Thromboembolic Risk in Nonanticoagulated Patients With Atrial Fibrillation and Valvular Heart Disease.

Abstract

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 CHA2DS2-VASc score. 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 CHA2DS2-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. 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. 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 CHA2DS2-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. 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.