Aortic tissue properties in porcine models: A comparison of ex vivo mechanical test results after simulated aortic arch reconstructions

Surgical interventions on the arterial wall can produce modifications to its tissue characteristics, and the addition of synthetic materials of different types can have implications on hemodynamics and blood vessel wall behavior. This work stud- ies the midterm 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 comprised of two groups of healthy Danish sows. The sows in the first group (short term (ST)) weighed about 40 kg, underwent a surgical operation and were sacrificed on the same day. The sows in the second group (midterm (MT)) weighed 5-10 kg, underwent a surgical operation and were then allowed to grow to a weight of about 30-40 kg, before being sacrificed. One sow in each group was scheduled for E/E and one sow for GGI. One sow in ST and two sows in MT received GPGA. The overall average wall thickness was 1.93 mm. Relaxation constant values were sig- nificantly higher for ST (5.221 ± 1.832 sec) than for MT (2.184 ± 1.216 sec). GPGA showed a greater impact on relaxation than other procedures, enhancing the viscous character. The working-point Young's modulus (Epw) was not significantly dif- ferent in ST and MT. Circumferential samples had different Epw (0.419 ± 0.77 MPa) from longitudinal samples (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 Epw value was 0.6609 ± 0.3641 MPa. (Journal of Applied Biomaterials & Biomechan- ics 2005; 3: 147-56)