Despite the favorable prognosis associated with intravascular imaging (IVI)-guided percutaneous coronary intervention (PCI) for complex coronary lesions, it is still unclear whether IVI-guided PCI for such lesions provides clinical benefit in patients with acute myocardial infarction (AMI) according to the ACC/AHA lesion classification.

This study was a patient-level pooled analysis of 2 nationwide Korean AMI registries. We identified 23 051 patients from KAMIR-V and KAMIR-NIH who underwent successful PCI for an infarct-related artery and stratified them by the ACC/AHA lesion classification. Clinical outcomes were compared between IVI-guided and angiography-guided PCI. The primary endpoint was major adverse cardiac events (MACE), a composite of cardiac death, AMI, repeat revascularization, and stent thrombosis, at 3 years.

IVI-guided PCI demonstrated a lower incidence of MACE compared with angiography-guided PCI in patients with type B2/C lesions (adjusted HR, 0.78; 95%CI, 0.70-0.88; P <.001), but not in patients with type A/B1 lesions (adjusted HR, 0.81, 95%CI, 0.60-1.11; P=.190). In both non–ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction, a significantly lower risk of MACE following IVI-guided PCI than angiography-guided PCI was observed in patients with type B2/C lesions (non–ST-segment elevation myocardial infarction: adjusted HR, 0.73; 95%CI, 0.63-0.84; P <.001; ST-segment elevation myocardial infarction: adjusted HR, 0.86, 95%CI, 0.75-0.98; P=.027), but not in those with type A/B1 lesions.

Among patients with AMI, IVI-guided PCI was associated with a significantly lower risk of MACE in those with type B2/C lesions, but not in those with type A/B1 lesions. The prognostic benefit of IVI-guided PCI increased with greater lesion complexity in the infarct-related artery.