Shy-Drager Syndrome

The main purpose of this study is to gather data and assess changes in patient-reported outcomes with the stellate ganglion blocks as treatment for their sympathetically-mediated long COVID symptoms.

Despite being studied less than half as frequently, autonomic dysfunction is a greater priority than walking again in spinal cord injury. One autonomic condition after spinal cord injury is orthostatic hypotension, where blood pressure dramatically declines when patients assume the upright posture. Orthostatic hypotension is associated with all-cause mortality and cardiovascular incidents as well as fatigue and cognitive dysfunction, and it almost certainly contributes to an elevated risk of heart disease and stroke in people with spinal cord injury. In addition, autonomic dysfunction leads to bladder, bowel, sexual dysfunctions, which are major contributors to reduced quality and quantity of life. Unfortunately, the available options for treating this condition, are primarily limited to pharmacological options, which are not effective and are associated with various side effects. It has been recently demonstrated that spinal cord stimulation can modulate autonomic circuits and improve autonomic function in people living with spinal cord injury. Neuroanatomically, the thoracolumbar sympathetic pathways are the primary spinal cord segments involved in blood pressure control. Recently, a pilot study has been published demonstrating that transcutaneous spinal cord stimulation of thoracolumbar afferents can improve cardiovascular function. However, some studies have shown that lumbosacral transcutaneous spinal cord stimulation can also elicit positive cardiovascular effects. Therefore, there is no consensus on the optimal strategy in order to deliver transcutaneous spinal cord stimulation to improve the function of the autonomic system, and it may be that lumbosacral (i.e. the stimulation site being used most commonly for restoring leg function is sufficient). Another key knowledge gap in terms of transcutaneous spinal cord stimulation is whether or not the current is directly or indirectly activating these spinal circuits. Last but not least, the effects of epidural spinal cord stimulation on the function of cardiovascular, bladder, bowel and sexual system in spinal cord injury have been investigated in no study yet.
AIMS AND HYPOTHESES:
Aim 1. To examine the effects of short-term (one session) transcutaneous spinal cord stimulation on the frequency and severity of episodes of orthostatic hypotension/autonomic dysfunction, and bladder, bowel, and sexual functions. These effects will be compared at two sites of stimulation.
Hypothesis 1.1: Short-term transcutaneous mid-thoracic cord stimulation will mitigate the severity and frequency of orthostatic hypotension/autonomic dysfunction.
Hypothesis 1.2: Lumbosacral transcutaneous spinal cord stimulation will improve bladder, bowel, and sexual functions.
Aim 2. To examine the effects of long-term (one month) transcutaneous spinal cord stimulation on the severity and frequency of orthostatic hypotension/autonomic dysfunction.
Hypothesis 2.1: Long-term stimulation of the mid-thoracic cord will result in sustained improvements in mitigated severity and frequency of orthostatic hypotension/autonomic dysfunction that is not dependent on active stimulation.
Hypothesis 2.2: Long-term lumbosacral transcutaneous spinal cord stimulation will result in sustained improvements in bowel, bladder, and sexual function that is not dependent on active stimulation.
Aim 3: To examine the effects of short-term (one session) epidural spinal cord stimulation on the severity and frequency of orthostatic hypotension/autonomic dysfunction, and bladder, bowel, and sexual functions.
Hypothesis 3.1: Epidural spinal cord stimulation will mitigate the severity and frequency of orthostatic hypotension/autonomic dysfunction and improve bladder, bowel, and sexual function.
Hypothesis 3.3: There is no significant difference between immediate effects of lumbosacral transcutaneous spinal cord stimulation and epidural spinal cord stimulation on bladder, bowel, and sexual function.
For aim 1, 14 participants with spinal cord injury and no implanted electrodes on the spinal cord will be recruited. Participants will randomly receive one-hour stimulation under each of the two stimulation conditions in a crossover manner: Mid-thoracic and Lumbosacral. For aim 2, 28 individuals with spinal cord injury and no implanted electrode will be pseudo-randomized (1:1) to one of two stimulation sites. Participants will receive one-hour stimulation, five sessions per week for four weeks. Cardiovascular and neurological outcomes will be measured before the first stimulation session and after the last stimulation session. For aim 3, 4 participants with spinal cord injury with implanted electrodes on the spinal cord will be recruited to study the immediate effects of invasive epidural spinal cord stimulation.
All outcomes will be measured in two positions: a) Supine, b)
70° upright tilt-test. Additionally, bowel, bladder, and sexual functions in project 2 will be assessed weekly.

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.