The combined use of fibrinolytic and anticoagulant agents: Laboratory and clinical considerations ∗

Abstract

The therapeutic goal in thromboembolism includes not only clot dissolution but also the maintenance of vascular patency. Clinical and experimental evidence, as well as theoretic considerations, suggest that a sequence of clot dissolution followed by a recurrence of thrombosis may occur when fibrinolytic therapy is relied upon exclusively. Concomitant use of anticoagulant drugs appears to offer the best current method for avoiding this sequence. Heparin, because of its mechanism of action, prompt onset of effect and easy reversibility, seems to provide the most desirable anticoagulant supplement to fibrinolytic therapy. To insure that no increased hemorrhagic risk attends this combined thrombolytic-anticoagulant program, the dosage-response characteristics of each type of fibrinolytic agent should be accurately defined. Evidence suggesting antagonism between thrombolytic and anticoagulant agents in vivo has not been encountered but several aspects of this problem require further study. Failure to provide protection against a recurrence of thrombosis after initial fibrinolytic therapy can not only lead to misinterpretation of experimental data regarding the efficacy of fibrinolytic drugs but also may prevent attainment of optimum clinical results in man. While further development of fibrinolytic agents may obviate or alter the need for combination therapy, the concurrent use of fibrinolytic and anticoagulant drugs appears to provide the optimum therapeutic approach to thromboembolism at the present time.