An 18-cm-Large Renal Arteriovenous Fistula Treated by Nephrectomy
Article Outline
Idiopathic renal arteriovenous fistulas are extremely rare. They are believed to occur as the result of congenital renal artery aneurysm that erodes into an adjacent vein. We report a case of a 48-year-old man in whom we discovered fortuitously a painless mass of the right flank. Computed tomography revealed a huge renal artery aneurysm with giant arteriovenous fistula in the absence of any clinical stigmata. Given the size of the fistula and the partial destruction of the renal parenchyma, nephrectomy was successfully performed.
Renal arteriovenous fistulas are anomalous connections between arterial and venous systems. They may be congenital or acquired. Acquired fistulas classified as idiopathic are rare and often diagnosed incidentally on imaging studies. Conventional renal artery aneurysm (RAA) and arteriovenous fistula (AVF) repair has consisted of open surgical techniques. We report a case of a man with an idiopathic giant renal AVF diagnosed fortuitously. Given the size of the fistula and the partial destruction of the renal parenchyma, nephrectomy was successfully performed.
Case Report
A 48-year-old man with an unremarkable medical history presented to the general surgery clinic for repair of an inguinal hernia. The physical examination revealed a painless mass of the right flank with a murmur. The laboratory evaluation demonstrated normal serum creatinine, and the urinalysis was negative.
Renal color Doppler ultrasound showed a very high-flow arteriovenous shunt of the right upper renal pole.
Computed tomography of the abdomen and pelvis demonstrated (Fig. 1) a giant right AVF (18
cm), which involved a notably enlarged and tortuous main renal artery with a width of approximately 3cm. Moreover, the high flow within the renal artery promptly emptied into the renal vein and vena cava. The renal parenchyma on the upper pole was completely destroyed by the giant RAA, and overall renal function was poor. The patient was transferred into our department for surgical repair.
Fig. 1
Computed tomography of the abdomen and pelvis.
At dissection and control of the great vessels (Fig. 2), the dilated right RAA (4cm) was readily apparent. In spite of the large caliber of the abnormal renal hilar vessels, we gained proximal and distal control of the aorta. Once the renal artery was divided and oversewn, the right renal vein (4×4.5cm) was divided at the confluence with the inferior vena cava, and the kidney was mobilized and removed (Fig. 3). The patient's postoperative course was uneventful, and he was discharged home on the sixth day.
Fig. 2
Control of the abdominal aorta, inferior vena cava, and renal vessels.
Fig. 3
The operative piece.
Discussion
RAAs are rare, with a reported incidence of 0.1-1.3% of the population.1, 2 They can be classified as congenital or acquired. Acquired fistulas classified as idiopathic have been reported in only 2.8% of cases of AVFs.3 RAAs are usually asymptomatic, but associated signs and symptoms can include flank pain, hematuria, hypertension, and palpable abdominal mass.2 AVFs in native kidneys are also rare and are usually acquired after percutaneous intervention or trauma. Idiopathic renal AVFs are described as solitary communications between the renal vessels and are believed to occur as the result of congenital RAA that erodes into an adjacent vein.4 Few cases of coexisting RAA and AVF have been reported.5, 6 The clinical presentation ranges from asymptomatic bruit to cardiac failure and dictates the need for surgical intervention.6
The etiology of our patient's AVF appeared to be related to the erosion of an intrarenal aneurysm into the venous system. He had no history of trauma or invasive procedure, and the physical examination findings were unremarkable. Conventional RAA and AVF repair has consisted of open surgical techniques.2 Reported operative management of concomitant RAAs and AVFs has consisted of nephrectomy for patients presenting with intra-abdominal hemorrhage6 and ex vivo bench repair in asymptomatic patients.7 With improvements in surgical reconstruction with ex vivo repair and advances in low-profile endovascular devices, the need for nephrectomy is a rare event in the current era. When feasible, preservation of a functional kidney with arterial reconstruction is preferred. The remaining indications for nephrectomy are nonfunctional kidney or life-theatening hemorrhage.
Endovascular treatment of large, high-flow AVFs is limited because of the risk of coil migration.8 However, studies have reported successful treatment of small AVFs and RAAs with catheter-directed embolization9, 10 and stent-graft occlusion.11, 12
In our case, open surgical repair was dictated by the size of both the RAA and the AVF. Although arterial reconstruction was discussed preoperatively, the renal parenchyma was found desolated upon surgical exploration and nephrectomy was performed. For incidentally diagnosed arteriovenous malformations, endovascular techniques and kidney-sparing open surgical management have been successful in patients who were asymptomatic or stable at presentation. Nephrectomy is a reasonable option in unstable patients or those with a nonfunctional kidney.
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PII: S0890-5096(09)00328-8
doi:10.1016/j.avsg.2009.09.011
© 2010 Published by Elsevier Inc.
