Patent Ductus and Vascular Occlusion Devices

Michelle Carlsen

Elaine Isom

Brad Klosterman

Ornob Roy

Advisor: Dr. Thomas Doyle

Project Definition

• Objective: Design, build, and market an occlusion device which can be used to close the Patent Ductus and cylindrical vasculature

• Presentation topics: – Background

– solution

– accomplishments

– current status

– future plans

Background:Patent Ductus

• Condition affecting Infants/Children

• ~ 10-12% of congenital defects• 40 cases/yr at Vanderbilt• > 20,000 nationwide• Connection btw pulmonary

artery and aorta

Background:General Vasculature

• Less common than PDA• Cylindrical shape• Reroute blood flow• Isolate defective vasculature• Impede significant flow

PDA/ Vascular Conditions

• Diagnosis:– Heart murmur

– Extreme weight loss

– Stunted growth

– Irregular blood flow*

* General vasculature

• Consequences:– Irreversible pulmonary-

vascular disease

– Congestive heart failure

– Hemorrhaging (e.g. diabetics, post-surgical patients)*

Requirements

• Biocompatible

• Quick endothelialization (1-2months)

• Delivered through a catheter < 2mm diameter

• Simple, Retrievable

• Inexpensive

• Various size (2 to 10mm)

• Form-fitting

• Maximum effectiveness

– Internal device– Complete closure

– Standard catheter size

– Minimum training– Cost effective - comparatively– Universal Device– Immovable and closure– No leakage

Current Solutions

• Endomethiasin

– initial form of treatment

– steroid medicine (vasoconstrictor)

– restricted to premature infants

• Suturing

– effective

– invasive, long recovery

• Coils– inexpensive– not form fitting

• Titanium devices– form fitting– very expensive

• Ultrasonic Devices– non-invasive– high-intensity– not human tested

Accomplishments

• Identification of associated diseases

• Analysis of previous device designs

• Studies in biocompatible materials (Prof. Kinser, Material Sciences)

• Fluoroscopy viewing

• SDRC I-DEAS CAD/CAM modeling

• Began mock circulation system

I-DEAS Modeling

• Goal– allow for quick and

accurate prototyping

– marketing and visualization

Current Status

• 3D modeling using SDRC I-DEAS

• Material search

• 4 design concepts

• Large scale simulation: drawings, materials, construction

Design 1

Advantages:

•adjust on contact

•expandable polymer

•form-fitting (PDA & general)

Disadvantages:

•FDA

•expensive (polymer & wire

•retrievable??

Design 2

Advantages:

•form-fitting (PDA & general)

•collapsible (>500%)

•endothelialize quickly

•inexpensive

Disadvantages:

•complex

•possible limited retrieval

Design 3

• Advantages

– very rigid

– easily retrievable

– adjustable

• Disadvantages– difficult to maneuver

– expensive

Design 4

Advantages:

•form-fitting (PDA & general)

•retrievable

•simple

•inexpensive

Disadvantages:

•expansion limitations??

•Two materials

Material Search

• Zotefoams– plastazote foam (polyethylene)

• Medicell– medical sponges

• Titanium/wire material

• Thrombosing fibers

• Polyurethane foam (earplugs)

• Polyurethane that is modified with lower alkyl Sulfonate and L(L-glutamic acid co L-leucine)– biocompatible, used in surgical implantations and blood contacting

procedures

Suitable Materials

• Hydromer– Medicell Hydrophilic Open Cell Medical Foam– consists of polyurethane and

polyvinylpyrrolidone polymers

• Foamex– Functional Flexibility

• Titanium Feet

Simulation

Echigo, S et al. “ Development of New Transvenous Patent Ductus Arteriosis Occlusion Technique Using a Shape Memory Polymer.” ASAIO Transactions: 1990 pg M197.

Simulation Protocol

• Large scale

• Fluid:– water glucose mixture– pig’s blood

• Pulsatile Pump

• Latex Tubing (18 flexitube)

• Plastic PDA (conical 2mm opening)

Division of Labor

• Elaine/Michelle:– PDA design

– material search

– literature analysis/search

• Ornob/Brad:– Vascular Occluder Design

– modeling using I-DEAS

– simulation design idea, construction

• Group:– device design ideas

– large scale prototypes

– designsafe analysis

Future Plans

• Decide on final design

• Acquire materials for design

• Continue meeting with Dr. Doyle

• Designsafe analysis

• Large scale replication

• Patent