Effects of Change in Blood Pressure on Retinal Capillary Rarefaction in Patients With Arterial Hypertension

January 4, 2024 updated by: Gerhard Garhofer, Medical University of Vienna

Effects of Change in Blood Pressure on Retinal Capillary Rarefaction in Patients With Arterial Hypertension - a Pilot Study

To evaluate whether in patients with initially poorly-controlled arterial hypertension, structural and functional differences in the retina and choroid remain after achieving a well-controlled blood pressure.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Optical Coherence Tomography Angiography (OCT-A) is an ocular imaging technique which allows fast and non-invasive assessment of the retinal microvasculature. With the OCT-A, a reduction in capillary density in patients with arterial hypertension has been found. In animal experiments, this so called retinal capillary rarefaction could be reversed after administration of antihypertensive medication.

The main aim of the present study is to evaluate whether in patients with initially poorly-controlled hypertension, an increase in capillary density can be demonstrated, if patients achieve well-controlled blood pressure with antihypertensive medication. In addition changes in retinal oxygen metabolism and choroidal blood flow will be investigated.

Study Type

Observational

Enrollment (Estimated)

30

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients with initially diagnosed or pre-existing mild to moderate primary arterial hypertension (systolic office blood pressure ≥ 140 mmHg and/or diastolic office blood pressure ≥ 90 mmHg) with a planned initiation or planned adaption of antihypertensive medication by the Department of Cardiology.

Description

Inclusion Criteria:

  • Men and Women aged ≥ 18 years
  • Signed informed consent
  • Apart from hypertensive retinopathy, normal ophthalmic findings
  • Non-Smokers
  • Patients with initially diagnosed or pre-existing mild to moderate primary arterial hypertension (systolic office blood pressure ≥ 140 mmHg and/or diastolic office blood pressure ≥ 90 mmHg)
  • Planned initiation of antihypertensive medication or planned adaption of antihypertensive medication by the Department of Cardiology
  • Subject agrees to perform regular blood pressure self-measurements and to document blood pressure values in a diary

Exclusion Criteria:

  • Participation in a clinical trial in the three weeks preceding the study
  • Blood donation in the three weeks preceding the study
  • Symptoms of a clinically relevant illness in the three weeks preceding the study
  • History of family history of epilepsy
  • Secondary hypertension (e.g.: hyperaldosteronism, pheochromocytoma, renal artery stenosis, renal parenchymal diseases, Cushing-syndrome, Coarctatio aortae)
  • History of hypertensive encephalopathy or intracerebral bleeding
  • Diabetes mellitus Type 1 or Type 2
  • Pregnant or breast-feeding women
  • Women of childbearing potential (neither menopausal, nor hysterectomized, nor sterilized) not using effective contraception

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in retinal vessel density after achieving blood pressure treatment target (OCT-A).
Time Frame: 12 weeks
As OCT devices are able to calculate the movements of erythrocytes, retinal perfusion can be visualized with Optical Coherence Tomography Angiography. No contrast media is necessary for the representation of retinal vessels.
12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in choroidal vascularity index after achieving blood pressure treatment target (EDI-OCT).
Time Frame: 12 weeks
The choroid will be imaged with the enhanced-depth-imaging-OCT (EDI-OCT) (Spectralis, Heidelberg Engineering, Heidelberg, Germany). By using an automatic detection algorithm, developed by Tian et al., the choroid will be separated from the sclera and Bruch´s membrane. Afterwards, the image will be binarized using the software Fiji ImageJ. An autolocal threshold will be applied and the image will be converted into an RGB (red, green, blue) image, thereby determining the luminal area of the choroid. The choroidal vascularity index is obtained by dividing the luminal area by the total choroidal area.
12 weeks
Change in neurovascular coupling after achieving blood pressure treatment target (DVA).
Time Frame: 12 weeks
The DVA allows for the real time measurement of retinal vessel diameters in vivo. The DVA is a commercially available system (IMEDOS, Jena, Germany) which comprises a fundus camera, a video camera, a real time monitor and a personal computer with an analyzing software for the accurate determination of retinal arterial and venous diameters. Every second a maximum of 25 readings of vessel diameter can be obtained. For this purpose the fundus is imaged onto the charge coupled device chip of the video camera. The consecutive fundus images are digitized using a frame grabber. In addition, the fundus image can be inspected on the real time monitor and, if necessary, stored on a video recorder. Evaluation of the retinal vessel diameters can either be done online or offline from the recorded video tapes.
12 weeks
Change in retinal oxygen saturation after achieving blood pressure treatment target (DVA).
Time Frame: 12 weeks
Retinal oxygen saturation measurement is based on the image analysis by the oxygen module of the commercially available Dynamic Vessel Analyzer (DVA, Imedos, Germany). Two monochromatic fundus images are recorded by the retinal oximeter. In an image, obtained by the camera and filter assembly, the operator has to mark the vessel of interest by a mouse click. The vessel is traced automatically applying the following procedure. The vessel walls are located as photometric edges in the vicinity of the mouse cursor in the green channel image. If edges are determined, the search is continued in their proximity.
12 weeks
Change in ocular blood flow after achieving blood pressure treatment target (LSFG).
Time Frame: 12 weeks
A commercially available LSFG (Nidek, Japan) system will be used in the present study. The LSFG device consists of a fundus camera equipped with a diode laser with a wavelength of 830 nm and a charge-coupled device. NB, the relative velocity of blood flow, is derived from the pattern of speckle contrast produced by the interference of a laser scattered by blood cells moving in the ocular fundus. Images are acquired continuously at the rate of 30 frames per seconds in a 4-second time period and stored on a personal computer. Equipped analysis software synchronizes the captured MBR images in each cardiac cycle, and averages the MBR in each heartbeat to produce a heartbeat map of the ONH and the retina/choroid.
12 weeks
Change in retinal oxygen extraction after achieving blood pressure treatment target.
Time Frame: 12 weeks
Retinal oxygen extraction will be determined by measuring retinal blood flow (LSFG), retinal oxygen saturation (DVA) and retinal vessel diameter (DVA). For the calculation of retinal oxygen extraction, the formula of Werkmeister et al. will be used, which will be slightly modified as retinal blood flow is measured with LSFG and not with Doppler OCT.
12 weeks
Change in ocular perfusion pressure and arterial blood pressure after achieving blood pressure treatment target.
Time Frame: 12 weeks
mOPP = 2/3 mBP- IOP Blood pressure will be measured with an automated oscillometric device
12 weeks
Change in retinal vessel diameter after achieving blood pressure treatment target (DVA).
Time Frame: 12 weeks
Two monochromatic fundus images are recorded by the retinal oximeter. In an image, obtained by the camera and filter assembly, the operator has to mark the vessel of interest by a mouse click. The vessel is traced automatically applying the following procedure. The vessel walls are located as photometric edges in the vicinity of the mouse cursor in the green channel image. If edges are determined, the search is continued in their proximity.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2023

Primary Completion (Estimated)

August 1, 2024

Study Completion (Estimated)

August 1, 2024

Study Registration Dates

First Submitted

September 5, 2023

First Submitted That Met QC Criteria

October 19, 2023

First Posted (Actual)

October 24, 2023

Study Record Updates

Last Update Posted (Estimated)

January 8, 2024

Last Update Submitted That Met QC Criteria

January 4, 2024

Last Verified

January 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OPHT-240323

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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