Quantifying the Mechanical Limitations of Dacron Grafts Within the Context of Thoracic Aortic Aneurysm Repair
Theses
Overview
Overview
abstract
Aortic aneurysms are a pressing health concern necessitating immediate surgical intervention to avert life-threatening complications. Within the domain of aortic reconstruction, Dacron grafts have emerged as a prevailing choice. These grafts exhibit a hyperelastic quasistatic response and non-linear viscoelastic behaviour, essential for enduring dynamic changes in pressure. However, Dacron lacks the degree of elasticity exhibited by the aorta, leading to adverse aortic remodeling and increased ventricular afterload. The study aims to develop an understanding of the interplay between aortic mechanics and graft characteristics within the context of thoracic aortic aneurysm (TAA) repair. Porcine aortas were selected for their biomechanical resemblance to human aortic tissue. The mechanical responses were evaluated using a custom-designed pressurization apparatus. Loading-unloading cycles under physiological pressures were performed on aorta samples, Dacron grafts, and the composite aorta-graft conjugate. The experimental findings revealed significant differences in the mechanical behaviour of porcine aortic tissue and Dacron grafts. While porcine aortas exhibited isotropic behavior, Dacron grafts primarily underwent longitudinal strain. Additionally, one side of the conjugates experienced lower average strain values compared to the other, and a decrease in circumferential strain along the aortic side of the conjugate towards the suture point was observed. This would indicate localized stress concentrations, potentially compromising the structural integrity of the aortic tissue in the long term. By addressing the mechanical limitations and stress distribution patterns associated with Dacron grafts, this study contributes to the ongoing efforts aimed at optimizing patient outcomes and advancing the field of aortic surgery.
