Arteries, interventional procedure, Fistula, arteriovenous, Aneurysm, aortic

56/M

A 56-year-old male presented with lower abdominal pain and both lower extremity swellings which had developed a month before admission and were accompanied by mild dyspnea, nausea, and intense sweating.

Spontaneous Right Common Iliac artery – IVC Fistula Due to a Rapid Aggravation of Infra-renal Aortoiliac Aneurysm

CT scan of the abdomen and pelvis revealed aortoiliac aneurysm with some complex intimal flaps. The aneurysm showed a maximal diameter 5.1 cm, with evidence of direct fistula from right common iliac artery into the IVC (Fig 1).The early synchronous and equivalent enhancement of the IVC and aorta accompanied by the early enhancing and dilated multiple superficial veins of anterior abdominal wall were the cardinal diagnosis signs.

Angiography was performed with a 6 Fr marker pigtail catheter (Cook, Bloomington, IN, U.S.A.) through the introducer sheath from the right femoral artery (Fig 2). The right femoral artery was catheterized percutaneously. Then, Gore Excluder endoprosthesis (W. L. Gore & Associates, Inc. Flagstaff, AZ, U.S.A.) with a 23-mm diameter aortic component, an 12-mm diameter iliac limb, and a 120-mm length was used via incision of left common femoral artery. A 0.035-inch, 260-cm Amplatz super stiff guidewire (Boston Scientific, MA, U.S.A.) was used to keep proper tension and straighten the axis. Two extension stent-graft(16-mm proximal diameter, 12-mm distal diameter, 120-mm length and 16-mm proximal diameter, 10-mm distal diameter, 70-mm length) were used in right side and one extension stent-graft with a 16-mm proximal diameter, a 10-mm distal diameter, and a 70-mm length were used in left side after embolization of left internal iliac artery using Nester metallic coils (Cook, Bloomington, IN, U.S.A). On final angiography and a follow-up CT scan, the right common iliac artery – IVC fistula had been successfully obliterated. Five days after treatment, the patient’s lower abdominal pain and both leg swellings had resolved, and he was discharged from the hospital in good condition (Fig 3).

Major abdominal arteriovenous fistulas are rare but they frequently occur in patients who are critically ill. Most have acute presentation and develop fistulas as the result of rupture of an atherosclerotic aortic or aortoiliac aneurysm into the IVC or iliac vein. The most common site of fistula is the IVC, with the iliac and renal veins rarely affected. Clear evaluation of all patients with aortoiliac aneurysms should include a search for signs and symptoms of an arteriovenous fistula, because major blood loss and pulmonary embolization of aneurismal debris through the fistula can occur if the interventional radiologist or surgeon is not aware of the fistula before the treatment. Lower extremity venous congestion, edema, abdominal bruit, congestive heart failure, widened pulse pressure, and decreased distal pulses may all occur in patients with major abdominal arteriovenous fistulas. In our case, it was initially felt that this represented an aorta-to-vena cava fistula in the area of the patient’s aneurysm. However, careful review of the CT scan revealed the location of the fistula clearly. In summary, we report a case of a spontaneous right common iliac artery –IVC fistula due to a rapid aggravation of infra-renal aortoiliac aneurysm, which presented as lower abdominal pain and both lower extremity swellings. In this case, primary endovascular stent-graft was successful in managing the condition.

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Fig. 1 (a-c) Arterial-phase abdominal CT scan and 3D reconstruction image showing earlyequivalent enhancement of the IVC and aorta accompanied by the early enhancing and dilated multiple superficial veins of anterior abdominal wall. An arteriovenous fistula is apparent between the right common iliac artery and IVC (arrow).

Fig. 1 (a-c) Arterial-phase abdominal CT scan and 3D reconstruction image showing earlyequivalent enhancement of the IVC and aorta accompanied by the early enhancing and dilated multiple superficial veins of anterior abdominal wall. An arteriovenous fistula is apparent between the right common iliac artery and IVC (arrow).

Fig. 1 (a-c) Arterial-phase abdominal CT scan and 3D reconstruction image showing earlyequivalent enhancement of the IVC and aorta accompanied by the early enhancing and dilated multiple superficial veins of anterior abdominal wall. An arteriovenous fistula is apparent between the right common iliac artery and IVC (arrow).

Fig. 2 Abdominal aortogram revealing an infra-renal AAA with early equivalent contrast filling of the IVC and aorta accompanied by the dilated multiple superficial veins of anterior abdominal wall due to a right common iliac artery – IVC fistula.

Fig. 3 Follow-up abdominal CT 3 months after treatment shows disappearance of the fistula and aortoiliac aneurysm, and properly located stent-graft with excellent patency