Heterotopic renal transplantation in piglets using vascular closure stapler metallic clips or conventional suturing techniques: comparison of vessel growth and macroscopical study

Abstract

Background/purpose: Our aim was to perform a macroscopic and imaging (ultrasonographic and angiographic) evaluation of vascular closure stapler (VCS) metallic clips for renal transplantation in growing piglets to assess their role for transplantation surgery in young children. If these techniques are to be useful, it is necessary to prove that their use avoids one of the main pitfalls of conventional sutures in this setting, namely lack of growth in the suture line.

Methods: Twenty-four piglets were used for this study. Animals were subjected to a heterotopic renal autotransplantation when they were 45 days old. The right kidney was moved from its normal location to the cranial area of the iliac fossa. The end-to-side anastomoses between the renal artery and vein and the aorta and vena cava, respectively, were performed using VCS metallic clips in 6 animals. Continuous polypropylene suturing was used in another 6 piglets, and continuous polyglycolic acid suture was used in 6 additional piglets. A control group of 6 animals without renal autotransplantation was also included in the study. All animals were allowed to grow for 6 months, during which time serial angiographic and ultrasonographic studies were carried out to assess the existence of vascular flow disturbances or stenosis. Similarly, angiographic measurements were obtained to document growth at the anastomotic site. Longitudinal growth was evaluated postmortem after the 6-month growing period.

Results: Angiography showed significant (P < .001) transverse growth in both arteries and veins belonging to the VCS clips, running absorbable suture, or control groups. No significant difference was observed among the 3 groups. Vascular growth in the running nonabsorbable suture (polypropylene) group, however, was significantly less than in the other 3 groups and did not significantly differ from baseline. Baseline luminal diameters at the anastomotic site as measured by angiography in the VCS group were 3.64 ± 0.40 mm in the artery and 5.30 ± 1.43 mm in the vein. After growth, these values increased to 6.87 ± 0.90 mm and 11.27 ± 2.53 mm, respectively. Significant longitudinal growth was evidenced macroscopically after 6 months in both aorta and vena cava in all groups. On the other hand, significant longitudinal growth in the renal artery and vein were only observed in the control, VCS, and absorbable suture groups.

Conclusions: In this experimental setting, satisfactory macroscopic and angiographic vascular growth results were obtained using the VCS clips, suggesting that this suture could be the technique of choice in pediatric transplantation surgery.