# Significant Microvascular Abnormalities Present in Autonomic Nervous System Dysfunction: Results of a Cross-Sectional Study

## TL;DR

This study shows that microvascular abnormalities, seen through nailfold capillaroscopy, are significantly more common in people with autonomic nervous system dysfunction compared to healthy individuals.

## Contribution

The study is the first to demonstrate a distinct capillaroscopic pattern in autonomic dysfunction, suggesting a potential noninvasive diagnostic tool.

## Key findings

- Patients with autonomic dysfunction had significantly more microhemorrhages, dilated capillaries, and ramifications compared to controls.
- Age and BMI were statistically significantly correlated with microvascular abnormalities in autonomic dysfunction patients.
- Nailfold video capillaroscopy showed diagnostic potential for identifying autonomic dysfunction.

## Abstract

Purpose: The prevalence and phenotype of capillaroscopic abnormalities in patients with autonomic nervous system dysfunction have not yet been investigated. Multiorgan involvement in dysautonomia entails abnormal vasoreactivity. We aim to correlate the diagnosis of autonomic dysfunction with certain clinical manifestations, which may provide prognostic or diagnostic information using a noninvasive technique, i.e., nailfold video capillaroscopy (NVC). Methods: Patients with autonomic nervous system dysfunction were recruited from rheumatology and neurology clinics with voluntary NVC procedures from 31 January 2024 to 10 January 2024, and a comparison with normal controls was performed. Additional recorded information include demographics and diagnoses of autonomic dysfunction types by autonomic testing, including, but not limited to, the following: reflex screen, sweat test, Valsalva maneuver, nerve fiber density, electromyography (EMG), serology, and history of autoimmune diseases. NVC was performed on a total of 27 patients. This study was approved by the Mayo Clinic Institutional Review Board. Results: The autonomic dysfunction group consisted of small-fiber neuropathy (37%), orthostatic hypotension (48%), autonomic neuropathy (30%), limited autonomic neuropathy (7%), postural orthostatic tachycardia syndrome (POTS) (7%), and connective tissue disease (7%), among other types. Patients with autonomic dysfunction had statistically significant increases in microhemorrhages, dilated capillaries, and ramifications when compared to controls. Conclusions: Autonomic dysfunction was associated with statistically significant microvascular abnormalities compared to normal controls with a distinct NVC pattern. There was a statistically significant correlation between age and BMI with microvascular abnormalities. Here, we demonstrate the diagnostic potential of NVC in autonomic dysfunction and advocate for further study of capillary structures in autonomic dysfunction.