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

NCT ID: NCT00432029

Last Updated: 2008-07-04

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

80 participants

Study Classification

INTERVENTIONAL

Study Start Date

2006-12-31

Study Completion Date

2008-01-31

Brief Summary

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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.

Detailed Description

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Conditions

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Diabetes Mellitus, Type 1 Hypertension Hypercholesterolemia Regional Blood Flow

Keywords

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

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

NONE

Study Groups

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1

IDDM

Group Type OTHER

Forearm blood flow measurement, Flow mediated dilation (FMD)

Intervention Type 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

Intervention Type DEVICE

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

2

Hypercholesterolemia and/or Hypertension

Group Type OTHER

Forearm blood flow measurement, Flow mediated dilation (FMD)

Intervention Type 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

Intervention Type DEVICE

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

3

age/sex matched healthy control subjects

Group Type OTHER

Forearm blood flow measurement, Flow mediated dilation (FMD)

Intervention Type 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

Intervention Type DEVICE

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

Interventions

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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

Intervention Type PROCEDURE

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

Intervention Type DEVICE

Eligibility Criteria

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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.
* 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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Medical University of Vienna

OTHER

Sponsor Role lead

Responsible Party

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Medical University of Vienna Department of Clinical Pharmacology

Principal Investigators

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Michael Wolzt, MD

Role: PRINCIPAL_INVESTIGATOR

Department of Clinical Pharmacology, Medical University of Vienna

Locations

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Department of Clinical Pharmacology, Medical University of Vienna

Vienna, , Austria

Site Status

Countries

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Austria

References

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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.

Reference Type DERIVED
PMID: 19369238 (View on PubMed)

Other Identifiers

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OPHT-180506

Identifier Type: -

Identifier Source: org_study_id