Clinical significance of non-culprit plaque regression following acute coronary syndrome: A serial intravascular ultrasound study

Background: The use of serial intravascular ultrasound (IVUS) for coronary atherosclerosis has offered valuable insight into plaque regression (PR) or progression. However, the beneficial effects of PR on the long-term clinical outcomes in patients with acute coronary syndrome (ACS) remain unclear. We aimed to evaluate the impact of coronary plaque change in patients following primary percutaneous coronary intervention. Methods: We retrospectively analyzed data from 4 prospective clinical trials involving 173 patients with ACS who underwent serial IVUS of non-culprit lesions on statin treatment at baseline and at 6 or 8 months of follow-up. The relationship of the IVUS findings with the change in percent atheroma volume (PAV), on-treatment low-density lipoprotein cholesterol (LDL-C), and major adverse cardiac and cerebrovascular events (MACCE) were investigated. Results: In our serial IVUS analysis, baseline plaque volume and PAV were 79.6 mm(3) and 46.0%, respectively. The overall change in PAV was -1.5% [interquartile range (IQR): -4.1% to 1.0%), and PR (i.e. PAV change from baseline <0) was observed in 67.1% of patients. They were followed up observationally for a mean of 3.5 years and a total of 37 MACCE occurred. The rate of MACCE tended to be lower in patients with PR than in those without PR (18.1% vs. 28.7%, p = 0.14). A multivariate Cox hazard model analysis demonstrated that achievement of both PR and on-treatment low LDL-C levels (<70 mg/dL) was the only significant independent predictor of MACCE (hazard ratio: 0.42, 95% confidence interval: 0.19-0.88: p = 0.02). Conclusions: Achievement of both PR and sufficient lowering of the LDL-C was clinically important in post-ACS management. (C) 2019 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.