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Heat Therapy in Older Hypertensive Women

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ClinicalTrials.gov Identifier: NCT03857490
Recruitment Status : Recruiting
First Posted : February 28, 2019
Last Update Posted : June 4, 2020
Sponsor:
Information provided by (Responsible Party):
University of Texas Southwestern Medical Center

Brief Summary:
The prevalence of hypertension is greater in older women than men, while the blood pressure (BP) control rate is lower in older women in US. Uncontrolled hypertension is a major risk factor for cardiovascular morbidity/mortality. Despite standard therapy and adherence to optimal drug regimens, >50% of older hypertensive women still have inadequate BP control, and the control rate is further reduced with more aggressive BP targets recommended recently by the new Hypertension Guidelines. Thus, the effectiveness of drug treatment alone in the control of hypertension among older women is limited; hence, non-pharmacological approaches are also needed to help reduce BP in older hypertensive women. One adjuvant, non-pharmacological approach that offers promise in lowering BP is "heat therapy". Indeed, repeated whole-body heat exposure decreases BP in healthy humans. Whether this is also true after regional limb heating in hypertensive patients is unknown. The objectives of this research are to investigate the BP lowering effect of home-based lower leg heat therapy in older women with hypertension, and to examine the impact of this therapeutic modality on neural-vascular health in these patients. Aim 1 will test the hypothesis that chronic lower leg heat therapy combined with an antihypertensive drug is superior to drug treatment alone in lowering BP in older hypertensive women. We will randomly assign older hypertensive women to either an intervention group or a control group. Patients in the intervention group will perform 8 weeks of lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times/week, 45 min/session), whereas patients in the control group will immerse their legs in a thermoneutral water bath (33°C) at the same frequency and duration. All patients will also receive a fixed dose of chlorthalidone (a diuretic, 25 mg orally daily). We will compare ambulatory BP, the BP control rate, and patient adherence and acceptability to treatment between the groups. Aim 2 will test the hypothesis that chronic lower leg heat therapy will improve nitric oxide bioavailability which can decrease sympathetic vasoconstriction and improve vascular function in older hypertensive women. We will use state-of-the-art techniques of microneurography, Doppler ultrasound, applanation tonometry, and cutaneous microdialysis to assess neural control, vasodilator function, and interstitial metabolites (i.e. nitrate and nitrite) indicative of basal nitric oxide bioavailability in all patients enrolled in Aim 1 before and after 8 weeks of heat therapy. Information obtained from this research project will guide evidence-based clinical practice. It is anticipated that our study may lead to revision of hypertension guidelines to incorporate home-based heat therapy as adjuvant to antihypertensive drug(s) for older women, as well as other patient populations.

Condition or disease Intervention/treatment Phase
Essential Hypertension Behavioral: Lower leg heat therapy Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 200 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: This is a randomized, placebo-controlled study. Older women with hypertension will randomly be assigned to either an intervention group or a control group (1:1 ratio). Patients in the intervention group will be required to perform 8 weeks of home-based lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times per week, 45 min per session), whereas patients in the control group will immerse their legs in a thermoneutral water bath (33°C) at the same frequency and duration.
Masking: Single (Outcomes Assessor)
Masking Description: The randomization will be programmed with SAS Proc Plan and implemented via a user friendly web-based interface using REDCap. The biostatistician will be responsible for randomization; however, he/she will not have any contact with the patients and will not be involved in outcome measures. All investigators, except the research nurses, will be blinded to the group status of the patient during 8-week treatment and post-treatment testing. The research nurses will not be involved in data analysis and interpretation.
Primary Purpose: Treatment
Official Title: Chronic Lower Leg Heating for the Treatment of Hypertension in Older Women
Actual Study Start Date : July 29, 2019
Estimated Primary Completion Date : September 2023
Estimated Study Completion Date : January 2024

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Intervention
Lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times per week, 45 minutes per session) for 8 weeks.
Behavioral: Lower leg heat therapy
Home-based 8 weeks of lower leg repeated heating.

Placebo Comparator: Control
Lower leg immerse in a thermoneutral water bath (33°C), 4 times per week, 45 minutes per session for 8 weeks.
Behavioral: Lower leg heat therapy
Home-based 8 weeks of lower leg repeated heating.




