Computational fluid dynamics analysis to determine shear stresses and rates in a centrifugal left ventricular assist device.
Artif Organs
; 36(4): E89-96, 2012 Apr.
Article
em En
| MEDLINE
| ID: mdl-22360826
ABSTRACT
Axial flow left ventricular assist devices (LVADs) are a significant improvement in mechanical circulatory support. However, patients with these devices experience degradation of large von Willebrand factor (vWF) multimers, which is associated with bleeding and may be caused by high shear stresses within the LVAD. In this study, we used computational fluid mechanics to determine the wall shear stresses, shear rates, and residence times in a centrifugal LVAD and assess the impact on these variables caused by changing impeller speed and changing from a shrouded to a semi-open impeller. In both LVAD types, shear rates were well over 10,000/s in several regions. This is high enough to degrade vWF, but it is unclear if residence times, which were below 5ms in high-shear regions, are long enough to allow vWF cleavage. Additionally, wall shear stresses were below the threshold stress of 10Pa only in the outlet tube so it is feasible to endothelialize this region to enhance its biocompatibility.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Coração Auxiliar
/
Hidrodinâmica
/
Hemodinâmica
Limite:
Humans
Idioma:
En
Revista:
Artif Organs
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos