Oral Anticoagulation Therapy After Radiofrequency Ablation of Atrial Fibrillation and the Risk of Thromboembolism and Serious Bleeding: Long-Term Follow-Up in Nationwide Cohort of Denmark
What are the long-term risks of thromboembolism and major bleeding associated with anticoagulation beyond 3 months after radiofrequency ablation (RFA) of atrial fibrillation (AF)?
Using a nation-wide administrative registry, patients who underwent a first RFA between 2000 and 2011 were identified. The risk of stroke, systemic thromboembolism, and major bleeding was assessed according to use of oral anticoagulant therapy through incidence rates and Cox proportional-hazard models. Age- and gender-matched AF patients (1:4 ratio) were identified who did not undergo RFA, and rates of stroke and systemic thromboembolism along with major bleeding were assessed.
In the 4,050 patients in the registry, median age was 59.9 (interquartile range [IQR], 52.8-65.2), 26.5% were female, and median follow-up was 3.4 years (IQR, 2.0-5.6). Seventy-one (1.8%) patients experienced a stroke or systemic embolism at a rate of 0.56 (95% confidence interval [CI], 0.40-0.78) and 0.64 (95% CI, 0.46-0.89) per 100 person-years for patients with and without use of oral anticoagulation beyond 3 months, respectively. Major bleeding occurred in 87 (2.1%) patients at a rate of 0.99 (95% CI, 0.77-1.27) and 0.44 (95% CI, 0.77-1.27) per 100 person-years for patients with and without use of oral anticoagulation beyond 3 months, respectively. Use of oral anticoagulants was associated with an increased risk of major bleeding (HR, 2.05; 95% CI, 1.25-3.35). In an age- and gender-matched cohort of 15,848 AF patients who did not undergo RFA, thromboembolic rates were 1.34 (95% CI, 1.21-1.49) and 2.14 (95% CI, 1.98-3.35) with and without oral anticoagulant therapy, respectively.
The authors concluded that thromboembolic risk beyond 3 months after RFA was relatively low compared to age- and gender-matched patients who did not undergo RFA.
This analysis adds to the mounting evidence that successful RFA in AF patients dramatically reduces the risk of stroke and systemic embolism. While retrospective analyses cannot definitively establish causation, large nation-wide retrospective analyses, such as the Danish national registry, do provide solid evidence for potential associations. Until randomized data are available, it would be appropriate to discuss withdrawing anticoagulation after 3 months of therapy in AF patients who underwent a successful RFA without AF recurrence, especially in patients at increased risk for anticoagulant-related bleeding.
Keywords: Thromboembolism, Stroke, Follow-Up Studies, Anticoagulants, Atrial Fibrillation, Confidence Intervals, Embolism, Hemorrhage
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