Abstract: Objective: To investigate the occurrence of adverse cardiovascular events in elderly patients with atrial fibrillation (AF) during anticoagulation with warfarin. Methods: One hundred and eight older patients (80 years or older) taking warfarin for AF were enrolled. According to the value of international normalized ratio (INR), patients were divided into 2 groups, low intensity warfarin group (INR between 1.40 and 1.80, n=52) and moderate intensity warfarin group (INR between 1.81 and 2.50, n=56), and effects and safety were compared. All patients were followed up for (1.8±1.2) years. The major end point events included the occurrence of ischemic stroke or systemic embolism;the secondary endpoint events included non-fatal myocardial infarction and all causes of death. The safety endpoint events included the occurrence of the mild, severe and fatal hemorrhage. Results: Embolism occurred in 3 patients (5.36%) in moderate intensity warfarin group and in 6 patients (11.54%) in low intensity warfarin group (all were cerebral stroke); the difference was statistically significant. Conjunctival and nasal hemorrhage occurred in 2 patients in low intensity warfarin group and in 3 patients in moderate intensity warfarin group; no severe hemorrhage was seen in all the patients. No significant difference in hemorrhagic rate was seen between the low intensity and moderate intensity warfarin groups (P>0.05). Conclusions: The INR ranged from 1.81-2.50 is safe for elderly patients with atrial fibrillation treated with warfarin for anticoagulation.

Key words: Atrial fibrillation, Warfarin, Elder, Safety