In vivo analysis of dynamic tensile stresses at arterial end-to-end anastomoses. Influence of suture-line and graft on anastomotic biomechanics

Abstract

Objective: to determine the influence of an anastomotic suture line and a graft on dynamic tensile stresses of vascular end-to-end anastomoses in vivo. Material and methods: the abdominal aorta of twelve 35-kg pigs was used as an experimental model. Simultaneous recordings of internal arterial diameter and pressure were performed on each pig at 3 successive stages: (1) The genuine artery (REF), (2) artery-artery (A-A) and (3) graft-artery (G-A) anastomosis at 1-mm increments in the immediate perianastomotic area. Thereby, RD (relative distension), CC (compliance coefficient), E(p) (dynamic pressure-strain elastic modulus) and hysteresis loop areas could be calculated for every measuring point. Results: the graft was significantly stiffer than REF. A-A and G-A anastomoses were significantly less compliant than REF. Maximum E(p), minimum CC and hysteresis loop areas were found at the anastomotic line due to minimum anastomotic RD. Downstream of the G-A anastomosis, the RD, CC, E(p) and loop areas were significantly different from REF, but significantly different from A-A. Conclusion: an animal model for acute studies of mechanical properties of vascular end-to-end anastomoses was developed. The main determinant for anastomotic biomechanics was the suture-line itself.