Risk of Thromboembolism Associated With Atrial Fibrillation Following Noncardiac Surgery
Key result
Postoperative AF after noncardiac surgery carries similar thromboembolism risk to nonsurgical NVAF.
- HR 0.95
- 95% CI 0.85-1.07
- n=19,150
Why the study?
The long-term risk of thromboembolism in patients developing new-onset post-operative atrial fibrillation following noncardiac surgery was unknown, and data on stroke prophylaxis in this setting were lacking.
Does new-onset post-operative atrial fibrillation following noncardiac surgery increase the long-term risk of thromboembolism compared to nonsurgical nonvalvular atrial fibrillation, and does oral anticoagulation therapy reduce this risk?
Key Points
- To assess the long-term risk of thromboembolism and the potential benefit of oral anticoagulation therapy in patients developing new-onset postoperative atrial fibrillation (POAF) following noncardiac surgery relative to nonsurgical nonvalvular atrial fibrillation (NVAF).
- Using Danish nationwide registries (1996–2015), 3,830 patients with new-onset POAF after noncardiac surgery were matched 1:4 with 15,320 nonsurgical NVAF patients by age, sex, comorbidities, and diagnosis year.
- Comparative long-term risks of thromboembolism and effects of oral anticoagulation therapy were analyzed using multivariable Cox regression models.
- POAF occurred in 6,048 (0.4%) noncardiac surgery patients during hospitalization, and oral anticoagulation was initiated within 30 days post-discharge in 24.3% of POAF patients versus 41.3% of NVAF patients (p < 0.001).
- Long-term thromboembolism risk was similar between matched cohorts, with 31.7 events per 1,000 person-years in POAF versus 29.9 in NVAF (HR: 0.95; 95% CI: 0.85 to 1.07).
Study Design
Type
Cohort (n=19,150)
Multicenter
Yes
Structured PICO
Does new-onset post-operative atrial fibrillation following noncardiac surgery increase the long-term risk of thromboembolism compared to nonsurgical nonvalvular atrial fibrillation, and does oral anticoagulation therapy reduce this risk?
P
Population
19,150 Danish patients (3,830 with new-onset post-operative atrial fibrillation following noncardiac surgery matched 1:4 with 15,320 nonsurgical, nonvalvular atrial fibrillation patients) from 1996 to 2015.
E
Exposure
New-onset post-operative atrial fibrillation (POAF) following noncardiac surgery (exposure); oral anticoagulation therapy during follow-up was also evaluated as an exposure.
C
Comparator
Nonsurgical, nonvalvular atrial fibrillation (NVAF) matched 1:4 by age, sex, heart failure, hypertension, diabetes, previous thromboembolism, ischemic heart disease, and year of diagnosis; no anticoagulation therapy served as comparator for the anticoagulation analysis.
O
Outcome
Long-term risk of thromboembolismhard clinical
Main Result
Hazard Ratio: 0.95 (95% CI 0.85–1.07)
Absolute Event Rate: 31.7% vs 29.9%
New-onset post-operative atrial fibrillation following noncardiac surgery carries a long-term thromboembolic risk comparable to nonsurgical nonvalvular atrial fibrillation, and oral anticoagulation is similarly associated with lower thromboembolic risk in both populations.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“These data support that new-onset postoperative A-fib should be regarded as primary nonvalvular A-fib in terms of long-term thromboembolic risk. The question remains whether these patients should initiate oral anticoagulant therapy for the prevention of thromboembolic events.”
ABAnne B. CurtisCardiologist, Jacobs School of Medicine, Buffalo
“The similarity in outcomes indicates that we should likely consider that a diagnosis of A-fib... indicates a risk of future thromboembolic events that needs to be managed with anticoagulation, and that ‘transient’ A-fib is a misnomer.”
Implication
POAF after noncardiac surgery was associated with thromboembolism risk similar to NVAF; leaves open whether anticoagulation should be routinely considered.
Abstract
BACKGROUND The long-term risk of thromboembolism in patients developing new-onset post-operative atrial fibrillation (POAF) following noncardiac surgery is unknown, and data on stroke prophylaxis in this setting are lacking. OBJECTIVES The purpose of this study was to assess the long-term risk of thromboembolism in patients developing new-onset POAF following noncardiac surgery relative to patients with nonsurgical, nonvalvular atrial fibrillation (NVAF). METHODS Using Danish nationwide registries, the authors identified all patients who developed POAF following noncardiac surgery from 1996 to 2015. These were matched by age, sex, heart failure, hypertension, diabetes, previous thromboembolism, ischemic heart disease, and year of diagnosis to patients with nonsurgical NVAF in a 1:4 ratio. Comparative long-term risk of thromboembolism was examined by multivariable Cox regression models. RESULTS In patients undergoing noncardiac surgery, 6,048 (0.4%) developed POAF during hospitalization, with the highest incidences following thoracic/pulmonary, vascular, and abdominal surgery. A total of 3,830 patients with POAF were matched with 15,320 patients with NVAF. Oral anticoagulation therapy was initiated within 30 days post-discharge in 24.3% and 41.3% of these patients, respectively (p value <0.001). The long-term risk of thromboembolism was similar in patients with POAF and NVAF (31.7 events vs. 29.9 events per 1,000 person years; hazard ratio [HR]: 0.95; 95% confidence interval [CI]: 0.85 to 1.07). Anticoagulation therapy during follow-up was associated with a comparably lowered risk of thromboembolic events in patients with POAF (HR: 0.52; 95% CI: 0.40 to 0.67) as well as NVAF (HR: 0.56; 95% CI: 0.51 to 0.62) compared with no anticoagulation therapy. CONCLUSIONS New-onset POAF following noncardiac surgery was associated with a long-term risk of thromboembolism similar to NVAF.
Discussion
No takes yet. Share an insight, caveat, or question.
Cite This Study
Butt et al. (2018) conducted a cohort in New-onset post-operative atrial fibrillation following noncardiac surgery (n=19,150). New-onset post-operative atrial fibrillation following noncardiac surgery vs. Nonsurgical, nonvalvular atrial fibrillation was evaluated on Long-term risk of thromboembolism (HR 0.95, 95% CI 0.85-1.07). New-onset POAF after noncardiac surgery had a similar long-term thromboembolism risk as nonsurgical NVAF (31.7 vs 29.9 per 1,000 person-years; HR 0.95; 95% CI 0.85-1.07).