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Case Report

iant Idiopathic Renal Arteriovenous Fistulaequiring Urgent Nephrectomy

arc C. Smaldone, Robert J. Stein, Jae-Sung Cho, and Wendy W. Leng

diopathic renal arteriovenous fistulas (AVFs) with acute hemorrhage are exceedingly rare. However, a rare entity suchs a renal AVF may be overlooked and have disastrous consequences, requiring an urgent management decisionetween endovascular or surgical treatment. We report the case of a 61-year-old man, who presented with painless grossematuria and clot retention. Computed tomography revealed a giant renal arteriovenous malformation, in the absencef any clinical stigmata such as hypertension or congestive heart failure. Gross hematuria resulted from AVF erosionnto the collecting system. Given the size of the AVF, endovascular coil embolization was attempted but deemed too

isky, necessitating urgent nephrectomy. UROLOGY 69: 576.e1–576.e3, 2007. © 2007 Elsevier Inc.

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asculature anomalies such as renal artery aneu-rysms (RAAs) and renal arteriovenous fistulas(AVFs) are uncommon and have been infre-

uently described. Often asymptomatic in nature, suchnomalies are now more commonly diagnosed by routinebdominal imaging, including renal ultrasonography,agnetic resonance imaging, and computed tomography

ngiography. Endovascular techniques for the treatmentf asymptomatic RAAs and AVFs have been described,ith excellent success rates in sporadic case reports. We

eport a case of man with an idiopathic giant renal AVFho presented with acute collecting system hemorrhage.ttempted endovascular coil embolization was unsuc-

essful, requiring urgent nephrectomy.

ASE REPORT61-year-old man with an unremarkable medical history

resented to the urologic clinic for additional workup ofew-onset painless gross hematuria. The previous week,he patient had been seen at a local emergency depart-ent and was treated empirically for a urinary tract

nfection. At the urologic clinic, outpatient flexible cys-oscopy and renal ultrasonography were scheduled, andhe patient was instructed to continue with his prescribedegimen of ciprofloxacin. However, before the scheduledxaminations, the patient returned with worsening pain-ess gross hematuria and difficulty voiding. The physicalxamination findings were unremarkable. The laboratoryvaluation demonstrated an elevated serum creatinine of.7 mg/dL, and the urinalysis was positive for red bloodells but was otherwise negative. The bladder was handrrigated, with copious clot return, and the patient was

rom the Department of Urology and Division of Vascular Surgery, Department ofeneral Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PennsylvaniaAddress for correspondence: Marc C. Smaldone, M.D., Department of Urology,niversity of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 700, Pittsburgh,

pA 15213-3232. E-mail: smaldonemc@upmc.eduSubmitted: May 9, 2006; accepted (with revisions): January 21, 2007

2007 Elsevier Inc.ll Rights Reserved

dmitted to the hospital for continuous bladder irrigationnd cystoscopic evaluation with possible clot evacuation.

Computed tomography of the abdomen and pelvishowed evidence of a giant, dilated, tortuous right renalrteriovenous malformation involving the main renalrtery and vein (Fig. 1). Cystoscopy with the patientnder anesthesia demonstrated an organized clot that waseadily evacuated, normal bladder mucosa, and a smallmount of clot emanating from the right ureteral orifice.etrograde pyelography revealed filling defects in the

ight renal pelvis consistent with free-floating clots.iven the preoperative computed tomography finding of

he giant renal arteriovenous malformation, ureteros-opic evaluation was not attempted. At the end of theystoscopy, the tentative plan was to discuss with thenterventional radiology department the feasibility of an-ioembolization in this situation.

The patient’s urine had been clear at the end of cystos-opy. After extubation, the patient developed respiratorytridor and was urgently reintubated for airway control. Thetridor and associated Valsalva efforts appeared to precipi-ate recurrent significant gross hematuria. At this point,he patient was quickly resuscitated. Although theatient remained hemodynamically stable, immediatecreening confirmed a significant decrease in his hemo-lobin count. Thus, a blood transfusion was initiated, andhe patient was urgently transferred to interventionaladiology.

Aortography clearly demonstrated the giant right renalVF, which involved a notably enlarged and tortuous

usiform main renal artery with a width of approximately.7 cm (Fig. 2). Moreover, the high flow within the renalrtery promptly emptied into the renal vein and venaava (Fig. 3). The AVF was catheterized, and attempts atmbolization with a series of 18-mm detachable coilsere deemed unfeasible because of the risk of pulmonarymbolus from the high-flow state. Simultaneously, the

atient’s hematuria worsened, with a drop in systolic

0090-4295/07/$32.00 576.e1doi:10.1016/j.urology.2007.01.041

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lood pressure requiring additional blood transfusions. Athis point, the decision was made to take the patient tourgery in conjunction with the vascular surgery team formergent nephrectomy.

