Unreliability of Depopulated Bovine Ureteric Xenograft for Infra Inguinal Bypass Surgery: Mid-term Results from Two Vascular Centres

Hybrid management of a false aneurysm complicating an arteriovenous graft in a patient with critical limb ischemia

End-stage renal diabetic patients undergoing dialysis through an arteriovenous graft (AVG) often present with multiple graft complications which demand a combined therapeutic approach. We report a case of a male suffering from a pseudoaneurysm and venous outflow stenosis of his thigh AVG, as well as from critical limb ischemia caused by multiple significant stenoses of the femoropopliteal arterial segment. The patient was managed in a single session with a combination of classic open surgical and endovascular techniques in order to treat his aneurysm, salvage the AVG and to revascularize his leg. This case illustrates the prospect of combining classic open surgical and endovascular techniques for the optimal management of complicated AVGs. Using the hybrid approach in these cases one can succeed in optimizing the result, while simultaneously minimizing the overall risk for the patient.

Massive aneurysmal dilatation of a depopulated ureteric hemodialysis xenograft

Use of depopulated bovine ureteric xenografts for hemodialysis vascular access has recently been described. Cellular components have been removed, giving a connective tissue matrix which can be neocellularized, retaining native biomechanics. A 24-year-old male with end-stage renal disease from focal segmental glomerulosclerosis presented with particularly difficult vascular access. A depopulated bovine ureteric xenograft was implanted from the left subclavian artery to innominate vein. It became massively aneurysmal, requiring emergency embolization. Biopsy of the graft stained positive for alpha-gal. We believe this is the first reported case of massive aneurysmal dilatation of a depopulated bovine ureteric xenograft.

Incomplete cellular depopulation may explain the high failure rate of bovine ureteric grafts

BACKGROUND

The aim was to assess the results of a decellularized bovine ureter graft (SynerGraft) for complex venous access.

METHODS

Bovine ureter conduits were implanted in patients with a failed fistula or access graft in whom native vessels were unsuitable as conduits. Graft histories were obtained from all patients who had undergone this procedure at one institution. Failed grafts were explanted and subjected to histological examination. A sample of fresh bovine ureter was immunostained for galactose (alpha1 --> 3) galactose (alpha-Gal).

RESULTS

Nine patients with a median age of 46 (range 25-70) years underwent complex venous access surgery between August 2004 and November 2006 using a SynerGraft. Graft types included loop superficial femoral artery to stump of long saphenous vein (four patients), loop brachial artery to vein (two), brachial artery to axillary vein (two) and left axillary artery to innominate vein (one). Three grafts developed aneurysmal dilatation and two thrombosed. Histological assessment of the explanted bovine ureters revealed acute and chronic transmural inflammation. Immunostaining of fresh bovine ureter suggested residual cells and the xenoantigen alpha-Gal.

CONCLUSION

Graft failure with aneurysmal dilatation and thrombosis in complex arteriovenous conduits using bovine ureter may be due to residual xenoantigens.