Cardiac Disease and Treatment Devices

1. Cardiac Disease and Treatment Devices Dorothy Ringer Sumner Biology Teacher Aldine 9th Grade School, Aldine ISD Enrichment Experience in Engineering E3 Research Experiences for Secondary Math and Science Teachers Dr. Duncan Maitland Associate Professor, Department of Biomedical Engineering Biomedical Device Laboratory Faculty Mentor

2. Understanding Aneurysms • Aneurysms are abnormal widening or ballooning of blood vessels. • Prevalent in 5% of the U.S. population. • Not life threatening unless it begins pressing on the brain or ruptures. • 30,000 people die or suffer neurological damage from rupture. (Stroke or subarachnoid hemorrhage) • Pre-existing conditions include hypertension, atherosclerosis, kidney disease, head trauma and birth defects.

3. Why Shape Memory Polymers (SMP) Foams Therapy SMP’s are polymers that remember their shape. Can be compressed drastically and still retain original shape when acted upon by stimulus. Biocompatible. Blood clots throughout the porous foam and forms a layer of endothelial cells across the aneurysm for faster healing. Lower and more uniform stresses on wall, lowers hemorrhage risk.

4. SMP Foam Mechanism of Deployment • Polymer foam is inserted through catheter in its compressed form. • Laser light beam is shone through an optical fiber in the catheter. • Laser hits the SMP cylinder, it expands and plugs the aneurysm as it returns to its original ball shape.

5. Embolic Shape Memory Polymer Foam Deployment Model of aneurysm that has a dye added to view the laser as the SMP foam is being deployed.

6. Overview: • This lesson unit introduces students to biomedical engineering and the technology of shape memory polymers. As they create a device to deliver a compressed polymer to an aneurysm, testing its reliability and considering pros and cons, they learn about issues and materials that biomedical engineers consider in designing medical devices. • Students learn how a shape memory polymer can clot an aneurysm and direct blood flow through the artery. Using everyday items, each team of students designs and builds an SMP Deployment Device capable of plugging the aneurysm. Students develop a plan, build and test their system, and then evaluate the effectiveness of their and other teams’ efforts. Finally, they present their findings to the class.

7. Unit Concepts • Circulatory diseases and treatment of organ systems • Chemical structure and properties of polymers • Engineering design

8. E3 Project Instructional Plan

9. E 3 Project instructional plan

13. Designing A Polymer Delivery Device Lesson Focus: • Aneurysms are abnormal widening or ballooning of blood vessels. They are prevalent in 5% of the U.S. population. They are not life threatening unless one begins pressing on the brain or ruptures. • 30,000 people die or suffer neurological damage from the rupture of an aneurysm. When this occurs it is referred to as a stroke or subarachnoid hemorrhage. People with conditions such as hypertension, atherosclerosis, kidney disease, head trauma and birth defects are more likely to develop an aneurysm. Aneurysms can be treated by cutting off the supply of blood to the aneurysm and allowing it to clot. Current research involves designing medical devices to deliver shape memory polymers to the aneurysm site, plugging it, and thereby, allowing uninterrupted blood flow through the artery.

14. Learning Objectives: • To gain knowledge of biomedical engineering, engineering design, planning, construction, teamwork, and working in collaborative groups. • Describe the engineering design considerations that go into developing quality medical devices. • List characteristics and features that are important for a medical device. • Analyze a prototype of a shape memory polymer deployment device and make suggestions for design improvements. Materials: • Clear plastic straws, aquarium tubing, gel capsules, wire, paper clips, string, sodium polyacrylate, coffee stirrer, alcohol burner, hot plate.

15. Procedure: • 1. Show students the power point presentation, “Using Shape Memory Polymers to Treat Cerebral Aneurysms”. This may be shown in class, or provided as handout slides to read for the prior night’s homework along with the assignment. • 2. Divide students into groups of 4 students, providing a set of materials per group. • 3. Explain that students must work as a team to design medical device to deploy (deliver) a shape memory polymer in its compressed form to the site of an aneurysm and include in the design, a stimulus for the polymer to expand or actuate • 4. Students discuss and develop a plan for their deployment device. They draw their plan, and then present their plan to the teacher or other teams. • 5. The teams execute their plans. They may need to rethink their design, or even start over. • 6. The teams will test their deployment device to see how it works. Students will measure how much simulated blood flowed through the artery and not into the aneurysm. The teams may test their systems three times and use the most successful test for their results. • 7. Teams then complete an evaluation/reflection worksheet, and present their findings to the class.

16. Pretest/ Post Test Questions • Which set contains one natural polymer and one synthetic polymer? A. cellulose and starch B. polyethylene and nylon C. protein and starch D. protein and polyacrylate • A polymer that can return to its original shape after being deformed is called________. A. plastic B. shape memory polymer C. polyacrylate D. polyacetate

17. Acknowledgements • TAMU E3 Program • National Science Foundation • Texas Workforce Commission • Dr. Duncan Maitland, Faculty Mentor • John Horn, graduate student (Biomedical Engineering ) • AshwinRao, graduate student (Mechanical Engineering) • Mary Biediger, lab partner