Personalized stroke prevention is important in patients with a CHA2DS2-VASc score of 1

This commentary refers to ‘Stroke and bleeding risk in atrial fibrillation with CHA2DS2-VASC risk score of one: the Norwegian AFNOR study’, by M. Anjum et al., https://doi.org/10.1093/eurheartj/ehad659 and the discussion piece ‘A CHA2DS2-VASc score of 1 is not the same for every patient with atrial fibrillation’, by J. Neefs et al., https://doi.org/10.1093/eurheartj/ehae511. We appreciate the comments on our study evaluating the benefit of oral anticoagulation (OAC) in individuals with atrial fibrillation (AF) and a non-sex CHA2DS2-VASc score of 1.1 The commentary highlights several critical aspects of risk stratification and patient management. The recognition that age 65–74 years is a significant driver of stroke risk is consistent with our findings. We found that this subgroup of AF patients had the highest incidence of stroke both with and without OAC. Nevertheless, even in AF patients < 65 years of age, we found an incidence rate of stroke and systemic embolism of 1.1%/person-year. Compared with individuals without AF and a CHA2DS2-VASc score of 1, AF patients had a 2.4 times increased risk of stroke. This indicates how even younger patients with AF and a CHA2DS2-VASc score of 1 have a significant stroke risk and seem to have a positive net clinical benefit of OAC. An important point raised is the dynamic nature of stroke risk in AF patients. The CHA2DS2-VASc score will increase due to aging and accumulation of comorbidities. Yet, the stroke risk is often only assessed at baseline without taking into account changes over time.2 Indeed, also the bleeding risk is dynamic and should be reassessed. For example, we found no benefit of OAC in AF patients with a CHA2DS2-VASc score of 1 who were also using antiplatelets. This is an important point in clinical decision-making in the setting of acute coronary syndrome. Advances in detection methods, including widespread use of ambulatory monitoring and wearable technology, have led to earlier and more frequent AF diagnosis. This has probably resulted in a lower overall AF burden among newly diagnosed AF patients. Patients today may even present with asymptomatic paroxysmal AF, a group of patients who were never enrolled in the original pivotal OAC trials. These epidemiological changes further emphasize the need for an individualized approach to OAC. Technological innovations now enable the estimation of AF burden in clinical care. Although evidence is limited, current data suggest that reducing AF burden could be a therapeutic goal, not only for symptom relief but also for stroke prevention.3 Atrial fibrillation burden has also been actualized by the recent NOAH-AFNET 6 and ARTESIA trials, questioning the net benefit of OAC in subclinical device-detected AF.4 The most striking finding in these trials was the low stroke rates, ∼1%/patient-year. This compares well to stroke rates in our AFNOR study of clinical AF and a CHA2DS2-VASc score of 1, although the median CHA2DS2-VASc score in these trials was 4. Indeed, the authors of a substudy of the ARTESIA trial suggest that a net clinical benefit of OAC in subclinical AF is seen only in patients with a CHA2DS2-VASc score of >4.5 In conclusion, anticoagulation in AF patients and a CHA2DS2-VASc score of 1 must be individualized, taking into account the dynamic nature of the risk factors, AF burden, patient preferences, and an overall assessment of the net clinical benefit for the patient. T.B. has received lecture fees from Bayer, Boehringer Ingelheim, Bristol Myers Squibb, and Pfizer. The other authors have nothing to declare.