- Email: [email protected]
Bifurcated Endograft Repair of Ilio-iliac Arteriovenous Fistula Secondary to Lumbar Diskectomy
Bifurcated Endograft Repair of Ilio-iliac Arteriovenous Fistula Secondary to Lumbar Diskectomy Jose M. Sarmiento,1 Paul J. Wisniewski,2 Natalie T. Do,3 Trung D. Vo,4 Paul K. Aka,4 Majid Tayyarah,4 and Jeffrey H. Hsu,4 Fontana, California
Ilio-iliac arteriovenous (AV) fistula is a rare complication after lumbar diskectomy. Endovascular repair of such fistulas is a growing trend in vascular surgery. This is a case report of an endovascular exclusion of an ilio-iliac AV fistula in a 51-year-old male. This man presented with high-output congestive heart failure and ascites. The AV fistula was discovered 17 years after a lumbar diskectomy. Computed topography (CT) revealed a right common iliac artery pseudoaneurysm connecting to the left common iliac vein. The fistula was repaired using a bifurcated Gore Excluder endograft. There were follow-up CT scans at 6 and 10 months confirming exclusion of the AV fistula. Endovascular AV fistula repair offers a safe, effective method for managing ilio-iliac AV fistulas.
Arteriovenous (AV) fistulas between the iliac artery and vein are a rare and potentially life-threatening complication of lumbar disk surgery. Ilio-iliac AV fistulas create a right-to-left shunt in the systemic circulation that leads to congestive heart failure, central venous overload, and distal limb ischemia. Repairing acquired and traumatic AV fistulas with an endovascular approach is becoming a favorable treatment option among vascular surgeons. In this case report, a bifurcated endograft was used to repair an ilio-iliac AV fistula originally caused by lumbar diskectomy 17 years prior.
CASE REPORT A 51-year-old, moderately anasarcous man presented to the emergency room with abdominal distention, dyspnea, 1
Division of Biomedical Sciences, University of California, Riverside, CA.
2
Arrowhead Regional Medical Center, Department of General Surgery, Colton, CA. 3 Western University of Health Sciences, College of Osteopathic Medicine of the Pacific, Pomona, CA. 4 Department of Vascular Surgery, Kaiser Permanente Fontana Medical Center, Fontana, CA.
Correspondence to: Jeffrey H. Hsu, MD, Department of Vascular Surgery, Kaiser Permanente Fontana Medical Center, 9961 Sierra Ave., Fontana, CA 92335, USA, E-mail: [email protected] Ann Vasc Surg 2010; 24: 551.e13-551.e17 DOI: 10.1016/j.avsg.2009.08.019 Ó Annals of Vascular Surgery Inc. Published online: February 8, 2010
and left leg numbness. He was diaphoretic and denied having chest pain. Several days earlier he had been admitted to the hospital for dyspnea, chest pain, and atrial flutter. The patient was discharged on digoxin, inderal, and warfarin. His medical history consisted of an L4-L5 diskectomy 17 years earlier and an umbilical hernia repair. He reported progressive fatigue over the last 5 years, but he attributed the symptoms to being out of shape. Significant findings on physical examination included tachycardia with a heart rate in the 130s, dyspnea at rest, and 4+ pitting peripheral edema. He had a 3/6 holosystolic murmur as well as rales in both lungs with ascites. A machine bruit was heard on abdominal examination. His laboratory data were unremarkable except for an elevated B-type natriuretic peptide level (1,090 pg/mL). Chest X-ray showed cardiomegaly with vascular congestion and mild pleural effusions bilaterally. Electrocardiography showed J point elevation septally and ST elevation inferiorly but no reciprocal changes. Transthoracic echocardiogram demonstrated left ventricular hypertrophy with an ejection fraction of 70-75%, mild aortic stenois, and aortic regurgitation. A contrast computed tomographic (CT) scan of the chest and abdomen revealed a 3.8 4.4 cm saccular right common iliac artery pseudoaneurysm with an enlarged (35.6 mm) left iliac vein and a rapid flush of contrast into the inferior vena cava. An enlarged liver with hepatic engorgement was also revealed. A CT angiogram showed a right common iliac artery pseudoaneurysm with an AV fistula to the left common iliac vein (Fig. 1).
