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Design, Development and Hemodynamic Analysis of A Low-Pressure Cavopulmonary Assist Device within the Total Cavopulmonary Connection
r. wang1, J. Hertzberg1, F. Lacour-Gayet2, R. Shandas3. 1university of colorado at boulder, boulder, CO, 2Childrens Hospital Heart Institute, University of Colorado Health Sciences Center, Denver, CO, 3University of Colorado at Boulder,University of Colorado Health Sciences Center, Boulder/denver, CO,
BACKGROUND: Serious late attrition, more notable with aging, commonly exists among patients following Fontan palliation. We hypothesize that a RV assist could reverse the deleterious effect of the Fontan paradox.
METHODS: The physiology of patients with total cavopulmonary connection (TCPC) was mimicked by a cylindrical geometry, with diameter of 10 mm, right angle intersections, and an offset between the IVC and superior vena cava (SVC) of 10 mm. Inside the IVC we numerically simulated a low-pressure microaxial pump which measured 25 mm axially and 9.5 mm radially, specially tailored for pediatric patients.
RESULTS: The pressure rise achieved across the device varied between -2.5 and 14.9 mm Hg, and nonlinearly decreased with higher cardiac output and lower rotor speed. The pressure in the upstream IVC fell below the baseline values, followed by a step rise in pressure across pump. The SVC pressure for all conditions remained within 20% of the value for the design point. The venous returns were almost equally split into the two pulmonary arteries. Most blood particles passed through the pump vicinity within 20 ms, with a maximum shear stress of 2355 ~ 6753 dyne/cm2. An average hemolysis index of 0.92% was estimated, indicating minimal hemolysis.
CONCLUSIONS: With a decreased caval pressure and minimum cell damage, this innovative cavopulmonary support exhibits promise for alleviating the downward hemodynamic spiral in TCPC patients.
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