Reduced patency in left-sided arteriovenous grafts in a porcine model

The porcine arteriovenous graft model is commonly used to study hemodialysis vascular access failure, with most studies using a bilateral, paired-site approach in either the neck or femoral vessels. In humans, left- and right-sided central veins have different anatomy and diameters, and left-sided central vein catheters have worse outcomes. We assessed the effect of laterality on arteriovenous prosthetic graft patency and hypothesized that left-sided carotid-jugular arteriovenous prosthetic grafts have reduced patency in the porcine model.

Arteriovenous polytetrafluoroethylene grafts were placed ipsilaterally or bilaterally in 10 Yorkshire male pigs from the common carotid artery to the internal jugular vein. Ultrasound measurements of blood flow velocities and diameters were assessed before graft placement. Animals were sacrificed at 1 week, 2 weeks, or 3 weeks. Patency was determined clinically; grafts and perianastomotic vessels were excised and analyzed with histology and immunostaining.

At baseline, left- and right-sided veins and arteries had similar blood flow velocities. Although internal jugular veins had similar diameters at baseline, left-sided carotid arteries had 11% smaller outer diameters (P = .0354). There were 10 left-sided and 8 right-sided polytetrafluoroethylene grafts placed; only 4 of 10 (40%) grafts were patent on the left compared with 7 of 8 (88%) grafts patent on the right (P = .04). Left-sided grafts had increased macrophages at the arterial anastomosis (P = .0007). Left-sided perianastomotic arteries had thicker walls (0.74 vs 0.60 mm; P = .0211) with increased intima-media area (1.14 vs 0.77 mm²; P = .0169) as well as a trend toward 38% smaller luminal diameter (1.6 vs 2.5 mm; P = .0668) and 20% smaller outer diameter (3.0 vs 3.7 mm; P = .0861). Left- and right-sided perianastomotic veins were similar histologically, but left-sided veins had decreased expression of phosphorylated endothelial nitric oxide synthase (P = .0032) and increased numbers of α-actin-positive smooth muscle cells (P = .0022).

Left-sided arteriovenous grafts are associated with reduced short-term patency compared with right-sided grafts in the Yorkshire pig preclinical model of arteriovenous prosthetic grafts. Laterality must be considered in planning and interpreting surgical preclinical models.