Expanding the Performance Envelope of the Total Artificial Heart: Physiological Characterization, Development of a Heart Failure Model, And Evaluation Tool for Mechanical Circulatory Support Devices

Persistent Link:
http://hdl.handle.net/10150/344221
Title:
Expanding the Performance Envelope of the Total Artificial Heart: Physiological Characterization, Development of a Heart Failure Model, And Evaluation Tool for Mechanical Circulatory Support Devices
Author:
Crosby, Jessica Renee
Issue Date:
2014
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 1-Jun-2015
Abstract:
Heart failure (HF) affects an estimated 5.8 million Americans, accounting for near 250,000 deaths each year. With shortages in available donor hearts, mechanical circulatory support (MCS) has emerged as a life-saving treatment for advanced stage HF. With growth in MCS use, a clinical and developmental need has emerged for a standard characterization and evaluation platform that may be utilized for inter-device comparison and system training. The goal of this research was to harness SynCardia's total artificial heart (TAH) to meet this need. We first sought to characterize the TAH in modern physiological terms - i.e. hemodynamics and pressure-volume loops. We then developed a model of HF using the TAH and mock circulatory system operating in a reduced output mode. We demonstrated that MCS devices could be incorporated and evaluated within the HF model. Finally, we characterized the operational envelope of SynCardia's Freedom (portable), Driver operating against varying loading conditions. Our results describe the hemodynamic envelope of the TAH. Uniquely, the TAH was found not to operate with time-varying elastance, to be insensitive to variations in afterload up to at least 135 mmHg mean aortic pressure, and exhibit Starling-like behavior. After transitioning the setup to mimic heart failure conditions, left atrial pressure and left ventricular pressure were noted to be elevated, aortic flow was reduced, sensitivity to afterload was increased, and Starling-like behavior was blunted, consistent with human heart failure. The system was then configured to allow ready addition of ventricular assist devices, which upon placement in the flow circuit resulted in restoration of hemodynamics to normal. Lastly, we demonstrated that the Freedom Driver is capable of overcoming systolic pressures of 200 mmHg as an upper driving limit. Understanding the physiology and hemodynamics of MCS devices is vital for proper use, future device development, and operator training. Characterization of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared to the human heart. The use of the system as a heart failure model has the potential to serve as a valuable research and teaching tool to foster safe MCS device use.
Type:
text; Electronic Dissertation
Keywords:
Heart Failure Model; Mechanical Circulatory Support Devices; Mock Circulatory System; Pressure-Volume Loops; Total Artificial Heart; Biomedical Engineering; Heart Failure
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Biomedical Engineering
Degree Grantor:
University of Arizona
Advisor:
Slepian, Marvin J.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleExpanding the Performance Envelope of the Total Artificial Heart: Physiological Characterization, Development of a Heart Failure Model, And Evaluation Tool for Mechanical Circulatory Support Devicesen_US
dc.creatorCrosby, Jessica Reneeen_US
dc.contributor.authorCrosby, Jessica Reneeen_US
dc.date.issued2014-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseRelease after 1-Jun-2015en_US
dc.description.abstractHeart failure (HF) affects an estimated 5.8 million Americans, accounting for near 250,000 deaths each year. With shortages in available donor hearts, mechanical circulatory support (MCS) has emerged as a life-saving treatment for advanced stage HF. With growth in MCS use, a clinical and developmental need has emerged for a standard characterization and evaluation platform that may be utilized for inter-device comparison and system training. The goal of this research was to harness SynCardia's total artificial heart (TAH) to meet this need. We first sought to characterize the TAH in modern physiological terms - i.e. hemodynamics and pressure-volume loops. We then developed a model of HF using the TAH and mock circulatory system operating in a reduced output mode. We demonstrated that MCS devices could be incorporated and evaluated within the HF model. Finally, we characterized the operational envelope of SynCardia's Freedom (portable), Driver operating against varying loading conditions. Our results describe the hemodynamic envelope of the TAH. Uniquely, the TAH was found not to operate with time-varying elastance, to be insensitive to variations in afterload up to at least 135 mmHg mean aortic pressure, and exhibit Starling-like behavior. After transitioning the setup to mimic heart failure conditions, left atrial pressure and left ventricular pressure were noted to be elevated, aortic flow was reduced, sensitivity to afterload was increased, and Starling-like behavior was blunted, consistent with human heart failure. The system was then configured to allow ready addition of ventricular assist devices, which upon placement in the flow circuit resulted in restoration of hemodynamics to normal. Lastly, we demonstrated that the Freedom Driver is capable of overcoming systolic pressures of 200 mmHg as an upper driving limit. Understanding the physiology and hemodynamics of MCS devices is vital for proper use, future device development, and operator training. Characterization of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared to the human heart. The use of the system as a heart failure model has the potential to serve as a valuable research and teaching tool to foster safe MCS device use.en_US
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectHeart Failure Modelen_US
dc.subjectMechanical Circulatory Support Devicesen_US
dc.subjectMock Circulatory Systemen_US
dc.subjectPressure-Volume Loopsen_US
dc.subjectTotal Artificial Hearten_US
dc.subjectBiomedical Engineeringen_US
dc.subjectHeart Failureen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineBiomedical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSlepian, Marvin J.en_US
dc.contributor.committeememberYoon, Jeong-Yeolen_US
dc.contributor.committeememberSmith, Richard G.en_US
dc.contributor.committeememberCohen, Zoeen_US
dc.contributor.committeememberUhlmann, Donalden_US
dc.contributor.committeememberSlepian, Marvin J.en_US
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