Abdominal aortoiliac aneurysm with spontaneous aortocaval fistula: An unusual cause of acute occlusion of the inferior vena cava

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This report documents an unusual case of intracaval rupture of an aortoiliac aneurysm, with occlusion of the inferior vena cava (IVC) and sudden cardiac improvement subsequent to acute caval occlusion by the aneurysmal thrombus followed by development of massive lower extremity edema. An 81-year-old man with a history of syncopal episode, right flank pain, dyspnea, tachycardia, hypotension, and hematuria was admitted to the emergency department of a local hospital. A pulsatile epigastric mass was found on physical examination, and abdominal sonography showed a 7 cm infrarenal aortic aneurysm that involved both common iliac arteries. The patient was transferred to our hospital. Physical examination revealed a blood pressure of 140/80 mm Hg. There was no jugular distention. The peripheral pulses were palpable. Of note was the massive scrotal and penile edema and the cyanosis of both lower extremities. The patient had anuria. The laboratory data were normal except for a platelet count of 132,000/mm3, a blood urea nitrogen level of 70 mg/dl, and a serum creatinine level of 2 mg/dl. The chest radiograph and electrocardiogram were normal. An emergency computed tomography (CT) scan confirmed an infrarenal aortic aneurysm (7 cm) that involved the common iliac arteries and the right internal iliac arteries (Fig. 1).It also demonstrated a thrombus in the IVC that extended just above the renal veins (Fig. 2).Fig. 2CT scan at level of renal veins. Note intracaval thrombus (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT) Emergency laparotomy confirmed the diagnosis of an aortocaval fistula. After aortic control was instituted the IVC was compressed by hand above the renal veins to avoid dislodging the intraluminal thrombus. A 6 cm communication was found between the right lateral wall of the aortic aneurysm and the IVC. The caval thrombus was extracted with forceps into the aortic aneurysm sac. The large defect and the friability of the IVC wall precluded repair and required ligation just below the renal veins and above the iliac vein confluence. The aneurysm was repaired with a bifurcated 16 × 8 mm Dacron graft to the external iliac arteries. On discharge on the eighteenth postoperative day, the patient had normal cardiac and renal function, and he is doing well at 18 months' postoperative follow-up, with minimal residual lower extremity edema. Spontaneous perforation of an artcriosclcrotic ancurysm into the IVC has been reported in 0.2% to 1.3% of patients with atherosclerotic aortic aneurysms.1Baker WH Sharzer LA Ehrenhalt JL Aortocaval fistula as a complication of abdominal aortic aneurysm.Surgery. 1972; 72: 933-938PubMed Google Scholar Its incidence has been reported to be twice as high in cases of ruptured infrarenal aortic aneurysms, with the most common location being at the distal aorta just above the confluence of the iliac veins, as in this case.2Gilling-Smith GL Mansfield AO Spontaneous abdominal arteriovenous fistula: report of eight cases and review of the literature.Br J Surg. 1991; 78: 421-426Crossref PubMed Scopus (67) Google Scholar Clinically, signs of high-output heart failure are present in approximately 50% of the cases. Venous hypertension transmitted to the pelvic veins and lower extremities may cause lower extremity edema, priapism, rectal bleeding, and hematuria. Other manifestations can be kidney failure, intestinal angina, intermittent claudication (lower extremity steal syndrome), and angina pectoris. The only available treatment for this unusual and life-threatening condition is surgery, with high mortality rates reported.3Alexander JJ Ibembo AL Aorta-vena cava fistula.Surgery. 1989; 105: 1-12PubMed Google Scholar Massive pulmonary embolization was avoided in this case by hand compression of the IVC before the infrarenal aorta was brought under control. Although intraaneurysmal repair of the caval opening should be recommended, IVC ligation is occasionally necessary in cases of significant vena cava wall disruption.4Calligaro KD Savarese RP DeLaurentia DA Unusual aspects of aortovenous fistulas associated with ruptured abdominal aortic ancurysms.J Vasc Surg. 1990; 5: 586-590Google Scholar We thank Dr. Gregorio A. Sicard for his help in the preparation of this manuscript and Debi Swap for her technical assistance. 24/41/42863