A Case of Inflammatory Abdominal Aortic Aneurysm with Occult Aorto-caval Fistula Presenting as Inferior Vena Caval Obstruction

A previously healthy 82-year-old man presented with a 3-month history of bilateral lower limb oedema. Abdominal examination revealed prominent abdominal veins extending to the thigh. A large pulsatile abdominal aortic aneurysm (AAA) was noted in the epigastrium. Bilateral pitting leg oedema was noted along with a bluish discoloration of the feet. Clinical diagnosis of IVC thrombosis secondary to pressure from an AAA was made. A subsequent CT revealed a 10.5 cm infrarenal AAA compressing the IVC and the left ureter resulting in a left hydronephrosis. The IVC distal to the aneurysm was found to be occluded with thrombus (Fig. 1). A Greenfield vena caval filter was placed in the IVC via the superior vena cava prior to surgery to prevent a pulmonary embolism during operative manoeuvres (Fig. 2). Peroperatively a big thrombus was removed from a large IAAA sac, and a previously unexpected and