View clinical trials related to Pure Autonomic Failure.
Filter by:A Phase 3, multi-center, open-label study to evaluate the safety and tolerability of ampreloxetine in subjects with primary autonomic failures (MSA, PD, and PAF) and symptomatic nOH over 182 weeks.
A Phase 3, 22-week, Multi-center, Randomized Withdrawal Study of ampreloxetine in Treating Symptomatic Neurogenic Orthostatic Hypotension in Subjects with Primary Autonomic Failure
Pharmacologic approaches to increase levels or actions of the vasodilatory peptide angiotensin-(1-7) are currently in development for the treatment of hypertension based on findings from animal models. There are limited and contradictory clinical studies, however, and it is not clear if this peptide regulates blood pressure in humans. The purpose of this study is to better understand the cardiovascular effects angiotensin-(1-7) in human hypertension, and to examine interactions of this peptide with the autonomic nervous system. The investigators propose that the difficulties in showing angiotensin-(1-7) cardiovascular effects in previous clinical studies relates to the buffering capacity of the baroreceptor reflex to prevent changes in blood pressure. Autonomic failure provides the ideal patient population to test this hypothesis. These patients have loss of baroreflex buffering and have low levels of angiotensin-(1-7) in blood. The investigators will test if angiotensin-(1-7) infusion can lower blood pressure in patients with autonomic failure, and will determine the hemodynamic and hormonal mechanisms involved in this effect.
The specific aim of this study is to determine whether water ingestion potentiates the pressor response to pseudoephedrine in patients with primary disorders of autonomic failure. The study design will enable us to also evaluate the pressor response to water alone and to pseudoephedrine alone. In a secondary analysis, we will compare the results in patients with two autonomic disorders, pure autonomic failure (PAF) and multiple system atrophy (MSA). We hypothesize that drinking water following a dose of pseudoephedrine will lead to a greater increase in blood pressure than pseudoephedrine alone.
Evaluate the clinical efficacy and safety of droxidopa versus placebo over a 17 week (maximum) treatment period in patients with symptomatic NOH.
This research study will be conducted in patients with primary autonomic failure, a disabling condition that is associated with low blood pressure upon standing. These patients are also not able to control for changes in their blood pressure due to a loss of cardiovascular reflexes that are mediated within the brain. The purpose of this study is to determine whether magnetic resonance spectroscopy (MRS), a non-invasive imaging technique, can measure levels of chemicals (neurotransmitters) in the dorsal medulla, a brain area important for control of cardiovascular function, in autonomic failure patients. Importantly, this study will determine whether there are differences in brain chemicals between patients with peripheral versus central origins of their autonomic failure. The hypothesis is that the neurotransmitter profile in the medulla will be intact in patients with peripheral autonomic failure compared to those with central impairment. Overall, this study will provide insight into understanding the mechanisms involved in autonomic failure and will determine whether a single session of MRS imaging can improve the ability to make an accurate diagnosis in these patients. This would lessen the need for more extensive and invasive clinical testing.
The purpose of this study is to test the hypothesis that angiotensin II plays a role in the supine hypertension of primary autonomic failure. To determine the contribution of angiotensin II to renin and blood pressure regulation in autonomic failure, patients with multiple system atrophy [MSA] or pure autonomic failure [PAF] and supine hypertension will undergo medication testing with the angiotensin II receptor blocker losartan. The investigators will compare the biochemical and hemodynamic effects between MSA and PAF patients. In a subset of patients, the investigators will also give the ACE inhibitor captopril. Our primary endpoint will be changes in plasma renin activity, and subsequent components of the circulating renin-angiotensin system, in response to angiotensin II blockade. Our secondary outcome will be changes in hemodynamic measures during administration of these drugs.
This study will conduct tests in patients with primary chronic autonomic failure (CAF) to learn more about these disorders, which include pure autonomic failure, multiple system atrophy, Parkinson's disease with autonomic failure, and autoimmune autonomic neuropathy. Healthy volunteers and patients with primary CAF 18 years of age or older may be eligible for this study. Participants undergo some of the following tests: - Blood studies, including arterial catheter insertion to measure blood pressure and collect arterial blood samples, blood flow studies using sensors applied to the skin and a pressure cuff around a limb, and blood draw for genetic studies. - Bladder motility: Ultrasound test of bladder function. - Electrocardiogram and heart ultrasound. - Responses to changes in temperature: Warm water and then room temperature water are passed through watertight pads applied to the back and front of the body and body temperatures are measured. - Gastrointestinal motility: Bowel sounds are recorded using a microphone placed on the abdomen. - Lower body negative pressure: The lower body is placed into an airtight barrel-like chamber. Some air is sucked out of the barrel, causing blood to pool in the legs, as occurs during standing. - Lumbar puncture: A needle is inserted in the space between the bones in the lower back to collect a small sample of cerebrospinal fluid. - Microdialysis to measures levels of chemicals in the body fluid of certain tissues. A solution is passed through a thin tube inserted into the skin. Chemicals in the body tissues enter the solution. The solution is collected and the chemical levels are measured. - PET scanning: A nuclear medicine test to produce images of body organs. For patients with urinary problems, a catheter is inserted into the bladder before starting the scan. - Pupillometry: The pupil of the eye is measured using a special camera in a light-controlled room. - QSART. A small amount of a brain chemical is applied to the skin with a tiny amount of electricity, and the sweat in a nearby patch of skin is measured. - Measurement of saliva production, using a cotton-like material placed between the teeth and gums to absorb saliva. - Skin electrical conduction test, using sensors on the skin to measure sweat production. - Skin and core temperature measurements using sensors on the skin and in the ear canal. - Speech and swallowing assessment for patients with speech and swallowing difficulties. - Stress echocardiogram: A catheter is placed in the subject's arm for sampling blood or giving a drug while the subject exercises. During the test, blood pressure, pulse rate, and EKG are continuously monitored.