Abstract 19494: 3D Volumetric Assessment of Coronary Plaque Change in Asymptomatic Subjects in Response to Therapy Using CT Angiography
Introduction: Studies using intravascular ultrasound have demonstrated that plaque can regress after statin treatment. However, due to the invasive nature of this method data on asymptomatic individuals is scarce. CT angiography (CTA) data on change in plaque volume has shown variable success and has been evaluated mainly in high risk individuals. The aim of this study was to determine the change in coronary plaque in asymptomatic subjects undergoing statin treatment.
Methods: Study subjects were recruited from an ongoing study (‘Randomized Trial of Imaging Versus Risk Factor-Based Therapy for Plaque Regression’). CTA (320-slice) was performed at baseline and after 2 years using a consistent protocol (kVp 120 or 100 kVp, iodine dose base on body weight). Plaque lesions (n = 100) were measured at baseline and follow up using customized tools to align coronary datasets based on anatomic landmarks. Plaque components were assessed by stratification of change in plaque volume by age.
Results: The mean subject age was 64 years (81 % male). The mean Framingham risk was 11%. The median statin dose was 40 mg simvastatin or equivalent. Plaque characterization showed that younger subjects had a significantly higher proportion of non-calcified plaque subcomponents compared with older subjects (86% vs 62% respectively, p ≤ 0.01). The median change in total and non-calcified plaque volume was +2.9% and -5.9% respectively (not statistically significant from 0). Overall 36% of the lesions showed progression of non-calcified plaque while 64% showed regression. Of note, older subjects (over 65y) showed progression of total plaque volume while younger subjects showed no significant change. Younger subjects experienced more reduction in non-calcified plaque volume compared with older subjects (median -12.1% vs -2% respectively, p=0.02).
Conclusions: Approximately 2/3 of the lesions showed plaque regression with 40 mg equivalent simvastatin dose over two years. Younger subjects (≤ 65 years) had larger percentages of soft plaque than older subjects, and showed significantly more regression of non-calcified plaque in relationship to statin therapy. Change in plaque using 3D volumetric registration of CTA data appears feasible and may help determine response to therapy.
Author Disclosures: V. Sandfort: None. M. Ahlman: None. M. Mallek: None. A. Broersen: None. A. Sams: None. D.A. Bluemke: None.
- © 2015 by American Heart Association, Inc.