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The AVB Study: Prospective Study Comparing the Ahmed Valve and the Baerveldt Implant for Treating Refractory Glaucoma

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ClinicalTrials.gov Identifier: NCT00940823
Recruitment Status : Completed
First Posted : July 16, 2009
Results First Posted : March 13, 2018
Last Update Posted : March 13, 2018
Sponsor:
Collaborator:
Glaucoma Research Society of Canada
Information provided by (Responsible Party):
Panos G. Christakis, Credit Valley EyeCare

Study Type Interventional
Study Design Allocation: Randomized;   Intervention Model: Parallel Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition Glaucoma
Interventions Device: Ahmed FP7 Valve
Device: Baerveldt-350 Tube
Enrollment 238
Recruitment Details  
Pre-assignment Details  
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description Ahmed FP7 Valve Implant Baerveldt-350 Implant
Period Title: Overall Study
Started 124 114
Completed 89 82
Not Completed 35 32
Reason Not Completed
Death             8             12
Lost to Follow-up             27             20
Arm/Group Title Ahmed Group Baerveldt Group Total
Hide Arm/Group Description Patients received an Ahmed-FP7 valve implant at the time of surgery. Patients received a Baerveldt-350 implant at the time of surgery. Total of all reporting groups
Overall Number of Baseline Participants 124 114 238
Hide Baseline Analysis Population Description
[Not Specified]
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 124 participants 114 participants 238 participants
65  (17) 67  (15) 66  (16)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 124 participants 114 participants 238 participants
Female
59
  47.6%
73
  64.0%
132
  55.5%
Male
65
  52.4%
41
  36.0%
106
  44.5%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 124 participants 114 participants 238 participants
American Indian or Alaska Native
0
   0.0%
0
   0.0%
0
   0.0%
Asian
13
  10.5%
15
  13.2%
28
  11.8%
Native Hawaiian or Other Pacific Islander
0
   0.0%
0
   0.0%
0
   0.0%
Black or African American
15
  12.1%
13
  11.4%
28
  11.8%
White
96
  77.4%
86
  75.4%
182
  76.5%
More than one race
0
   0.0%
0
   0.0%
0
   0.0%
Unknown or Not Reported
0
   0.0%
0
   0.0%
0
   0.0%
Intraocular Pressure  
Mean (Standard Deviation)
Unit of measure:  mmHg
Number Analyzed 124 participants 114 participants 238 participants
31.1  (10.5) 31.7  (11.1) 31.4  (10.8)
Glaucoma Medication Use  
Mean (Standard Deviation)
Unit of measure:  Medications
Number Analyzed 124 participants 114 participants 238 participants
3.1  (1.0) 3.1  (1.1) 3.1  (1.0)
Prior Laser Therapies  
Mean (Standard Deviation)
Unit of measure:  Laser procedures
Number Analyzed 124 participants 114 participants 238 participants
0.8  (1.1) 1.0  (1.1) 0.9  (1.1)
Prior Ocular Surgeries  
Mean (Standard Deviation)
Unit of measure:  Ocular Surgeries
Number Analyzed 124 participants 114 participants 238 participants
1.8  (1.3) 1.6  (1.1) 1.7  (1.2)
Mean logMAR (converted) Visual Acuity   [1] 
Mean (Standard Deviation)
Unit of measure:  Units on a scale
Number Analyzed 124 participants 114 participants 238 participants
1.3  (1.0) 1.3  (1.1) 1.3  (1.1)
[1]
Measure Description:

LogMAR Visual Acuity is calculated by taking the log(Snellen Acuity/20). Normal vision (20/20) corresponds to 0 and complete blindness (no light perception, designated as 20/64000) corresponds to 3.5.

Hence, the lower the logMAR value, the better the vision.

