Embolization of a large arteriovenous fistula in a transplanted kidney: a case report

Abstract Background Arteriovenous fistulas of transplant kidneys are uncommon but potentially serious vascular complications, most often occurring after biopsy or surgical trauma. While many are small and resolve spontaneously, large fistulas can cause persistent hematuria, graft dysfunction, and hemodynamic compromise. Early recognition is critical, as delayed diagnosis may lead to significant morbidity or unnecessary graft loss. This case highlights the evolution of a large transplant kidney arteriovenous fistula and demonstrates successful minimally invasive management using endovascular coil embolization. Case presentation: A 56-year-old male with a history of end-stage renal disease on hemodialysis and prior kidney transplantation presented with persistent hematuria and altered mental status. Initial computed tomography of the abdomen and pelvis revealed diffuse enlargement of the transplant kidney with loss of normal corticomedullary differentiation, concerning for lymphoproliferative disease, along with a pseudoaneurysm. Conservative management was initially pursued. Due to ongoing hematuria, repeat computed tomography angiography demonstrated a markedly enlarged vascular structure within the transplant kidney with early venous opacification, consistent with a large arteriovenous fistula. Interventional radiology performed endovascular embolization via femoral artery access. Selective catheterization identified anterior and posterior renal arterial feeders, which were successfully embolized using a combination of detachable coils. Completion angiography confirmed complete occlusion of the fistula with preservation of the main renal arterial flow. Post-procedural ultrasound and follow-up computed tomography angiography showed no residual flow. Conclusions This case demonstrates that large arteriovenous fistulas in transplanted kidneys can develop and progress during hospitalization and should be considered in patients with persistent hematuria. Endovascular coil embolization is a safe and effective treatment that allows for targeted occlusion of the fistula while preserving renal perfusion. Early diagnosis and minimally invasive intervention can prevent complications and may avoid the need for surgical graft removal.