Percutaneous Closure of
Patent Foramen Ovale
Sponsors:
Kung Ming Jan, M.D., Ph.D.
Judah Weinberger, M.D., Ph.D.
Columbia University Medical Center
Department of Cardiology
Project TA: Jeffrey Garanich, Ph.D.
Design Team:
Ali Stern
Dmitry Oulianov
Dolores Miranda
Henry Qazi
Safiya Arif
The City College of New York / Department of Biomedical Engineering
Fetal Circulation


Prenatal oxygenation
of blood bypasses
lungs.
Oxygenated blood
passes from right to
left atrium through
the foramen ovale
(FO).
Fetal circulation
Prenatal Septal Development
•Septum primum and
secundum overlap.
•Septa create an
opening to allow direct
shunting of fetal blood.
Neonatal Septal Development



Following birth the P of
each chamber changes.
P changes force septum
primum to close over
septum secundum.
In a period of 1-2 weeks
70% of population have
fusion of septa primum
and secundum.
Atrial Septal Defect


The condition in which
the septa fail to seal over
and remain patent is
known as ASD.
ASD is an opening (hole)
between right and left
atria.
Patent Foramen Ovale

PFO, a type of
ASD, is a flaplike opening
between the
atrial septa
primum and
secundum
Clinical Need

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PFO is present in 20-25% of
the population
PFO has been associated with:



Migraines
Cryptogenic strokes
Systemic embolism
Migraine

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
Migraine is a vascular headache
Over 2,500,000 people in the U.S. have at least
one migraine weekly, with a lifetime prevalence
of 18%
PFO are related to Migraines if paradoxic
embolism causes headache
Cryptogenic strokes

There are 700,000 strokes per year in the U.S.

30-40% of these are cryptogenic

40-70% of cryptogenic strokes are PFO related

84,000-196,000 strokes per year in the United
States are by paradoxical embolism due to PFO
Treatment Options

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Medical Treatment
Open heart surgery
to close the PFO
Percuteneous
closure of the PFO
CardioSeal




2 Double Umbrella
implant
MP35N Framework
Dacron
Sizes: 17-33mm
Amplazter




Self expandable
Short
connecting
waist
Nitinol Wires
Sizes: 4-38mm
Amplazter Delivery
Disadvantages

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
Designed for ASD
Large surface Area
Thrombus formation
Reduced Endothelialization
Poor Apposition
Device Fracture
Device Embolization
Required Specifications
 Seals PFO only
 Consists of two components
 Delivery unit
 Means of closure
 Size requirements
 Delivery size: 3 - 4 mm diameter
 Deployment size: 3.6 x 4.2 cm
 Seals area of 8 mm radius around PFO
 Biocompatibility
 Immunological response
 Thrombogenic response
 Single use
Mechanical & Electrical Stability
 Electrical isolation
 Isolate main voltage source
 Prevent current leakage
 Current limits
 Direct current < 1 μA
 Alternating current < 0.4 μA
 Mechanical forces
 Structural flexibility
Desired Specifications
 Easily operable
 Cost efficient
 Biodegradable
 Degradation time
 Particle size
 Visible by ultrasound
 Non-magnetic
Device Evaluation
 In Vitro
 Reaction to environment
 Fatigue test
 Maneuverability
 Catheter-device integrity
 In Vivo*
 Dog testing
 Human testing
*Evaluation may not be performed in the scope of the project
Concepts

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Glue or collagen plugs
Magnetic suturing
Energy welding devices
Staple pins/sutures
Scaffold
Clipping device
Intra atrium device
Coiled suturing device
“Sutura” model
Hooked Scaffold Implant

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Polyester scaffold
Advantages:


Material Degradation
into H2O & CO2
Disadvantages :

Material: too stiff for
delivery
Intra atrium device (IAD)

Advantages:

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
Minimal amount of
foreign material in the
body
Does not require exact
positioning
Disadvantages:
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Material selection:
Complicated knot
delivery method
Coiled needle


Components: coiled
needle, 16mm base unit
Advantages:


Does not require exact
positioning
Disadvantages:

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Complicated mechanics
Requires electrical energy
Complicated knot delivery
method
Sutura Model

Suturing device

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Advantages:

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Components: 2
retractable arms,
thread attached, 2
needles, handle
Existing device
provides successful
mechanism
Disadvantages:

Complicated
manufacturing
Clipping Device

Advantages:

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
Procedure using the
device is reversible in
case of failure
Simple deployment
mechanism
Disadvantages:


Requires precision
Material properties
Acknowledgements

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Kung Ming Jan, M.D., Ph.D.
Judah Weinberger, M.D., Ph.D.
Columbia University Medical Center
Department of Cardiology
Project TA: Jeffrey Garanich, Ph.D.
Robert Sommer, M.D., Ph.D.