1. Pulmonary Flow Resistive Device Taya Furmanski Albert Attia Advisor: Thomas Doyle, M.D. February 12, 2003

2. Background Hypoplastic Left Heart Syndrome (HLHS) is a condition in which the patient is missing his/her left ventricle 1440 babies are born each year with HLHS Approximately 75% 3-year survival rate No medical treatment for HLHS Only options are operation (reconstruction) or transplantation 300 patients with HLHS are seen at VUMC per year

3. The Problem Inadequate systemic blood flow Amount of O 2 delivered to the organs decreases significantly “Blue Baby” http://www.nemours.org /no/ncc/cardiac/crd1524.html

4. How to Solve the Problem Place nozzle in pulmonary arteries (see figure) Device will act as resistor Decrease in pulmonary blood flow will cause increase in systemic blood flow

5. Dimensions of the Nozzle Calculations by Craig Russell (ME student) Theories required to solve problem Conservation of mass Conservation of momentum Dimension of end of nozzle still to be determined Pulmonary artery pressure ~20 mmHg 4 mm

6. Alternate Solutions Place nozzle inside stent Use bow-tie shaped stent (see figure) Placing a mesh-like device in the pulmonary arteries

7. Problems With Alternate Solutions Extremely difficult to place in the artery Placement also a problem Would cause hemolysis (tiny holes would damage red blood cells)

8. What We Need - Modeling - In vitro model to simulate the blood vessels Prototype can be tested through model to determine effectiveness Computer model would allow variables to be altered easily to determine the optimal dimensions of the device

9. Blood Vessel Model

10. What We Need - Materials & Assistance - Use Vanderbilt shop to mold conical device Use materials to create physical model that accurately portrays operation of device Assistance of mechanical engineering students (Craig Russell and Chris Owen) and professor (Dr. Mark Stremler) for fluid dynamics Find experienced programmer to develop computer modeling system or use one currently in existence

11. What We Have Accomplished Thus Far… In-depth research of HLHS Several meetings with Dr. Doyle to discuss the problem and possible solutions Finalizing a design plan Create a plan of attack: start simple and increase complexity Ordered and received nitinol wire Beginning calculations of fluid dynamics Finalized method of implantation

12. What We Have Yet to Do… Find exact dimensions of device necessary to alleviate the problem Produce prototype of device Test prototype Create or find computer model simulation of cardiovascular system Go to Boston!!!!

13. References 1. Barber, Gerald. Hypoplastic Left Heart Syndrome. Structural Congenital Defects, section 3. 2. www.ucch.org/sections/cardio/new/hlhs.htm l; date accessed: January 30, 2003. 3. web1.tch.harvard.edu/chnews/03-15- 02/fetalcath.html; date accessed: February 10, 2003. 4. Dr. Thomas Doyle; Vanderbilt University Medical Center.