1.Primary Outcome
Title Number of Participants With Surgical Failure (Composite Measure)
Hide Description
  1. IOP out of target range (5-18 mmHg inclusive) or <20% reduction from baseline for 2 consecutive visits after 3 months.
  2. De novo glaucoma surgery required (e.g., cyclodestructive procedure, additional tube shunt).
  3. Removal of the implant.
  4. Severe vision loss related to the surgery (endophthalmitis, suprachoroidal hemorrhage with vision loss, enucleation, evisceration, or phthisis bulbi) or progression to no light perception for any reason.
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
Ahmed FP7 Valve Implant
Baerveldt-350 Implant
Overall Number of Participants Analyzed 124 114
Measure Type: Number
Unit of Measure: participants
63 40
2.Secondary Outcome
Title Intraocular Pressure (IOP)
Hide Description [Not Specified]
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
124 patients were randomized to the Ahmed Group.
114 patients were randomized to the Ahmed Group.
Overall Number of Participants Analyzed 124 114
Mean (Standard Deviation)
Unit of Measure: mmHg
16.6  (5.9) 13.6  (5.0)
3.Secondary Outcome
Title Anti-glaucoma Medications
Hide Description [Not Specified]
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
124 patients were randomized to the Ahmed Group.
114 patients were randomized to the Ahmed Group.
Overall Number of Participants Analyzed 124 114
Mean (Standard Deviation)
Unit of Measure: glaucoma medications
1.8  (1.5) 1.2  (1.3)
4.Secondary Outcome
Title LogMAR Snellen Visual Acuity
Hide Description Visual acuity (VA) was tested monocularly (one eye at a time) using the manifest refraction adjusted for optical infinity using a standard Snellen Visual Acuity chart at 20 feet. Normal vision, or 20/20 vision, means that the participant can see at 20 feet what a healthy control can also see at 20 feet. Legal blindness, or 20/200 vision, means the participant can see at 20 feet what a healthy control can see at 200 feet. Hence, an increasing denominator implies visual impairment. Counting fingers was designated as 20/2000 vision, hand motions was 20/16000, light perception was 20/32000 and no light perception was 20/64000. To allow for appropriate statistical analysis, logMAR Snellen Visual Acuity was calculated using the formula: -logMAR (Snellen Acuity). This means that normal vision (20/20) would correspond to a value of 0, legal blindness (20/200) would correspond to a value of 1, and no light perception (20/64000) would correspond to 3.5.
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
124 patients were randomized to the Ahmed Group.
114 patients were randomized to the Ahmed Group.
Overall Number of Participants Analyzed 124 114
Mean (Standard Deviation)
Unit of Measure: logMAR units on a scale
1.6  (1.0) 1.6  (1.2)
5.Secondary Outcome
Title Number of Participants With Complications During or After Surgery
Hide Description [Not Specified]
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
124 patients were randomized to the Ahmed Group.
114 patients were randomized to the Ahmed Group.
Overall Number of Participants Analyzed 124 114
Measure Type: Count of Participants
Unit of Measure: Participants
78
  62.9%
79
  69.3%
6.Secondary Outcome
Title Number of Participants With Interventions After Surgery
Hide Description [Not Specified]
Time Frame 5 years
Hide Outcome Measure Data
Hide Analysis Population Description
[Not Specified]
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description:
124 patients were randomized to the Ahmed Group.
114 patients were randomized to the Ahmed Group.
Overall Number of Participants Analyzed 124 114
Measure Type: Count of Participants
Unit of Measure: Participants
64
  51.6%
58
  50.9%
Time Frame [Not Specified]
Adverse Event Reporting Description [Not Specified]
 
Arm/Group Title Ahmed Group Baerveldt Group
Hide Arm/Group Description Ahmed FP7 Valve Implant Baerveldt-350 Implant
All-Cause Mortality
Ahmed Group Baerveldt Group
Affected / at Risk (%) Affected / at Risk (%)
Total   --/--      --/--    
Show Serious Adverse Events Hide Serious Adverse Events
Ahmed Group Baerveldt Group
Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   14/124 (11.29%)      19/114 (16.67%)    
Eye disorders     
Suprachoroidal Hemorrhage   2/124 (1.61%)  2 3/114 (2.63%)  3
Phthisis Bulbi   1/124 (0.81%)  1 2/114 (1.75%)  2
Retinal Detachment   1/124 (0.81%)  1 0/114 (0.00%)  0
Endophthalmitis   1/124 (0.81%)  1 0/114 (0.00%)  0
Progression to no light perception   7/124 (5.65%)  7 7/114 (6.14%)  7
Device Explantation   1/124 (0.81%)  1 2/114 (1.75%)  2
Evisceration or enucleation   3/124 (2.42%)  3 0/114 (0.00%)  0
Hypotony Requiring Additional Surgery   1/124 (0.81%)  1 6/114 (5.26%)  6
Aqueous misdirection   2/124 (1.61%)  2 4/114 (3.51%)  4
Indicates events were collected by systematic assessment
Show Other (Not Including Serious) Adverse Events Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 0%
Ahmed Group Baerveldt Group
Affected / at Risk (%) # Events Affected / at Risk (%) # Events
Total   78/124 (62.90%)      79/114 (69.30%)    
Eye disorders     
Shallow Anterior Chamber   18/124 (14.52%)  18 19/114 (16.67%)  19
Choroidal Effusions   16/124 (12.90%)  16 18/114 (15.79%)  18
Tube Complications   17/124 (13.71%)  17 19/114 (16.67%)  19
Corneal Edema   14/124 (11.29%)  14 14/114 (12.28%)  14
Iritis   9/124 (7.26%)  9 14/114 (12.28%)  14
Cataract Progression   11/34 (32.35%)  11 13/32 (40.63%)  13
Encapsulated Bleb   14/124 (11.29%)  14 4/114 (3.51%)  4
Hyphema   4/124 (3.23%)  4 6/114 (5.26%)  6
Motility Disorder   6/124 (4.84%)  6 2/114 (1.75%)  2
High IOP requiring surgery   19/124 (15.32%)  19 11/114 (9.65%)  11
Other   6/124 (4.84%)  6 7/114 (6.14%)  7
Indicates events were collected by systematic assessment
  1. Using predetermined IOP cutoffs may not reflect individual patient outcomes.
  2. Visual field progression was not an outcome criteria due to the poor baseline vision of patients.
  3. Results can only be applied to patients with advanced glaucoma.
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
Name/Title: Dr. Iqbal Ike K. Ahmed
Organization: Prism Eye Institute
Phone: 905-456-3937
Other Publications:
Responsible Party: Panos G. Christakis, Credit Valley EyeCare
ClinicalTrials.gov Identifier: NCT00940823     History of Changes
Other Study ID Numbers: CVEC-AVB
GRSC-2005 ( Other Identifier: Glaucoma Research Society of Canada )
First Submitted: July 15, 2009
First Posted: July 16, 2009
Results First Submitted: August 21, 2016
Results First Posted: March 13, 2018
Last Update Posted: March 13, 2018