Results:

From the 584 subjects screened, 528 patients were included in the study. Mean age was 59 ± 8 years and 58.2% were male. Mean follow-up was 37 ± 10 months and there were 22 adverse events (eight ACS, one cardiac death, and 13 late revascularizations). High-risk patients were more likely to be on antihypertensives, statins, and antiplatelet medications; and had higher rates of obstructive CAD (45.0 vs. 27.3%, p < 0.001) and multivessel or left main CAD (12.3 vs. 5.8%, p = 0.01), as well as higher rates of adverse plaque characteristics. On univariate analysis, all measured plaque characteristics were associated with increased risk of each of the adverse endpoints (p < 0.01 for each). On multivariable analysis, greater total plaque volume and noncalcified plaque volume were each independently associated with greater adverse events using all three endpoints. Noncalcified plaque volume was the only measurement that resulted in net reclassification improvement and integrated discrimination improvement for all three endpoints when added to Framingham risk score and the presence of multivessel CAD.