Perioperative atrial fibrillation in relation to major emergency abdominal surgery and non-perioperative new onset atrial fibrillation: is there a difference in outcome?
Authors: Tas A , Fosboel E , Vester-Andersen M , Burcharth J , Koeber L , Gundlund A 
Published: November 2023

Abstract

Background
Major emergency abdominal surgery (e.g. ileus, perforation) is relatively common and associated with postoperative complications and mortality. Long-term management of patients with atrial fibrillation (AF) associated with a secondary precipitant has recently received increased attention. It is further unknown whether the conflicting results regarding long-term outcomes in patients with new onset AF depends on surgical subtype or the arrhythmia itself.

Purpose
The aim of this study was to compare long-term clinical outcomes (AF related hospitalization, stroke, and mortality) in patients with perioperative new onset AF in relation to major emergency abdominal surgery and patients with non-perioperative new onset AF.

Methods
We crosslinked data from Danish nationwide registries and identified all patients who underwent major emergency abdominal surgery (2000-2018) and were diagnosed with new onset AF perioperatively, and patients who developed new onset AF in a non-perioperative setting. Patients with new onset perioperative AF were matched in a 1:5 ratio on age, sex and year of AF diagnosis with patients with non-perioperative new onset AF. From discharge, we examined unadjusted rates of outcomes and adjusted hazard ratios of outcomes were assessed using multivariable Cox regression analysis.

Results
The study population comprised 794 (out of 42,021) patients with perioperative new onset AF and 3970 patients with non-perioperative new onset AF (median age of 78 years [interquartile range: 70-83] and 57.3% women in both groups). In general, patients with new-onset perioperative AF had lower comorbid burden compared with patients with non-perioperative new onset AF. During the first month after the hospital admission, 15.0% of the patients with perioperative AF and 36.1% of the patients with new onset AF initiated oral anticoagulation therapy (after 2010, 19.7% and 41.2%, respectively).
Two years after discharge, 3.9% of patients with perioperative AF and 5.8% of patients with new onset AF (p = 0.031) had had a stroke, while 32.9% and 40.1% (p = 0.002) had had a new hospitalization with AF. Cumulative incidences of stroke and AF related hospitalization are depicted in the Figure. In the multivariable models, perioperative AF was associated with a similar rate of stroke and lower rate of AF related hospitalization compared with non-perioperative new onset AF (HR 1.03, 95% confidence interval, CI: 0.54-1.96 for stroke and HR 0.68, 95% CI: 0.50-0.92 for AF related hospitalization, respectively).

Conclusion
Perioperative new onset atrial fibrillation in relation to major emergency abdominal surgery was associated with long-term similar rates of stroke and lower rates of AF related hospitalization compared with new onset atrial fibrillation in the non-perioperative setting. This study demonstrates a need for more knowledge about the progress of atrial fibrillation in the setting of non-cardiac surgery.Cumulative Incidence - strokeCumulative Incidence - AF_re