Abstract 3328: Baseline and Changes in Atheroma Volume Predict Clinical Outcome in Patients with Coronary Artery Disease: Insights from ILLUSTRATE
Background: Intravascular ultrasound (IVUS) has been employed in clinical trials to evaluate the impact of medical therapies on the progression of coronary atherosclerosis. This analysis assessed the relationship between percent atheroma volume (PAV) at baseline and its change with clinical outcomes.
Methods: 1183 patients with angiographic coronary artery disease underwent IVUS imaging within a single coronary artery before (n=1183) and during (n=910) 24 months of treatment with torcetrapib or placebo on a background of atorvastatin therapy. The relationship between baseline and changes in percent atheroma volume (PAV) with a composite of adjudicated cardiovascular events (death, myocardial infarction, coronary revascularization, stroke, unstable angina, heart failure) were investigated.
Results: 331 cardiovascular events (8.8% myocardial infarction, 62.8% coronary revascularization, 24.2% hospitalisation for unstable angina) occurred in the patient cohort (median age 57 years, 70% male, 21% diabetes, 76% hypertension, 18% smoking, 26% previous MI). Baseline PAV was higher in patients who underwent coronary revascularization (40.2 v 36.6%, p<0.001), myocardial infarction (39.3 v 37.0%, p=0.005) and the composite endpoint (40.2 v 36.4%, p<0.001). The change in PAV was greater in those undergoing revascularization (0.7 v 0.1%, p=0.02). Compared with the lowest quartile, patients with the highest quartile of PAV at baseline were 2.3-fold more likely to have revascularization (p=0.001) and 2.3-fold more likely to have a cardiovascular event (p<0.001). A trend towards a greater likelihood of myocardial infarction (hazard ratio 5.2, p=0.13) was also observed in patients with the highest quartile of PAV at baseline. Patients with the highest quartile of change of PAV were 2-fold more likely to undergo coronary revascularization compared with the lowest quartile (p=0.006). A multivariate model revealed that baseline PAV remained an independent predictor of cardiovascular events (p<0.0001).
Conclusion: IVUS derived measures of atheroma burden at baseline and its serial change predicts a number of measures of clinical outcome.