Abstract Body (Do not enter title and authors here): Introduction: High platelet reactivity (HPR) phenotype, as well as complex coronary artery lesion increases the incidence of atherothrombotic events after percutaneous coronary intervention (PCI). Among patients with complex coronary artery lesions, intravascular imaging-guided showed a lower risk of an ischemic events than angiography-guided PCI. However, intravascular imaging-guided PCI benefit in patients with HPR is unclear.

Hypothesis: Intravascular imaging-guided PCI, as well as platelet inhibition through pharmacologic strategy, may improve outcomes in patients with HPR.

Methods: We retrospectively included all-comer coronary artery disease patients who underwent successful PCI. Intravascular imaging group included intravascular ultrasonography (IVUS) and optical coherence tomography (OCT) by the operators' discretion. HPR was defined by P2Y₁₂ reaction unit (PRU) ≥253. The primary endpoint was the major adverse cardiac events (MACE) including all-cause death, myocardial infarction, or revascularization.

Results: Between 2011 and 2018, a total of 5,814 patients treated with aspirin and clopidogrel after PCI were enrolled. HPR patient was 27.9% and intravascular imaging group was 77.7% (IVUS 74.8% and OCT 2.3%). The Kaplan-Meier estimates of the primary outcome for 3 years were significantly different according to HPR or complex PCI (HPR, 15.5% vs. 11.7%, p=0.002; complex PCI, 15.9% vs. 13.1%, p=0.008, respectively). Compared to angiography-guided PCI, intravascular imaging-guided PCI showed a lower risk of 3-year MACE among patients with complex PCI and HPR (complex PCI, 15.7% vs. 22.9%, p=0.010; HPR, 14.2% vs. 20.0%, p=0.008, respectively) (Figure).

Conclusions: In this large-scale cohort, intravascular imaging-PCI compared to angiography-guided PCI showed a lower risk of a 5-year MACE in patients with HPR.