Performance Characteristics of Centrifugal Pump Impeller for Heart Failure Therapy: Numerical and In-vitro Approach
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Heart failure (HF) is a common cause of hospitalisation and mortality across
industrialised countries. The number of hospitalisations and deaths attributed
to heart failure is increasing, and this trend is predicted to continue. Numerical
and in-vitro simulations of the human cardiovascular system constitute the
basic tools for enhancing diagnostic and therapeutic technologies for HF and
this would in turn, have significant effects on morbidity,mortality, and healthcare
expenditure. Mechanical Circulatory Support (MCS) as a destination
therapy for HF is rising significantly as it provides a cost-effective alternative
to long-term treatment and cardiac transplantation. However, long-term
versatility is far from ideal and incidence of transient and permanent neurological
events is still high. To this end, evolution of MCS devices calls for
more sophisticated design and evaluation methods.
The purpose of this work is to develop a numerical model and to implemented
a novel in-vitro model of the cardiovascular system with the intention of
evaluating the performance characteristics of a purposely selected centrifugal
pump impeller for the treatment of both Class III and IV HF conditions when
placed in series with the heart at two different anatomic locations: Ascending
Aorta and Descending Aorta.
An existing lumped-parameter model of the CV system, that included models
for the heart, the pulmonary and the systemic circulatory loops by adapting
a modified version of the fourth-element Windkessel model was enhanced
by dividing the systemic circulation into six parallel vascular beds, and by
including an autoregulatory system to control both pressures and volumes
throughout the system. As part of the novelty of the present work, a volume
reflex loop was included with the purpose of simulating volume overload conditions,
as commonly found in HF conditions, and obtaining a more realistic
analysis of volume displacement, while using a MCS device.
The in-vitro model implemented in this work adopted most of the features
included in the mathematical counterpart with the purpose of validating the
numerical results. As a result of the combination of models and proper optimisation
of the system parameters, predictions of pathophysiological trends
and MCS usage are satisfactorily obtained.
The models implemented in this work offer a valuable tool for the selection
and performance evaluation of MCS devices for the treatment of HF conditions.
Authors
Hincapie, Paula Andrea RuizCollections
- Theses [4122]