551.e13
551.e14 Case reports
Annals of Vascular Surgery
Fig. 1. a CT angiogram image of fistula between the right common iliac artery and left common iliac vein. b CT image of pseudoaneurysm with adjacent vessels. PA,
pseudoaneurysm; Lt. CIA, left common iliac artery; Lt. CIV, left common iliac vein; Rt. CIV, right common iliac vein; Rt. CIA, right common iliac artery.
The CT was reviewed in detail, and the proximal neck of the iliac artery was determined to be too large for a single iliac stent. The iliac artery was dilated on the proximal side of the fistula and narrowed on the distal side, similar to the shape of a funnel. This anatomy was concerning because it made getting a proximal seal on the fistula difficult. We opted to exclude and stent over the pseudoaneurysm with a bifurcated aortic stent graft as this device allowed for adequate landing and sealing of both proximal and distal iliac arteries. Prior to the operation the patient was medically maximized and spinal anesthesia was used as the anesthetic agent. Percutaneous access of both femoral arteries was obtained. Based on aortogram and intravascular ultrasound measurements, a 23 mm diameter 12 cm length 14.5 mm iliac diameter device was chosen. A stiff wire was placed up into the aortic arch from the left side and the left femoral artery was progressively dilated up to an 18-French sheath. The main body of the device was delivered through this access into the aorta, where it was deployed. Next, a roadrunner wire and angle glide catheter were used to cannulate the contralateral limb through the right femoral artery and a stiff wire was placed inside the gate. After the right femoral artery was progressively dilated to an 18-French size, a 16 9.5 mm device was delivered into the contralateral gate. The device was deployed right at the takeoff of the right hypogastric artery in order to completely cover the fistula. The AV fistula was completely excluded as determined by a flush aortogram. Both hypogastric arteries were patent. Immediately after exclusion of the AV fistula, the patient became hypertensive; and he was started on
nitroglycerine and nitroprusside. The patient’s systolic blood pressure went as high as 240 mm Hg. It took both agents to bring the patient’s systolic blood pressure down to approximately 170 mm Hg. It was at this point that the sheaths could be removed safely and the Perclose sutures could be tied down with confidence that good hemostasis and vessel closure could be attained. After the procedure, the abdominal machine bruit and the heart murmur had resolved. The patient was put on warfarin for 6 months for his paroxysmal atrial flutter. Two weeks after surgery the patient had diuresed approximately 20 lb. A CT angiogram was ordered 1 month after the operation (Fig. 2) and a CT scan was done on postoperative day 4 (Fig. 3) to confirm complete exclusion of the AV fistula. Follow-up visits were scheduled at 6 months and 10 months after surgery. In both visits, the patient showed no signs of heart failure and his ascites and anasarca were completely resolved. CT scans confirmed ongoing closure of the AV fistula without endoleak. At 6 months, the left iliac vein was much less dilated and the patient had no further episodes of atrial flutter. The patient is doing well 18 months after the procedure and is undergoing yearly surveillance of the endograft.
DISCUSSION Acquired fistulas between the aorta and vena cava are commonly caused by spontaneous rupture of atherosclerotic abdominal aortic aneurysms into the vena cava.1 A less known cause of AV fistulas
Vol. 24, No. 4, May 2010
Fig. 2. CT angiogram image of excluded ilio-iliac AV fistula with bifurcated Gore (Flagstaff, AZ) Excluder endograft.
