Tenosynovial complications identify TTR cardiac amyloidosis among patients with hypertrophic cardiomyopathy phenotype

Recent evidence suggests that carpal tunnel syndrome (CTS) and brachial biceps tendon rupture (BBTR) represent red flags for ATTR cardiac amyloidosis (ATTR‐CA). The prevalence of upper limb tenosynovial complications in conditions entering differential diagnosis with CA, such as HCM or Anderson–Fabry disease (AFD), and hence their predictive accuracy in this setting, still remains unresolved. Objective: To investigate the prevalence of CTS and BBTR in a consecutive cohort of ATTR‐CA patients, compared with patients with HCM or AFD and with individuals without cardiac disease history. Participants: Consecutive patients with a diagnosis of ATTR‐CA, HCM and AFD were evaluated. A control group of consecutive patients was recruited among subjects hospitalized for noncardiac reasons and no cardiac disease history. The presence of BBTR, CTS or prior surgery related to these conditions was ascertained. Results: 342 patients were prospectively enrolled, including 168 ATTR‐CA (141 ATTRwt, 27 ATTRm), 81 with HCM/AFD (N = 72 and 9, respectively) and 93 controls. CTS was present in 75% ATTR‐CA patients, compared with 13% and 10% of HCM/AFD and controls (P = 0.0001 for both comparisons). Bilateral CTS was present in 60% of ATTR‐CA patients, while it was rare (2%) in the other groups. BBTR was present in 44% of ATTR‐CA patients, 8% of controls and 1% in HCM/AFD. Conclusions: CTS and BBTR are fivefold more prevalent in ATTR‐CA patients compared with cardiac patients with other hypertrophic phenotypes. Positive predictive accuracy for ATTR‐CA is highest when involvement is bilateral. Upper limb assessment of patients with HCM phenotypes is a simple and effective way to raise suspicion of ATTR‐CA.