Transplant Renal Artery Stenosis

Introduction: Transplant renal artery stenosis is a rare vascular complication that arises in approximately 1 to 26% of patients after receiving kidney transplant. It should raise awareness for prompt diagnosis as it can lead to volume overload, hypertension, worsening graft function, and allograft loss. We describe a case of transplant renal artery stenosis that was successfully revascularized and was able to maintain a stable allograft function thereafter. Case Description: A 60 year old male with history of hypertension, diabetes, CKD stage 4 underwent deceased donor transplant with immediate graft function. During surgery, doppler ultrasound of artery and veins, including upper, middle, lower pole, and external iliac artery below and above anastomosis were within normal ranges. Post-operative course was uneventful other than a complication with bleeding from a small perihilar arterial branch, which was controlled by surgical reopening of the incision and by using hemostatic clips. Due to worsening hypertension during a follow-up visit 3 months post-transplantation, doppler ultrasound of transplant kidney was performed, which revealed increasing velocities of renal artery. This was remeasured 1 month after with worsening parameters. The renal artery waveform showed a sharp upstroke, without evidence for a parvus tardus waveform. Patient underwent a arteriography of the renal artery and was found to have stenosis at the anastomoses of the superior and inferior transplant renal arteries with the external iliac artery. Stenosis improved after balloon angioplasty with improvement of pressures of the superior and inferior transplant renal arteries, and thereby improving his worsening hypertension. Patient's kidney function has been stable without any evidence of loss of graft function. Discussion: Transplant renal artery stenosis (TRAS) is a complication that should be sought out with doppler ultrasound. Symptoms that can arise are worsening hypertension, worsening graft function, volume overload, pulmonary edema. Our patient was promptly investigated for TRAS due to his worsening hypertension despite having stable allograft function, and was found to have stenosis of renal arteries at anastomosis sites. The pathophysiology for TRAS varies, and mainly is due to turbulent blood flow at anastomosis. Treatment is either angioplasty alone or angioplasty with stents, and generally have success rates of 90%.