Local Heat Stress in Autonomic Failure Patients With Supine Hypertension
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|ClinicalTrials.gov Identifier: NCT02417415|
Recruitment Status : Suspended (Recruitment is temporarily suspended due to COVID-19 outbreak)
First Posted : April 15, 2015
Last Update Posted : April 10, 2020
|Condition or disease||Intervention/treatment||Phase|
|Hypertension Pure Autonomic Failure Multiple System Atrophy Autonomic Failure||Other: Passive heat stress Other: Control (non-heating)||Not Applicable|
Primary autonomic failure is a neurodegenerative condition characterized by severe impairment of the autonomic nervous system. The clinical hallmark of autonomic failure is disabling orthostatic hypotension, but at least half of patients are also hypertensive while lying down. This supine hypertension can be severe and associated with end-organ damage and worsening of orthostatic hypotension due to increased pressure natriuresis. It also complicates the management of these patients by limiting the use of daytime pressor agents for the treatment of orthostatic hypotension.
It is well known that heat exposure (e.g. hot weather or a hot bath or shower) produces an acute and temporary worsening of orthostatic hypotension in autonomic failure patients. However, the mechanisms underlying this phenomenon are completely unexplored. Factors that may predispose autonomic failure patients to the acute lowering blood pressure effects of heat stress include 1) impaired heat dissipation due to inability to sweat, 2) preserved heat-mediated skin vasodilation, and 3) blunted sympathetic hemodynamic responses to maintain blood pressure. In this study, we test the hypothesis that moderate levels of local (abdominal) passive heat stress will lower blood pressure in autonomic failure patients with supine hypertension.
To test this hypothesis, we propose this pilot study with the following specific aims:
- To evaluate the acute blood pressure effects of local passive heat stress in autonomic failure patients with supine hypertension, we will compare changes in BP between controlled local heat stress (~44ºC) using a commercial heating pad that covers the abdomen and part of the torso, and a control (non-heating) study day using the same heating pad but turned off.
- To evaluate the mechanisms underlying BP changes during local heat stress, we will compare changes in hemodynamic parameters (cardiac output, stroke volume and peripheral vascular resistance), segmental fluid shifts (measured by segmental bioimpedance), skin blood flow and skin temperature between the heat and non-heating study days.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||21 participants|
|Intervention Model:||Crossover Assignment|
|Intervention Model Description:||randomized, 2-arm crossover study (heat vs. sham)|
|Masking:||None (Open Label)|
|Official Title:||Local Heat Stress in Autonomic Failure Patients With Supine Hypertension|
|Study Start Date :||April 2015|
|Estimated Primary Completion Date :||April 2021|
|Estimated Study Completion Date :||September 2021|
Experimental: Local Heat Stress
Passive heat-stress using a commercial heating pad applied over the abdomen and part of the torso
Other: Passive heat stress
Passive heat stress will be applied with a commercial heating pad that covers all the abdomen and part of the torso to provide local heating at ~44ºC continuously for 2 hr.
Other Name: Heating pad
Sham Comparator: Control (Non-heating)
Commercial heating pad applied over the abdomen and part of the torso but turned off
Other: Control (non-heating)
Heating pad will be applied over the abdomen and part of the torso but it will be turned off.
Other Name: sham
- Systolic blood pressure [ Time Frame: 2 hours of heat stress or when Tcore increases 1ºC ]Change from baseline in systolic blood pressure at the maximal Tcore (at 2 hr or Tcore +1ºC)
- Hemodynamic measures [ Time Frame: 1 hour and 2 hours of heat stress or when Tcore increases 1ºC ]Changes in cardiac output, stroke volume and systemic vascular resistance
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02417415
|United States, Tennessee|
|Nashville, Tennessee, United States, 37232|
|Principal Investigator:||Italo Biaggioni, MD||Vanderbilt University|