ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

COMPUTATIONAL AND EXPERIMENTAL MODELING OF A
UNIVENTRICULAR CIRCULATION WITH SYSTEMIC-TO-
PULMONARY SHUNT AND AORTIC COARCTATION
C. Corsini 1,2 , G. Biglino 3 , S. Schievano 3 , R.S. Figliola 4 , T-Y Hsia 3 , A.M. Taylor 3 , F.
Migliavacca 1 , G. Dubini 1 and G. Pennati 1
1. ABSTRACT
Circulation in a univentricular physiology, palliated with a systemic-to-pulmonary
shunt, is highly dependent on the hemodynamic behavior of the shunt and presence of
an aortic coarctation (AC). Both local (shunt and AC) and peripheral (pulmonary and
systemic, arranged in parallel) impedances need to be properly described to evaluate
this unique circulation. One approach is based on in-vitro experiments, testing a threedimensional
(3D) phantom in a mock circulatory system. Similarly, this may be
achieved in-silico, coupling a 3D model to a lumped parameter network (LPN),
requiring substantial computational cost. In this study the results obtained by applying
the two methodologies are compared, enabling a mutual validation when matching each
other, and using their differences to better understand single-ventricle hemodynamics. A
patient-specific aortic arch model with AC and proximal shunt anastomosis was inserted
into a mock loop with several resistive and compliant elements representing the
downstream circulation. Pressures and flows were measured during pulsatile flow. A
computational analogue was developed, coupling a 3D model to a LPN, and a pulsatile
simulation with the same boundary conditions as in-vitro was performed. Comparison
of the experimentally measured hemodynamic variables with those calculated in-silico
suggested that typical in-vitro resistive components should be modeled as non-linear
terms, although they do not reproduce the linear behavior of peripheral vascular
resistances in-vivo. Moreover, pipe connections are likely to give a non-negligible
contribution to the resistances downstream the 3D phantom. Computational modeling of
complex hemodynamics is an important tool that can improve the understanding of invitro
experiments. At the same time, validating the computational model against
experimental data can result in a more flexible tool for further investigating complex
hemodynamics.
2. INTRODUCTION
Univentricular circulation is a congenital pathological condition where the sole
functioning ventricle, tipically the right one in the hypoplastic left heart syndrome
(HLHS), has to support the entire vascular system. In the first days of life, HLHS is
1
Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di
Milano, p.zza L. da Vinci 32, 20133, Milan, Italy
2
Bioengineering Department, Politecnico di Milano, p.zza L. da Vinci 32, 20133, Milan, Italy
3
Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, and Great Ormond Street
Hospital for Children, NHS Trust, London, UK
4
Departments of Mechanical Engineering and Bioengineering, Clemson University, Clemson, SC, USA