Modelling and numerical simulation of the in-vivo mechanical response of the ascending aortic aneurysm in Marfan syndrome

Abstract

Marfan syndrome (MFS) is a genetic disorderthat affects connective tissue, impairing cardiovascularstructures and function, such as heart valves and aorta.Thus, patients with Marfan disease have a higher risk ofdeveloping circulatory problems associated with mitraland aortic valves prolapse, manifested as dilated aorta andaortic aneurysm. However, little is known about the biomechanicalcharacteristics of these structures affected withMFS. This study presents the modelling and simulation ofthe mechanical response of human ascending aortic aneurysmsin MFS under in vivo conditions with intraluminalpressures within normotensive and hypertensive ranges. Weobtained ascending aortic segments from five adults withMFS subjected to a vascular prosthesis implantation replacingan aortic aneurysm. We characterised the arterial samplesvia ex vivo tensile test measurements that enable fittingthe material parameters of a hyperelastic isotropic constitutivemodel. Then, these material parameters were used in anumerical simulation of an ascending aortic aneurysm subjectedto in vivo normotensive and hypertensive conditions.In addition, we assessed different constraints related to themovement of the aortic root. Overall, our results providenot only a realistic description of the mechanical behavior of the vessel, but also useful data about stress/stretch-basedcriteria to predict vascular rupture. This knowledge may beincluded in the clinical assessment to determine risk andindicate surgical intervention.