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Title: Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
926394
Report Number(s):
UCRL-JRNL-227936
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Biomedical Optics, vol. 12, no. 3, May 1, 2007, pp. 030504
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 71 CLASSICAL AND QUANTUMM MECHANICS, GENERAL PHYSICS; 42 ENGINEERING

Citation Formats

Maitland, D J, Small IV, W, Ortega, J M, Buckley, P R, Rodriguez, J, Hartman, J, and Wilson, T S. Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms. United States: N. p., 2007. Web. doi:10.1117/1.2743983.
Maitland, D J, Small IV, W, Ortega, J M, Buckley, P R, Rodriguez, J, Hartman, J, & Wilson, T S. Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms. United States. doi:10.1117/1.2743983.
Maitland, D J, Small IV, W, Ortega, J M, Buckley, P R, Rodriguez, J, Hartman, J, and Wilson, T S. Mon . "Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms". United States. doi:10.1117/1.2743983. https://www.osti.gov/servlets/purl/926394.
@article{osti_926394,
title = {Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms},
author = {Maitland, D J and Small IV, W and Ortega, J M and Buckley, P R and Rodriguez, J and Hartman, J and Wilson, T S},
abstractNote = {},
doi = {10.1117/1.2743983},
journal = {Journal of Biomedical Optics, vol. 12, no. 3, May 1, 2007, pp. 030504},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 05 00:00:00 EST 2007},
month = {Mon Feb 05 00:00:00 EST 2007}
}
  • A system for treating an aneurysm in a blood vessel or vein, wherein the aneurysm has a dome, an interior, and a neck. The system includes a shape memory polymer foam in the interior of the aneurysm between the dome and the neck. The shape memory polymer foam has pores that include a first multiplicity of pores having a first pore size and a second multiplicity of pores having a second pore size. The second pore size is larger than said first pore size. The first multiplicity of pores are located in the neck of the aneurysm. The second multiplicitymore » of pores are located in the dome of the aneurysm.« less
  • Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with devicemore » deployment. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.« less
  • Due to the narrow (3-hour) treatment window for effective use of the thrombolytic drug recombinant tissue-type plasminogen activator (rt-PA), there is a need to develop alternative treatments for ischemic stroke. We are developing an intravascular device for mechanical thrombus removal using shape memory polymer (SMP). We propose to deliver the SMP microactuator in its secondary straight rod form (length = 4 cm, diameter = 350 {micro}m) through a catheter distal to the vascular occlusion. The microactuator, which is mounted on the end of an optical fiber, is then transformed into its primary corkscrew shape by laser heating (diode laser, {lambda}more » = 800 nm) above its soft phase glass transition temperature (T{sub gs} = 55 C). Once deployed, the microactuator is retracted and the captured thrombus is removed to restore blood flow. The SMP is doped with indocyanine green (ICG) dye to increase absorption of the laser light. Successful deployment of the microactuator depends on the optical properties of the ICG-doped SMP and the optical coupling efficiency of the interface between the optical fiber and the SMP. Spectrophotometry, thermal imaging, and computer simulation aided the initial design effort and continue to be useful tools for optimization of the dye concentration and laser power. Thermomechanical testing was performed to characterize the elastic modulus of the SMP. We have demonstrated laser-activation of the SMP microactuator in air at room temperature, suggesting this concept is a promising therapeutic alternative to rt-PA.« less
  • Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pinmore » was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of {approx}8 W. We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated.« less
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