title: Ex Vivo Assessment of a Parabolic-Tip Inflow Cannula for Pediatric Continuous-Flow VADs.
abstract: To address the challenge of unloading the left ventricle during pediatric mechanical circulatory support using next-generation rotary blood pumps, a novel inflow cannula was developed. This unique inflow cannula for pediatric, continuous-flow, left ventricular assist devices (VADs) with a parabolic-shaped inlet entrance was evaluated alongside a bevel-tip and fenestrated-tip cannula via an ex vivo, isolated-heart experimental setup. Performance was characterized using two clinical scenarios of over-pumping and hypovolemia, created by varying pump speed and filling preload pressure, respectively, at ideal and off-axis cannula placement to assess ventricular unloading and positional sensitivity. Quantitative and qualitative assessments were performed on the resultant hemodynamics and intra-ventricular boroscopic images to classify conditions of nonsuction, partial, gradual or severe entrainment, and ventricular collapse. The parabolic-tip cannula was found to be significantly less sensitive to placement position (p < 0.001) than the bevel-tip cannula under all conditions, while not statistically different from the fenestrated cannula. Visual analysis of the parabolic-tip cannula showed complete resistance to entrainment, whereas the fenestrated-tip had partial entrainment in 90% and 87% of the over-pumping and hypovolemic studies, respectively. We conclude that future pediatric VAD designs may benefit from incorporating the parabolic-tip inflow cannula design to maximize unloading of the left ventricle in ideal and nonoptimal conditions.
authors.affiliation: From the *Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania; †McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania; ‡Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and §Artificial Heart Program, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Griffin
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Grzywinski
authors.forename: Hannah J
authors.initials: HJ
authors.lastname: Voorhees
authors.forename: Marina V
authors.initials: MV
authors.lastname: Kameneva
authors.forename: Salim E
authors.initials: SE
authors.lastname: Olia
mesh_terms: D000818:Animals; D000072601:Cannula; D002404:Catheterization / Q000295:instrumentation; D006041:Goats; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D010372:Pediatrics / Q000295:instrumentation*; D013552:Swine