is lumbar diskectomy. Ilio-iliac AV fistulas may result from lumbar disk surgery if the iliac vessels are injured from penetration of the anterior longitudinal ligament with dissecting instruments.2 Lumbar diskectomy involving the L4-L5 disk is the most common site for AV fistula formation,3 and approximately 90.9% of fistulas formed due to this procedure occur between the iliac artery and iliac vein or vena cava.4 If an insult to the vessels is missed intraoperatively, an AV fistula may develop and diagnosis may be delayed for months or even years.5 Over a 27-year period, Davis et al.6 encountered 18 patients with AV fistulas, five of which were ilio-iliac but only one of which was due to lumbar disk surgery. In addition, Brewster et al.7 reported 20 AV fistulas over a 30-year period, with
Case reports 551.e15
only four caused by iatrogenic injury during lumbar disk surgery. AV fistulas typically present with a triad of findings: (1) sudden onset of high-output cardiac failure, (2) pulsatile abdominal mass with accompanying bruit, and (3) unilateral lower limb ischemia or venous engorgement.8 AV fistulas are difficult to diagnose because patients may be aymptomatic,9 may have no abdominal pain,10 and may present with unusual features.11 Our patient was in highoutput congestive heart failure when the AV fistula was noticed, and medical records indicated that he showed left ventricular hypertrophy on an echocardiograph 2 years prior to fistula repair. Also, his dramatically elevated B-type natriuretic peptide levels strongly suggested cardiac failure. He did not have a pulsatile or palpable abdominal mass, but a machine-like bruit was heard on physical examination. He complained of left leg numbness, and there was bilateral lower extremity edema. AV fistulas shunt blood from the high-resistance arterial circuit to the low-resistance venous circuit and produce a decrease in mean arterial pressure. Cardiovascular compensation takes place, and there is an increase in heart rate, stroke volume, and, consequently, cardiac output. In this case, the patient had early diastolic dysfunction due to excessive preload from the AV fistula. This led to hypertrophy of the left ventricle. Venous pressure increases as blood is shunted from the arterial to the venous circuit preferentially. Prolonged periods of increased central venous pressure can result in post-sinusoidal portal hypertension, causing ascites, hepatomegaly, and hepatic vein engorgement. The decreased mean arterial pressure leads to a low renal arterial perfusion pressure, which activates the renineangiotension system to stimulate fluid retention in an effort to increase perfusion pressure. High aldosterone levels coupled with an increase in venous volume explain why patients with AV fistulas are hypervolemic preoperatively. There was a sudden increase in our patient’s blood pressure upon closing the fistula. In 1946 Holman12 reported average increases of 39% and 32.5% in systolic and diastolic blood pressures, respectively, upon permanent closure of femoral vessel AV fistulas in two patients. The heart rate of both patients subsequently slowed after closing the fistulas, a response referred to as ‘‘Branham’s sign.’’13 According to Holman, the immediate increase in blood pressure observed after AV fistula closure is due to distention of an already dilated heart and aorta. This distention is caused by an increased total blood volume that often
551.e16 Case reports
Annals of Vascular Surgery
Fig. 3. CT images of excluded AV fistula at postoperative day 4: a proximal to aortic bifurcation, b distal to aortic bifurcation, and c proximal to iliac bifurcation.
accompanies patients with chronic AV fistulas and backup of arterial blood that formerly flowed through the fistula to the venous system. Blood pressure and pulse return to normal as blood volume gradually returns to normal levels. Surgeons should anticipate the hemodynamic changes that are induced after AV fistula exclusion and respond accordingly. Diagnosis of AV fistulas may be confirmed preoperatively by digital subtraction arteriography,14 CT scan,15,16 and duplex ultrasonography.16 Our preferential diagnostic test was CT angiogram because it is noninvasive and provides accurate anatomical details of blood vessels. The CT scan with contrast of our patient revealed early venous filling in the inferior vena cava, which is the hallmark of an AV fistula.14 However, clinicians should have a high index of suspicion if the aforementioned triad of symptoms are present in a patient with a history of lumbar diskectomy. The surgical objectives of an AV fistula repair are to (1) exclude the fistula, (2) restore proper hemodynamics, and (3) reestablish proper vascular continuity by inserting an appropriately sized covered stent graft.14 Open surgery is the traditional method of repair; however, this method is associated with mortality rates of 10-66%.1,7,17-19 Advances in endovascular technology have shown increasing potential for AV fistula repair. The use of endovascular stent grafts for arterial injury repair has been reported to decrease blood loss, minimize invasiveness at insertion, and reduce the requirements for anesthesia.20 In 1995 Zajko et al.21 performed the first reported endovascular repair of an iliac AV fistula caused by laparoscopic injury. In 1996
McCarter et al.22 reported percutaneous endolumnial stent grafting of a left ilio-iliac AV fistula 4 years after lumbar diskectomy, and in 2003 Hart et al.2 reported endoluminal stent-graft exclusion of a right ilio-iliac AV fistula 8 years after lumbar diskectomy. Many other authors have communicated the effectiveness of endovascular stent grafts to repair AV fistulas, such as Ventura et al.,23 Schneider et al.,24 and Cronin et al.,25 who recently reported repair of a left ilioiliac AV fistula with a thoracic endograft. We report exclusion of a right common iliac artery to left common iliac vein AV fistula with a bifurcated endograft 17 years after lumbar diskectomy. Careful follow-up of patients who have undergone endovascular surgical repair is needed to determine the future role of bifurcated stent grafts in the repair of ilio-iliac AV fistulas.
