La INR durante los ictus y las hemorragias en pacientes con fibrilación auricular tratados con antagonistas de la vitamina K

Abstract

Introduction and objectivesAtrial fibrillation has a poor prognosis, mainly due to the occurrence of cardioembolic stroke. Despite the use of anticoagulants some patients can develop stroke as well as severe bleeding. Treatment with vitamin K antagonists is usually controlled by means of the international normalized ratio (INR). The aim of this study was to investigate the incidence of stroke and major bleedings, as well the values of INR and the time in therapeutic range within the previous 6 months during these events. MethodsThe study included 1483 patients with atrial fibrillation treated with vitamin K antagonists for at least 6 months prior to inclusion, consecutively recruited from June 2013 to October 2014, with a median follow-up of 32.4 months. Those patients admitted due to an episode of stroke or severe bleeding were identified, and an analysis was performed on the INR values obtained for each episode. ResultsThere was a total of 40 strokes (1.07/100 patients/year) and 120 severe bleedings (3.28/100 patients/year) during the study period. The mean INR value during stroke episodes was 2.33±0.59, and during severe bleeding 3.17±1.48, with 57.5% of patients having had an INR of 2-3 during strokes, and 48.3% during bleedings. Patients with an INR out of range during the stroke had a time in therapeutic range lower than those with an INR between 2 and 3 during the event (49.2±20.8% vs. 68.8±19.4%; P=.043). ConclusionsMore than 50% of strokes and almost 50% of severe bleedings occur with ‘adequate’ (2 to 3) INR values. Changes in the anticoagulation strategy seem to be necessary to decrease this high rate of severe events.