Relation of Hemorrhage and Thrombosis to Prothrombin during Treatment with Coumarin-Type Anticoagulants

Abstract

THE increasing enthusiasm for treating thromboembolic diseases with prothrombin-reducing drugs for long periods in ambulatory patients has emphasized the lack of clear definition of the therapeutic range of anticoagulation. These are now more often older patients with vascular disease who are difficult to manage, sometimes follow instructions poorly and are more prone to bleeding complications than the younger patients, who are usually treated for recurrent phlebitis, pulmonary embolism or peripheral embolism from heart disease.Control of therapy has traditionally been carried on with the "prothrombin-time" test of Quick.∥ This test has proved remarkably satisfactory considering the great variation of opinion . . .