CONCLUSION Endovascular repair appears to provide a safe and effective approach for managing ilio-iliac AV fistulas. REFERENCES 1. Alexander JJ, Imbembo AL. Aorta-vena cava fistula. Surgery 1989;105:1e12. 2. Hart JP, Wallis F, Kenny B, et al. Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery. J Vasc Surg 2003;37:1091e1093. 3. Villano M, Cantatore G, Narciso N, Santilli F, Bifano D, Cerillo A. Vascular injury related to lumbar disk surgery. Neoruchirurgia 1992;32:57e59. 4. Jarstfer BS, Rich NM. The challenge of arteriovenous fistula formation following disk surgery: a collective review. J Trauma 1976;16:726e733.
Vol. 24, No. 4, May 2010
5. Raptis S, Quigley F, Barker S. Vascular complications of elective lower lumbar disc surgery. Aust NZJ Surg 1994;64:216e219. 6. Davis PM, Gloviczki P, Cherry KJ, Jr, et al. Aorto-caval and ilio-iliac arterovenous fistulae. Am J Surg 1998;176:115e118. 7. Brewster DV, Cambria RP, Moncure AC, et al. Aortocaval and iliac arteriovenous fistulas: recognition and treatment. J Vasc Surg 1991;13:253e265. 8. McAuley CE, Peitzman AB, deVries EJ, et al. The syndrome of spontaneous iliac arteriovenous fistula: a distinct clinical and pathophysiologic entity. Surgery 1986;99:373e377. 9. Tsolakis JA, Papadoulas S, Kakkos SK, et al. Aortocaval fistula in ruptured aneurysms. Eur J Vasc Endovasc Surg 1999;17:390e393. 10. Duffy JP, Gardham JRC. Spontaneous aortocaval fistulad preoperative diagnosis and management. Postgrad Med J 1989;65:397e399. 11. Weinbaum FI, Riles TS, Imporato AM. Asymptomatic vena cava fistulization complicating abdominal aortic aneurysm. Surgery 1984;96:126e128. 12. Holman E. Kymographic studies of the heart in the presence of an arteriovenous fistula and their interpretation. Ann Surg 1946;124:920e932. 13. Branham HH. Aneurismal varix of the femoral artery and vein following a gunshot wound. Int J Surg 1890;3:250. 14. Rutherford RB. Vascular Surgery. 6th ed. Philadelphia: WB Saunders, 2005. 15. Rosenthal D, Atkins CP, Jerrius HS, et al. Diagnosis of aortocaval fistula by computed tomography. Ann Vasc Surg 1998;12:86e87. 16. Goto T, Enmoto T, Akimoto K. Diagnosis of an ilio-iliac arteriovenous fistula by multidetector row computed tomography
Case reports 551.e17
17.
18.
19. 20.
21.
22.
23.
24.
25.
