POS-751 AN UNUSUAL PRESENTATION OF ARTERI-VENOUS FISTULA AFTER RENAL BIOPSY: CASE REPORT

Abstract

Renal biopsy is an important diagnostic procedure but is associated with a number of significant complications even when performed by a skilled operator. While most of these complications present with haemodynamic disturbance, pain or macroscopic haematuria, some – such as the development of a post-biopsy arteriovenous fistula may be occult. We present an unusual presentation of a post-biopsy arteriovenous fistula which was diagnosed after the patient reported an audible bruit. A 39-year-old woman with end stage renal disease of unknown etiology received her first kidney transplant in February 2020. The right kidney from a deceased after cardiac death donor was transplanted into her right iliac fossa. Before transplantation, she had been on hemodialysis via an arteriovenous fistula (AVF) for a year. There was delayed graft function and the patient was dialysed through her AVF on the 2nd day of transplantation. Graft function was slow to improve and a kidney biopsy was performed on the 6th day post-transplantation. The biopsy was performed under ultrasound (US)control with two passes of a 16 G needle. Post-procedure observations were unremarkable and the patient went home after 6 hours of bed rest.The biopsy showed borderline rejection and the patient was prescribedthree doses of intravenous methylprednisolone. On the second day post-biopsy, graft function remained poor and routine bloods showed a drop in haemoglobin from 107 to 78 g/L. Abdominal US did not show any abnormality. Patient received blood transfusion and was observed overnight. The patient was discharged home next day. On the 5th day post-biopsy, the patient presented with reports of hearing “buzzing” sounds. ENT review was unremarkable. Graft function was poor and the patient remained on dialysis. Abdominal US and Doppler studies showed a large AVF within the transplanted kidney at the site of the earlier biopsy (fig 1). Figure 1: Doppler ultrasound of renal transplant showing post biopsy AVF The fistula was large and, with evidence of recent bleeding, thus underwent coil embolisation in the interventional radiology department (fig 2). Figure 2: Coil embolisation of AVF. Left panel shows initial angiographic appearance; right panel shows appearance following coil embolisation At present, the patient is nine months post-transplantation and remains dialysis independent with stable graft function and an eGFR 25-30 mL/min/1.73m2. Most biopsy-associated AVFs close spontaneously, are asymptomatic, and do not require intervention. The indication for intervention is usually an increase in the size of fistula over time, the development of signs of heart failure, deterioration in kidney function, or a rise in blood pressure. Embolisation of biopsy-associated AVFs has been reported to result in good outcomes with minimal changes in serum creatinine and estimated glomerular filtration rate. The risks include proximal dissemination of the embolisation material and the resultant focal occlusion of the arterial system causing renal, gut and pulmonary ischaemia. Surgical procedures are reserved for large AVFs with high velocity flows. Complications of kidney biopsy can be asymptomatic, and missed because of late and atypical presentation. A possibility of kidney biopsy related complication should always be considered when a patient presents within few weeks of the kidney biopsy.