Residual Plaque Burden in Patients With Acute Coronary Syndromes After Successful Percutaneous Coronary Intervention

OBJECTIVES The aim of this study was to characterize and evaluate the clinical impact of untreated atherosclerotic disease after percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS). BACKGROUND Residual atherosclerotic disease after successful PCI may predispose future major adverse cardiovascular events (MACE). Compared with intravascular ultrasound (IVUS), angiography underestimates the presence and severity of coronary artery disease. METHODS Following successful PCI of all clinically significant lesions in 697 patients with ACS, 3-vessel grayscale and radiofrequency IVUS was performed. Lesions were prospectively characterized, and patients were followed for a median of 3.4 years. A total of 3,229 untreated lesions (4.89 +/- 1.98 lesions/patient) were identified by IVUS, with mean plaque burden (PB) of 49.6 +/- 4.2%. RESULTS By angiography these nonculprit lesions were mild, with mean diameter stenosis of 38.9 +/- 15.3%. At least 1 lesion with a PB >= 70% (PB70 lesion) was found in 220 (33%) patients. By multivariable analysis, a history of prior PCI and angiographic 3-vessel disease were independent predictors of PB70 lesions. Patients with PB70 lesions had greater total percent plaque volume, normalized PB, fibroatheromas, thin-cap fibroatheromas, and normalized volumes of necrotic core and dense calcium. Patients with PB70 lesions had greater 3-year rates of MACE due to untreated nonculprit lesions (20.8% vs. 7.7%, p < 0.0001). Among imaged nonculprit lesions, the proportion of PB70 lesions causing MACE was significantly greater than non-PB70 lesions (8.7% vs. 1.0%, p < 0.0001). CONCLUSIONS After successful PCI of all angiographically significant lesions, overall untreated atherosclerotic burden remains high, and PB70 lesions are frequently present in the proximal and mid-coronary tree. Patients with PB70 lesions have greater atherosclerosis throughout the coronary tree, have more thin-cap fibroatheromas, and are at increased risk for future cardiovascular events. (PROSPECT: An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466) (J Am Coll Cardiol Img 2012;5:S76-85) (C) 2012 by the American College of Cardiology Foundation