BIOENGINEERING 323 Benedum Hall | 3700 O’Hara Street | Pittsburgh, PA 15261 P: 412-624-4725 C: 412-855-0717 borovetz@pitt.edu
Harvey Borovetz, PhD Distinguished Professor of Bioengineering (The PediaFlow Consortium)
The PediaFlow® Pediatric Ventricular Assist Device (VAD) PediaFlow R&D With the support of two NHLBI contract awards, our consortium has developed mixedflow turbodynamic (continuous flow) pediatric ventricular assist devices (VAD) utilizing a magnetically levitated impeller capable of producing 0.3-1.5 liters per minute (LPM) of blood flow for supporting infants and small children weighing 3-15 kg for up to six months duration. A particular focus of our work has been on achieving exceptional biocompatibility of our prototypes through state-of-the art CFD design of the blood flow path. The goal of our program is to operate our pediatric VAD clinically with minimal anticoagulation requirement and optimal biocompatibility. Over 20 design variations were initially considered, with three pump topologies selected for further design refinement and evaluation. The three designs, two centrifugal and one mixed-flow pumps, were judged based on a multi-component objective function which factored several criteria including anatomic fit, estimated biocompatibility, heat generation and transfer, magnetically levitated suspension robustness, and manufacturability. This evaluation led to selection of the mixed-flow configuration. The design was improved using computational fluid dynamics to minimize flow-induced blood damage via modification of the geometry of the predicted blood flow path. The housing was modified to improve surgical fixation. A transparent replica of the blood flow path was built to perform validation of the computer predictions by flow visualization analyses. Other ongoing efforts were focused on controller development, materials selection, biocompatible coating application, nanotechnology based infection control, cannula design, and overall assessment of hemodynamic performance and cellular biocompatibility. Pre-clinical testing of the current PediaFlow prototype ventricular assist device (the smallest mag lev blood pump to date, the size of an AA cell battery) was performed in vitro and in vivo. Our most recent 60-day implant demonstrated very low levels of both hemolysis and platelet activation. No thrombi were noted on explant, further validating the excellent biocompatibility of the PediaFlow pediatric VAD in anticipation of eventual clinical trial testing.
DEPARTMENT OF BIOENGINEERING
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