Carotid artery reactivity to isometric hand grip exercise identifies persons at risk and with coronary disease

Background: The change in brachial artery diameter (DBAd) following release of an occluding cuff (BAOcclR) has been used to characterize local endothelial function and coronary risk. We designed a study to determine the CA diameter (CAd) response to exercise (IHG), whether the response is influenced by coronary risk, and compare it with the BAOcclR method. Method and Results: High resolution ultrasound was used to detect the DCAd in response to120 s of 33% of maximum and DBAd was measured 60 s following release of an occluding cuff. There was no change in CAd during IHG. At 90 s following release, CAd dilated >0.1 mm in 95% of volunteers with average risk (mean 0.42±0.25 mm or 5.97±3.5%). There was no change or constriction in 62% of high risk (0.01±0.28 mm, 0.0±3.6%), and predominantly constriction in CAD subjects (−0.22±0.23 mm, −0.01±3.2%), P=0.0001 for trend and 0.01 between groups. The %DCAd following IHG and %DBAd following OcclR were highly correlated, r=0.66, P=0.0001. The major determinant of response to each stressor was group (%DBAdR2=0.55 and %DCAdR2=0.52). Conclusions: The reactivity of the carotid artery to IHG is highly influenced by coronary risk, and may be an additional modality to characterize pre-clinical CAD and assess treatment strategies.