Pre-existing histopathological changes in the cephalic vein of renal failure patients before arterio-venous fistula (AVF) construction.

BACKGROUND Native cephalic vein remains the superior dialysis conduit, even 30 years after it was first described. However, up to 37% of hemodialysis patients develop progressive stenosis in the venous circuit of arterio-venous fistula (AVF), which may later cause thrombosis and occlusion. MATERIAL AND METHODS To study the pre-existing morphological changes in the wall of the cephalic vein before AVF construction, we collected 23 cephalic vein specimens from 3 normal, young trauma patients and 20 renal failure patients. The samples were collected at the time of vascular repair in the first group and AVF construction in the second group. Sections were prepared and stained with hematoxylin & eosin (H&E), Masson's trichrome and Verhoff von Gieson's stains. RESULTS Compared with normal cephalic veins, all pre-access cephalic veins showed generalized thickening of the wall due to intimal hyperplasia and replacement by collagenous, fibrous tissue. Other changes were disruption or loss of internal elastic lamina in 9 (45%) patients, loss of endothelial cell layer in 6 (30%), atrophy or loss of the muscle layer in 6 (30%), mucoid or myxoid degeneration in 6 (30%), inflammatory cell infiltration of the wall in 5 (25%), mural calcification in 3 (15%) and telangiectasia in 2 (10%). Another important finding was the marked accumulation of spindle-shaped smooth muscle cells (SMCs) on the de-epithelialized intimal surface in areas of intimal hyperplasia. CONCLUSION In conclusion, most of the apparently normal cephalic veins of the renal failure patients showed morphological abnormalities at the time of AVF construction. This may influence the outcome of shunts in terms of future stenosis and failure.