Systemic embolism in amyloid transthyretin cardiomyopathy

AIMS: Although systemic embolism is a potential complication in transthyretin amyloid cardiomyopathy (ATTR‐CM), data about its incidence and prevalence are scarce. We studied the incidence, prevalence and factors associated with embolic events in ATTR‐CM. Additionally, we evaluated embolic events according to the type of oral anticoagulation (OAC) and the performance of the CHA(2)DS(2)‐VASc score in this setting. METHODS AND RESULTS: Clinical characteristics, history of atrial fibrillation (AF) and embolic events were retrospectively collected from ATTR‐CM patients evaluated at four international amyloid centres. Overall, 1191 ATTR‐CM patients (87% men, median age 77.1 years [interquartile range‐IQR 71.4–82], 83% ATTRwt) were studied. A total of 162 (13.6%) have had an embolic event before initial evaluation. Over a median follow‐up of 19.9 months (IQR 9.9–35.5), 41 additional patients (3.44%) had an embolic event. Incidence rate (per 100 patient‐years) was 0 among patients in sinus rhythm with OAC, 1.3 in sinus rhythm without OAC, 1.7 in AF with OAC, and 4.8 in AF without OAC. CHA(2)DS(2)‐VASc did not predict embolic events in patients in sinus rhythm whereas in patients with AF without OAC, only those with a score ≥4 had embolic events. There was no difference in the incidence rate of embolism between patients with AF treated with vitamin K antagonists (VKAs) (n = 322) and those treated with direct oral anticoagulants (DOACs) (n = 239) (p = 0.66). CONCLUSIONS: Embolic events were a frequent complication in ATTR‐CM. OAC reduced the risk of systemic embolism. Embolic rates did not differ with VKAs and DOACs. The CHA(2)DS(2)‐VASc score did not correlate well with clinical outcome in ATTR‐CM and should not be used to assess thromboembolic risk in this population.