(1783) Anticoagulation Initiation for New-Onset Atrial Fibrillation in Critical Illness

Introduction: New onset Atrial fibrillation (NOAF) related to critical illness is associated with poor prognosis. Recent evidence showed that NOAF in intensive care units (ICU) has a high risk of atrial fibrillation (AF) recurrence and AF-related complications. Currently, the data are insufficient regarding the estimates of stroke risk reduction and the safety of anticoagulation (AC) used for NOAF in the ICU. Our study aimed to determine the safety of lifelong AC initiation in critically ill patients with NOAF.

Methods: A multicenter, retrospective cohort study was conducted at four hospitals in Saudi Arabia from January 1, 2018, to February 28, 2024. The study included critically ill adult patients aged 18 years and older with documented NOAF during ICU admission. The study excluded patients on full AC at baseline and patients with pre-existing AF. Patients were divided into two groups: those who received anticoagulation (AC group) and those who did not (non-AC group). Study endpoints included the rate of bleeding or thrombotic events, 30-day mortality, and documented recurrent AF during 1-year follow-up.

Results: A total of 179 patients were included, 52.51% and 47.49% in AC and non-AC group, respectively. The mean age was 68.1 ± 13.4 years, and 54.8% were male. The median CHA2DS2-VASc and HAS-BLED scores were 3 [2-4] and 2 [2-4], respectively. The mean APACHE II score was (19.1 ± 6.8 vs. 23.8 ± 9.4, P= 0.0002) in AC and non-AC group, respectively. The rate of bleeding event was (21.3% vs. 21.2%; P= 0.9869); The rate of Thrombotic event was (2.1% vs. 5.9%; P= 0.2592); The 30-day mortality rate was (41.5% vs. 68.2%;P = 0.0003); Recurrent AF episodes within one year of follow-up occurred in (25% vs. 14.4%; P=0.0571) of AC and non-AC groups, respectively. The multivariable analysis found that history of bleeding and use of propylactic AC were factors associated with bleeding; while APACHE II score and bleeding event within 1 year of NOAF onset were associated with 30-day mortality.

Conclusions: The study showed no statistically significant differences in bleeding and thrombotic events between critically ill patients with NOAF who received anticoagulation and those who did not receive anticoagulation within one year of follow-up. However, bleeding events and severity of illness were associated with mortality.