Effectiveness and safety of non-vitamin K antagonist oral anticoagulants in patients with hypertrophic cardiomyopathy with non-valvular atrial fibrillation

Hypertrophic cardiomyopathy (HCM) patients with nonvalvular atrial fibrillation (AF) have an increased risk of suffering thromboembolic events. Vitamin K antagonists (VKA) are recommended as therapy but there is still limited data regarding the efficacy of prescribing non-vitamin K antagonist oral anticoagulants (NOACs). This retrospective study investigates the effectiveness and safety of NOAC administration in patients with HCM and AF. A total of 124 patients with HCM and AF on an oral anticoagulant therapy were recruited between January 2015 and December 2019; these patients were followed up until March 31, 2020. Kaplan-Meier analysis was used to compare the clinical outcomes in patients treated with NOACs versus warfarin. The Cox model was used to estimate the risk of clinically relevant bleeding. Our study included 124 patients, of which 48 (38.7%) received warfarin and 76 (61.3%) received NOACs. Survival analysis showed the patients undergoing NOACs had a lower risk of clinically relevant bleeding (log-rank P = 0.039) over a period of 53.6 months. The median time in therapeutic range (TTR) score was 50% (interquartile range: 40.43 to 57.08%). A total of nine patients (18.75%) had a good TTR with a median score of 66.35% (interquartile range: 64.58 to 77.75%). The incidence of death by all causes, cardiovascular death and thromboembolism were similar between NOAC and warfarin-treated patients (log-rank P = 0.239, log-rank P = 0.386, and log-rank P = 0.257, respectively). Patients treated with NOACs showed a significant reduction in the risk of clinical (P = 0.011) and gastrointestinal bleeding (P = 0.032). Cox multiple regression analysis showed age (HR 1.13, 95% CI 1.03-1.24; P = 0.013) and warfarin therapy (HR 7.37, 95% CI 1.63-33.36; P = 0.010) were independent predictors of clinically relevant bleeding. Compared to warfarin, NOACs were associated with a lower incidence of clinically relevant bleeding in HCM patients with AF, as demonstrated by the similar incidence of death by all causes, cardiovascular death and thromboembolic events.