MRI-based multiscale models for the haemodynamic and structural evaluation of surgically reconstructed aortic arches

Surgical interventions on the arterial wall may bring forth modification to its tissue characteristics and the addition of synthetic materials of different types can have implications on haemodynamics and blood vessel wall behaviour. This work studies the mid-term effects of end-to-end anastomosis (E/E), Gore-tex graft interposition (GGI) and Gore-tex patch graft aortoplasty (GPGA) in aortic arch reconstruction. The study comprises two groups of healthy sows of Danish breed. The animals in the first group (ST) weighed around 40 kg, underwent a surgical operation and were put down on the same day. The animals in the second group (MT) weighed 5-10 kg, underwent a surgical operation and were then allowed to grow up to a weight of around 30-40 kg, before being sacrificed. One pig in each group was scheduled in for E/E and one for GGI. One pig in ST and two in MT received GPGA. The overall average wall thickness was 1.93 mm. Relaxation constant values were significantly higher for ST (5.221 +/- 1.832 s) than for MT (2.184 +/- 1.216 s). GPGA showed a greater impact on relaxation than other operations, enhancing the viscous character. Working-point Young’s modulus (Epw ) was not significantly different in ST and MT. Circumferential samples had different Epw (0.419 +/- 0.77 MPa) from longitudinal ones (0.902 +/- 0.378 MPa). There also appeared to be a significant difference between samples cut longitudinally on the left and the right sides of the wall. The overall average value of Epw was 0.6609 +/- 0.3641 MPa.