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

This study has been completed.
Sponsor:
Information provided by:
Medical University of Vienna
ClinicalTrials.gov Identifier:
NCT00432029
First received: February 5, 2007
Last updated: July 1, 2008
Last verified: June 2008
  Purpose

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 Intervention
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 Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: Correlation of Flicker Induced and Flow Mediated Vasodilatation in Patients With Endothelial Dysfunction and Healthy Volunteers

Resource links provided by NLM:


Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:
  • Retinal vessel diameters (Retinal vessel analyzer) [ Time Frame: 8 min ] [ Designated as safety issue: No ]
  • Forearm Blood Flow [ Time Frame: 8 min ] [ Designated as safety issue: No ]

Enrollment: 80
Study Start Date: December 2006
Study Completion Date: January 2008
Primary Completion Date: December 2007 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: 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

No publications provided by Medical University of Vienna

Additional 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
Study First Received: February 5, 2007
Last Updated: July 1, 2008
Health Authority: Austria: Agency for Health and Food Safety

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
Diabetes Mellitus, Type 1
Hypercholesterolemia
Hypertension
Flushing
Hyperemia
Hot Flashes
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Autoimmune Diseases
Immune System Diseases
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Vascular Diseases
Cardiovascular Diseases
Signs and Symptoms

ClinicalTrials.gov processed this record on July 23, 2014