What influences the bleeding risk of long-term anticoagulation after catheter ablation in patients with atrial fibrillation at high risk of thromboembolism?

This commentary refers to ‘Oral anticoagulation after atrial fibrillation catheter ablation: benefits and risks’, by K. Kanaoka et al., https://doi.org/10.1093/eurheartj/ehad798 and the discussion piece ‘Oral anticoagulant use after catheter ablation for atrial fibrillation based on thrombo-embolic risk: future studies will be needed for bleeding high-risk group’, by K. Kanaoka and Y. Iwanaga, https://doi.org/10.1093/eurheartj/ehae389. Current guidelines recommend systemic anticoagulation for at least 2 or 3 months after atrial fibrillation (AF) catheter ablation, and long-term continuation of systemic anticoagulation should be based on the patient’s stroke risk profile.1,2 Recently, Kanaoka et al.3 included 231 374 patients from the Japanese nationwide administrative claims database who underwent catheter ablation for AF and evaluated the association between continuation of oral anticoagulant (OAC) therapy 6 months after a first AF catheter ablation and thrombo-embolic and bleeding events according to the CHADS2 score. The authors found that in the CHADS2 scores ≤ 1 and 2 groups, as compared with OAC therapy discontinuation, OAC therapy continuation was associated with a higher risk of bleeding and there were no significant differences in thromboembolism, but in the CHADS2 score ≥ 3 group, OAC therapy continuation could significantly decrease the risk of thromboembolism with no significant difference in bleeding. Based on the above results, we have two questions. First, by reading the article and its supplementary material carefully, we found that the risk of thromboembolism in the CHADS2 scores of ≤1, 2, and ≥3 groups and the risk of major bleeding in the CHADS2 scores of ≤1 and 2 groups were consistent with that in the sensitivity analysis according to the CHA2DS2-VASc score. However, the risk of major bleeding in the CHADS2 score ≥ 3 group according to the CHADS2 score was not consistent with that in the sensitivity analysis according to the CHA2DS2-VASc score, that is, patients with high risk of thromboembolism according to the CHA2DS2-VASc score also have a significantly increased risk of major bleeding for long-term anticoagulation (see Table 1). Although the authors described that the CHADS2 score is widely used as the thrombo-embolic risk score of the AF population because other risk scores do not improve the predictive performance in the Japanese population, the original article showed that both CHADS2 score and CHA2DS2-VASc score had good prediction ability for ischaemic stroke (the C-statistics were 0.680 and 0.671, respectively).4 Second, it is widely known that the HAS-BLED is the most commonly used scores to identify patients at high risk of bleeding and the risk is increased with the addition of each risk factor.5 In theory, patients with a high risk of thromboembolism are usually at high risk of bleeding because they have common factors such as age and stroke. Therefore, we think that it is necessary to assess the risk of bleeding in each group with HAS-BLED score. To sum up, whether patients with high risk of thromboembolism could benefit from long-term OAC therapy after catheter ablation needs further evaluation and analysis. Hazard ratio for thromboembolism and major bleeding according to the CHADS2 score and CHA2DS2-VASc score HR, hazard ratio; CI, confidence interval; PS, propensity score; IPTW, inverse probability of treatment weighting. Hazard ratio for thromboembolism and major bleeding according to the CHADS2 score and CHA2DS2-VASc score HR, hazard ratio; CI, confidence interval; PS, propensity score; IPTW, inverse probability of treatment weighting.