The study assessed brachial artery reactivity among 100 CAD subjects and 100 controls who had been previously enrolled in a study of the relationship between extracranial intima media thickness (ECIMT) as assessed by B mode ultrasonographic measurements and CAD status. Most subjects had three consecutive B mode measurements at 12 month intervals. These subjects had brachial artery reactivity measurements according to a standardized protocol. Linear regression analysis was used to relate brachial artery reactivity to CAD status, gender and risk factors as predictors. Interaction effects were also assessed between CAD status and other risk factors and also between gender and other risk factors. Similar analyses were performed to relate percent dilation to ECIMT measurements.