and surgical repair. Interact Cardiovasc Thorac Surg 2009;8: 387e389. Cinara IS, Davidovic LB, Kostic DM, Cvetkovic SD, Jakovljevic NS, Koncar IB. Aorto-caval fistulas: a review of eighteen years experience. Acta Chir Belg 2005;105: 616e620. Gilling-Smith GL, Mansfiled AO. Spontaneous abdominal arteriovenous fistulae: report of eight cases and review of the literature. Br J Surg 1991;78:421e426. Davidovic L, Kostic D, Cvetkovic S, et al. Aortocaval fistulas. Cardiovasc Surg 2002;10:555e560. Marin M, Veith F, Panetta T, et al. Transluminally placed endovascular stented graft repair for arterial trauma. J Vasc Surg 1994;20:466e472. Zajko AB, Little AF, Steed D, Curtiss EI. Endovascular stentgraft repair of common iliac artery-to-inferior vena cava fistula. J Vasc Interv Radiol 1995;6:803e806. McCarter DH, Johnstone RD, McInnes GC, Reid DB, Pollock JG, Reid AW. Iliac arteriovenous fistula following lumbar disc surgery treated by percutaneous endolumnal stent grafting. Br J Surg 1996;83:796e797. Ventura M, Rivellini C, Saracino G, et al. Endovascular treatment of a postlaminectomy arteriovenous fistula. A case report J Cardiovasc Surg 2002;43:523e526. Schneider JR, Alonzo MJ, Hahn D. Successful endovascular management of an acute iliac venous injury during lumbar discectomy and anterior spinal fusion. J Vasc Surg 2006;44: 1353e1356. Cronin B, Kane J, Lee W, Shriki J, Weaver FA. Repair of a high-flow iliac arteriovenous fistula using a thoracic endograft. J Vasc Surg 2009;49:767e770.
Ilio-iliac arteriovenous (AV) fistula is a rare complication after lumbar diskectomy. Endovascular repair of such fistulas is a growing trend in vascular surgery. This is a case report of an endovascular exclusion of an ilio-iliac AV fistula in a 51-year-old male. This man presented with high-output congestive heart failure and ascites. The AV fistula was discovered 17 years after a lumbar diskectomy. Computed topography (CT) revealed a right common iliac artery pseudoaneurysm connecting to the left common iliac vein. The fistula was repaired using a bifurcated Gore Excluder endograft. There were follow-up CT scans at 6 and 10 months confirming exclusion of the AV fistula. Endovascular AV fistula repair offers a safe, effective method for managing ilio-iliac AV fistulas.
Arteriovenous (AV) fistulas between the iliac artery and vein are a rare and potentially life-threatening complication of lumbar disk surgery. Ilio-iliac AV fistulas create a right-to-left shunt in the systemic circulation that leads to congestive heart failure, central venous overload, and distal limb ischemia. Repairing acquired and traumatic AV fistulas with an endovascular approach is becoming a favorable treatment option among vascular surgeons. In this case report, a bifurcated endograft was used to repair an ilio-iliac AV fistula originally caused by lumbar diskectomy 17 years prior.
CASE REPORT A 51-year-old, moderately anasarcous man presented to the emergency room with abdominal distention, dyspnea, 1
Division of Biomedical Sciences, University of California, Riverside, CA.
2
Arrowhead Regional Medical Center, Department of General Surgery, Colton, CA. 3 Western University of Health Sciences, College of Osteopathic Medicine of the Pacific, Pomona, CA. 4 Department of Vascular Surgery, Kaiser Permanente Fontana Medical Center, Fontana, CA.
Correspondence to: Jeffrey H. Hsu, MD, Department of Vascular Surgery, Kaiser Permanente Fontana Medical Center, 9961 Sierra Ave., Fontana, CA 92335, USA, E-mail: [email protected] Ann Vasc Surg 2010; 24: 551.e13-551.e17 DOI: 10.1016/j.avsg.2009.08.019 Ó Annals of Vascular Surgery Inc. Published online: February 8, 2010
and left leg numbness. He was diaphoretic and denied having chest pain. Several days earlier he had been admitted to the hospital for dyspnea, chest pain, and atrial flutter. The patient was discharged on digoxin, inderal, and warfarin. His medical history consisted of an L4-L5 diskectomy 17 years earlier and an umbilical hernia repair. He reported progressive fatigue over the last 5 years, but he attributed the symptoms to being out of shape. Significant findings on physical examination included tachycardia with a heart rate in the 130s, dyspnea at rest, and 4+ pitting peripheral edema. He had a 3/6 holosystolic murmur as well as rales in both lungs with ascites. A machine bruit was heard on abdominal examination. His laboratory data were unremarkable except for an elevated B-type natriuretic peptide level (1,090 pg/mL). Chest X-ray showed cardiomegaly with vascular congestion and mild pleural effusions bilaterally. Electrocardiography showed J point elevation septally and ST elevation inferiorly but no reciprocal changes. Transthoracic echocardiogram demonstrated left ventricular hypertrophy with an ejection fraction of 70-75%, mild aortic stenois, and aortic regurgitation. A contrast computed tomographic (CT) scan of the chest and abdomen revealed a 3.8 4.4 cm saccular right common iliac artery pseudoaneurysm with an enlarged (35.6 mm) left iliac vein and a rapid flush of contrast into the inferior vena cava. An enlarged liver with hepatic engorgement was also revealed. A CT angiogram showed a right common iliac artery pseudoaneurysm with an AV fistula to the left common iliac vein (Fig. 1).
