title: Stereo-particle image velocimetry measurements of a patient-specific Fontan physiology utilizing novel pressure augmentation stents.
abstract: Single ventricle anomalies are a challenging set of congenital heart defects that require lifelong clinical management due to progressive decline of cardiovascular function. Few therapeutic devices are available for these patients, and conventional blood pumps are not designed for the unique anatomy of the single ventricle physiology. To address this unmet need, we are developing an axial flow blood pump with a protective cage or stent for Fontan patients. This study investigates the 3-D particle image velocimetry measurements of two cage designs being deployed in a patient-specific Fontan anatomy. We considered a control case without a pump, impeller placed in the inferior vena cava, and two cases where the impeller has two protective stents with unique geometric characteristics. The experiments were evaluated at a cardiac output of 3 L/min, a fixed vena caval flow split of 40%/60%, a fixed pulmonary arterial flow split of 50%/50%, and for operating speeds of 1000-4000 rpm. The introduction of the cardiovascular stents had a substantial impact on the flow conditions leaving the pump and entering the cavopulmonary circulation. The findings indicated that rotational speeds above 4000 rpm for this pump could result in irregular flows in this specific circulatory condition. Although retrograde flow into the superior vena cava was not measured, the risk of this occurrence increases with higher pump speeds. The against-with stent geometry outperformed the other configurations by generating higher pressures and more energetic flows. These results provide further support for the viability of mechanical cavopulmonary assistance as a therapeutic treatment strategy for Fontan patients.
authors.affiliation: Department of Mechanical and Nuclear Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Chopski
authors.forename: Owen M
authors.initials: OM
authors.lastname: Rangus
authors.forename: Carson S
authors.initials: CS
authors.lastname: Fox
authors.forename: William B
authors.initials: WB
authors.lastname: Moskowitz
authors.forename: Amy L
authors.initials: AL
authors.lastname: Throckmorton
mesh_terms: D004867:Equipment Design; D004869:Equipment Safety; D018729:Fontan Procedure / Q000295:instrumentation*; D006330:Heart Defects, Congenital / Q000601:surgery*; D006352:Heart Ventricles / Q000002:abnormalities*; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008955:Models, Cardiovascular; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D015607:Stents; D018785:Tricuspid Atresia / Q000601:surgery
keywords: Blood pump; Fontan; Heart pump; Mechanical circulatory assistance; Particle image velocimetry; Pediatric circulatory support; Rotary blood pump; Single ventricle physiology