BACKGROUND Data regarding clinical outcomes after intravascular imaging-guided percutanegrees, ous coronary intervention (PCI) for complex coronary-artery lesions, as compared with outcomes after angiography-guided PCI, are limited. METHODS In 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 intra-vascular 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 myocarto dial infarction, or clinically driven target-vessel revascularization. Safety was also assessed. RESULTS A total of 1639 patients underwent randomization, with 1092 assigned to undergo intravascular imaging-guided PCI and 547 assigned to undergo angiographyguided 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, 7.796) in the intravascular imaging group and in 60 patients (cumulative incidence, 12.3°/0) 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, 1.790) in the intravascular imaging group and in 17 patients (cumulative incidence, 3.890) in the angiography group; target-vessel-related myocardial infarction occurred in 38 (cumulative incidence, 3.796) and 30 (cumulative incidence, 5.696), respectively; and clinically driven target-vessel revascularization in 32 (cumulative incidence, 3.4%) and 25 (cumulative incidence, 5.596), respectively. There were no apparent between-group differences in the incidence of procedurerelated safety events. CONCLUSIONS Among patients with complex coronary-artery lesions, intravascular imagingguided PCI led to a lower risk ofa composite ofdeath from cardiac causes, targetvessel-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). [ABSTRACT FROM AUTHOR]