Biomedical Engineering Reference
In-Depth Information
assessing TAV outcomes in patient-specific models. Capelli and collaborators [
13
]
simulated the implantation of a balloon-expandable TAV stent in five patient-specific
models and investigated the effects related to different positions of the device. They
also simulated a valve-in-valve procedure in a model where a previous bioprosthetic
valve was present in the implantation site. The authors were able to study the stent
configuration following implantation, its interaction with the surrounding structures
and the mechanical loadings in the struts of the TAV stent.
A similar study was carried out by Wang and collaborators [
14
], in which the authors
also modeled focal calcifications on the AV.
More recently, the work published by Auricchio and co-authors [
15
] introduced TAV
leaflets in the FE analyses of TAV: after simulating the stent deployment in a patient-
specific model of the AR, they mapped the TAV leaflet model on the implanted stent
configuration and was able to simulate the valve closure, thus investigating also its
diastolic behaviour.
While the two former studies have the limitation to focus only on TAV stent implan-
tation and do not investigate the behaviour of TAV after implantation and during the
cardiac cycle, the latter has the advantage to partially study this aspect by introduc-
ing the TAV leaflet model. Conversely, the work made by Auricchio and colleagues
neglects the native AV that, as stated before, is the main structure interacting with
the TAV device.
In this paper, we present a FE study in which both the implantation and function of
a balloon-expandable TAV device has been investigated; moreover, in the analyses,
the presence of the AV leaflet calcifications has been modeled and their influence on
TAV outcomes has been evaluated by modeling different stenotic AVs.
2 Methods
In this work, FE analyses of the implantation and function of a balloon-expandable
TAV in AR models were carried out using the explicit solver of LS-DYNA
©
v. 971
(LSTC, Livermore, CA, USA).
The methods will be divided in two main sections:
•
the first section will concern the realization of the AR models and the analysis of
their dynamic behaviour;
•
the second section will concern the implantation simulation and the dynamic func-
tion of the TAV within the AR models.
2.1 Aortic Root Models Definition and Dynamics
In order to investigate the influence of AV calcifications, three different AR models
were considered:
