Patients with mild congenital heart defects and atrial arrhythmias: anticoagulate all or follow the CHA2DS2-VASc score?

Abstract Purpose Clinical practice used to anticoagulated all patients with mild congenital heart defects (CHD) and atrial arrhythmias (AA) because of the presence of structural abnormalities. Current guidelines on adult congenital heart disease indicate that in these patients, as per general, the CHA2DS2-VASc score should be followed when deciding upon thromboprophylaxis in case AA. To validate this recommendation, we aimed to assess the incidence of thromboembolism in patients with mild CHD according to CHA2DS2-VASc score using non-vitamin K oral anticoagulants (NOACs) for AA. Methods Data are retrieved from the multinational NOTE-registry, which follows ACHD patients on NOACs for several indications since 2014. Patients in whom NOAC was prescribed for atrial arrhythmias were included in this study. The primary endpoint was the incidence of thromboembolism (TE) and major bleeding (MB). Secondary outcomes were minor bleeding and mortality. Risk stratification was performed using CHA2DS2-VASc score at baseline. Results The NOTE registry has up to date engaged leading ACHD-centers of up to 14 different countries throughout the world, thereby demonstrating a significant effort to fill the gap in science regarding the efficacy and safety of NOACs in the ACHD population. Out of a total of 638 patients, 72 patients had mild congenital defects and NOACs prescribed for AA. The mean age at baseline was 57 (±12) years and 56% was female. Patients were followed up to a maximum of 7 years (202 patient-years; median 2.5, IQR 1.2–4.0). In all patients with a CHA2DS2-VASc score of 0 (n=24), no TE occurred (annualized TE-rate 0%), while 2 patients suffered a MB (annualized MB-rate 3.3%; Figure 1). In patients with a CHA2DS2-VASc score of 1 (n=8) or ≥2 (n=40) the annualized eventrates were 0% and 0.8% for TE, and 0% and 1.7% for MB, respectively. Conclusion These reassuring results demonstrated that the annualized eventrate for TE in patients with mild CHD and a CHA2DS2-VASc score of 0 under treatment with NOACs is very low, at the cost of major bleedings. Following the guidelines seems justified: similar to patients with acquired heart disease the prescription of oral anticoagulant therapy can be refrained from in patients with CHA2DS2-VASc score of 0 and in those with CHA2DS2-VASc score 1 it can be debated weighing the risks and benefits. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Netherlands Heart Institute Figure 1. Eventrates of TE and MB