New-onset atrial fibrillation developed after noncardiac surgery is associated with a long-term risk of thromboembolism that is similar to nonsurgical nonvalvular atrial fibrillation, according to a study published in the Journal of the American College of Cardiology.

To assess the long-term thromboembolism risk for patients who develop new-onset atrial fibrillation after noncardiac surgery vs patients with nonsurgical and nonvalvular atrial fibrillation, researchers used multivariable Cox regression models to analyze Danish nationwide registry data from 1996 to 2015. They compared data on patients developing postoperative atrial fibrillation to data on patients with nonsurgical atrial fibrillation matched by sex, age, hypertension, diabetes, ischemic heart disease, heart failure, previous thromboembolism, and year of diagnosis in a 1:4 ratio.

Of the patients with no history of atrial fibrillation who received noncardiac surgery (n=1,520,109), 0.4% (n=6048) developed postoperative atrial fibrillation, with the highest incidences seen in patients receiving abdominal, vascular, and thoracic/pulmonary surgery.

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For the purposes of the study, 3830 of these patients were matched with 15,320 patients with nonsurgical and nonvalvular atrial fibrillation. Of the patients with postoperative atrial fibrillation, 24.3% initiated oral anticoagulation therapy within 30 days of discharge, compared with 41.3% of patients with nonsurgical and nonvalvular atrial fibrillation (P <.001).

Similar rates of long-term thromboembolism risk were seen in both groups (31.7 events per 1000 person years in postoperative atrial fibrillation group vs 29.9 events in nonsurgical atrial fibrillation group; HR, 0.95; 95% CI, 0.85-1.07).

Use of anticoagulation therapy was associated with a similarly lowered thromboembolic risk in patients with postoperative atrial fibrillation and nonsurgical atrial fibrillation compared with no anticoagulation therapy (HR, 0.52; 95% CI, 0.40-0.67 vs HR, 0.56; 95% CI, 0.51-0.62).

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Study investigators conclude that “[n]ew-onset POAF following noncardiac surgery was associated with a similar long-term thromboembolic risk compared with NVAF. Although OAC therapy was associated with a comparably lowered risk of thromboembolic events… more studies addressing the role of OAC therapy in POAF in the setting of noncardiac surgery are warranted.”


Butt, JH, Olesen JB, Havers-Borgersen E, et al. Risk of thromboembolism associated with atrial fibrillation following noncardiac surgeryJ Am Coll Cardiol. 23 Oct. 2018. doi: 10.1016/j.jacc.2018.07.088.