Biomedical Engineering Reference
In-Depth Information
Nowadays it can be treated through several conservative surgical techniques based
on artificial neochordae implantation (NCI) [
2
] which allow for respecting rather than
resecting the diseased portion of the mitral valve [
3
]. Replacement of the chordae
tendinae by ePTFE sutures was introduced into clinical practice more than 20years
ago [
4
] and various reports have been published in literature documenting good early
and long-term results with these techniques [
5
,
6
].
However, MVP repair through chordal replacement is technically demanding and
determining the appropriate length of the ePTFE suture is one the major concerns
[
7
]: therefore a long-standing experience is required in order to properly face the
problem and perform a successful repair. Several patient-dependent aspects (i.e.
lesion severity, prolapse extension etc.) must be taken into account, and the optimal
NCI. approach has to be chosen among the several ones available, which differ by
number and configuration of neochordae [
8
]. This choice should be based on sound
biomechanical criteria in order to select the appropriate solution, for each clinical
scenario, and optimize the surgical repair through a patient-specific approach to the
problem.
Although FEmodeling is well recognized as a suitable approach to investigateMV
biomechanics [
9
] only a few literature studies have attempted to virtually reproduce
MVP repair through NCI. A pioneer study simulated ePTFE suture replacement of
ruptured posterior chordae tendinae on a paradigmatic and symmetrical MV geome-
try, derived from measures on fresh porcine heart [
10
]. A more recent computational
study moved towards a more realistic MV model, derived from three-dimensional
echocardiography, and simulated MVP repair with ePTFE sutures [
11
]. Nonetheless,
further investigations are necessary in order to deeper assess and understand the wide
spectrum effects of NCIs on MV biomechanics.
At this aim, a computational FE strategy, based on in vivo CMR data, is presented
herein to deeper investigate MV prolapse repair through implantation of ePTFE-
neochordae: the developed approach focuses on MV leaflets repositioning, chordal
tension redistribution and tissue stresses assessment after MV repair.
2 Methods
An integrated framework was developed combining CMR technology, FE methods
and the use of dedicated software packages: the developed analysis allows the quan-
titative assessment of MV apparatus and the simulation of different NCI techniques
as detailed in the following paragraphs.
2.1 CMR Acquisition and Image Segmentation
Cardiac Magnetic Resonance (CMR) was performed on a male patient (75years
old, 83kg, 168 cm) who underwent surgery for isolated prolapse of mitral posterior
P2 scallop due to multiple rupture of marginal chordae. A customized sequence of
acquisition was carried out on a 3.0T TX Achieva (Philips Medical System, Irvine,
