The morbidity related to atrial fibrillation at a tertiary centre in one year: 9.0% of all strokes are potentially preventable

Abstract

Atrial fibrillation is a major risk factor for stroke. Anticoagulant therapy reduces this risk but increases the risk of haemorrhage. We aimed to compare the morbidity related to the treatment of atrial fibrillation with warfarin seen in one year at our hospital, with the morbidity in those patients in whom embolism was potentially preventable. There were 111 patients admitted to our hospital in a 12 month period with nonvalvular atrial fibrillation (NVAF) who had stroke, TIA or peripheral embolism. Atrial fibrillation was identified prior to admission in 87 of these 111 (78%) patients with thromboembolism, yet only 14 of these (16%) were receiving warfarin for stroke prophylaxis. Through chart review, a further 56 (64%) patients with embolism could have been receiving anticoagulant therapy if published clinical guidelines(1) were applied. Therefore, 40 episodes of thromboembolism were potentially preventable. Over the same period, there were 18 patients admitted with haemorrhage related to warfarin therapy for stroke prophylaxis in NVAF, including 10 gastrointestinal, five intracerebral, and three peripheral haemorrhages. Most haemorrhages were associated with a high International Normalized Ratio (INR) and the patients were left less disabled than those with embolism. Only one patient with haemorrhage had an absolute contraindication to warfarin therapy (6%). We conclude that the number of preventable strokes far outweighed the morbidity due to warfarin use in the management of NVAF.