Effects of exercise training on fibrinolytic function in individuals with peripheral arterial disease.

Endogenous fibrinolysis is a physiological mechanism in removal of stable fibrin in blood clot and maintaining vascular blood flow. There has been evidence suggesting that the severity of intermittent claudication in patients with peripheral arterial disease (PAD) is associated with impaired endogenous fibrinolytic activity as compared to healthy controls. Cross-sectional studies also found that patients with PAD who have a higher level of daily physical activity usually have a higher fibrinolytic function. The purpose of the present study was to examine whether a 12-week supervised exercise training would affect fibrinolysis in patients with PAD. This study has two stages, the first 12-week was a nonexercise control stage and the second 12-week was an exercise training stage. Seventeen patients were recruited, with average age (+/-SD) of 71.4+/-7.9 years, resting ankle-to-brachial index (ABI) 0.61+/-0.13 and post-exercise ABI 0.41+/-0.22, at the baseline. Fasting blood samples were analyzed for the activities of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1), using a bio-functional immunosorbent assay (BIA). Although the walking capacity was increased significantly after 12 weeks of training (p<0.01), the activities of t-PA (pre 1.04+/-0.68, post 0.93+/-0.71 UI/ml), and PAI-1 (pre 18.43+/-17.19, post 23.08+/-20.01 UI/ml) did not show significant changes. The results suggest that 12 weeks of supervised exercise training did not increase, while there was a trend of decrease in the resting fibrinolytic function in this group of patients. The reason of this change needs to be studied in the future.