551.e13
551.e14 Case reports
Annals of Vascular Surgery
Fig. 1. a CT angiogram image of fistula between the right common iliac artery and left common iliac vein. b CT image of pseudoaneurysm with adjacent vessels. PA,
pseudoaneurysm; Lt. CIA, left common iliac artery; Lt. CIV, left common iliac vein; Rt. CIV, right common iliac vein; Rt. CIA, right common iliac artery.
The CT was reviewed in detail, and the proximal neck of the iliac artery was determined to be too large for a single iliac stent. The iliac artery was dilated on the proximal side of the fistula and narrowed on the distal side, similar to the shape of a funnel. This anatomy was concerning because it made getting a proximal seal on the fistula difficult. We opted to exclude and stent over the pseudoaneurysm with a bifurcated aortic stent graft as this device allowed for adequate landing and sealing of both proximal and distal iliac arteries. Prior to the operation the patient was medically maximized and spinal anesthesia was used as the anesthetic agent. Percutaneous access of both femoral arteries was obtained. Based on aortogram and intravascular ultrasound measurements, a 23 mm diameter 12 cm length 14.5 mm iliac diameter device was chosen. A stiff wire was placed up into the aortic arch from the left side and the left femoral artery was progressively dilated up to an 18-French sheath. The main body of the device was delivered through this access into the aorta, where it was deployed. Next, a roadrunner wire and angle glide catheter were used to cannulate the contralateral limb through the right femoral artery and a stiff wire was placed inside the gate. After the right femoral artery was progressively dilated to an 18-French size, a 16 9.5 mm device was delivered into the contralateral gate. The device was deployed right at the takeoff of the right hypogastric artery in order to completely cover the fistula. The AV fistula was completely excluded as determined by a flush aortogram. Both hypogastric arteries were patent. Immediately after exclusion of the AV fistula, the patient became hypertensive; and he was started on
nitroglycerine and nitroprusside. The patient’s systolic blood pressure went as high as 240 mm Hg. It took both agents to bring the patient’s systolic blood pressure down to approximately 170 mm Hg. It was at this point that the sheaths could be removed safely and the Perclose sutures could be tied down with confidence that good hemostasis and vessel closure could be attained. After the procedure, the abdominal machine bruit and the heart murmur had resolved. The patient was put on warfarin for 6 months for his paroxysmal atrial flutter. Two weeks after surgery the patient had diuresed approximately 20 lb. A CT angiogram was ordered 1 month after the operation (Fig. 2) and a CT scan was done on postoperative day 4 (Fig. 3) to confirm complete exclusion of the AV fistula. Follow-up visits were scheduled at 6 months and 10 months after surgery. In both visits, the patient showed no signs of heart failure and his ascites and anasarca were completely resolved. CT scans confirmed ongoing closure of the AV fistula without endoleak. At 6 months, the left iliac vein was much less dilated and the patient had no further episodes of atrial flutter. The patient is doing well 18 months after the procedure and is undergoing yearly surveillance of the endograft.
