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In vitro fluid dynamics of the Ahmed glaucoma valve modified with expanded polytetrafluoroethylene.

dc.contributor.author DeCroos, Francis Char
dc.contributor.author Kondo, Yuji
dc.contributor.author Mordes, Daniel
dc.contributor.author Lee, Maria Regina
dc.contributor.author Ahmad, Sameer
dc.contributor.author Asrani, Sanjay
dc.contributor.author Allingham, R Rand
dc.contributor.author Olbrich, Kevin C
dc.contributor.author Klitzman, Bruce
dc.coverage.spatial England
dc.date.accessioned 2015-07-30T23:02:06Z
dc.date.issued 2011-02
dc.identifier http://www.ncbi.nlm.nih.gov/pubmed/21281065
dc.identifier.uri https://hdl.handle.net/10161/10348
dc.description.abstract PURPOSE: Long-term intraocular pressure reduction by glaucoma drainage devices (GDDs) is often limited by the fibrotic capsule that forms around them. Prior work demonstrates that modifying a GDD with a porous membrane promotes a vascularized and more permeable capsule. This work examines the in vitro fluid dynamics of the Ahmed valve after enclosing the outflow tract with a porous membrane of expanded polytetrafluoroethylene (ePTFE). MATERIALS AND METHODS: The control and modified Ahmed implants (termed porous retrofitted implant with modified enclosure or PRIME-Ahmed) were submerged in saline and gelatin and perfused in a system that monitored flow (Q) and pressure (P). Flow rates of 1-50 μl/min were applied and steady state pressure recorded. Resistance was calculated by dividing pressure by flow. RESULTS: Modifying the Ahmed valve implant outflow with expanded ePTFE increased pressure and resistance. Pressure at a flow of 2 μl/min was increased in the PRIME-Ahmed (11.6 ± 1.5 mm Hg) relative to the control implant (6.5 ± 1.2 mm Hg). Resistance at a flow of 2 μl/min was increased in the PRIME-Ahmed (5.8 ± 0.8 mm Hg/μl/min) when compared to the control implant (3.2 ± 0.6 mm Hg/μl/min). CONCLUSIONS: Modifying the outflow tract of the Ahmed valve with a porous membrane adds resistance that decreases with increasing flow. The Ahmed valve implant behaves as a variable resistor. It is partially open at low pressures and provides reduced resistance at physiologic flow rates.
dc.language eng
dc.publisher Informa UK Limited
dc.relation.ispartof Curr Eye Res
dc.relation.isversionof 10.3109/02713683.2010.512115
dc.subject Gelatin
dc.subject Glaucoma Drainage Implants
dc.subject Hydrodynamics
dc.subject In Vitro Techniques
dc.subject Polytetrafluoroethylene
dc.subject Pressure
dc.subject Sodium Chloride
dc.subject Transducers, Pressure
dc.title In vitro fluid dynamics of the Ahmed glaucoma valve modified with expanded polytetrafluoroethylene.
dc.type Journal article
duke.contributor.id Asrani, Sanjay|0198933
duke.contributor.id Allingham, R Rand|0112728
duke.contributor.id Klitzman, Bruce|0017727
pubs.author-url http://www.ncbi.nlm.nih.gov/pubmed/21281065
pubs.begin-page 112
pubs.end-page 117
pubs.issue 2
pubs.organisational-group Basic Science Departments
pubs.organisational-group Cell Biology
pubs.organisational-group Clinical Science Departments
pubs.organisational-group Duke
pubs.organisational-group Ophthalmology
pubs.organisational-group Ophthalmology, Glaucoma
pubs.organisational-group School of Medicine
pubs.organisational-group Surgery
pubs.organisational-group Surgery, Plastic, Maxillofacial, and Oral Surgery
pubs.publication-status Published
pubs.volume 36
dc.identifier.eissn 1460-2202


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