Measurement of carotid plaque and effect of vitamin therapy for total homocysteine.
BACKGROUND
Many new therapies are being developed that are anti-atherosclerotic, but which do not change clinical parameters such as blood pressure or cholesterol. In order to measure the effects of these therapies it will be necessary to measure atherosclerosis. Elevated levels of plasma total homocysteine (tHcy) are associated with increased risk of stroke and myocardial infarction. Measurement of the effect of vitamin therapy on atherosclerosis has therefore been used as an example of this approach.


METHODS
2-Dimensional measurement of carotid plaque cross-sectional area has been used to measure effects of vitamin therapy in patients whose plaque is progressing despite intensive treatment of traditional risk factors. In clinic patients, addition of vitamin therapy halted progression of atherosclerosis, in samples of 50 patients over 2.5 years. However, in patients randomized to high-dose vs. low-dose vitamins in the Vitamin Intervention for Stroke Prevention trial, no difference in plaque progression was seen between high-dose and low-dose vitamin therapy. New methods have been developed for the measurement of 3-dimensional plaque volume, and for the measurement of plaque surface roughness.


RESULTS
The accuracy and reliability of the measurement of plaque volume is 95%. This will permit measurement of effects of new anti-atherosclerotic therapies with much smaller sample sizes, in a much shorter time, than previously available methods such as intima-media thickness.


CONCLUSIONS
Measurement of atherosclerotic plaque volume and roughness will greatly enhance the study of new anti-atherosclerotic therapies.
Spence
J David
JD
Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, London, ON, Canada. dspence@robarts.ca
Blake
Christopher
C
Landry
Anthony
A
Fenster
Aaron
A
D000368:Aged; D016893:Carotid Stenosis / Q000097:blood / Q000000981:diagnostic imaging* / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D005492:Folic Acid / Q000008:administration & dosage / Q000627:therapeutic use; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D021621:Imaging, Three-Dimensional; D015203:Reproducibility of Results; D020521:Stroke / Q000097:blood / Q000517:prevention & control*; D014463:Ultrasonography; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000627:therapeutic use; D025101:Vitamin B 6 / Q000008:administration & dosage / Q000627:therapeutic use; D014815:Vitamins / Q000008:administration & dosage / Q000627:therapeutic use*
D014815:Vitamins; D006710:Homocysteine; D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12