis, an independent core laboratory (CRF) blinded to the treatment performed the angiographic analysis of 10,939 of the randomized patients. Stent thrombosis was defined as the occurrence of either intraprocedural ST (IPST) or ARC defined ST (definite or probable). Adverse events were adjudicated by an independent clinical events committee.
ST occurred in 120 patients (1.1 percent) at 48 hours and in 175 patients (1.6 percent) at 30 days. The occurrence of ST at 48 hours and 30 days was associated with a marked increase in 30-day mortality (OR [95%CI] = 15.3 [8.6, 27.2], p<0.001; and 55.2 [36.6, 83.3] p<0.001, respectively). IPST, ARC acute ST (≤24 hrs), and ARC subacute ST (1-30 days) occurred in 89 (0.8 percent), 32 (0.3 percent), and 60 (0.5 percent) patients respectively. Each type of ST was also associated with an increase in 30-day mortality (IPST: 17.4 [8.4, 36.1], p<0.001, ARC acute ST: 43.3 [18.1, 103.5], p<0.001, ARC sub-acute ST: 189.1, [107.9, 331.4], p<0.001).
"Regardless of the exact type of stent thrombosis, it remains associated with a high rate of death," stated Deepak L. Bhatt, MD, MPH, Executive Director of Interventional Cardiovascular Programs at Brigham and Women's Hospital Heart & Vascular Center, Professor of Medicine at Harvard Medical School, and Co-Chair of the CHAMPION program.
Cangrelor was associated with a significant reduction in 48-hour (0.8 vs. 1.4 percent, p=0.01) and 30-day ST (1.3 vs. 1.9 percent, p=0.01), compared with clopidogrel. Cangrelor also had consistent effect in IPST (0.6 vs. 1.0 percent, p=0.04), acute ARC ST (0.2 vs. 0.4 percent, p=0.8), and sub-acute ARC ST (0.5 vs. 0.6 percent, p=0.60). After multivariable analysis, the use of cangrelor was identified as an independent predictor of freedom of ST at 30 days.
"The benefits of cangrelor were consistent across all these different categories of stent thrombosis," stated Robert A. Harrington, MD, Chairman of Medicine and Bloomfield Professor of Medicine at Stanford University, and Co-Chair of the CHAMPION program.
"In the large-scale CHAMPION PHOENIX trial, the occurrence of stent thrombosis was strongly associated with increased mortality. Cangrelor use resulted in a significant reduction in ST, with consistent outcomes on intraprocedural, and outside the cath lab acute and sub-acute ARC defined ST," stated lead investigator Philippe Généreux, MD. Dr. Généreux is Director of the Angiographic Core Laboratory at the CRF Clinical Trials Center. The CRF Angiographic Core Lab conducted the analyses.