Prevalence and prognostic value of autonomic neuropathy assessed by Sudoscan® in transthyretin wild‐type cardiac amyloidosis

AIMS: The prevalence of autonomic neuropathy (AN) is high in patients with hereditary transthyretin amyloidosis but remains unknown in transthyretin wild‐type cardiac amyloidosis (ATTRwt‐CA). This study aimed to determine the prevalence of AN in patients with ATTRwt‐CA using Sudoscan®, a non‐invasive method used to provide evidence of AN in clinical practice and based on measurement of electrochemical skin conductance at the hands and feet (fESC). METHODS AND RESULTS: A series of 62 non‐diabetic patients with ATTRwt‐CA was prospectively included over 2 years and compared with healthy elderly subjects, matched by age, gender, and body mass index. The presence of AN was defined as electrochemical skin conductance at the hands <60 μS and/or fESC <70 μS, and conductances were analysed according to clinical, biological, and echocardiographic data. Mean fESC was significantly lower in patients with ATTRwt‐CA compared with elderly controls: 68.3 (64.1–72.5) vs. 76.9 (75.6–78.1) μS (P < 0.0001), respectively. Prevalence of fESC <70 μS was higher in ATTRwt‐CA patients than in controls: 48.4% vs. 19.9%, P < 0.05. Univariate analysis showed that fESC, N‐terminal pro‐B‐type natriuretic peptide, creatinine plasma levels, and echocardiographic global longitudinal strain were associated with decompensated cardiac failure and death. Multivariate analysis revealed that fESC was an independent prognostic factor, and Kaplan–Meier estimator evidenced a greater occurrence of cardiac decompensation and death in patients with fESC <70 μS, P = 0.046. CONCLUSIONS: Reduced fESC was observed in almost 50% of patients with ATTRwt‐CA and was associated with a worse prognosis. Sudoscan® could easily be used to screen ATTRwt‐CA patients for the presence of AN and identify patients at higher risk for a poor outcome.