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RECRUITINGINTERVENTIONAL

The Venous Distension Reflex and Orthostatic Hypertension

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

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

Who May Be Eligible (Plain English)

Who May Qualify: - Are capable of giving willing to sign a consent form - 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 Who Should NOT Join This Trial: - 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 Always talk to your doctor about whether this trial is right for you.

Original Eligibility Criteria

View original clinical language
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

Treatments Being Tested

OTHER

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.

OTHER

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.

OTHER

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.

OTHER

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.

Locations (1)

Penn State Milton S. Hershey Medical Center
Hershey, Pennsylvania, United States