Recruiting

Observational Study

Sponsor:

Milton S. Hershey Medical Center

Code:

NCT03496792

Conditions

Blood Pressure

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Interventions

Tilt + external pressure

Tilt + no external pressure.

Limb occlusion + negative pressure

Limb occlusion + no negative pressure

Study Details

Brief summary:

This research is being done to find out whether distension of veins in legs will cause a rise in blood pressure (orthostatic hypertension).

Conditions

Blood Pressure

Study ID

NCT03496792

Start date

Mar 10, 2020

Status verified date

Jul, 2026

Completion date

Nov 1, 2027

Anticipated

Primary completion date

Nov 1, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Are capable of giving informed consent
  • Are of any race or ethnicity
  • Are fluent in written and spoken English
  • Whose history and physical exam did not uncover any exclusion criteria
  • Are 18 years of age

For subjects with elevated standing BP

  • Systolic BP (SBP) during standing is at least 10 mmHg > the supine SBP
  • Patients with a diagnosis of stage I hypertension without other chronic diseases may be INCLUDED

For normal subjects without elevated standing BP

  • The change in SBP by standing is within ± 5 mmHg from the supine SBP
  • Matched gender, similar age and BMI (within 10%) to participants with elevated standing BP
  • Free of acute or chronic medical conditions

Exclusion Criteria:

  • Age < 18 years of age
  • Are a pregnant or nursing woman
  • Are a prisoner or institutionalized individual or unable to consent
  • Have chronic diseases (e.g. heart, lung, neuromuscular disease, or cancer) other than stage I hypertension
  • Have orthostatic hypotension or a history of syncope
  • Current smoker
  • History of blood clots

Study Design

Enrollment

30 participants

Anticipated

Allocation

Non randomized

Intervention Model

Parallel Assignment

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Tilt + external pressure

Tilt + external pressure on legs performed in both "BP elevated with standing" and "BP maintained with standing" groups.

placebo comparator: Tilt + no external pressure

Tilt + no external pressure performed in both "BP elevated with standing" and "BP maintained with standing" groups.

experimental: Limb occlusion + negative pressure

Limb occlusion + negative pressure performed in both "BP elevated with standing" and "BP maintained with standing" groups.

placebo comparator: Limb occlusion + no negative pressure

Limb occlusion + no negative pressure performed in both "BP elevated with standing" and "BP maintained with standing" groups.

Interventions

Tilt + external pressure

In Visit 1, the anti-shock trousers will be inflated to 20, 40, or 60 mmHg. BP will be measured 3 times from the brachial artery. Then the table will be tilted head up to a maximum of 70o for up to 10 min, while BP will be measured from the brachial artery at 1 min intervals. The tilt table is returned to 0o and the resting supine baseline BP will be collected. Then, the anti-shock trousers will be inflated to a different pressure (20, 40, or 60 mmHg) and the head up tilt will be repeated. Repetitions at the various pressures will be performed in a random order with suitable resting intervals in between the tilting bouts.

Tilt + no external pressure.

In Visit 1, the anti-shock trousers will NOT be inflated. Auscultatory BP will be measured 3 times from the brachial artery. Thereafter, the table will be tilted head up to a maximum of 70o for up to 10 min, while BP will be measured from the brachial artery at 1 min intervals.

Limb occlusion + negative pressure

In Visit 2, a cuff will be placed on the thigh of a leg that is sealed in an airtight pressure tank. After the cuff is inflated to 250 mmHg, the pressure in the tank will be reduced to -100mmHg for 2 minutes. The application of negative pressure creates a suction effect on the leg, and leads to an overall increase in pressure gradient across the blood vessel wall and induces vascular distension.

Limb occlusion + no negative pressure

In Visit 2, a cuff will be placed on the thigh of a leg that is sealed in an airtight pressure tank. The cuff is inflated to 250 mmHg for 2 minutes, but the pressure in the tank is not changed.

Primary outcome measure

  • Muscle Sympathetic Nerve Activity (MSNA) in bursts/min or arbitrary units/min [ Time Frame: Recorded continuously during Visit 2, the 4-5 hr Negative Pressure study visit. ]

Central Contacts and Locations

Central contacts

Jian Cui, PhD

717-531-1799jcui@pennstatehealth.psu.edu

Kris Gray

717-531-4589kgray1@pennstatehealth.psu.edu

Locations

Penn State Milton S. Hershey Medical Center

Recruiting

Hershey, Pennsylvania, United States, 17033

Contacts

Kristen Gray

7175314589kgray1@pennstatehealth.psu.edu

Jian Cui

717-531-1799jcui@pennstatehealth.psu.edu

More Information

Sponsor

Milton S. Hershey Medical Center

Last update posted

Jul 9, 2026

Last verified

Jul, 2026

Keywords

  • venous distension reflex

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Milton S. Hershey Medical Center on 2026-07-09.