AN INVESTIGATION OF THE HEMORRHAGIC DIATHESIS IN PATIENTS RECEIVING COUMARIN AND INDANEDIONE ANTICOAGULANTS.

Coagulation studies were carried out on 10 patients who bled during anticoagulant therapy, in whom no other underlying cause for bleeding could be demonstrated, and 10 patients with similar degrees of hypoprothrombinemia who were not bleeding. The average age and sex distribution of the two groups was similar, and no association was noted between the occurrence of hemorrhage and the type of anticoagulant used, the duration of treatment or the nature of the underlying disease. Comparison of the results revealed no differences in the levels of factors II, VII, IX and X or in the glass and silicone (Siliclad) clotting time, the thromboplastin generation test and Thrombotest. It was concluded that all patients on anticoagulant drugs whose prothrombin time is in the therapeutic range or longer are potential bleeders and that one cannot necessarily predict those who will bleed on the basis of coagulation studies.