development of a thin film nitinol heart valve

UCLA

Lenka Stepan1, Daniel Levi2, & Greg P. Carman3

1Biomedical Engineering IDP, UCLA2Mattel Children’s Hospital at UCLA

3Mechanical & Aerospace Engineering Department, UCLA

A Thin Film Nitinol Heart ValveA Thin Film Nitinol Heart Valve

UCLA

MotivationMotivation Replacement Heart Valves

Mechanical Valves Require medication Noisy

Bioprosthetic Valves Only Last 15 years

Open Heart Surgery

Thin Film NiTi Heart Valve Anti-thrombogenic

Doesn’t require medication Quiet Superior Durability

Doesn’t need replacement Percutaneously Placed

Goal: Test Durability of Thin Film NiTi Valve

UCLA

Valve DesignValve Design

Thin film NiTi leaflets anchored on NiTi wire using a C-tube

NiTi wire mesh embedding in inner Teflon scaffold

Outer Teflon tubing houses anchoring wire and inner teflon scaffold.

UCLA

Valve TestingValve Testing Pulsatile Flow Testing

Flow Rates Pressure Traces Durability Tests (10^6 cycles)

Biocompatibility Immersion Tests – Corrosion Animal Testing – Biological Response

Flow rate and Film Thickness

1.01

1.22 1.291.37

1.71

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

8 micron withSi

12 micron 16 micron 20 micron Edwards

Flow

rate

(L/m

in)

Durability: 10^6 cycles, Crystalline Thin Film NiTi leaflets with and without Silicone

0

0.4

0.8

1.2

1.6

2

1E+00 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06 1E+07

Cycles

Flow

Rat

e (L

/min

)

NiTi with Silicone

NiTi

Intimal proliferation

Bare stentThin Film NiTi Covered stent

Strut damage

UCLA

Future WorkFuture Work

• Percutaneous Designs– Integrate Leaflets into a collapsible scaffold

• Biocompatibilty– Cytotoxicity– Electrochemical Corrosion Testing

• Accelerated Wear Testing– Fatigue