Prognosis and antithrombotic practice patterns in recurrent and transient atrial fibrillation following acute coronary syndrome: a nationwide study
Authors: Petersen J , Butt J H , Yafasova A , Torp-Pedersen C , Soerensen R , Kruuse C , Vinding N E , Gundlund A , Koeber L , Fosboel E L , Oestergaard L 
Published: October 2022

Abstract

Background
First-time detected atrial fibrillation (AF) during acute coronary syndrome (ACS) aggravates the prognosis and increases the risk of ischemic stroke. In this setting, AF may present as brief and transient or with recurrent episodes after discharge. However, data on the association between transient or recurrent AF and ischemic stroke in patients with ACS are sparse. Further, despite being associated with ischemic stroke, first-time detected AF patients have been reported with low oral anticoagulation (OAC) rates.

Purpose
To examine the associated rate of ischemic stroke and mortality in ACS survivors with transient or recurrent AF and to assess the antithrombotic practice patterns one year after ACS.

Methods
Using data from Danish nationwide registries, we identified all patients with first-time ACS, without known AF prior to ACS, from 2000–2017 who were alive one year after ACS discharge (index date). According to a grace period between ACS discharge and one year after ACS discharge, patients were categorized into: i) no AF; ii) first-time detected AF during ACS admission without AF recurrence (transient AF); and iii) first-time detected AF during ACS admission with a subsequent recurrent AF episode (recurrent AF). Patients who developed AF during the grace period were excluded. Patients were followed from one year post ACS discharge, and two-year rates of ischemic stroke and mortality were compared using multivariable adjusted Cox proportional hazards analysis. Further, we assessed the prescribed OAC rates in a three-month period following the index date.

Results
We included 116,793 patients surviving one year post ACS discharge: 111,708 (95.6%) without AF (64.9% male, median age 64 years), 2,671 (2.3%) with transient AF (58.0% male, median age 74 years), and 2,414 (2.1%) with recurrent AF (55.2% male, median age 76 years). The cumulative two-year incidence of ischemic stroke was 0.9%, 1.5%, and 2.3% for patients without AF, transient AF, and recurrent AF, respectively (Figure 1). The cumulative two-year incidence of mortality was 7.4%, 12.1%, and 20.3% for patients without AF, transient AF, and recurrent AF, respectively (Figure 1). Compared to those without AF, the adjusted two-year rates of outcomes were as follows: ischemic stroke: HR 1.15 (95% CI: 0.81–1.61) for patients with transient AF and HR 1.50 (95% CI: 1.14–1.98) for patients with recurrent AF; mortality: HR 0.98 (95% CI: 0.87–1.10) for patients with transient AF and HR 1.35 (95% CI: 1.23–1.49) for patients with recurrent AF (Figure). We identified that 20.9% for transient AF and 42.2% for recurrent AF were prescribed OAC therapy in the three-month period after one year.

Conclusion
In patients surviving one year after ACS with first-time detected AF, a recurrent AF episode was associated with an increased long-term rate of ischemic stroke and mortality, while transient AF yielded no statistically difference as compared with patients without AF.

Funding Acknowledgement
Type of funding sources: None.