CvLPRIT Substudy Demonstrates Effect of Complete Revascularization on Infarct Size

December 18, 2015—Findings from a substudy of the CvLPRIT (Complete Versus Lesion-Only Primary PCI trial) study were published by Gerry P. McCann, MD, et al in the Journal of the American College of Cardiology (JACC, 2015;66:2715–2724).

The background of the substudy is that complete revascularization may improve outcomes compared with an infarct-related artery (IRA)-only strategy in patients being treated with primary percutaneous coronary intervention (PCI) who have multivessel disease presenting with ST-segment elevation myocardial infarction (STEMI). However, there is concern that non-IRA PCI may cause additional non-IRA myocardial infarction (MI). In March, Anthony H. Gershlick, MD, et al published the main CvLPRIT findings in JACC (2015;65:963–972).

The randomized cardiovascular magnetic resonance (CMR) substudy sought to determine whether in-hospital complete revascularization was associated with increased total infarct size compared with an IRA-only strategy.

As summarized in JACC, this multicenter prospective, randomized, open-label, blinded endpoint clinical trial evaluated STEMI patients with multivessel disease having primary PCI within 12 hours of symptom onset. Patients were randomized to either IRA-only PCI or complete in-hospital revascularization.

Contrast-enhanced CMR was performed after primary PCI (median, day 3) and stress CMR at 9 months. The prespecified primary endpoint was infarct size on predischarge CMR. The study had 80% power to detect a 4% difference in infarct size with 100 patients per group.

Of the 296 patients in the main CvLPRIT trial, 205 participated in the CMR substudy, and 203 patients (98 complete revascularization and 105 IRA-only) completed the predischarge CMR. 

The investigators reported that the groups were well matched. Total infarct size (median, interquartile range) was similar for IRA-only revascularization versus complete revascularization: 13.5% (6.2%–21.9%) versus 12.6% (7.2%–22.6%) of left ventricular mass (95% confidence interval for difference in geometric means 0.82–1.41; P = .57). 

The complete revascularization group had an increase in non-IRA MI on the predischarge CMR (22 of 98 vs 11 of 105; P = .02). There was no difference in total infarct size or ischemic burden between treatment groups at follow-up CMR.

Multivessel PCI in the setting of STEMI leads to a small increase in CMR-detected non-IRA MI, but total infarct size was not significantly different from an IRA-only revascularization strategy, concluded the investigators in JACC.