Acquired vein stenosis of renal allograft--percutaneous treatment with self-expanding metallic stent

The use of ferumoxytol for high-resolution vascular imaging and troubleshooting for abdominal allografts

Ferumoxytol is an ultrasmall superparamagnetic iron oxide which has been used as an off-label intravenous contrast agent for MRI. Unlike gadolinium-based contrast agents, ferumoxytol remains in the intravascular space with a long half-life of 14-21 h. During the first several hours, it acts as a blood-pool agent and has minimal parenchymal enhancement. Studies have shown adequate intravascular signal for up to 72 h after initial contrast bolus. Ferumoxytol has been shown to be safe, even in patients with renal failure. Ferumoxytol has shown promise in a variety of clinical settings. The exquisite resolution enabled by the long intravascular times and lack of background parenchymal enhancement is of particular interest in the vascular imaging of solid organ allografts. Ferumoxytol magnetic resonance angiography (MRA) may identify clinically actionable findings months before ultrasound, CT angiography, or Gadolinium-enhanced MRA. Ferumoxytol MRA is of particular benefit as a troubleshooting tool in the setting of equivocal ultrasound and CT imaging. In the following review, we highlight the use of ferumoxytol for high-resolution MR vascular imaging for abdominal solid organ allografts, with representative cases.

Transplant renal vein stent placement complicated by obstructive hematuria: A case report

BACKGROUND

Renal vein stenosis is uncommon following transplantation. We report acute renal vein stenosis post-transplant treated with an endovascular stent and complicated by urinary obstruction from clot formation.

METHODS

Retrospective case report.

RESULTS

A 16-year-old female 3 years post-transplant suffered anuria post-stenting with renal ultrasound demonstrating obstructive clot in the collecting system, a previously unreported complication. Subsequent nephroureteral JJ stent placement resulted in high-volume urine output.

CONCLUSION

This article underscores the high index of suspicion required for renal vein stenosis following transplantation and the need to monitor urine output closely following stent placement.

Biopsy Induced Arteriovenous Fistula and Venous Stenosis in a Renal Transplant

Renal transplant vein stenosis is a rare cause of allograft dysfunction. Percutaneous stenting appears to be safe and effective treatment for this condition. A 56-year-old Caucasian female with end stage renal disease received a deceased donor renal transplant. After transplant, her serum creatinine improved to a nadir of 1.2 mg/dL. During the third posttransplant month, her serum creatinine increased to 2.2 mg/dL. Renal transplant biopsy showed BK nephropathy. Mycophenolate was discontinued. Over the next 2 months, her serum creatinine crept up to 6.2 mg/dL. BK viremia improved from 36464 copies/mL to 15398 copies/mL. A renal transplant ultrasound showed lower pole arteriovenous fistula and abnormal waveforms in the renal vein. Carbon dioxide (CO₂) angiography demonstrated severe stenosis of the transplant renal vein. Successful coil occlusion of fistula was performed along with angioplasty and deployment of stent in the renal transplant vein. Serum creatinine improved to 1.5 mg/dL after.

Minimal Change Disease as a Secondary and Reversible Event of a Renal Transplant Case with Systemic Lupus Erythematosus

Secondary causes of minimal change disease (MCD) account for a minority of cases compared to its primary or idiopathic form and provide ground for consideration of common mechanisms of pathogenesis. In this paper we report a case of a 27-year-old Latina woman, a renal transplant recipient with systemic lupus erythematosus (SLE), who developed nephrotic range proteinuria 6 months after transplantation. The patient had recurrent acute renal failure and multiple biopsies were consistent with MCD. However, she lacked any other features of the typical nephrotic syndrome. An angiogram revealed a right external iliac vein stenosis in the region of renal vein anastomosis, which when restored resulted in normalization of creatinine and relief from proteinuria. We report a rare case of MCD developing secondary to iliac vein stenosis in a renal transplant recipient with SLE. Additionally we suggest that, in the event of biopsy-proven MCD presenting as an atypical nephrotic syndrome, alternative or secondary, potentially reversible, causes should be considered and explored.

Ipsilateral leg swelling after renal transplantation as an alarming sign of Iliac vein stenosis

Iliac vein stenosis is a rare vascular complication of renal transplantation that may compromise allograft function if not recognized and corrected in a timely fashion. Because chronic venous stenosis may remain undiagnosed for several years, a high index of suspicion should be maintained until diagnosing this rare disease. A 56-year-old renal transplant recipient presented with unilateral leg swelling and renal dysfunction 16 years after transplantation. Computed tomography excluded deep vein thrombosis and revealed tight iliac vein stenosis on the side of the renal transplant. Following angiographic confirmation of the stenosis, endovascular treatment was successfully performed with a purposefully designed, self-expanding, venous stent. Ipsilateral leg swelling is an alarming sign for the diagnosis of iliac vein stenosis after renal transplantation. Percutaneous intervention with venous stent placement seems to be a safe and effective treatment of this rare condition.

Ultrasonographic evaluation of the renal transplant

Ultrasonography is an excellent tool for evaluation of the renal transplant in the immediate postoperative period and for long-term follow-up. In this article, normal imaging findings and complications of renal transplantations are described. Disease processes are divided into vascular, perinephric, urologic and collecting system, and parenchymal abnormalities. Attention is paid to the time of occurrence of each complication, classic imaging findings, and potential pitfalls.

Renal vein stenosis with transudative ascites from graft after renal transplantation with good response after percutaneous stent placement

Ascites sometimes occurs as a result of technical complications of transplant surgery or other medical reasons, including hepatic, cardiac, or oncologic pathology. Renal vein stenosis after renal transplant resulting in transudative ascites is rare; thus there are few if any data on such cases. Stent implantation seems to be a safe and elective approach to treatment of this rare condition. We present the case of a 22-year-old woman in whom massive ascites developed 33 months after renal transplantation. After the analysis of the ascites fluid and exclusion of transplant artery stenosis, graft rejection, infection, portal hypertension, and other possible etiologies, the final diagnosis of graft renal vein stenosis with transudative ascites derived from the graft was made based on imaging studies, including Doppler ultrasonography and computed tomography. The patient underwent angiographic stent placement, and the ascites markedly improved after the procedure. Renal vein stenosis complicated with ascites after renal transplantation is highly unusual; the patient's response to angiographic stent placement was beneficial, with satisfactory resolution of the blockage and ascites.

Severe renal vein stenosis of a kidney transplant with beneficial clinical course after successful percutaneous stenting

A 51-year-old renal transplant recipient presented with marked renal function deterioration 13 months after renal transplantation. After exclusion of ureteral obstruction, transplant artery stenosis and acute rejection, the diagnosis of a severe renal vein stenosis was made by an MR scan. After angiographic confirmation of the stenosis, treatment was attempted with percutaneous stent angioplasty. The long-term clinical course was favorable, with marked improvement in renal function. Transplant renal vein stenosis is a rare, but potentially curable, cause of renal allograft functional deterioration.

Percutaneous stent placement as treatment of renal vein obstruction due to inferior vena caval thrombosis

A patient who had undergone his third orthotopic liver transplantation nearly 9 years prior to presentation developed worsening hepatic and renal function, as well as severe bilateral lower extremity edema. Magnetic resonance imaging demonstrated vena caval thrombosis from the suprahepatic venous anastomosis to the infrarenal inferior vena cava, obstructing the renal veins. This was treated by percutaneous placement of metallic stents from the renal veins to the right atrium. At 16 months clinical follow-up, the patient continues to do well.