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Correlation of Flicker Induced and Flow Mediated Vasodilatation in Patients With Endothelial Dysfunction and Healthy Volunteers.

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ClinicalTrials.gov Identifier: NCT00432029
Recruitment Status : Completed
First Posted : February 6, 2007
Last Update Posted : July 4, 2008
Sponsor:
Information provided by:

Study Description
Brief Summary:

A couple of studies have shown that illuminating the eye with diffuse flickering light is accompanied by an increase of retinal vessel diameters, optic nerve head blood flow and retinal blood flow. We have recently used this visual stimulation technique as a new and powerful tool for the non-invasive investigation of vascular reactivity. Additionally, we could show that this response is diminished in patients with vascular pathologies and that the response is dependent on nitric oxide, indicating that flicker induced vasodilatation may reflect endothelial dysfunction and may be a new approach to test endothelial function in vivo.

One of the most widely used method for the assessment of endothelial function is flow mediated dilatation (FMD). FMD has been shown to give a reliable estimate of vascular function in vivo. In the present study, we set out to compare the standard method for the evaluation of endothelial function, FMD, to flicker induced vasodilatation in the retina.


Condition or disease Intervention/treatment
Diabetes Mellitus, Type 1 Hypertension Hypercholesterolemia Regional Blood Flow Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD) Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light

Study Design

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 80 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Correlation of Flicker Induced and Flow Mediated Vasodilatation in Patients With Endothelial Dysfunction and Healthy Volunteers
Study Start Date : December 2006
Primary Completion Date : December 2007
Study Completion Date : January 2008

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U.S. FDA Resources

Arms and Interventions

Arm Intervention/treatment
1
IDDM
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin
2
Hypercholesterolemia and/or Hypertension
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin
3
age/sex matched healthy control subjects
Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD)
Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin
Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light
Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin


Outcome Measures

Primary Outcome Measures :
  1. Retinal vessel diameters (Retinal vessel analyzer) [ Time Frame: 8 min ]
  2. Forearm Blood Flow [ Time Frame: 8 min ]

Eligibility Criteria

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

Patients with diabetic retinopathy:

  • Men and women aged > 18 years.
  • Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant.
  • Inclusion criteria of patients are insulin dependent diabetes mellitus (IDDM) with non or mild non-proliferative diabetic retinopathy. Patients with no signs of diabetic retinopathy (level 1) or patients with one or more microaneurysms (level 2) will be included. Level of diabetic retinopathy will be assessed according to the criteria defined in the AREDS-study.(1991)
  • serum cholesterol < 250 mg/dl (treated or untreated)

Patients with mild hypertension and/or hypercholesterinemia:

  • Men and women aged > 18 years.
  • mild essential hypertension defined as a blood pressure meeting the criterion of hypertension grade 1 of the World Health Organisation blood pressure classification
  • systolic blood pressure between 140 and 159 mmHg and diastolic blood pressure between 90 and 99 mmHg and/or
  • serum cholesterol > 250 mg/dl
  • blood pressure will be measured at two different occasion in a sitting positions

Healthy subjects:

  • Men and women aged > 18 years.
  • Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
  • normal ocular findings
  • serum cholesterol < 200 mg/dl
  • systolic blood pressure between 110mmHg and 140mmHg
  • diastolic blood pressure < 90 mmHg

Exclusion Criteria:

  • Abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
  • Symptoms of a clinically relevant illness in the 3 weeks before the first study day
  • Blood donation during the previous 3 weeks
  • other ocular pathologies than diabetic retinopathy level 1 or 2
  • History or family history of epilepsy
  • Ametropy greater or equal than 3 dpt
  • systolic blood pressure < 100mmHg
  • diastolic blood pressure < 75mmHg
  • pregnant or lactating women
Contacts and Locations

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): NCT00432029


Locations
Austria
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
Investigators
Principal Investigator: Michael Wolzt, MD Department of Clinical Pharmacology, Medical University of Vienna
More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Michael Wolzt, Medical University of Vienna Department of Clinical Pharmacology
ClinicalTrials.gov Identifier: NCT00432029     History of Changes
Other Study ID Numbers: OPHT-180506
First Posted: February 6, 2007    Key Record Dates
Last Update Posted: July 4, 2008
Last Verified: June 2008

Keywords provided by Medical University of Vienna:
Flicker induced vasodilatation
Flow mediated vasodilatation
Forearm blood flow
Retinal vessel diameter
Endothelial dysfunction

Additional relevant MeSH terms:
Diabetes Mellitus
Hypercholesterolemia
Diabetes Mellitus, Type 1
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Autoimmune Diseases
Immune System Diseases
Glucuronyl glucosamine glycan sulfate
Anticoagulants
Hypolipidemic Agents
Antimetabolites
Molecular Mechanisms of Pharmacological Action
Lipid Regulating Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Hypoglycemic Agents
Physiological Effects of Drugs