Exercise in claudicants is associated with systemic fibrinolysis

Background: Claudicants have been shown to mount a potentially harmful systemic inflammatory response to exercise, characterized by vascular endothelial activation and thrombin generation. However, the fibrinolytic response to exercise remains unknown. This study aimed to determine the nature of the fibrinolytic response to exercise in claudicants and normal controls. Methods: Peripheral venous blood was drawn from 18 claudicants and eight age- and sex-matched controls before, immediately and 1, 5, 10, 20, 40 and 60 min after treadmill exercise (Gardner protocol). Claudicants exercised to the point of maximal ischaemic pain and controls to the point of fatigue. Plasma tissue plasminogen activator (tPA) activity and plasminogen activator inhibitor (PAI) 1 activity were measured by ‘Coaset’ PAI and ‘Coatest’ tPA assays (Chromogenix, Sweden). Results: There was no significant difference in tPA or PAI-1 activity between the groups at baseline. tPA activity increased significantly immediately after exercise in all claudicants (median (interquartile range) 2·8 (1·6–4·0) versus 5·6 (3·5–7·7) units ml−1; P = 0·003, Wilcoxon test) and remained significantly raised for 10 min. This was accompanied by an immediate significant fall in PAI-1 activity (8·5 (4·3–12·7) versus 8·3 (5·0–11·6) units ml−1; P = 0·04) which normalized by 10 min. Neither tPA activity or PAI-1 levels changed significantly in the control group. Conclusion: These data indicate that exercise in claudicants is associated with systemic fibrinolysis. The immediacy and short-lived nature of the response suggests that it occurs as a consequence of muscle ischaemia rather than reperfusion. © 2000 British Journal of Surgery Society Ltd