A Retrospective Observational Study of Anticoagulation Practices in Critically ill Patients with Atrial Fibrillation Admitted to the Intensive Care Unit

Abstract

Background: Atrial Fibrillation (AF) is the most common arrhythmia in critically ill patients. AF precipitates thromboembolic (TE) events. International guidelines recommend long-term anticoagulation for AF patients dependent upon the risk of TE versus major bleeding events. The CHA₂DS₂VASc and HAS-BLED scores are used to calculate these risks, but have not been validated in intensive care. Little is known about the risk/benefit ratio of prescribing anticoagulation to patients with AF in the intensive care setting.

Methods: This observational study included patients who were admitted to intensive care and had AF episodes during admission. We aimed to 1) describe the anticoagulation strategies used in critically ill patients with AF, 2) determine the percentage of patients who received guideline-compliant anticoagulation and 3) compare anticoagulation strategies in patients with new onset AF (NOAF) and known AF. Demographic data was extracted from electronic health records. Therapeutic anticoagulation prescribed during AF episodes and outcomes were collected. CHA₂DS₂VASc and HAS-BLED scores were calculated and correlated with TE and bleeding events.

Results: The incidence of AF in our cohort was 13.8%. Anticoagulation was administered in 34.0% of patients. Anticoagulation use did not affect morbidity or mortality outcomes. Patients with pre-existing AF were anticoagulated more often compared to patients with NOAF. CHA₂DS₂VASc scores and TE events, and HAS-BLED scores and bleeding events did not correlate well.

Conclusion: AF is common in critical care. Current guidelines on anticoagulation in AF may not be directly transferable to the critical care setting.

Keywords: anticoagulation; atrial fibrillation; critically ill patients; intensive care unit.