Primary Outcome Measures :
  1. Physiological parameter (awake ambulatory systolic pressure) [ Time Frame: After 8 weeks of treatment. ]
    24-hour ambulatory blood pressure monitoring will be performed and systolic blood pressure during the awake period before and after treatment will be compared in older women with hypertension.

  2. Physiological parameter (muscle sympathetic nerve activity) [ Time Frame: After 8 weeks of treatment. ]
    We will us the microneurographic technique to measure muscle sympathetic nerve activity in all older hypertensive women before and after treatment. Results will be compared between the intervention group and the control group.

  3. Physiological parameter (vascular function) [ Time Frame: After 8 weeks of treatment. ]
    We will use the Ultrasound Doppler technique to measure vascular function including arterial stiffness and endothelial function in older hypertension women before and after treatment. Results will be compared between the groups.



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Ages Eligible for Study:   65 Years to 85 Years   (Older Adult)
Sexes Eligible for Study:   Female
Gender Based Eligibility:   Yes
Gender Eligibility Description:   All subjects in this research project will be women by design. Women between the ages of 65 and 85 years old will be enrolled.
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Women between the ages of 65-85 years with essential hypertension (systolic BP 140-179 and/or diastolic BP 90-109 mmHg)
  • Must be able to understand and speak English

Exclusion Criteria:

  • Illness or disabilities that preclude home-based heat therapy
  • Any evidence of cardiopulmonary disease
  • Severe hypertension (BP ≥180/110 mmHg; for safety reasons)
  • Secondary hypertension
  • Being on ≥3 antihypertensive agents
  • Chronic kidney disease
  • Diabetes mellitus or other systemic illness
  • Any history of substance abuse (other than tobacco)
  • Current cigarette smokers
  • History of gouty arthritis
  • Taking hormonal replacement therapy
  • Being obese (body mass index ≥30 kg/m2)
  • Endurance trained athletes
  • Impaired cognitive function or diagnosed dementia

Information from the National Library of Medicine

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): NCT03857490


Contacts
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Contact: Qi Fu, MD, PhD 214-345-8125 QiFu@texashealth.org
Contact: Steven Romero, PhD 817-735-5159 StevenRomero@unthsc.edu

Locations
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United States, Texas
Institute for Exercise and Environmental Medicine Recruiting
Dallas, Texas, United States, 75231
Contact: Qi Fu, MD, PhD    214-345-8125    QiFu@texashealth.org   
Contact: Monique Roberts-Reeves, RN    214-345-4656    MoniqueRobert-Reeves@texashealth.org   
Sponsors and Collaborators
University of Texas Southwestern Medical Center
Investigators
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Principal Investigator: Qi Fu, MD, PhD University of Texas Southwestern Medical Center
Principal Investigator: Steven Romero, PhD University of North Texas Health Science Center
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Responsible Party: University of Texas Southwestern Medical Center
ClinicalTrials.gov Identifier: NCT03857490    
Other Study ID Numbers: STU 072018-091
First Posted: February 28, 2019    Key Record Dates
Last Update Posted: June 4, 2020
Last Verified: June 2020
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description:

The PD/PIs will comply with the NIH policy of data sharing. Our goal is to make all our data available as quickly as possible to the scientific community. The privacy and rights of the participants will be protected. To address this goal, a Data Sharing Committee will be formed, made up of the two PIs and the statistician.

5) Researchers will make written application to the Data Sharing Committee, and once approved, data will be provided via a secure DropBox or ftp site.

Supporting Materials: Study Protocol
Statistical Analysis Plan (SAP)
Clinical Study Report (CSR)
Time Frame: Data will remain available for a period of time no less than 10 years after the close of the study, per University of Texas System guidelines for records retention.
Access Criteria: There are no specific access criteria IPD and no additional supporting information will be shared.

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University of Texas Southwestern Medical Center:
Ambulatory Blood Pressure Monitoring
Sympathetic Neural Control
Vascular Function
Additional relevant MeSH terms:
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Hypertension
Essential Hypertension
Vascular Diseases
Cardiovascular Diseases