L-arginine reduces neointimal hyperplasia in cold-stored arterial allografts in a rabbit low-flow-through model

An "off the shelf" vascular conduit for free flap surgery that remained patent until the flap is vascularized from the recipient bed would be useful to avoid autograft donor-site morbidity and reduce operation time. To date, no successful studies of microvascular prostheses in low-flow states exist. This study investigated the effects of L-arginine on neointimal hyperplasia and the overall patency of cold-stored femoral arterial allografts implanted into a low-flow arterial defect model in rabbits. A cutaneous island flap based on the inferior epigastric artery was raised, and the femoral artery was ligated distally. Immediately proximal to the inferior epigastric artery, the femoral artery was divided and a 1-cm long cold-stored femoral arterial allograft was inserted into the defect. Half of the animals received L-arginine as a subcutaneous injection. When harvested at 4 weeks, 9 out of 11 allografts of the L-arginine-treated group and 8 out of 14 grafts of the control group were patent. Intimal thickening and graft stenosis were significantly reduced in the L-arginine group. Our findings reveal the potential of a combined approach of an arterial allograft and the use of L-arginine as a short-term vein graft substitute.