DISCUSSION Acquired fistulas between the aorta and vena cava are commonly caused by spontaneous rupture of atherosclerotic abdominal aortic aneurysms into the vena cava.1 A less known cause of AV fistulas
Vol. 24, No. 4, May 2010
Fig. 2. CT angiogram image of excluded ilio-iliac AV fistula with bifurcated Gore (Flagstaff, AZ) Excluder endograft.
is lumbar diskectomy. Ilio-iliac AV fistulas may result from lumbar disk surgery if the iliac vessels are injured from penetration of the anterior longitudinal ligament with dissecting instruments.2 Lumbar diskectomy involving the L4-L5 disk is the most common site for AV fistula formation,3 and approximately 90.9% of fistulas formed due to this procedure occur between the iliac artery and iliac vein or vena cava.4 If an insult to the vessels is missed intraoperatively, an AV fistula may develop and diagnosis may be delayed for months or even years.5 Over a 27-year period, Davis et al.6 encountered 18 patients with AV fistulas, five of which were ilio-iliac but only one of which was due to lumbar disk surgery. In addition, Brewster et al.7 reported 20 AV fistulas over a 30-year period, with
Case reports 551.e15
only four caused by iatrogenic injury during lumbar disk surgery. AV fistulas typically present with a triad of findings: (1) sudden onset of high-output cardiac failure, (2) pulsatile abdominal mass with accompanying bruit, and (3) unilateral lower limb ischemia or venous engorgement.8 AV fistulas are difficult to diagnose because patients may be aymptomatic,9 may have no abdominal pain,10 and may present with unusual features.11 Our patient was in highoutput congestive heart failure when the AV fistula was noticed, and medical records indicated that he showed left ventricular hypertrophy on an echocardiograph 2 years prior to fistula repair. Also, his dramatically elevated B-type natriuretic peptide levels strongly suggested cardiac failure. He did not have a pulsatile or palpable abdominal mass, but a machine-like bruit was heard on physical examination. He complained of left leg numbness, and there was bilateral lower extremity edema. AV fistulas shunt blood from the high-resistance arterial circuit to the low-resistance venous circuit and produce a decrease in mean arterial pressure. Cardiovascular compensation takes place, and there is an increase in heart rate, stroke volume, and, consequently, cardiac output. In this case, the patient had early diastolic dysfunction due to excessive preload from the AV fistula. This led to hypertrophy of the left ventricle. Venous pressure increases as blood is shunted from the arterial to the venous circuit preferentially. Prolonged periods of increased central venous pressure can result in post-sinusoidal portal hypertension, causing ascites, hepatomegaly, and hepatic vein engorgement. The decreased mean arterial pressure leads to a low renal arterial perfusion pressure, which activates the renineangiotension system to stimulate fluid retention in an effort to increase perfusion pressure. High aldosterone levels coupled with an increase in venous volume explain why patients with AV fistulas are hypervolemic preoperatively. There was a sudden increase in our patient’s blood pressure upon closing the fistula. In 1946 Holman12 reported average increases of 39% and 32.5% in systolic and diastolic blood pressures, respectively, upon permanent closure of femoral vessel AV fistulas in two patients. The heart rate of both patients subsequently slowed after closing the fistulas, a response referred to as ‘‘Branham’s sign.’’13 According to Holman, the immediate increase in blood pressure observed after AV fistula closure is due to distention of an already dilated heart and aorta. This distention is caused by an increased total blood volume that often
551.e16 Case reports
Annals of Vascular Surgery
Fig. 3. CT images of excluded AV fistula at postoperative day 4: a proximal to aortic bifurcation, b distal to aortic bifurcation, and c proximal to iliac bifurcation.
