Influence of Blood Rheology and Outflow Boundary Conditions in Numerical Simulations of Cerebral Aneurysms - Mathematical Methods and Models in Biomedicine - page 142

Influence of Blood Rheology and Outflow
Boundary Conditions in Numerical Simulations
of Cerebral Aneurysms

Susana Ramalho, Alexandra B. Moura, Alberto M. Gambaruto,
and Adelia Sequeira

1 Introduction

Disease in human physiology is often related to cardiovascular mechanics.
Impressively, strokes are one of the leading causes of death in developed countries,
and they might occur as a result of an aneurysm rupture, which is a sudden event in
the majority of cases. On the basis of several autopsy and angiography series, it is
estimated that 0.4-6 % of the general population harbors one or more intracranial
aneurysms, and on average the incidence of an aneurysmal rupture is of 10 per
100,000 population per year, with tendency to increase in patients with multiple
aneurysms [ 14 , 20 ].
An aneurysm is a localized pathological dilation of the wall of a blood vessel,
due to the congenital or acquired structural weakening of the wall media, and
potentially results in severe complications, or even sudden death, through press-
ing on adjacent structures, or rupturing causing massive hemorrhage [ 10 ]. They
are primarily located in different segments of the aorta and in the intracranial
arteries supplying the brain. Moreover, intracranial aneurysms are most likely to
be encountered on or close to the circle of Willis, particularly in apices of the
bifurcation of first- and second-order arteries, and in curved arterial segments [ 28 ].
The natural history of this pathology is far from being fully understood, which can
be related to the paucity of temporal investigations, since aneurysms are rarely
detected before rupture. It is believed that the formation, growth, and rupture of
intracranial aneurysms are associated with local hemodynamics, other than lumen
structural mechanics and biomedical responses.

S. Ramalho ￿ A.B. Moura ￿ A.M. Gambaruto ￿ A. Sequeira ( )
Department of Mathematics and CEMAT, Instituto Superior Tecnico, Technical University
of Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal
e-mail: [e-mail] ; [e-mail] ; [e-mail] ;
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