Bleeding during oral anticoagulant therapy: warning against a greater hazard.

BACKGROUND: Bleeding is one of the main concerns in patients undergoing oral anticoagulation therapy.

OBJECTIVE: To investigate the determinant causes of bleeding in patients undergoing oral anticoagulant therapy.

METHODS: A total of 360 patients with atrial fibrillation (AF) undergoing oral anticoagulant (ACo) therapy, with a target INR of 2.0-3.5, were followed prospectively for a period of 48 +/- 7.2 months. The patients were evaluated on average every 30 days and were investigated regarding the presence of associated pathology that could lead to bleeding.

RESULTS: A total of 338 patients participated in the present study. Of these, 210 (62.13%) were females. Mitral stenosis was present in 218 patients (64.4%), a mitral biological prosthesis in 64 (18.9%) and mitral valve failure in 56 (16.5%) patients. Bleeding occurred in 65 patients (19.2%), being severe in 7 (10%) patients. In 38/65 patients, a new associated disease was identified, which facilitated bleeding. An associated disease was identified in 100% of the patients with bleeding within the therapeutic range, against 49.05% of associated disease diagnosis in those with an INR > 3.5 (p=0.001).

CONCLUSION: The diagnosis of a local disease associated to the bleeding was frequent among those patients undergoing oral anticoagulant therapy (58.5%). There was an association between bleeding with an INR within the therapeutic range (INR=2.0-3.5) and the diagnosis of a pathology predisposing to bleeding (p<0.001). It is mandatory to investigate the cause of bleeding in patients undergoing oral anticoagulant therapy, especially if the INR is within the therapeutic range.