Reasons and Consequences of Vitamin K Antagonists Discontinuation in Very Elderly Patients with Non-Valvular Atrial Fibrillation

Anticoagulation in elderly patients with non-valvular atrial fibrillation (NVAF) is still a challenge and suspension of warfarin is common. Aim of this study is to analyse the aspects related to warfarin discontinuation in a real world population.This was an observational cohort study on Very Elderly NVAF patients naïve to warfarin therapy (VENPAF). Included subjects were at least 80 years old and started warfarin after NVAF diagnosis. Warfarin discontinuation was assessed and reason reported for discontinuation, person who decided to stop treatment, subsequent antithrombotic therapy and mortality, ischemic and bleeding events were collected. During five years, 148 of 798 patients discontinued warfarin. Despite similar CHA2 DS2 -VASc score, thromboembolic and major bleeding events were significantly higher (p=0.01 and p=0.001, respectively) and time in therapeutic range (TTR) significantly lower (p<0.001) in patients who discontinued warfarin. Independent risk factors for warfarin discontinuation were vascular disease (HR 2.5, p<0.001), 85 years of age or older (HR 1.4, p=0.04), TTR <60% (HR 1.8, p=0.001) and bleeding events (HR 2.3, p<0.001). Main reasons for warfarin discontinuation were physician perceived frailty or low life expectancy (45.9%), bleeding complications (19.6%) and sinus rhythm restoration (16.9%). Event rate and deaths were very high especially in frail patients and in those with bleeding complications. Discontinuation of warfarin is frequent in very elderly patients and is associated to increased risk of death and adverse events. Identification of elderly patients at high risk of bleeding and poor quality of anticoagulation during warfarin is still an unmet clinical problem.