Exhaustion of arm fibrinolytic potential after repeated venous occlusions and local exercise.

The effect of repeated venous occlusions of the arm combined with local exercise was assessed in 10 healthy volunteers. The blood was drawn before and after three venous occlusions of 20 minutes. Between occlusions I - II, and II - III, twelve occlusions of 10 minutes were performed on the same arm while a small rubber ball was compressed 30 times per minute. Plasminogen activator (PA) activity was measured on plasminogen rich fibrin plates and by the euglobulin clot lysis time. A high increase in PA activity after venous occlusion (fibrinolytic potential) was present in all three occlusions on the first day, but fell to a very low level on the fourth day. The restitution of potential followed, but was not complete even on fifteenth day. These results indicate that PA continues to be released even after the termination of stimulation and can be temporarily depleted some days afterwards. An increase of fibrin(ogen) degradation products together with a slight decrease of alpha-2-antiplasmin in postocclusion samples, but no change in fibrinogen concentration speak in favour of a small fibrin(ogen)olysis during venous occlusion.