Autonomic dysfunction in patients with wild-type transthyretin amyloidosis

Autonomic dysfunction is well recognized in hereditary transthyretin amyloidosis (ATTRv), but it has not been systematically studied in wild-type transthyretin amyloidosis (ATTRwt). Because ATTRwt primarily presents with cardiomyopathy, autonomic symptoms may mimic heart failure and lead to inappropriate treatment. Here we aimed to investigate the presence and extent of autonomic dysfunction in ATTRwt.

In ATTRwt patients and controls, we performed an extensive autonomic examination, including standardized questionnaires, passive and active orthostatic challenges, Valsalva maneuver, deep breathing and sudomotor assessment.

20 ATTRwt patients and 20 controls were included. Composite Autonomic Symptom Score 31-scores were similar between the groups. Orthostatic challenges revealed impaired blood pressure (BP) and heart rate regulation in ATTRwt compared to controls (for passive orthostatic challenge: HR p = 0.001, systolic BP p = 0.010) and diastolic BP p = 0.006; for active orthostatic challenge: HR p = 0.001, systolic BP p = 0.002, diastolic BP p = 0.002). A lack of late phase 2 BP overshoot during Valsalva maneuver was observed in ATTRwt and Valsalva Ratio was pathological in 83% of ATTRwt versus 30% of controls (p = 0.020). The rate of pathological sweat tests did not differ between ATTRwt patients and controls.

Autonomic symptoms in ATTRwt were infrequently reported. However, detailed assessment revealed cardiovascular autonomic dysfunction, which contributes to the overall clinical phenotype of ATTRwt.