3D ultrasound measurement of change in carotid plaque volume: a tool for rapid evaluation of new therapies.
OBJECTIVE
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 >60%, age+/-SD 69.42+/-7.87 years, 15 female, randomly assigned in a double-blind fashion to 80 mg atorvastatin daily (n=17) versus placebo (n=21), 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 16.81+/-74.10 mm3 in patients taking placebo versus regression of -90.25+/-85.12 mm3 in patients taking atorvastatin (P<0.0001).


CONCLUSIONS
3D plaque volume measurement can show large effects of therapy on atherosclerosis in 3 months in sample sizes of approximately 20 patients per group. Sample sizes of 22 per group would be sufficient to show an effect size of 25% that of atorvastatin in 6 months. This technology promises to be very useful in evaluation of new therapies.
Ainsworth
Craig D
CD
Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, 1400 Western Rd, London, ON, N6G 2V2, Canada.
Blake
Christopher C
CC
Tamayo
Arturo
A
Beletsky
Vadim
V
Fenster
Aaron
A
Spence
J David
JD
D000368:Aged; D000924:Anticholesteremic Agents / Q000627:therapeutic use; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D000069059:Atorvastatin; D001794:Blood Pressure; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D015331:Cohort Studies; D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D005260:Female; D006538:Heptanoic Acids / Q000627:therapeutic use; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D010919:Placebos; D011758:Pyrroles / Q000627:therapeutic use; D012044:Regression Analysis; D012107:Research Design; D012307:Risk Factors; D013997:Time Factors; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
D000924:Anticholesteremic Agents; D006538:Heptanoic Acids; D008055:Lipids; D010919:Placebos; D011758:Pyrroles; D000069059:Atorvastatin