Complete Versus Lesion-Only Primary PCI: The Randomized Cardiovascular MR CvLPRIT Substudy.

<bold>Background: </bold>Complete revascularization may improve outcomes compared with an infarct-related artery (IRA)-only strategy in patients being treated with primary percutaneous coronary intervention (PPCI) 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).<bold>Objectives: </bold>This study sought to determine whether in-hospital complete revascularization was associated with increased total infarct size compared with an IRA-only strategy.<bold>Methods: </bold>This multicenter prospective, randomized, open-label, blinded endpoint clinical trial evaluated STEMI patients with multivessel disease having PPCI within 12 h of symptom onset. Patients were randomized to either IRA-only PCI or complete in-hospital revascularization. Contrast-enhanced cardiovascular magnetic resonance (CMR) was performed following PPCI (median day 3) and stress CMR at 9 months. The pre-specified primary endpoint was infarct size on pre-discharge CMR. The study had 80% power to detect a 4% difference in infarct size with 100 patients per group.<bold>Results: </bold>Of the 296 patients in the main trial, 205 participated in the CMR substudy, and 203 patients (98 complete revascularization and 105 IRA-only) completed the pre-discharge CMR. The groups were well-matched. Total infarct size (median, interquartile range) was similar to IRA-only revascularization: 13.5% (6.2% to 21.9%) versus complete revascularization, 12.6% (7.2% to 22.6%) of left ventricular mass, p = 0.57 (95% confidence interval for difference in geometric means 0.82 to 1.41). The complete revascularization group had an increase in non-IRA MI on the pre-discharge CMR (22 of 98 vs. 11 of 105, p = 0.02). There was no difference in total infarct size or ischemic burden between treatment groups at follow-up CMR.<bold>Conclusions: </bold>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. (Complete Versus Lesion-Only Primary PCI Pilot Study [CvLPRIT]; ISRCTN70913605). [ABSTRACT FROM AUTHOR]