Abstract 2797: Progression of Coronary Artery Disease as Assessed by Serial 64-Slice Contrast Enhanced Computed Tomography
Volumetric methods to quantify coronary atherosclerotic plaque suffer from high measurement variability, limiting the assessment of plaque progression. We propose a novel semi-quantitative assessment of coronary plaque and determined the rate and predictors of progression in patients with acute chest pain within 2-years. We included 69 patients (mean age 55±12 years, 59% male) from the Rule-Out Myocardial Infarction using Computer Assisted Tomography (ROMICAT) trial who underwent 64-slice coronary CT at baseline and after 2-years (24±3 months). At baseline and follow-up CT, 1-mm cross-sections of the proximal 40 mm of each major coronary artery were reconstructed and assessed for the presence of calcified and non-calcified plaque by two blinded observers. We determined inter- and intra-observer agreement, number of cross-sections with plaque, significance of plaque progression using paired t-test, and predictors of plaque progression over time (adjusted for age and gender) using longitudinal regression analysis. Intra- and inter-observer agreement (k=0.95 and k=0.93) was excellent. At baseline, any plaque, calcified plaque, and non-calcified were detected in 12.5%, 10.1%, and 4.4% of cross-sections per patient. There was significant progression in the mean number of cross section containing any plaque (16.5±25.3 versus 18.6±25.5, p=0.01) and non-calcified plaque (3.1±5.8 versus 4.4_7.0, p=0.04), and no significant increase in calcified plaque (13.3±23.1 versus 14.2±22.0, p=0.2). In unadjusted longitudinal regression models age, male gender, hypertension, hyperlipidemia, smoking, history of CAD, Framingham risk score, and the presence of baseline plaque were significantly associated with plaque progression (P<0.05). After adjustment for age, gender and the follow up time interval, the presence of baseline plaque and smoking were independently associated with increase in plaque progression (P<0.05). We introduce a highly reproducible method to quantify coronary plaque that is able to detect progression over a 2-year follow up period. Increase in plaque was associated with known cardiovascular risk markers.