3D Ultrasound Measurement of Change in Carotid Plaque Volume

Abstract

Background and Purpose-New therapies are being developed that are antiatherosclerotic but that lack intermediate end points, such as changes in plasma lipids, which can be measured to test efficacy. To study such treatments, it will be necessary to directly measure changes in atherosclerosis. The study was designed to determine sample sizes needed to detect effects of treatment using 3D ultrasound (US) measurement of carotid plaque. Methods-In 38 patients with carotid stenosis Ͼ60%, ageϮSD 69.42Ϯ7.87 years, 15 female, randomly assigned in a double-blind fashion to 80 mg atorvastatin daily (nϭ17) versus placebo (nϭ21), we measured 3D plaque volume at baseline and after 3 months by disc segmentation of voxels representing carotid artery plaque, after 3D reconstruction of parallel transverse duplex US scans into volumetric 3D data sets. Results-There were no significant differences in baseline risk factors. The rate of progression was 16.81Ϯ74.10 mm 3 in patients taking placebo versus regression of Ϫ90.25Ϯ85.12 mm 3 in patients taking atorvastatin (PϽ0.0001) Conclusions-3D plaque volume measurement can show large effects of therapy on atherosclerosis in 3 months in sample sizes of Ϸ20 patients per group.

Statins Reduce Extensive Aortic Atheromas in Patients with Abdominal Aortic Aneurysms

“…Carotid artery plaques have been previously reported to show reduction within 3 months. 26) We speculate that the pleiotropic effect may appear in parallel with the lipidlowering effect, which has been shown previously and in our study to be apparent within 3 months. According to this hypothesis, strong statins may have greater effects on atheromas; however, we were unable to detect the significant difference between strong and mild statins in our small series.…”

Reproducibility and Reliability of Atherosclerotic Plaque Volume Measurements in Peripheral Arterial Disease with Cardiovascular Magnetic Resonance

“…Using carotid intimal medial thickness measurements as a surrogate efficacy end-point, Bots et al reported that 468 patients would be required to detect a treatment effect of 30% (power 0.80) (33). Three-dimensional ultrasound of plaque in the carotids would require fewer patients to demonstrate efficacy, yet a recent study reported that 203 patients would still be needed to detect a 10% change in plaque volume (power = 0.90) measured over a three month period (34). Measuring the progression of coronary calcium with cardiac computed tomography has been proposed as yet another noninvasive alternative to evaluating disease progression, yet sample sizes required for these studies remain large, and there is the strong suggestion that calcification represents a fundamentally distinct biological process which may correlate less with clinical events than plaque volume progression (35)(36)(37).…”

The Use of Plaque Score Measurements to Assess Changes in Atherosclerotic Plaque Burden Induced by Lipid-Lowering Therapy Over Time: The METEOR Study

“…Further- Abbreviations: MaxMaxPS, mean of the single maximum plaque score of each of the 12 carotid segments (range 0-3) at duplicate examinations; PS, plaque score more, it is important to mention that our plaque score is a categorical variable which may be less powerful to track changes in plaque burden over time than a continuous measure. Continuous plaque measures, such as the carotid plaque area, carotid plaque volume or vessel wall value, might therefore be more efficient in terms of sample size and duration of follow-up to measure changes 31,32) ; however, continuous plaque measures are much more expensive and time-consuming, which limits their extensive use. Additionally, we were able to track changes in atherosclerotic plaque burden over time despite this limitation.…”