BackgroundData regarding clinical outcomes after intravascular imaging–guided percutaneous coronary intervention (PCI) for complex coronary-artery lesions, as compared with outcomes after angiography-guided PCI, are limited.MethodsIn this prospective, multicenter, open-label trial in South Korea, we randomly assigned patients with complex coronary-artery lesions in a 2:1 ratio to undergo either intravascular imaging–guided PCI or angiography-guided PCI. In the intravascular imaging group, the choice between intravascular ultrasonography and optical coherence tomography was at the operators’ discretion. The primary end point was a composite of death from cardiac causes, target-vessel–related myocardial infarction, or clinically driven target-vessel revascularization. Safety was also assessed.ResultsA total of 1639 patients underwent randomization, with 1092 assigned to undergo intravascular imaging–guided PCI and 547 assigned to undergo angiography-guided PCI. At a median follow-up of 2.1 years (interquartile range, 1.4 to 3.0), a primary end-point event had occurred in 76 patients (cumulative incidence, 7.7%) in the intravascular imaging group and in 60 patients (cumulative incidence, 12.3%) in the angiography group (hazard ratio, 0.64; 95% confidence interval, 0.45 to 0.89; P=0.008). Death from cardiac causes occurred in 16 patients (cumulative incidence, 1.7%) in the intravascular imaging group and in 17 patients (cumulative incidence, 3.8%) in the angiography group; target-vessel–related myocardial infarction occurred in 38 (cumulative incidence, 3.7%) and 30 (cumulative incidence, 5.6%), respectively; and clinically driven target-vessel revascularization in 32 (cumulative incidence, 3.4%) and 25 (cumulative incidence, 5.5%), respectively. There were no apparent between-group differences in the incidence of procedure-related safety events.ConclusionsAmong patients with complex coronary-artery lesions, intravascular imaging–guided PCI led to a lower risk of a composite of death from cardiac causes, target-vessel–related myocardial infarction, or clinically driven target-vessel revascularization than angiography-guided PCI. (Supported by Abbott Vascular and Boston Scientific; RENOVATE-COMPLEX-PCI ClinicalTrials.gov number, NCT03381872).