accompanies patients with chronic AV fistulas and backup of arterial blood that formerly flowed through the fistula to the venous system. Blood pressure and pulse return to normal as blood volume gradually returns to normal levels. Surgeons should anticipate the hemodynamic changes that are induced after AV fistula exclusion and respond accordingly. Diagnosis of AV fistulas may be confirmed preoperatively by digital subtraction arteriography,14 CT scan,15,16 and duplex ultrasonography.16 Our preferential diagnostic test was CT angiogram because it is noninvasive and provides accurate anatomical details of blood vessels. The CT scan with contrast of our patient revealed early venous filling in the inferior vena cava, which is the hallmark of an AV fistula.14 However, clinicians should have a high index of suspicion if the aforementioned triad of symptoms are present in a patient with a history of lumbar diskectomy. The surgical objectives of an AV fistula repair are to (1) exclude the fistula, (2) restore proper hemodynamics, and (3) reestablish proper vascular continuity by inserting an appropriately sized covered stent graft.14 Open surgery is the traditional method of repair; however, this method is associated with mortality rates of 10-66%.1,7,17-19 Advances in endovascular technology have shown increasing potential for AV fistula repair. The use of endovascular stent grafts for arterial injury repair has been reported to decrease blood loss, minimize invasiveness at insertion, and reduce the requirements for anesthesia.20 In 1995 Zajko et al.21 performed the first reported endovascular repair of an iliac AV fistula caused by laparoscopic injury. In 1996
McCarter et al.22 reported percutaneous endolumnial stent grafting of a left ilio-iliac AV fistula 4 years after lumbar diskectomy, and in 2003 Hart et al.2 reported endoluminal stent-graft exclusion of a right ilio-iliac AV fistula 8 years after lumbar diskectomy. Many other authors have communicated the effectiveness of endovascular stent grafts to repair AV fistulas, such as Ventura et al.,23 Schneider et al.,24 and Cronin et al.,25 who recently reported repair of a left ilioiliac AV fistula with a thoracic endograft. We report exclusion of a right common iliac artery to left common iliac vein AV fistula with a bifurcated endograft 17 years after lumbar diskectomy. Careful follow-up of patients who have undergone endovascular surgical repair is needed to determine the future role of bifurcated stent grafts in the repair of ilio-iliac AV fistulas.
CONCLUSION Endovascular repair appears to provide a safe and effective approach for managing ilio-iliac AV fistulas. REFERENCES 1. Alexander JJ, Imbembo AL. Aorta-vena cava fistula. Surgery 1989;105:1e12. 2. Hart JP, Wallis F, Kenny B, et al. Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery. J Vasc Surg 2003;37:1091e1093. 3. Villano M, Cantatore G, Narciso N, Santilli F, Bifano D, Cerillo A. Vascular injury related to lumbar disk surgery. Neoruchirurgia 1992;32:57e59. 4. Jarstfer BS, Rich NM. The challenge of arteriovenous fistula formation following disk surgery: a collective review. J Trauma 1976;16:726e733.
Vol. 24, No. 4, May 2010
5. Raptis S, Quigley F, Barker S. Vascular complications of elective lower lumbar disc surgery. Aust NZJ Surg 1994;64:216e219. 6. Davis PM, Gloviczki P, Cherry KJ, Jr, et al. Aorto-caval and ilio-iliac arterovenous fistulae. Am J Surg 1998;176:115e118. 7. Brewster DV, Cambria RP, Moncure AC, et al. Aortocaval and iliac arteriovenous fistulas: recognition and treatment. J Vasc Surg 1991;13:253e265. 8. McAuley CE, Peitzman AB, deVries EJ, et al. The syndrome of spontaneous iliac arteriovenous fistula: a distinct clinical and pathophysiologic entity. Surgery 1986;99:373e377. 9. Tsolakis JA, Papadoulas S, Kakkos SK, et al. Aortocaval fistula in ruptured aneurysms. Eur J Vasc Endovasc Surg 1999;17:390e393. 10. Duffy JP, Gardham JRC. Spontaneous aortocaval fistulad preoperative diagnosis and management. Postgrad Med J 1989;65:397e399. 11. Weinbaum FI, Riles TS, Imporato AM. Asymptomatic vena cava fistulization complicating abdominal aortic aneurysm. Surgery 1984;96:126e128. 12. Holman E. Kymographic studies of the heart in the presence of an arteriovenous fistula and their interpretation. Ann Surg 1946;124:920e932. 13. Branham HH. Aneurismal varix of the femoral artery and vein following a gunshot wound. Int J Surg 1890;3:250. 14. Rutherford RB. Vascular Surgery. 6th ed. Philadelphia: WB Saunders, 2005. 15. Rosenthal D, Atkins CP, Jerrius HS, et al. Diagnosis of aortocaval fistula by computed tomography. Ann Vasc Surg 1998;12:86e87. 16. Goto T, Enmoto T, Akimoto K. Diagnosis of an ilio-iliac arteriovenous fistula by multidetector row computed tomography
Case reports 551.e17
17.
18.
19. 20.
21.
22.
23.
24.
25.
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