Percutaneous Closure of Patent Foramen Ovale

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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
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Fetal Circulation

• Prenatal oxygenation of blood bypasses lungs.
• Oxygenated blood passes from right to left atrium
  through the foramen ovale (FO).

Fetal circulation
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Prenatal Septal Development

• Septum primum and
• secundum overlap.
• Septa create an
• opening to allow direct
• shunting of fetal blood.

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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.

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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.

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Patent Foramen Ovale

• PFO, a type of ASD, is a flap-like opening
  between the atrial septa primum and secundum

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Clinical Need

• PFO is present in 20-25 of the population
• PFO has been associated with
• Migraines
• Cryptogenic strokes
• Systemic embolism

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Migraine

• 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

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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

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Treatment Options

• Medical Treatment
• Open heart surgery to close the PFO
• Percuteneous closure of the PFO

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CardioSeal

• 2 Double Umbrella implant
• MP35N Framework
• Dacron
• Sizes 17-33mm

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Amplazter

• Self expandable
• Short connecting waist
• Nitinol Wires
• Sizes 4-38mm

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Amplazter Delivery

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Disadvantages

• Designed for ASD
• Large surface Area
• Thrombus formation
• Reduced Endothelialization
• Poor Apposition
• Device Fracture
• Device Embolization

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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

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Mechanical Electrical Stability

• Electrical isolation
• Isolate main voltage source
• Prevent current leakage
• Current limits
• Direct current lt 1 µA
• Alternating current lt 0.4 µA
• Mechanical forces
• Structural flexibility

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Desired Specifications

• Easily operable
• Cost efficient
• Biodegradable
• Degradation time
• Particle size
• Visible by ultrasound
• Non-magnetic

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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
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Concepts

• Glue or collagen plugs
• Magnetic suturing
• Energy welding devices
• Staple pins/sutures
• Scaffold
• Clipping device
• Intra atrium device
• Coiled suturing device
• Sutura model

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Hooked Scaffold Implant

• Polyester scaffold
• Advantages
• Material Degradation into H2O CO2
• Disadvantages
• Material too stiff for delivery

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Intra atrium device (IAD)

• Advantages
• Minimal amount of foreign material in the body
• Does not require exact positioning

• Disadvantages
• Material selection
• Complicated knot delivery method

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Coiled needle

• Components coiled needle, 16mm base unit
• Advantages
• Does not require exact positioning
• Disadvantages
• Complicated mechanics
• Requires electrical energy
• Complicated knot delivery method

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Sutura Model

• Suturing device
• Components 2 retractable arms, thread attached,
  2 needles, handle
• Advantages
• Existing device provides successful mechanism
• Disadvantages
• Complicated manufacturing

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Clipping Device

• Advantages
• Procedure using the device is reversible in case
  of failure
• Simple deployment mechanism
• Disadvantages
• Requires precision
• Material properties

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Acknowledgements

• 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.