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NCT Number: NCT00432029

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

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.

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Key information

Conditions

Diabetes Mellitus, Type 1 Autoimmune Diseases Cardiovascular Diseases Diabetes Mellitus Dyslipidemias Endocrine System Diseases Glucose Metabolism Disorders Hypercholesterolemia Hyperlipidemias Hypertension Immune System Diseases Lipid Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Regional Blood Flow Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, 1090, Austria

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Forearm blood flow measurement, Flow mediated dilation (FMD)

Procedure

Forearm blood flow measurement: baseline 1 min, 3 min after inflation of cuff, 4 min after 0.8mg Nitroglycerin

Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light

Device

Stimulation with Flicker-light: 1 min, measurement without flickering light 4 min after 0.8 mg Nitroglycerin

Primary outcomes

  1. Retinal vessel diameters (Retinal vessel analyzer)

    Time frame: 8 min

  2. Forearm Blood Flow

    Time frame: 8 min

Sponsors and collaborators

Lead sponsor

Medical University of Vienna

Other

Registry information

Official study title

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

Important dates

Study start
2006
Primary completion
2007
Study completion
2008
First posted
Feb 6, 2007
Registry last updated
Jul 4, 2008

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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