The advantage to complete revascularization as the primary percutaneous coronary intervention (PCI) strategy for ST-segment elevation myocardial infarction (STEMI) and multivessel disease in a key trial might have been biased by the extent of disease, a study suggested.
Myocardial perfusion scintigraphy analysis of the CvLPRIT trial showed that the group getting PCI of only the culprit artery had more extensive infarction (10.3% of left ventricular myocardium [%LV] versus 8.8% for their peers with complete revascularization, P=0.049) and a trend toward more infarction in culprit artery territory (8.8% versus 5.9%, P=0.09).
Additionally, patients who died or developed myocardial infarction or heart failure had bigger infarcts than those with no such events (median 23.5%LV versus 8.8%LV, P<0.01), Andrew D. Kelion, MA, BMBCh, DM, of John Radcliffe Hospital in England, and colleagues reported in the June 7 issue of the Journal of the American College of Cardiology.
“It is therefore plausible that a small reduction in median infarct size explains the lower rate of early heart failure events and death seen in the complete revascularization arm of the CvLPRIT trial,” they wrote, citing the main results of that study.
“The reduction in infarct size after complete revascularization might represent early improvement in collateral perfusion from treated non-infarct-related arteries to the watershed of the infarct-related artery territory,” they authors suggested.
Kelion’s substudy included 205 patients — out of the 295 CvLPRIT trial participants — who survived PCI long enough to undergo myocardial perfusion scintigraphy 6 to 8 weeks later. Data were collected from seven U.K. centers.
Most patients were asymptomatic and on optimal medical therapy at the time of scintigraphy, according to Kelion’s group.
“Interestingly, the CvLPRIT cardiac magnetic resonance substudy showed no significant difference in infarct size between the randomized groups prior to hospital discharge,” they noted. “This discrepancy probably reflects differences in the substudy populations, and the likelihood that early imaging overestimated infarct size.”
Kelion disclosed no relevant conflicts of interest.
Several co-authors reported relationships with industry.
Journal of the American College of Cardiology
Kelion AD, et al “Ischemia and infarction in STEMI patients with multivessel disease: insights from the CvlPRIT nuclear substudy” J Am Coll Cardiol 2016; DOI: 10.1016/j.jacc.2016.03.544.