Non-invasive Measurement of Retinal Blood Flow Based on Vessel Analysis and Fourier Domain Optical Coherence Tomography in Patients With Hypertensive Retinopathy

Recently, a new and sophisticated method for assessment of retinal blood flow and retinal blood flow velocity profiles has become available. This technique is based on the combination of measurement of retinal vessel calibers with bidirectional Fourier domain optical coherence tomography (FDOCT). The valid measurement of retinal blood flow is of significant importance, because it is known that major ophthalmic diseases, such as hypertensive retinopathy, are associated with alterations in blood flow.

Hypertensive retinopathy is the most common manifestation of arterial hypertension in the eye. Elevated systemic blood pressure leads to generalized arteriolar narrowing caused by vasospasms and increased vascular tone. Further in the disease process, focal arteriolar narrowing, retinal haemorrhages, hard exudates and cotton wool spots can occur. Previous studies have shown that blood flow in the extraocular vessels and in the choroid is compromised in patients with arterial hypertension. However, data on the impact of arterial hypertension on retinal blood flow and retinal blood flow velocities are lacking.

The present study sets out to compare total retinal blood flow and retinal velocity profiles in patients with hypertensive retinopathy and healthy age- and sex-matched controls. Ocular perfusion pressure will be calculated based on measurements of blood pressure and intraocular pressure to allow for calculation of vascular resistance. In addition, velocity profiles at arterio-venous crossings will be measured. It is hypothesized that these velocity profiles are considerably modified in patients with stage 2 and 3 hypertensive retinopathy compared to healthy controls because of pronounced arterio-venous compression.

Study Overview

• Status: Recruiting
• Conditions: Hypertensive Retinopathy
• Intervention / Treatment: Device: Dynamic Vessel Analyzer; Other: FDOCT; Other: Ocular perfusion pressure

• Study Type: Interventional
• Enrollment (Anticipated): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1090
    • Recruiting
    • Department of Clinical Pharmacology, Medical University of Vienna

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

Inclusion criteria for healthy subjects

• Men and women aged over 18 years
• Non-smokers
• Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
• Systolic Blood Pressure ≤ 120 mmHg and Diastolic Blood Pressure ≤ 80 mmHg
• Normal ophthalmic findings, ametropia < 6 Dpt.

Inclusion criteria for patients with hypertensive retinopathy

• Men and women aged over 18 years
• Hypertensive retinopathy stage 2 or 3
• Normal ophthalmic findings except hypertensive retinopathy stage 2 and 3, ametropia < 6 Dpt.

Exclusion Criteria:

Any of the following will exclude a healthy subject from the study:

• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Presence or history of a severe medical condition as judged by the clinical investigator
• Presence or history of arterial hypertension
• Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study (except oral contraceptive)
• Blood donation during the previous three weeks
• Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator
• Ametropia >= 6 Dpt
• Pregnancy, planned pregnancy or lactating

Any of the following will exclude a patient with hypertensive retinopathy from the study:

• Participation in a clinical trial in the 3 weeks preceding the screening visit
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Presence or history of a severe medical condition as judged by the clinical investigator
• Blood donation during the previous three weeks
• Hypertensive retinopathy stage 4
• Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator
• Ametropia >= 6 Dpt
• Pregnancy, planned pregnancy or lactating

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: hypertensive retinopathy; 30 patients with hypertensive retinopathy stage 2 or 3	Device: Dynamic Vessel Analyzer; Retinal vessel diameter, total retinal blood flow (together with FD-OCT), retinal oxygen saturation; Other: FDOCT; total retinal blood flow (together with DVA), retinal blood velocities; Other Names: Fourier Domain Color Doppler Optical Coherence Tomography; Other: Ocular perfusion pressure; Measurement of intraocular pressure and mean arterial blood pressure for determination of ocular perfusion pressure
Experimental: healthy controls; 30 healthy age- and sex-matched controls	Device: Dynamic Vessel Analyzer; Retinal vessel diameter, total retinal blood flow (together with FD-OCT), retinal oxygen saturation; Other: FDOCT; total retinal blood flow (together with DVA), retinal blood velocities; Other Names: Fourier Domain Color Doppler Optical Coherence Tomography; Other: Ocular perfusion pressure; Measurement of intraocular pressure and mean arterial blood pressure for determination of ocular perfusion pressure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Total retinal blood flow	1 day

Secondary Outcome Measures

Outcome Measure	Time Frame
Retinal vessel diameter	1 day
Retinal blood velocities	1 day
Ocular perfusion pressure	1 day
Retinal (arterial and venous) oxygen saturation	1 day

Collaborators and Investigators

• Sponsor: Medical University of Vienna

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (Anticipated): December 1, 2023
• Study Completion (Anticipated): December 1, 2023

Study Registration Dates

• First Submitted: December 7, 2012
• First Submitted That Met QC Criteria: December 17, 2012
• First Posted (Estimate): December 20, 2012

Study Record Updates

• Last Update Posted (Actual): April 7, 2022
• Last Update Submitted That Met QC Criteria: April 6, 2022
• Last Verified: April 1, 2022

More Information

Terms related to this study

• Keywords: retinal blood flow; retinal vessel diameter; retinal oxygen saturation; retinal blood velocity; ocular perfusion pressure
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Eye Diseases; Hypertension; Retinal Diseases; Hypertensive Retinopathy
• Other Study ID Numbers: OPHT-220612