At dissection and control of the great vessels, theilated, thin-walled, right RAA (2.7 cm) was readilypparent. Given the large caliber of the abnormal renalilar vessels, it was difficult to gain proximal and distalontrol of the aorta. Once the renal artery was dividednd oversewn, the right renal vein (4.1 � 4.2 cm) wasivided at the confluence with the inferior vena cava,nd the kidney was mobilized and removed. Examinationf the gross specimen and the pathology report confirmedhat the renal AVF had eroded into the collecting sys-em. The patient’s postoperative course was uncompli-ated, and he was discharged home on the fourth day. Atis 1-month follow-up visit, the patient’s urine was clear

igure 1. Nephrographic-phase computed tomography secB) large arteriovenous malformation at anterior mid-pole o

igure 2. Abdominal aortogram demonstrating large, tor-urous, fusiform, right RAA.

nd his creatinine was 1.4 mg/dL. i

76.e2

OMMENTAAs are rare, with a reported incidence of 0.1% to.3% of the population.1 They can be classified as con-enital or acquired and are most commonly described asaccular, fusiform, dissecting, and arteriovenous.2 RAAsre usually asymptomatic, but associated signs and symp-oms can include flank pain, hematuria, hypertension,nd a palpable abdominal mass. Although the risk ofupture is small, surgical excision is recommended forneurysms greater than 2 cm in diameter, in women ofhild-bearing age, with an expanding size on serial an-iograms, with an incomplete ring-like calcification onadiography, in the presence of uncontrollable hyperten-ion, or in the presence of an AVF.3,4

AVFs in native kidneys are also rare and are usuallycquired after percutaneous intervention or trauma. Id-

demonstrating (A) large dilated tortuous renal artery andht kidney.

igure 3. Later phase of aortogram revealing fistulous con-ection to right renal vein with early filling of inferior venaava.

tions

opathic renal AVF are described as noncirsoid, solitary

UROLOGY 69 (3), 2007

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ommunications between the renal vessels and are be-ieved to occur as the result of a congenital RAA thatrodes into an adjacent vein.5 Few cases of coexistingAA and AVF have been reported.6–8 The clinical pre-

entation ranges from an asymptomatic bruit to high-utput cardiac failure and dictates the need for surgicalntervention.8 The etiology of our patient’s AVF ap-eared to be related to the erosion of an intrarenalneurysm into the venous system. He had no history ofrauma or an invasive procedure, and the physical exam-nation findings were unremarkable. Gross specimen ex-mination revealed a tortuous fusiform renal artery, 2.7m in maximal diameter, with a solitary direct commu-ication to the dilated 4.1 � 4.2-cm renal vein that wasasily cannulated with a lacrimal duct probe.

Conventional RAA and AVF repair has consisted ofpen surgical techniques. Reported operative manage-ent of concomitant RAAs and AVFs has consisted ofephrectomy for patients presenting with intraabdominalemorrhage8 and ex vivo bench repair in asymptomaticatients.7 Endovascular treatment of large high-flowVFs is limited because of the risk of coil migration.owever, studies have reported successful treatment of

mall AVFs and RAAs with catheter-directed emboliza-ion9,10 and stent-graft occlusion.11,12 Coil embolizationas attempted but was unsuccessful in our patient be-ause of the large diameter and high-flow state of theenal vasculature. Ongoing bleeding into the collectingystem and the continued transfusion requirement neces-itated emergent nephrectomy.

Idiopathic AVFs are rare and are often diagnosed in-identally on imaging studies. At our institution, abdom-nal computed tomography with and without intravenousontrast (including 2.5-mm cuts through the collectingystem and delayed imaging) is routinely obtained duringworkup for gross hematuria. In patients with renal insuf-

ciency or a contrast allergy, magnetic resonance urography

r renal ultrasonography is done. Routine abdominal imag-

ROLOGY 69 (3), 2007

ng of the upper tract during the workup for gross hematuriaan detect potentially catastrophic anomalies in asymptom-tic patients. For incidentally diagnosed arteriovenous mal-ormations, endovascular techniques and renal-preservingpen surgical management have been successful in patientsho were asymptomatic or stable at presentation. Nephrec-

omy is a reasonable option in unstable patients or whenenal vascular anatomy does not permit endovascular treat-ent.

eferences1. Tham G, Ekelund L, Herrlin K, et al: Renal artery aneurysms:

natural history and prognosis. Ann Surg 197: 348–352, 1983.2. Abeshouse BS: Aneurysm of the renal artery: report of two cases

and review of the literature. Urol Cutaneous Rev 55: 451–463,1951.

3. Poutasse EF: Renal artery aneurysms. J Urol 113: 443–449, 1975.4. English WP, Pearce JD, Craven TE, et al: Surgical management of

renal artery aneurysms. J Vasc Surg 40: 53–60, 2004.5. Tynes WV, Devine CJ Jr, Devine PC, et al: Surgical treatment of

renal arteriovenous fistulas: report of 5 cases. J Urol 103: 692–698,1970.

6. Trocciola SM, Chaer RA, Lin SC, et al: Embolization of renalartery aneurysm and arteriovenous fistula—a case report. VascEndovascular Surg 39: 525–529, 2005.

7. Torres G, Terramani TT, and Weaver FA: Ex vivo repair of a largerenal artery aneurysm and associated arteriovenous fistula. AnnVasc Surg 16: 141–144, 2002.

8. Maldonado JE, and Sheps SG: Renal arteriovenous fistula. PostgradMed 40: 263–269, 1966.

9. Klein GE, Szolar DH, Breinl E, et al: Endovascular treatment ofrenal artery aneurysms with conventional non-detachable micro-coils and Guglielmi detachable coils. Br J Urol 79: 852–860, 1997.

0. Rimon U, Garniek A, Golan G, et al: Endovascular closure of alarge renal arteriovenous fistula. Catheter Cardiovasc Interv 59:66–70, 2003.

1. Rundback JH, Rizvi A, Rozenblit GN, et al: Percutaneous stent-graft management of renal artery aneurysms. J Vasc Interv Radiol11: 1189–1193, 2000.

2. Sprouse LR II, and Hamilton IN Jr: The endovascular treatment ofa renal arteriovenous fistula: placement of a covered stent. J Vasc

Surg 36: 1066–1068, 2002.

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