Vagus nerve ultrasound in transthyretin familial amyloid polyneuropathy: A pilot study

Abstract

Background and Purpose: Autonomic dysfunction is common in transthyretin familial amyloid polyneuropathy (TTR-FAP). Because ultrasonography is a powerful tool to study peripheral neuropathy, vagus nerve (VN) ultrasonography was used in our study to investigate the possible changes of the dimension of VN in TTR-FAP. Methods: Eighteen patients with TTR-FAP and 17 age- and gender-matched individuals without any neuropathies were enrolled in a pilot study. The cross-sectional areas (CSAs) were measured bilaterally on transverse scans of vagus, median, and ulnar nerves. Clinical data were collected to explore the correlations with CSAs of VN. Results: The median CSAs of VN in TTR-FAP were 3.5 (2.0-6.0) mm2 on the right side and 2.5 (1.0-6.0) mm2 on the left side, compared with 2.0 (1.0-3.0) mm2 and 1.0 (1.0-2.0) mm2 for healthy controls (HCs). There was a significant difference between the two groups on both sides (p