Study of the Relation Between In Vivo and In Vitro Response of Human Small Vessels
investigate the relationship between in vivo and in vitro vascular responses
Cardiovascular Diseases+7
+ Hyperlipidemias
+ Metabolic Diseases
Treatment Study
Summary
Study start date: March 1, 1997
Actual date on which the first participant was enrolled.Over the last ten years, we have been interested in the investigation of endothelial function in patients with essential hypertension and patients with hypercholesterolemia. We have performed intra-arterial infusion of endothelium-dependent and endothelium-independent drugs into the brachial artery with noninvasive measurement of the response of the forearm vasculature by means of strain gauge plethysmography. Those studies have allowed us to: a) demonstrate the presence of endothelial dysfunction in patients with essential hypertension and in patients with hypercholesterolemia; and b) identify an abnormality in the endothelium-derived nitric oxide system that is responsible for endothelial dysfunction in these patients. Further studies to more precisely determine the intracellular processes that mediate this abnormality in endothelial function in these patients are limited by the inherent shortcomings of the in vivo technique. An alternative possibility is the study of human small vessels in vitro; however, the relationship between in vivo and in vitro vascular responses to endothelium-dependent and -independent agonists has not been established. In the present study, we propose to investigate this relationship in normal volunteers, patients with essential hypertension, and patients with hypercholesterolemia.
Protocol
This section provides details of the study plan, including how the study is designed and what the study is measuring.87 patients to be enrolled
Total number of participants that the clinical trial aims to recruit.Treatment Study
Eligibility
Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.Any sex
Biological sex of participants that are eligible to enroll.Healthy volunteers allowed
If individuals who are healthy and do not have the condition being studied can participate.Conditions
Pathology
Criteria
Patients (men and nonpregnant women) with systemic hypertension, patients with hypercholesterolemia, and normal volunteers. All blood pressure recordings must be consistently elevated. No renovascular hypertension or other etiologies for elevated blood pressure. No definite evidence of accelerated or malignant hypertension (diastolic pressures above 115 mmHg, with associated encephalopathic changes, papilledema, progressive renal failure, or congestive heart failure), or serious intercurrent illness. Patients in whom withdrawal of antihypertensive medications is considered hazardous are ineligible. Patients in whom the blood pressure remains at normal levels 2 weeks after withdrawal of antihypertensive treatment will be closely monitored until they become hypertensive, at which time they will undergo the study. Patients in whom blood pressure does not increase after 2 months of discontinuation of therapy will be excluded from the study. Patients with coexistent hypertension and hypercholesterolemia are ineligible. Normal volunteers who are not taking any kind of medication are eligible. No history of diabetes, peripheral vascular disease, coagulopathy, or any other disease predisposing to vasculitis or Raynaud's phenomenon. No history of keloid formation. All patients must be capable of giving informed consent for all procedures.
Study Centers
These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.This study has 1 location
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, United StatesOpen National Heart, Lung and Blood Institute (NHLBI) in Google Maps