Reduction in Splanchnic Capacitance Contributes to Sympathetically Dependent Hypertension in Autonomic Aim 1 of Rare Diseases Clinical Research Network (RDCRN) Project 2

151947

The purpose of this study is to learn more about the regulation of the veins of the abdomen by the autonomic (involuntary) nervous system, and how this may affect high blood pressure. Normally, the autonomic nervous system controls how much blood flows in the veins. In people with high blood pressure, however, the autonomic nervous system is changed. This change may affect the way blood flows in the veins of the abdomen which may play a role in their high blood pressure. About 32 participants will be screened for the study. The investigators estimate 16 will be eligible to participate in all of the study days.

2016-04-01

2024-08-01

2024-11-01

Active (not recruiting)

Early phase I

2

Inclusion Criteria: * Male and female subjects, age 40-80 years, with possible or probable Multiple System Atrophy, as defined by Consensus Criteria. * Neurogenic orthostatic hypotension defined as a ≥30-mmHg decrease in systolic blood pressure within 3 minutes of standing associated with impaired autonomic reflexes determined by autonomic testing in the absence of other identifiable causes. * Supine hypertension, defined as systolic blood pressure ≥150 mmHg measured on two separate occasions. * Subjects able and willing to provide informed consent. Exclusion Criteria: * Pregnancy. * Systemic illnesses known to produce autonomic neuropathy, including but not limited to diabetes mellitus, amyloidosis, monoclonal gammopathies, and autoimmune neuropathies * History of known aortic aneurysms, thoracic, abdominal or pelvic surgery in the past 6 months * Symptomatic abdominal or inguinal hernias * Severe gastroesophageal reflux * Recent fractures or fissures of ribs, thoracic or lumbar spine * Medical devices implanted on the abdominal wall or abdomen that would interfere with the abdominal compression * Intolerance to any increase in intra-abdominal pressure * Clinically unstable coronary artery disease or major cardiovascular or neurological event in the past 6 months, and other factors which in the investigator's opinion would prevent the subject from completing the protocol including clinically significant abnormalities in clinical, mental or laboratory testing.

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2023-11-28