Clinical Laboratory Evaluation of Chronic Autonomic Failure

Background: The autonomic nervous system controls automatic body functions. Researchers want to improve the tests used to diagnose autonomic failure. Orthostatic hypertension is a drop in blood pressure when a person stands up. Researchers want to focus on this sign of autonomic failure. Objective: To improve testing for conditions that cause autonomic nervous system failure. Eligibility: People ages 18 and older in one of these categories: * Their blood pressure drops when they get up. * They have had a heart transplant or bilateral endoscopic thoracic sympathectomies or have had or will have renal sympathetic ablation Design: All participants will be screened with: * Medical history * Physical exam * Blood and urine tests Some participants will be screened with: * Heart and breathing tests * IV placement into an arm vein * Tilt table testing: Participants lie on a table that tilts while an IV is used to draw their blood. Participants may stay in the hospital for up to 1 week depending on their tests. Tests may include repeats of screening tests and: * Sweat testing: A drug is placed on the skin to cause sweating. Sensors on the skin measure moisture. * Lumbar puncture: A needle is inserted between the bones in the back to collect fluid. * MRI and PET/CT scan: Participants lie on a table that slides into a scanner. For the PET/CT, a small amount of a radioactive chemical will be injected with a small amount of a radioactive chemical. * Bladder catheter placement to collect urine * Skin biopsies: A punch tool removes a small skin sample. * Tests to see how the pupils react to light * Smelling tests * Thinking and memory tests * Questionnaires Participants may have a visit about 2 years later to repeat tests.

NCT Number	NCT03648905
Lead Sponsor	National Institute of Neurological Disorders and Stroke (NINDS)
Conditions	Parkinson's Disease, Multiple System Atrophy, Autonomic Failure
Enrollment	89 participants
Start Date	2018-09-06
Primary Completion	2026-07-15 (estimated)
Study Completion	2026-07-15 (estimated)
Updated on ClinicalTrials.gov	2026-08-04