Physiology, OcularPhase 2NCT00810927
Role of Nitrogen Oxide (NO) in the Control of Choroidal Blood Flow During a Decrease in Ocular Perfusion Pressure
A Phase 2 study testing Suction cup application, Laser Doppler flowmetry and Measurement of intraocular pressure in people with Physiology, Ocular and Microcirculation, run by Medical University of Vienna at 1 site in Austria.
Trial summary
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. Read more about this study
- Who is it for?
- Ages 19 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Physiology, Ocular, Microcirculation, Regional Blood Flow
- What is being tested?
- Suction cup application, Laser Doppler flowmetry and Measurement of intraocular pressure
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 22 participants
- Where
- 1 siteAustria
- Study dates
- Sep 2003to Aug 2005
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropia < 3 Dpt.
Who cannot join
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
- Blood donation during the previous 3 weeks
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, 1090
About this study
Official title: Role of NO in the Control of Choroidal Blood Flow During a Decrease in Ocular Perfusion Pressure
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. However, the mechanism behind choroidal autoregulation remains unclear.
In the present study autoregulation of the choroid will be investigated during a decrease in ocular perfusion pressure, which will be achieved by an increase in intraocular pressure. Pressure/flow relationships will be investigated in the absence or presence of a NO synthase inhibitor. As a control substance the alpha-receptor agonist phenylephrine will be used.
- Being tested
- Suction cup application, Laser Doppler flowmetry, Measurement of intraocular pressure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Suction cup applicationProcedure or surgery
he IOP will be raised by a 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus.
Laser Doppler flowmetryProcedure or surgery
Measurement of choroidal blood flow
Measurement of intraocular pressureProcedure or surgery
| Study group | Role | What they receive |
|---|---|---|
| 1 | Active comparator | Phenylephrine (Neosynephrine®, Abbott Laboratories, North Chicago, IL, USA) dose: 1µg/(kg.min), infusion period 20 minutes Receives: Procedure: Suction cup application; Procedure: Laser Doppler flowmetry; Procedure: Measurement of intraocular pressure |
| 2 | Active comparator | NG-monomethyl-L-arginine (L-NMMA, Clinalfa, Läufelfingen, Switzerland) dose: bolus 6mg/kg over 5 minutes followed by a continuous infusion of 60µg/(kg.min) over 15 minutes Receives: Procedure: Suction cup application; Procedure: Laser Doppler flowmetry; Procedure: Measurement of intraocular pressure |
| 3 | Placebo comparator | Physiologic saline solution Receives: Procedure: Suction cup application; Procedure: Laser Doppler flowmetry; Procedure: Measurement of intraocular pressure |
What is being measured
The primary outcome is the main question the study is designed to answer.
ocular perfusion pressure - choroidal blood flow relationship
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Dec 2008 (estimated)
- Study startSep 2003
- Primary completionFeb 2004
- Study completionAug 2005
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Physiology, OcularStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 22 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Investigators
- Gabriele Fuchsjäger-Mayrl, MD, Principal investigator, Department of Clinical Pharmacology, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00810927
- Sponsor's protocol ID
- OPHT-270602
- Status last verified
- Dec 2008
- First submitted
- 17 Dec 2008
- Last updated
- 18 Dec 2008
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 18 Dec 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Role of NO in the Control of Choroidal Blood Flow During a Decrease in Ocular Perfusion Pressure
- ClinicalTrials.gov ID
- NCT00810927
- Acronym / sponsor ID
- OPHT-270602
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 22 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Sep 2003
- Primary completion
- Feb 2004 (actual)
- Study completion
- Aug 2005 (actual)
- First posted
- 18 Dec 2008 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. However, the mechanism behind choroidal autoregulation remains unclear.
In the present study autoregulation of the choroid will be investigated during a decrease in ocular perfusion pressure, which will be achieved by an increase in intraocular pressure. Pressure/flow relationships will be investigated in the absence or presence of a NO synthase inhibitor. As a control substance the alpha-receptor agonist phenylephrine will be used.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 1 | Active comparator | Procedure: Suction cup application, Procedure: Laser Doppler flowmetry, Procedure: Measurement of intraocular pressurePhenylephrine (Neosynephrine®, Abbott Laboratories, North Chicago, IL, USA) dose: 1µg/(kg.min), infusion period 20 minutes |
| 2 | Active comparator | Procedure: Suction cup application, Procedure: Laser Doppler flowmetry, Procedure: Measurement of intraocular pressureNG-monomethyl-L-arginine (L-NMMA, Clinalfa, Läufelfingen, Switzerland) dose: bolus 6mg/kg over 5 minutes followed by a continuous infusion of 60µg/(kg.min) over 15 minutes |
| 3 | Placebo comparator | Procedure: Suction cup application, Procedure: Laser Doppler flowmetry, Procedure: Measurement of intraocular pressurePhysiologic saline solution |
Who may qualify
- Ages
- 19 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropia < 3 Dpt.
Key exclusion criteria (6 listed)
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Suction cup applicationhe IOP will be raised by a 11 mm diameter, standardized suction cup placed on the temporal sclera with the anterior edge at least 1 mm from the limbus. | Procedure or surgery | 1, 2, 3 |
| Laser Doppler flowmetryMeasurement of choroidal blood flow | Procedure or surgery | 1, 2, 3 |
| Measurement of intraocular pressure | Procedure or surgery | 1, 2, 3 |
Primary outcome
ocular perfusion pressure - choroidal blood flow relationship
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Dec 2008.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gabriele Fuchsjäger-Mayrl, MD principal investigator
Department of Clinical Pharmacology, Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Suction cup application, Laser Doppler flowmetry and Measurement of intraocular pressure in people with Physiology, Ocular and Microcirculation, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Dec 2008. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
ocular perfusion pressure - choroidal blood flow relationship. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Dec 2008.