Thromboembolic Risk in Non-Anticoagulated Patients With Atrial Fibrillation and Valvular Heart Disease

Objectives: This study sought to describe the risk of thromboembolism in nonanticoagulated atrial fibrillation patients with Evaluated Heartvalves, Rheumatic or Artificial (EHRA) Type 2 valvular heart disease (VHD) <65 or 65 to 74 years of age and with 0 or 1 non-sex comorbidity of the CHA ₂DS ₂-VASc score. Background: A minor, but important, proportion of patients with atrial fibrillation and VHD beyond moderate-to-severe mitral stenosis and/or a mechanical prosthetic valve, so-called EHRA Type 2 VHD, have 0 or 1 coexisting non-sex comorbidities of the CHA ₂DS ₂-VASc score, and are therefore not strongly recommended oral anticoagulant therapy according to guidelines. Whether these patients are truly low risk of thromboembolism has not been investigated. Methods: This was a cohort study of 55,613 patients identified in nationwide Danish registries from 2000 to 2018, of which 1,907 patients had EHRA Type 2 VHD. Risk of thromboembolism after 1 and 5 years of follow-up were calculated. Results: At 1 year after atrial fibrillation diagnosis, patients with EHRA Type 2 VHD had a risk of thromboembolism between 1.2% and 1.5%, according to age group (<65 or 65 to 74 years of age), and number of non-sex comorbidities of the CHA ₂DS ₂-VASc score (0 or 1). Interestingly, in patients with EHRA Type 2 VHD <65 years of age with 0 or 1 comorbidity, the risk was 1.5% (95% confidence interval: 0.7% to 2.8%) and 1.5% (95% confidence interval: 0.6% to 3.4%) at 1 year after the atrial fibrillation diagnosis. Conclusions: These observations suggest that in atrial fibrillation patients with EHRA Type 2 VHD, who are not currently recommended oral anticoagulant therapy according to guidelines, the risk of thromboembolism may exceed the level above which oral anticoagulation is considered beneficial.