BLEEDING COMPLICATIONS IN ORAL ANTICOAGULATION

Five selected case reports of patients suffering from rather unusual b leeding complications during oral anticoagulant therapy are presented. The reported frequency of bleeding during oral anticoagulation varies greatly. An inacceptably high incidence of hemorrhages has been repor ted in North American studies of the early 1980ies. The therapeutic ta rget INR of 2.5-4.9 in these series is comparable to that in European studies where bleeding occurred much less frequently. We suggest that the insensitive thromboplastin reagents used in North America are unsu ited to guide coumarin dosage, because too many prothrombin time value s were outside the INR target range. In contrast, most prothrombin tim e values in European studies where a sensitive thromboplastin reagent was used, were within the target range. A recent prospective investiga tion by 25 Swiss practitioners showed an acceptably low bleeding compl ication rate (2.1 hemorrhagic complications severe enough to necessita te hospitalization per 100 patient years). Observation of contraindica tions, regular control of the prothrombin time using a sensitive and c orrectly calibrated thromboplastin, participation of practitioners and hospital laboratories at quality control exercises and consideration of drug interferences with coumarins help to reduce the incidence of h emorrhagic side effects. In case of either a PT value outside the targ et range or manifest bleeding, the necessary measures have to be tailo red to the individual situation considering the Quick value as well as the severity and localization of hemorrhage.