Renal Vein Thrombosis After Renal Transplantation: An Important Cause of Graft Loss P. Giustacchini, F. Pisanti, F. Citterio, A.M. De Gaetano, M. Castagneto, and G. Nanni R ENAL vein thrombosis (RVT) is a serious early postoperative complication of kidney transplantation (KT), leading to graft loss in almost all cases. 1–4 The incidence of RVT ranges from 0.5% to 4% in different series, with a peak of 10%. 5 It occurs mostly between the second and seventh postoperative day. Although associated with an acute or hyperacute rejection episode or surgical misadventure, in a large proportion of cases, the cause of RVT is unexplained. Uremic coagulopathy may predispose to RVT. Although it is a rare complication, RVT can be considered one of the most frequent events affecting graft survival during the first month. 3 Our report presents 6 cases and evaluates the risk factors and the modality of treatment of RVT. CLINICAL EXPERIENCE We analyzed the incidence of RVT among a series of 370 consecutive KT patients, 247 male and 123 female. Immu- nosuppressive treatment consisted of cyclosporine (CsA) and steroids in 269 patients; CsA, sirolimus (SRL), and steroid in 45 patients; and tacrolimus (TAC), mycopheno- late mofetil (MMF), and steroid in 56 patients. During the first postoperative week, we observed 6 cases of suspected RVT (1.6%), all associated with swelling of the leg and of the kidney, anuria, and disappearance of renal vein flow by duplex Doppler sonography. Urgent surgical exploration was performed in all cases. No graft showed evidence of a technical anastomotic failure or an inadequate length of the renal vein. In 3 cases (true RVT), the kidney was immedi- ately removed due to irreversible ischemia. In 3 other cases, RVT was not present but the renal vein was kinked relative to an increased kidney volume. In the latter cases, the kidney was repositioned, leaving the musclar layer of the abdominal wall open. In 1 case, the graft survived and still shows good function after 4 years; the other 2 kidneys were removed after a few days of apparently good perfusion. The characteristics of our 6 patients were donor age between 32 and 54 years, recipient age between 20 and 55 years, only primary transplants, no rejection episodes, 5 males (5/247, 2%) and 1 female (1/123, 0.8%), 2 diabetic patients (out of 9 in our series, 22%), absence of medical conditions associated with the risk of thrombosis, 3 perito- neal dialysis (out of 19 patients on peritoneal dialysis of our series, 16%), 4 right kidneys, 3 left iliac fossa, 1 severe arterial postoperative hypotension, 2 acute tubular necrosis (ATN). Three events occurred on postoperative day 4, 2 events on day 5, and 1 event on day 6. Four patients were on CsA therapy, 1 patient on CsA and SRI, and 1 patient on TAC and MMF. DISCUSSION Our data confirm that RVT is an uncommon (1.6%) complication of kidney transplantation leading to graft loss in almost all cases. Nonetheless, it is one of the most frequent events affecting graft survival during the first month. 6 In fact, in our transplant population, the rate of graft loss during the first posttransplant month due to different causes is 6.7% (25 out of 370 patients), RVT represents 20% of the failures (5 out of 25 patients). Chronic renal failure and renal transplantation are asso- ciated with an increased risk of venous thrombosis. 5 Several factors have been identified to be associated with an increased risk of RVT when acute or hyperacute rejection is absent 2,3,5,7,8 : relatively young or old donor age, repeat transplantation, diabetes mellitus, peritoneal dialysis, use of right kidney, use of right kidney, use of left iliac fossa, long ischemic time, ATN, presence of cold hemoagglutinins, systemic lupus erythematosus as cause of end-stage renal disease, recipient gender, impaired perioperative recipient hemodynamic status, carriers of factor V Leiden 506Q mutation, 5 presence of antiphospholipid antibodies, and presence of anticardiolipin antibodies. 9 Among our patients we only identified as risk factors male sex, diabetes and peritoneal dialysis. Even though we did not have the opportunity to document the presence of antiphospholipid or anticardiolipin antibodies, none of our patients had a history of thrombosis or pretransplant dis- ease associated with an increased risk of thrombosis; thus; we could exclude the presence of clinical conditions leading to venous complications. Though in the case of RVT, the graft usually has to be removed, strict clinical and Doppler sonography monitoring in the first posttransplant week followed by prompt inter- From the Transplant Unit and Department of Radiology, Cath- olic University, Rome, Italy. Address reprint request to Giuseppe Nanni, via Livio Pentimalli 30, 00136 Roma, Italy. 0041-1345/02/$–see front matter © 2002 by Elsevier Science Inc. PII S0041-1345(02)02876-2 655 Avenue of the Americas, New York, NY 10010 2126 Transplantation Proceedings, 34, 2126 –2127 (2002)