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New-onset postoperative AF associated with long-term risk for thromboembolism
After noncardiac surgery, patients developing new-onset postoperative atrial fibrillation may have long-term risk for thromboembolism similar to patients with nonvalvular AF unrelated to surgery, according to a study published in the Journal of the American College of Cardiology.
“It is well-established that patients with nonvalvular AF carry a fivefold increase of ischemic stroke and systemic embolism,” Jawad H. Butt, MD, of the department of cardiology at Copenhagen University Hospital in Denmark, and colleagues wrote. “However, it is unknown whether new-onset AF secondary to noncardiac surgery differs from [nonvalvular] AF in terms of long-term thromboembolic risk. In addition, data on practice patterns and outcomes associated with use of anticoagulation in new-onset [postoperative] AF are lacking, and international guidelines on the management of patients with AF do not provide new recommendations regarding oral anticoagulation therapy in this setting.”
To investigate the long-term risk for thromboembolism in patients with new-onset postoperative AF — and to compare this risk with patients with nonsurgical nonvalvular AF — researchers conducted a retrospective cohort study of Danish residents aged at least 30 years with no prior history of AF who developed postoperative AF after noncardiac surgery from 1996 to 2015 (n = 3,830; mean age, 77 years; 43% men). These patients were matched by age, sex, HF, hypertension, diabetes, previous thromboembolism, ischemic heart disease and year of diagnosis to a cohort of patients diagnosed with nonvalvular AF after hospitalization (n = 15,320).
Patients were followed up until occurrence of a thromboembolic event, death, emigration or the end of the study period (median of 3.2 years for patients with postoperative AF; median of 3.8 years for patients with nonvalvular AF). During this time, 13% of patients with postoperative AF and 13.6% of patients with nonvalvular AF experienced a thromboembolic event.
Among patients undergoing noncardiac surgery, researchers found that the highest incidences of developing postoperative AF followed thoracic/pulmonary, vascular and abdominal surgery.
Regarding the long-term risk for thromboembolism, patients with postoperative AF experienced an average of 31.7 thromboembolic events per 1,000 person-years and patients with nonvalvular AF experienced 29.9 per 1,000 person-years (HR = 0.95; 95% CI, 0.85-1.07).
Among the cohort, 24.3% of patients with postoperative AF and 41.3% with nonvalvular AF had oral anticoagulation therapy initiated within 30 days after discharge (P < .001), which was associated with lower risk for thromboembolic events in both groups (postoperative AF: HR = 0.52; 95% CI, 0.4-0.67; nonvalvular AF: HR = 0.56; 95% CI, 0.51-0.62) vs. no anticoagulation.
“New-onset [postoperative] AF following noncardiac surgery was associated with a similar long-term thromboembolic risk compared with [nonvalvular] AF,” the researchers wrote. “Although [oral anticoagulation] therapy was associated with a comparably lowered risk of thromboembolic events in patients with [postoperative] AF and [nonvalvular] AF, more studies addressing the role of [oral anticoagulation] therapy in [postoperative] AF in the setting of noncardiac surgery are warranted to examine the efficacy and safety as well as the timing and duration of [oral anticoagulation] therapy.” – by Melissa J. Webb
Disclosures: Butt reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.