The randomised Complete versus Lesion-only PRimary percutaneous coronary Intervention Trial: Cardiovascular Magnetic Resonance imaging substudy (CvLPRIT-CMR)

Background: Complete revascularisation in patients with multivessel disease who are treated with primary percutaneous coronary intervention (PPCI) may improve outcomes compared with an infarct-related artery (IRA)-only strategy. However, non-IRA percutaneous coronary intervention (PCI) may result in additional myocardial infarction (MI). Objectives: To determine whether or not in-hospital complete revascularisation was associated with increased total infarct size (IS) in patients participating in the Complete versus Lesion-only PPCI trial (CvLPRIT). Secondary objectives were to assess whether or not myocardial salvage index, myocardial ischaemia and final IS at follow-up were different with a complete revascularisation versus an IRA-only strategy. Design: Multicentre, prospective, randomised, controlled and open-label trial with blinded end-point analysis. Setting: Seven PPCI centres in England, UK. Participants: ST-segment elevation MI (STEMI) patients with multivessel disease (angiographic stenosis > 70% in one view or > 50% in orthogonal views) presenting within 12 hours of symptom onset and treated with the PPCI. Coronary artery bypass surgery, cardiogenic shock and contraindications to cardiovascular magnetic resonance (CMR; substudy only) imaging were exclusions. Interventions: Patients were randomised to either complete in-hospital revascularisation or an IRA-only strategy. Main outcome measures: The primary outcome was IS as measured by CMR undertaken at 48–72 hours post PPCI. Secondary outcome measures included microvascular obstruction, myocardial salvage index, left ventricular volumes and ejection fraction and final IS on the acute and follow-up CMR carried out at 9 months post STEMI. Results: Patients were recruited from May 2011 until May 2013 and followed up for 12 months. Of 296 patients randomised in the main CvLPRIT, 205 consented to participate in the CMR substudy and 203 had analysable images for the primary end point. Patients in the IRA-only group (n = 105) were well matched to those in the complete revascularisation group (n = 98) for all baseline characteristics {mean age 64.1 years [standard deviation (SD) 10.8 years] vs. 63.1 years (SD 11.3 years); male sex 89% vs. 79%, respectively}. Total IS was not significantly different in the IRA-only and complete revascularisation groups {median 13.5% [interquartile range (IQR) 6.2–21.9%] of left ventricular (LV) mass vs. median 12.6% (IQR 7.2–22.6%) LV mass, respectively; 95% confidence interval –4.09% to 31.17%; p = 0.57}. Myocardial salvage index was also not significantly different in the IRA-only and complete revascularisation groups [median 58.5% (IQR 32.8–74.9%) vs. median 60.5% (IQR 40.6–81.9%), respectively; p = 0.14]. The prevalence of non-IRA MI on acute CMR was higher in the complete revascularisation group than in the IRA-only group (22/98 vs. 11/105, respectively; p = 0.02). There was no difference in total IS, ischaemic burden or LV volumes between treatment groups at follow-up CMR. Limitations: The CMR substudy population may not be a true representation of the overall study population. The optimal timing of CMR to measure IS post PPCI is uncertain. Myocardial salvage was assessable in only 70% of patients. Conclusions: Multivessel PCI, compared with an IRA-only revascularisation, in the setting of STEMI led to a small increase in CMR imaging-detected non-IRA MI, but total IS was not increased. Future work: Larger studies are required to (1) confirm that death and MI are reduced by a complete revascularisation strategy; (2) assess whether or not functional assessment of non-IRA lesions results in similar outcomes to a pragmatic angiographic-based revascularisation strategy; and (3) assess the timing of in-hospital versus staged outpatient complete revascularisation. Trial registration: Current Controlled Trials ISRCTN70913605. Funding: This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. The main CvLPRIT was funded by the British Heart Foundation (SP/10/001) with support from the NIHR Comprehensive Local Research Networks