Lipid-rich plaques predict non-target-lesion ischemic events in patients undergoing percutaneous coronary intervention-insights from integrated backscatter intravascular ultrasound

Background: Despite growing interest in non-target lesion events in patients undergoing percutaneous coronary intervention (PCI), there has been little discussion of predictors. Methods and Results: A total of 155 consecutive patients who underwent PCI were enrolled. Conventional and integrated backscatter intravascular ultrasound (IB-IVUS) parameters were measured in non-target lesions utilizing a 40-MHz intravascular catheter. Lipid-rich plaques (LRP) were defined as lesions with an increased lipid volume (>median) and greater lipid content. Non-target ischemic events were defined as death, non-fatal myocardial infarction, any repeat revascularization and rehospitalization for angina involving the non-target vessel or the target vessel outside the index lesion. During the follow-up period (median: 1,265 days), non-target events were observed in 16 patients (11%). Using the Cox proportional hazard model, LRP (odds ratio [OR], 6.06; 95% confidence interval [CI]: 1.81-20.4, P=0.0035), elevated serum C-reactive protein (CRP) levels (OR, 6.83; 95%CI: 2.19-21.3, P=0.0009) and acute coronary syndrome present at baseline (OR, 4.08; 95%CI: 1.21-13.8, P=0.024) were significantly and independently associated with non-target events. Synergistic effects of LRP and elevated serum CRP levels for prediction of non-target events (OR, 14.8; 95%CI: 4.57-48.0, P<0.0001) were found even after adjusting for confounders. Conclusions: LRP measured using IB-IVUS proved to be an independent morphologic predictor of non-target ischemic events after PCI, particularly enhancing the risk in patients with elevated serum CRP levels.