Differences in the 2020 ESC versus 2019 ACC/AHA/HRS guidelines on atrial fibrillation

The recent publication of the 2020 European Society of Cardiology (ESC) and the 2019 American College of Cardiology (ACC) guidelines have updated the knowledge about multiple aspects of atrial fibrillation (AF) management.1,2 However, some discrepancies exist between the two guidelines regarding management approaches and classes of recommendations. A risk-based approach using the CHA2DS2-VASc risk score has been recommended in both guidelines for stroke risk assessment and decision-making for oral anticoagulant (OAC) therapy. Both guidelines strongly recommend OAC therapy in AF patients at high thrombo-embolic risk with CHA2DS2-VASc score ≥2 in men or ≥3 in women (I-A). Furthermore, both guidelines agree on the omission of OAC therapy in low-risk patients. However, classes of recommendation are not consistent between the two guidelines for patients with intermediate scores. The 2020 ESC guideline states that OAC ‘should be considered’ for stroke prevention in patients with a CHA2DS2-VASc score of 1 in men or 2 in women (IIa-B) as a net clinical benefit was observed with OAC therapy in AF patients with one non-sex stroke risk factor in a large community-based cohort.3 Nevertheless, the 2019 ACC guideline lowers the level of evidence by stating that OAC ‘may be considered’ in these patients to reduce thrombo-embolic risk (IIb-C) and argues that the observed relatively small net clinical benefit with warfarin requires further validation and similar studies assessing novel OACs in these patients are needed. Overall, the European guideline implies a more conservative approach to stroke prevention while simultaneously emphasizing the importance of discussing the risks and benefits of OAC therapy and considering patient values and preferences. Further discrepancies are present regarding peri-cardioversion anticoagulation. While the 2020 ESC guideline recommends initiation of effective anticoagulation as soon as possible before every AF cardioversion (IIa-B), the 2019 ACC considers ‘no anticoagulation therapy’ as an alternative in patients with AF duration <48 h and CHA2DS2-VASc score of 0 in men or 1 in women (IIb-B). Both guidelines recommend long-term post-cardioversion anticoagulation in high-risk patients for thrombo-embolic events based on the CHA2DS2-VASc score. However, recommendations regarding short-term anticoagulation for at least 4 weeks after cardioversion slightly differ between the two guidelines. The 2020 ESC guideline suggests that anticoagulation therapy may be omitted in patients with low thrombo-embolic risk and a definite AF duration ≤24 h (IIb-C) while the 2019 ACC guideline recommends a similar strategy in low-risk patients with AF duration <48 h (IIb-B). Despite a very low thrombo-embolic risk in patients with AF of <48 h duration and CHA2DS2-VASc score of <2 in previous studies,4 no randomized controlled trial has investigated the efficacy and safety of anticoagulation in this setting. Hence, short-term post-cardioversion anticoagulation in low-risk patients with AF duration of 24–48 h can be optional, considering the fact that the European guideline takes a more conservative approach by limiting the recommendation to AF episodes of <24 h duration. The relatively high success rate of AF catheter ablation using recent technological advancements has gained increasing attention over the past years. However, there are some inconsistencies between the two guidelines regarding catheter ablation of persistent AF. While the European guideline highly recommends catheter ablation for persistent AF refractory or intolerant to AAD either in the presence (I-B) or absence (I-A) of major risk factors for AF recurrence, the American guideline considers AF ablation a reasonable option in selected patients with the mentioned features (IIa-A). Atrial fibrillation catheter ablation in the setting of left ventricular (LV) dysfunction is another major discrepancy between the two guidelines. The CASTLE-AF and ATTAC studies showed that AF catheter ablation in patients with heart failure and reduced ejection fraction (HFrEF) was superior to medical therapy in reducing all-cause mortality and hospitalization.5,6 Due to their relatively small and highly selective patient population, the 2019 ACC guideline emphasizes the need for further large studies to confirm these findings and recommends that AF ablation may be a reasonable option in selected patients with symptomatic AF and HFrEF (IIb-B). On the other hand, the 2020 ESC guideline highly recommends AF catheter ablation in selected patients with HFrEF (IIa-B) while further increasing the class of recommendation to I-B for catheter ablation to reverse LV dysfunction in AF patients when tachycardia-induced cardiomyopathy is highly suspected. These recommendations are based on the evidence from pooled analysis of RCTs showing improved survival and HF hospitalization after catheter ablation in AF patients with HF compared to medical therapy.7,8 Moreover, a recent subgroup analysis of the CABANA study further supported the beneficial effect of AF ablation on reducing mortality and study primary endpoints (death, stroke, cardiac arrest, bleeding) among patients with HFrEF.9 The duration of a short-course triple therapy (OAC, aspirin, and P2Y12 inhibitor) in AF patients following percutaneous coronary intervention (PCI) is controversial. The 2019 ACC guideline recommends that a transition from triple therapy to dual therapy (OAC and P2Y12 inhibitor) at 4–6 weeks after PCI may be considered in AF patients at increased risk of stroke (IIb-B). However, the 2020 ESC guideline recommends an earlier (≤1 week) transition to dual therapy in AF patients at low risk of stent thrombosis (I-B) with further continuation of triple therapy up to 1 month when the risk of stent thrombosis outweighs the bleeding risk (IIa-C). In contrast with the 2020 ESC guideline, the recommended approach in the 2019 ACC is confined to AF patients with CHA2DS2-VASc score of ≥2 as the evidence is derived from the ISAR-TRIPLE trial in which almost all patients had a CHA2DS2-VASc score of ≥2. Although there is evidence from multiple RCTs to support the better safety and similar efficacy of dual therapy compared to triple therapy,10 physicians should carefully decide on their approach as some patients are at high risk of stent thrombosis. While some discrepancies result from insufficient evidence to support strong recommendations, different years of publication account for an additional source of difference between the two guidelines. Hence, further large studies are needed to investigate the gaps of knowledge in AF management. Conflict of interest: none declared.