Arteriovenous fistulas after renal allograft biopsy: A serious complication in patients beyond one year

Cyclosporine (CsA) immunosuppressive therapy has raised the diagnostic dilemma of differentiating drug-induced renal injury from renal allograft rejection. Renal transplant biopsy has emerged as an important tool to resolve this question. Among 744 patients treated with CsA-prednisone (P) and 221 patients with azathioprine (Aza)-P therapy, 352 (47%) and 41 (19%; p < 0.01) respectively, underwent renal transplant biopsy. Of the latter, 81% were needle biopsy (NB). The present reported 6 arteriovenous fistulas (AVF) all occurred in the CsA-P-treated group after NB, yielding an incidence of 1.3%. While 37 and 75% of NB were performed within the 1st month and 1st year post-transplant, respectively, the occurrence of AVF was low, 0 and 2 lesions (0.6%), respectively. Contrariwise, 4 of 6 AVF (3.5%; p = 0.015) developed beyond the 1st yr, all in patients displaying hypertension as well as histopathologic findings of interstitial fibrosis and arteriolopathy in the biopsy specimen. Among a set of 54 NB performed beyond 1 yr after transplantation for renal dysfunction, but not complicated by AVF, fibrosis and arteriolopathy were present in 98% and 73%, respectively, suggesting that the remote time-frame of the NB associated with this histopathologic picture may predispose to the increased risk of AVF. Two patients with AVF were managed expectantly; while 4 required interventional therapy. One patient in the former group and 3 in the latter lost their grafts within 1-6 months. These findings suggest that CsA-treated patients undergoing allograft NB beyond 1 year following transplantation are at increased risk of AVF, which was associated with loss of the graft in 4 of 6 cases.