CASE REPORT
SPONTANEOUS THROMBOSIS OF AN IATROGENIC ARTERIOVENOUS FISTULA OF THE KIDNEY ¨ RG SOMMERFELD, J. MIGUEL GARCIA-SCHU¨RMANN, HANS-JO
AND
JU¨RGEN PANNEK
ABSTRACT A 44-year-old woman underwent radial nephrotomy for a symptomatic stone in a caliceal diverticulum. Five days after an uneventful postoperative course of 1 week, she presented with gross hematuria. Routine ultrasound demonstrated a hypoechoic lesion in the kidney; color-coded sonography revealed an arteriovenous fistula. The hematuria ended before the scheduled angiography to embolize the fistula was performed. Repeated color-coded sonography revealed spontaneous thrombosis of the lesion. The follow-up examination 6 months later confirmed these findings. As traumatic arteriovenous fistulas have a good chance of spontaneous closure, invasive treatment should be postponed for as long as possible. UROLOGY 58: 106xxi–106xxiii, 2001. © 2001, Elsevier Science Inc.
A
rteriovenous shunts are rare complications of kidney surgery. Most frequently, they appear in conjunction with renal biopsies in nephrologic and transplant medicine procedures. Even less frequently, spontaneous fistulas are associated with tumor progression or are congenital malformations. In renal surgery, arteriovenous shunt formation is closely related to the operative technique, with a single ligature used for the renal artery and vein the most common cause.1–3 CASE REPORT A 44-year-old woman was admitted for treatment of a caliceal stone in her right kidney. With the exception of extracorporeal shock wave treatment of the right kidney several years previously, her past urologic history was uneventful. On routine intravenous urography, the stone appeared to be in a caliceal diverticulum, which was confirmed by retrograde pyelography. Because she was symptomatic with recurrent flank pain despite extracorporeal shock wave treatment, the patient opted for nephrotomy to remove the stone and close the diverticulum. Surgical treatment consisted of radial nephrotomy, removal of the stone, and cauterizaFrom the Department of Urology, Marienhospital, RuhrUniversita¨t Bochum, Herne, Germany Address for correspondence: J. Miguel Garcia-Schu¨rmann, M.D., Department of Urology, Marienhospital Herne, RuhrUniversita¨t Bochum, Widumerstrasse 8, 44627 Herne, Germany Submitted: December 20, 1999, accepted (with revisions): February 7, 2001 © 2001, ELSEVIER SCIENCE INC. ALL RIGHTS RESERVED
tion of the diverticulum. Closure of the nephrotomy was achieved with parenchymal self-absorbable sutures to control the hemostasis. No intraoperative or perioperative complications occurred. The postoperative course was uneventful, and the patient was discharged 1 week after surgery. Five days later, she presented with gross hematuria. Ultrasound revealed a clot in her bladder, which was evacuated transurethrally with a catheter. Sonography of the right kidney showed a hypoechoic lesion in the upper pole and a small perirenal hematoma. Intravenous urography demonstrated no excretion of the contrast media from the right side. To exclude renal vein thrombosis, we performed color Doppler sonography, which confirmed the normal perfusion of the kidney, with a slightly elevated (0.87) resistance index. Duplex sonography in the b-mode revealed a hypoechoic lesion (Fig. 1) with a combined arteriovenous signal and high flow, confirming an arteriovenous fistula. A double-J stent was placed to allow drainage of the clotted collecting system. The gross hematuria persisted for 3 more days, and angiography was scheduled to embolize the arteriovenous shunt. After improvement of the gross hematuria, we repeated the color duplex examination, which surprisingly revealed that the hypoechoic lesion in the upper pole of the kidney had disappeared. Color Doppler revealed a normal perfusion pattern of the upper pole with physiologic blood flow in the segmental arteries and veins. Figure 2 (b-mode and 0090-4295/01/$20.00 PII S0090-4295(01)00982-7 106xxi
FIGURE 1. Hypoechoic lesion in the upper pole of the right kidney with arteriovenous signal on b-mode (A) and color-coded duplex sonography (B).
FIGURE 2. b-mode (A) and color Doppler sonography (B) 3 days later showing same kidney as in Figure 1 with disappearance of the lesion.
color Doppler images) depicts the spontaneous closure of the arteriovenous fistula. After the removal of the stent 1 week later, the patient was discharged with a urographically normal upper tract. This was confirmed 6 months later by repeated intravenous urography. COMMENT Four known causes for arteriovenous fistulas of the kidney are described in published reports. The most common is iatrogenic and is caused by renal biopsy (eg, as performed in transplant surgery to detect acute rejection). Moreover, surgical interventions, such as nephrotomy in stone or tumor surgery, may lead to spontaneous formation of an 106xxii
arteriovenous fistula. Other rare causes are congenital arteriovenous angioma, spontaneous arteriovenous aneurysm, and neoplasia-conditioned arteriovenous fistula.1 In general, arteriovenous fistulas are extremely rare complications of surgical procedures.1–3 Most published case reports reflect the diagnosis and treatment of fistulas in transplanted kidneys after renal biopsies. The reference standard in the diagnosis of an arteriovenous fistula is digital subtraction angiography, which can detect very small lesions. With the ongoing development of ultrasonography, color Doppler scanning has become a valuable tool in the diagnosis of vascular malformations and shunts. The standard therapy is closure of the lesion by UROLOGY 58 (1), 2001
embolization using interventional radiologic techniques. Thus, the diagnosis and therapy of an arteriovenous fistula is usually performed in a single session of digital subtraction angiography combined with embolization using microcoils. This may be the reason we did not find another report of a spontaneous closure of a traumatic arteriovenous fistula within the past 30 years. Nevertheless, we believe that conservative treatment including an adequate time of watchful waiting is an acceptable regimen for young patients without any signs of progression of the lesion. If no additional compli-
UROLOGY 58 (1), 2001
cations such as massive blood loss occur, invasive therapy should be postponed, as there seems to be a good chance of spontaneous closure of these traumatic arteriovenous fistulas. REFERENCES 1. Esser PW, and Dux A: Arteriovenous fistula of the kidney—angiography case descriptions. Ro¨ntgenbla¨tter 42: 417– 423, 1989. 2. Linder F: Acquired arterio-venous fistulas: report of 223 operated cases. Ann Chir Gynaecol 74: 1–5, 1985. 3. Itzchak Y, and Deutsch V: Congenital renal arterio-venous fistula. Angiology 25: 441– 443, 1974.
106xxiii