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Retinal Blood Flow in Response to an Intravitreal Injection of Ranibizumab for Central Retinal Vein Occlusion (CRVO)

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified February 2011 by University of Toronto.
Recruitment status was:  Not yet recruiting
Information provided by:
University of Toronto Identifier:
First received: February 15, 2011
Last updated: February 22, 2011
Last verified: February 2011
Ranibizumab (Lucentis, Genentech) is an off-label drug used for the clinical treatment of central retinal vein occlusion, which is one of the most common retinal vascular disorders. Despite its clinical effectiveness, concerns remain regarding the systemic effects of the drug and previous studies have noted retinal arteriolar vasoconstriction following a ranibizumab injection. We aim to provide a physiological basis to these observations by assessing retinal blood flow before and after the ranibizumab injections. Specifically, we will assess the blood flow parameters (i.e. retinal vessel diameter, velocity & flow) immediately before the first injection and post-injection over a follow-up continued treatment period.

Central Retinal Vein Occlusion

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Retinal Blood Flow in Response to an Intravitreal Injection of Ranibizumab for Central Retinal Vein Occlusion

Resource links provided by NLM:

Further study details as provided by University of Toronto:

Primary Outcome Measures:
  • Quantitative change in retinal blood flow [ Time Frame: Baseline, 7, 30 days ]
    Retinal blood flow will be measured using Canon Laser Blood Flowmeter

Secondary Outcome Measures:
  • Best Corrected Visual Acuity (LogMAR, EDTRS) [ Time Frame: Baseline, 7, 30 days ]
    Best Corrected Visual Acuity will be examined using 96% and 10 % contrast EDTRS letter charts

Estimated Enrollment: 30
Study Start Date: June 2011
Anti-VEGF group
Patients who are clinically indicated for the intravitreal injection of ranibizumab
Age-matched controls
Group of healthy participants who will be age and gender matched

Detailed Description:

Ranibizumab is an antibody fragment designed to inhibit the activity of Vascular Endothelial Growth Factor (VEGF), which is responsible for the neovascularization and retinal edema responsible for interference of normal vision in central retinal vein occlusion. However, VEGF has a role in the vasculature as a vasodilator where it alters the expression of tight junction proteins and upregulates the release of the vasodilator nitric oxide. Consequently, intravitreal ranibizumab injections could result in systemic inhibition of VEGF, leading to long-term retinal arteriolar vasoconstriction and potentially adverse cerebrovascular and myocardial accidents. Therefore, evaluating retinal blood flow would provide a physiological foundation to this concern and provide physicians with valuable information regarding the risks of continued ranibizumab therapy.

Given the role of VEGF as a vasodilator in the vasculature where it works to alter the expression of tight junction proteins and the production of vasoactive substances especially nitric oxide, inhibiting this molecule with ranibizumab could result in vasoconstriction in these vessels. We hypothesize that vasoconstriction and decreased retinal blood flow will be observed after an intravitreal injection of ranibizumab for treatment of central retinal vein occlusion.


Ages Eligible for Study:   50 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Patients with central retinal vein occlusion will be recruited from the Retina Clinics of Toronto Western Hospital

Inclusion Criteria:

  • Age > 50 years
  • central retinal vein occlusion scheduled for first intravitreal injection of ranibizumab as part of their clinical care

Exclusion Criteria:

  • previous history of intravitreal therapy,
  • history of thromboembolic events,
  • glaucoma or an intraocular pressure >21 mmHg
  • diabetes mellitus or altered blood viscosity syndromes
  • blood donation in the previous 2 weeks
  • refractive error of +/- 6.00 DS and/or 2.00 DC
  Contacts and Locations
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Please refer to this study by its identifier: NCT01303276

Contact: Edmund Tsui, BSc (416)603-5694 ext 5694
Contact: Tien Wong, BSc (416)603-5694 ext 5694

Canada, Ontario
Toronto Western Hospital Not yet recruiting
Toronto, Ontario, Canada, M5T 2S8
Contact: Edmund Tsui, BSc    (416)603-5694 ext 5694   
Contact: Tien Wong, BSc    (416)603-5694 ext 5694   
Principal Investigator: Christopher Hudson, PhD         
Sub-Investigator: Michael Brent, MD         
Sub-Investigator: Wai-Ching Lam, MD         
Sub-Investigator: Robert G Devenyi, MD         
Sub-Investigator: Mark Mandelcorn, MD         
Sponsors and Collaborators
University of Toronto
Principal Investigator: Christopher Hudson, PhD University of Toronto
  More Information

Responsible Party: Christopher Hudson, University of Toronto Identifier: NCT01303276     History of Changes
Other Study ID Numbers: CRVO-blood flow study
Study First Received: February 15, 2011
Last Updated: February 22, 2011

Keywords provided by University of Toronto:
retinal vein occlusion
blood flow

Additional relevant MeSH terms:
Retinal Vein Occlusion
Retinal Diseases
Eye Diseases
Venous Thrombosis
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases
Immunologic Factors
Physiological Effects of Drugs
Angiogenesis Inhibitors
Angiogenesis Modulating Agents
Growth Substances
Growth Inhibitors
Antineoplastic Agents processed this record on May 25, 2017