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

Primary Purpose

Diabetes Mellitus, Type 1, Hypertension, Hypercholesterolemia

Status

Completed

Phase

Not Applicable

Locations

Austria

Study Type

Interventional

Intervention

Forearm blood flow measurement, Flow mediated dilation (FMD)

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

About this trial

This is an interventional diagnostic trial for Diabetes Mellitus, Type 1 focused on measuring Flicker induced vasodilatation, Flow mediated vasodilatation, Forearm blood flow, Retinal vessel diameter, Endothelial dysfunction

Eligibility Criteria

18 Years - undefined (Adult, Older Adult)All SexesAccepts Healthy Volunteers

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

Sites / Locations

Department of Clinical Pharmacology, Medical University of Vienna

Arms of the Study

Arm 1

Arm 2

Arm 3

Arm Type

Other

Arm Label

Arm Description

IDDM

Hypercholesterolemia and/or Hypertension

age/sex matched healthy control subjects

Outcomes

Primary Outcome Measures

Retinal vessel diameters (Retinal vessel analyzer)

Forearm Blood Flow

Secondary Outcome Measures

Full Information

NCT ID

NCT00432029

First Posted

February 5, 2007

Last Updated

July 1, 2008

Sponsor

Medical University of Vienna

1. Study Identification

Unique Protocol Identification Number

NCT00432029

Brief Title

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

Official Title

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

Study Type

Interventional

2. Study Status

Record Verification Date

June 2008

Overall Recruitment Status

Completed

Study Start Date

December 2006 (undefined)

Primary Completion Date

December 2007 (Actual)

Study Completion Date

January 2008 (Actual)

3. Sponsor/Collaborators

Name of the Sponsor

Medical University of Vienna

4. Oversight

5. 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.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study

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

Keywords

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

7. Study Design

Primary Purpose

Diagnostic

Study Phase

Not Applicable

Interventional Study Model

Parallel Assignment

Masking

None (Open Label)

Allocation

Non-Randomized

Enrollment

80 (Actual)

8. Arms, Groups, and Interventions

Arm Title

Arm Type

Other

Arm Description

IDDM

Arm Title

Arm Type

Other

Arm Description

Hypercholesterolemia and/or Hypertension

Arm Title

Arm Type

Other

Arm Description

age/sex matched healthy control subjects

Intervention Type

Procedure

Intervention Name(s)

Forearm blood flow measurement, Flow mediated dilation (FMD)

Intervention Description

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

Intervention Type

Device

Intervention Name(s)

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

Intervention Description

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

Primary Outcome Measure Information:

Title

Retinal vessel diameters (Retinal vessel analyzer)

Time Frame

8 min

Title

Forearm Blood Flow

Time Frame

8 min

10. Eligibility

Sex

All

Minimum Age & Unit of Time

18 Years

Accepts Healthy Volunteers

Eligibility 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

Overall Study Officials:

First Name & Middle Initial & Last Name & Degree

Michael Wolzt, MD

Organizational Affiliation

Department of Clinical Pharmacology, Medical University of Vienna

Official's Role

Principal Investigator

Facility Information:

Facility Name

Department of Clinical Pharmacology, Medical University of Vienna

City

Vienna

ZIP/Postal Code

1090

Country

Austria

12. IPD Sharing Statement

Citations:

PubMed Identifier

19369238

Citation

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.

Results Reference

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

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