Clinical trial NCT01753648: Non-invasive Measurement of Retinal Blood Flow Based on Vessel Analysis and Fourier Domain Optical Coherence Tomography in Patients With Hypertensive Retinopathy
Official title: Non-invasive Measurement of Retinal Blood Flow Based on Vessel Analysis and Fourier Domain Optical Coherence Tomography in Patients With Hypertensive Retinopathy
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Hypertensive Retinopathy
Keywords: retinal blood flow
retinal blood velocity
retinal oxygen saturation
retinal vessel diameter
ocular perfusion pressure
Lead sponsor: Medical University of Vienna
Sponsor class: OTHER
First posted: 2012-12-20
Enrollment: 60
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: 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.


Eligibility criteria: 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

Primary outcomes:
measure: Total retinal blood flow
timeFrame: 1 day
Secondary outcomes:
measure: Retinal vessel diameter
timeFrame: 1 day
measure: Retinal blood velocities
timeFrame: 1 day
measure: Ocular perfusion pressure
timeFrame: 1 day
measure: Retinal (arterial and venous) oxygen saturation
timeFrame: 1 day
Other outcomes:
Locations:
city: Vienna
country: Austria
facility: Department of Clinical Pharmacology, Medical University of Vienna
Study officials:
References: