Atherosclerotic coronary plaque regression and the risk of adverse cardiovascular events: A meta-regression of randomized clinical trials

Introduction: Atherosclerotic coronary plaques represent the main substrate for coronary artery disease (CAD), and changes in plaque volume, investigated with intravascular ultrasound (IVUS), have been used as surrogate end-points in several clinical trials. However, no conclusive data are available to support the exploitation of IVUS-based plaque changes as a measure of clinically meaningful treatment's effect. Methods: Biomed Central, CENTRAL, and Medline/PubMed were searched for randomized clinical trials investigating IVUS variations of plaque and reporting clinical events. End-points of interest were major adverse cardiovascular events (MACE, a composite of death, myocardial infarction [MI] or revascularization), and the rates of MI or revascularization combined. Meta-regression analysis was performed to appraise the association between plaque changes and clinical events during follow-up. Results: Eleven studies (2 focusing on patients with ACS) with 7864 patients were included. After a median follow-up of 18 months, percentage of atheroma volume (PAV) was 0.50 (95% confidence interval -0.25; 1.00), with a 15.0% (95% CI 9.6%; 22.5%) rate of MACE and a 14.1% (95% CI 10.2%; 19.5%) rate of MI or revascularization. Rates of plaque volume regression were significantly associated with the incidence of MI or revascularization (Beta = 6.3; p = 0.006) but not with MACE (Beta = 0.42; p = 0.208). Conclusion: Regression of atherosclerotic coronary plaque volume may represent a surrogate for myocardial infarction and repeat revascularization but not for MACE. These results derive largely from stable patients, and should consequently be applied only to this population. (C) 2012 Elsevier Ireland Ltd. All rights reserved.