Mechanical behaviour of healthy and damaged human arteries and validation of parameters derived from experiments

Abstract

Our research group aimed to develop a numerical model for the analysis of healthy and damaged human blood vessels (e.g. an aneurysm, an adverse vasodilatation) and to investigate the hyperelastic mechanical response of human brain arterial tissue. One of our tasks was to perform laboratory analysis on the specimens taken from the wall of the vessel, to calculate material model parameters for numerical models based on our measurements. Biaxial biomechanical characterization of living tissues -like the artery walls -provides important information about their in vivo behaviour. The aim of our research is to estimate stresses of the aneurysm wall and its parent artery, and to estimate the likelihood of a later aneurysm rupture, too. Laboratory measurements have been undertaken, we have taken the specimens of the vessel wall from human cerebral aneurysms and from control healthy artery carotis interna (both from surgery and cadavers), and then we investigated the biomechanical properties of samples in uniaxial and biaxial tensile tests. We attained for this by means of processing the values of the deformations and (Cauchy-)stresses arising from the wall. We verified the necessity of the parameters calculated from the laboratory measurements with finite element simulations performed on a real geometry aneurysm sack. From our study it may be concluded that there is a need for a constitutive model which describes the hyperelastic behavior of the human arterial wall. We demonstrated with numerical simulations that consideration for inhomogenity in investigations of diseased segments of blood vessels has crucial importance. We proved that damage taking place in aneurysm-sacks is many times more presumable than in healthy material parent arterial segments.

Sensor-Based Measurement Method to Support the Assessment of Robot-Assisted Radiofrequency Ablation

“…There are numerous bioengineering research issues that remain open in this field. These include developing detailed models of the human tissue–tool interaction [ 18 ], the heat dissipation of different catheter shapes [ 19 ], and the effect of applied forces during ablation [ 20 ].…”