Pharmacological stimulation of fibrinolytic activity in the surgical patient

Postoperative venous thromboembolism and brain tumors: Part III. Biochemical profile

The plasminogen activator activity of 31 human brain tumor samples was assessed and the results correlated with clinical parameters and the postoperative occurrence of venous thrombosis. A significant negative correlation was found between plasminogen activator activity and venous thrombosis (P = 0.02), while positive correlations were observed between plasminogen activator activity and peritumoral brain edema (P = 0.03) and alpha 2 antiplasmin measured in the systemic circulation (P = 0.01). Tissue plasminogen activator was found in higher concentrations in meningioma tissue but did not correlate significantly with the occurrence of venous thrombosis. The results of this study suggest a local enzymatic degradation effect of plasminogen activator on thrombogenic substances present in the brain tumor and/or its environment.

Hemostasis and intracranial surgery

Preoperative and postoperative coagulation studies were performed in 25 patients undergoing various intracranial surgical procedures. Coagulation abnormalities, mostly consisting of an increase of fibrin/fibrinogen degradation product concentration, either appeared or increased postoperatively in 18 patients. This incidence of postoperative appearance or increase of coagulation abnormalities is higher than that reported in a comparable study of patients after general surgical procedures, and also higher than that of coagulation abnormalities in a previous study of patients after blunt head injury. Although the coagulation abnormalities after intracranial surgery were usually small, they tended to be larger in patients with more extensive intracranial procedures.

Surgical hemostasis

Every surgical procedure taxes the hemostatic defenses of the patient. If his hemostatic mechanism is sound, he is unlikely to have a bleeding problem during or after an operation, unless, of course, a suture or clip slips off. Two classes of patients do present bleeding problems to the surgeon. One group has a pre-existing bleeding tendency, the other acquires it during or after the operation. The recognition of patients with severe hemostatic disabilities, such as hemophilia, presents no problem since the patient is aware of the disease. The mild bleeder is less likely to be detected by screening tests than by adroit questioning. The major hemostatic defect that may develop during an operation, or shortly thereafter, is disseminated intravascular coagulation. This syndrome, always secondary, may accompany shock, mismatched blood transfusion, septicemia, or extensive malignancy. Its prevention or early recongnition is much easier than treatment after circulating platelets and some coagulation factors have been consumed and fibrinolysis is destroying fibrin and fibrinogen.

Fibrinolytic activator in the endothelium of the veins of the lower limb

The local fibrinolytic acitivity of the femoral, popliteal and soleal veins has been studied using a histochemical technique. The results suggest that the fibrinolytic activity in the soleal veins may be low when compared with that in the femoral and popliteal veins. This may be an aetiological factor responsible for the high incidence of thrombi occurring in the soleal veins.

Phenformin and ethyloestrenol in recurrent venous thrombosis

Altogether 75 patients, 60 of whom had recurrent idiopathic deep venous thrombosis, 10 recurrent superficial thrombophlebitis and 5 retinal venous thrombosis, were given a combination of 100 mg phenformin and 8 mg ethyloestrenol a day for periods varying between 3 and 48 months (mean 16.2). Initially, all the patients had an abnormally low plasminogen activator content in the walls of superficial veins and/or a decreased capacity to release plasminogen activator from the vein walls on venous occlusion of the arms. The combination elicited a significant increase in the spontaneous fibrinolytic activity and in the local fibrinolytic activity during standardized venous occlusion of the arms (assayed on fibrin plates) after treatment for 3 months (p less than 0.001). These activities then remained normal throughout the observation period. In 65 of the 75 patients studied, the plasminogen activator level in the vein wall (histochemically assayed by the method of Pandolfi) was abnormally low intitially. The level had increased significantly after treatment for 3 months (p less than 0.001). After treatment for 12 months all the patients except 2 were normal. The patients in this material had had 2-20 episodes of venous thrombosis, the most recent 5 years before the institution of treatment, in spite of dicoumarol treatment. During treatment 9 thrombotic episodes occurred; in 5 of these patients the fibrinolytic activity of the vessel wall was not normal at the time of the recurrence. Except in 1 patient, who developed lactic acidosis, the side-effects were not severe.

Postoperative fibrinolytic activity and deep vein thrombosis

The changes in blood fibrinolytic activity, measured by an isotopic method, have been studied in 50 patients following a major surgical operation.

A phase of enhanced fibrinolytic activity occurred at the time of operation. Subsequently no evidence of prolonged depression of fibrinolytic activity was demonstrated.

Patients who developed postoperative deep vein thrombosis, as diagnosed by the 125I fibrinogen technique, exhibited significantly lower fibrinolytic activity on the first postoperative day than patients with no thrombosis (P < 0.01); apart from this the two groups of patients showed no demonstrable difference in fibrinolytic activity in the 7 days after operation.

The use of intra-arterial Urokinase in a case of recurrent arterial occlusion

The present case report describes the use of intraarterial Urokinase in an occlusive episode involving the right radial and ulnar arteries. Details of the case history are given and the choice of thrombolytic therapy, plus its route of administration are discussed.