Compromise of renal transplant blood flow by an arteriovenous graft.

A 61-year-old male developed end-stage renal failure in January 1994, with a presumptive diagnosis of hypertensive nephrosclerosis but no renal biopsy, and commenced peritoneal dialysis which failed in April 1996, requiring a change to haemodialysis via a left subclavian tunnelled venous line. A succession of arteriovenous fistulae (AVFs) was formed in both arms but by August 2004, native AVFs and anatomical arteriovenous grafts (AVGs) exhausted. He required placement of a series of central venous cannulae, complicated by complete superior vena cava obstruction. A subcutaneous right axillary artery to popliteal vein Poly Tetra Fluoro Ethylene AVG was formed in August 2004 and he was anticoagulated with warfarin. This allowed satisfactory dialysis until a transplant kidney became available 12 days later. He received a renal allograft (left kidney, single vein, single artery) from a 22-year-old non-heartbeating cadaveric donor with a 210 A/B/DR mismatch and a cold-ischaemia time of 16 h. The kidney was anastomosed to the right external iliac artery and vein, as is the standard practice for left kidneys (position on the right side makes access for correction of urological complications, such as hydronephrosis, easier). Initial immunosuppression was with corticosteroid, basiliximab, tacrolimus and mycophenolate mofetil. Warfarin was discontinued at the time of the transplant and replaced by aspirin. Delayed graft function was investigated by an ultrasound scan, which demonstrated a well-perfused kidney, and a technetium-99m mercaptoacetyltriglycine (MAG-3) renogram compatible with acute tubular necrosis (ATN). He remained dialysis-dependent, and a biopsy 7 days after transplantation confirmed the presence of ATN and excluded rejection. Subsequently, his renal function improved and dialysis was stopped on the twelfth post-operative day. Three months later, he presented with swelling of the right leg and oligo-anuric acute renal failure requiring haemodialysis. A Doppler ultrasound scan revealed thrombosis of the superficial femoral and popliteal veins on the right and venography demonstrated the presence of a thrombus in the common iliac and the transplant renal veins. The obstruction was successfully cleared by local thrombolysis followed by the reintroduction of anticoagulation. He began to pass urine immediately after the procedure and recovered fully from this episode of renal failure with a serum creatinine concentration of 119 mmol/l. One month later, the patient was re-admitted with pulmonary oedema and a significant deterioration in graft function. He required haemodialysis via the extra-anatomical AVG which had remained patent. A Doppler ultrasound scan of the transplant kidney showed poor flow in the transplant and common iliac veins, raising the possibility of partial re-thrombosis or of stenosis. These veins were treated with venoplasty and stenting (Figure 1A and B). Despite this treatment, renal function did not recover completely and a new duplex scan showed a reversal of blood flow in the renal vein without any thrombosis, narrowing or external compression. The AVG thrombosed 2 days later and dialysis became impossible. Following loss of flow in the extra-anatomical graft, renal function rapidly recovered and the swelling in the right leg improved. At the latest follow-up, the patient remains well with a serum creatinine concentration of 90 mmol/l. Correspondence and offprint requests to: Mr Eric Chemla FRCS, Consultant Transplant Surgeon, Department of Renal Medicine and Transplantation, St George’s Hospital, Blackshaw Road, Tooting, London, SW17 0QT, United Kingdom. Email: [email protected]