Physical activity during daily life and brachial artery flow-mediated dilation in peripheral arterial disease

We determined whether higher levels of physical activity in daily life are associated with better brachial artery flow-mediated dilation (FMD) among individuals with lower extremity peripheral arterial disease (PAD). Participants were 111 men and women with PAD (ankle-brachial index (ABI) ≤ 0.95) who completed baseline testing in the Study to Improve Leg Circulation (SILC). We evaluated FMD of the brachial artery at baseline and at 60 seconds following 4 minutes of suprasystolic blood pressure cuff inflation. Physical activity was measured continuously over 7 days using a vertical accelerometer (Caltrac) and a pedometer (Digiwalker). Adjusting for age, sex, race, ABI, cardiovascular risk factors and other potential confounders, higher levels of physical activity were associated with a greater percent change in brachial artery FMD at 60 seconds post cuff deflation for both Caltrac (1st tertile of activity +4.81% change; 2nd tertile +4.60% change; 3rd tertile +7.23% change; p-trend = 0.018) and the Digiwalker (1st tertile of activity +3.76% change; 2nd tertile +6.25% change; 3rd tertile +7.25% change; p-trend = 0.001). Similar findings were observed for absolute change in brachial artery FMD 60 seconds after cuff deflation. In conclusion, higher levels of physical activity during daily life are associated significantly and independently with better brachial artery FMD among individuals with PAD, even after adjusting for confounders.