[Giant renal arteriovenous malformation: a suspicious bruit]

Arteriovenous (AV) malformations remain relatively rare clinical lesions consisting in abnormal shunts between the arterial and venous vascular systems. Both,congenital or acquired fistulas, are unusual causes of renal or heart failure. Congenital AV fistulas usually present with hematuria, while acquired ones are more likely to present with hemodynamic changes, such as hypertension, cardiomegaly and congestive heart failure. Here we present a 61 year-old woman studied before by probable pulmonary arteriovenous fistula and referred to nephrologist with a six-month history of dyspnea and peripheral edema. Physical examination was remarkable for an apical systolic ejective murmur as well as another bruit over the right pulmonary base. Blood tests showed a sCr of 1.7 mg/dl with normal urinalysis. On imaging, renal duplex ultrasound showed a pulsatile hiliar mass on the right kidney with an arterial flow of 300 cm/sec that was identified as a giant AV fistula on MRA. An echocardiogram revealed severe pulmonary hypertension with a cardiopulmonary output of 12,9 l/min that doubled the systemic one (6,49 l/min). In view of the large size of the AV fistula occupying the majority of the parenchyma, endovascular approach was turned down and a laparoscopic nephrectomy was performed successfully. There was an immediate clinical improvement and 45 days after the procedure, a control-echocardiogram showed normalization of the cardiopulmonary parameters with minimal changes in glomerular filtration rate.