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

NCT00432029 | Completed

• 1 other identifier: OPHT-180506
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

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.

Conditions

Diabetes Mellitus, Type 1; Hypertension; Hypercholesterolemia; Regional Blood Flow

Keywords

Flicker induced vasodilatation; Flow mediated vasodilatation; Forearm blood flow; Retinal vessel diameter; Endothelial dysfunction

Outcome Measures

Primary Outcomes (2)

• Retinal vessel diameters (Retinal vessel analyzer)

  8 min

• Forearm Blood Flow

  8 min

Study Arms (3)

1

OTHER

IDDM

Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD); Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light

2

OTHER

Hypercholesterolemia and/or Hypertension

Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD); Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light

3

OTHER

age/sex matched healthy control subjects

Procedure: Forearm blood flow measurement, Flow mediated dilation (FMD); Device: Zeiss Retinal Vessel Analyzer (RVA), Stimulation with Flicker-light

Interventions

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

1; 2; 3

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

1; 2; 3

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.
• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Medical University of Vienna: lead

Study Sites (1)

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, 1090, Austria

Location

Related Publications (1)

• Pemp B, Garhofer G, Weigert G, Karl K, Resch H, Wolzt M, Schmetterer L. Reduced retinal vessel response to flicker stimulation but not to exogenous nitric oxide in type 1 diabetes. Invest Ophthalmol Vis Sci. 2009 Sep;50(9):4029-32. doi: 10.1167/iovs.08-3260. Epub 2009 Apr 15.

  PMID: 19369238 DERIVED

MeSH Terms

Conditions

Diabetes Mellitus, Type 1; Hypertension; Hypercholesterolemia

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases; Vascular Diseases; Cardiovascular Diseases; Hyperlipidemias; Dyslipidemias; Lipid Metabolism Disorders

Study Officials

• Michael Wolzt, MD

  Department of Clinical Pharmacology, Medical University of Vienna

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: February 5, 2007
• First Posted: February 6, 2007
• Study Start: December 1, 2006
• Primary Completion: December 1, 2007
• Study Completion: January 1, 2008
• Last Updated: July 4, 2008

Record last verified: 2008-06

Locations

AU (1)