Pupillary autonomic dysfunction in patients with ANCA-associated vasculitis.

Objective: To assess autonomic function by infrared dynamic pupillometry in patients with ANCA-vasculitis (AAV) in correlation to autonomic symptoms, disease specific clinical parameters and cardiovascular reflex tests.

Methods: Patients with AAV and healthy controls underwent pupillometry at rest and after sympathetic stimulation (cold pressor test). Three parasympathetic parameters (amplitude, relative amplitude, maximum constriction velocity) and one sympathetic parameter (late dilatation velocity) were assessed. Results were correlated with clinical parameters, symptoms of autonomic dysfunction (COMPASS31 questionnaire), heart rate variability during deep breathing test and blood pressure response to pain.

Results: 23 patients and 18 age-matched controls were enrolled. Patients had a smaller amplitude (1.44 vs. 1.70 mm; p = 0.009) and a slower constriction velocity (4.15 vs. 4.71 mm/s; p = 0.028) at baseline and after sympathetic stimulation (1.47 vs. 1.81 mm, p = 0.001; 4.38 vs. 5.19 mm/s, p = 0.006, respectively). Relative amplitude was significantly smaller in patients after sympathetic stimulation (28.6 vs. 32.5%; p = 0.043), but not at baseline. There was no difference in sympathetic pupillary response between the groups. In patients, parasympathetic pupil response was correlated negatively with age and positively with parasympathetic cardiac response. After adjusting for age, no significant correlation was observed with clinical parameters. However, there was a trend towards a negative correlation with disease duration, vasculitis damage index and CRP.

Conclusion: Patients with AAV exhibit parasympathetic pupillary autonomic dysfunction. Although correlations were weak and not significant, pupillary autonomic dysfunction is rather linked to chronic damage than to active inflammation or symptoms of autonomic dysfunction.