Medical Device Design for Improved Cardiopulmonary Bypass Perfusion and Hemodynamic Optimality during Cardiovascular procedures using Image-Based Computational Fluid Dynamics.

摘要

Each year 1 in 100 children are born with a congenital heart defect, representing 40,000 children each year in the US and 1,300,000 children worldwide with clinically significant congenital heart disease (CHD). Cardiopulmonary bypass (CPB) is the fundamental tool of the pediatric surgeon to realize complex cardiovascular repairs in pediatric and neonatal CHD patients. The core focus of this thesis represents a methodical computational and experimental approach for CPB perfusion control which focuses on aortic cannula tip design and jet flows, with specific application to neonatal / pediatric interventions. The overarching goal of re-engineering the aortic cannula tip is to enable physiologic cardiac output during CPB at low driving pressure gradients while maintaining low jet exit velocities, therefore mitigating potential vascular/blood damage while simultaneously satisfying the prevailing focus on engineering favorable pressure-flow characteristics. The primary strategy of studies presented in this thesis has been to apply new knowledge on aortic outflow cannula jet flow regimes derived using high-performance computational fluid dynamics (CFD) as well as shape-sensitivity studies in designing the next generation of aortic outflow cannula tips. The results of this novel design approach have been encouraging and the predicted outcomes from studies have provided insight into engineering tiny hemodynamically efficient arterial cannulae based upon the novel paradigm of jet flows, which may further have an impact on design of blood handling vascular access devices in general.;In addition to computational modeling, design and evaluation of novel neonatal/pediatric sized vascular-access medical devices, this thesis also discusses a host of clinically relevant applications of CFD to in-silico vascular flow evaluation and pre-surgical planning, in the context of pediatric as well as adult vascular anatomies. The general applicability of this work transcends medical device design and establishes methodologies for quantitative evaluation of cardiovascular medical images for morphology, function and flow, followed by high performance CFD simulation driven modeling of vascular flows in normal or pathological vascular anatomies. The latter is presented with application to in-silico pre-surgical 'what-if analyses to quantitatively evaluate surgical options, coupled shape-morphing to determine optimal intervention strategies and finally in monitoring postsurgical outcomes.