AIMS: To compare the frequency and extent of Troponin I and late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) defined injury following PCI compared with CABG in patients with multivessel and/or left main coronary artery disease (CAD), and interpret these finding in light of the new ESC/ACCF/AHA/WHF Task Force definitions for necrosis and infarction.METHODS AND RESULTS: Prospective, registered, single centre randomised controlled trial. Eighty patients with 3 vessel CAD (≥ 50% stenoses), or 2 vessel CAD including a type C lesion in the LAD, and/or left main disease were enrolled. Mean SYNTAX and EuroSCOREs were similar for both groups. Forty patients underwent PCI with drug eluting stents and 39 underwent CABG (one died prior to CABG). In the PCI group 6/38 (15.8%) patients had LGE, compared with 9/32 (28.1%) CABG patients (p = 0.25). Using the new Task Force definitions, necrosis occurred in 30/40 (75%) PCI patients and 35/35 (100%) CABG patients (p = 0.001), whilst infarction occurred in 30/40 (75%) PCI patients and 9/32 (28.1%) CABG patients (p = 0.0001).CONCLUSIONS: Periprocedural necrosis according to the Task Force definition was significantly lower in the PCI group, and universal in the CABG group. The incidence and extent of CMR defined infarction following PCI did not differ compared with CABG. This demonstrates that PCI can achieve revascularisation in complex patients without increased procedural myocardial damage.