Giant Sac Growth: A Hybrid Approach to Treat a Misdiagnosed Late Type IIIb Endoleak

INTRODUCTION: Endoleaks are a common complication following endovascular aneurysm repair, yet type IIIb are rare, especially with newer devices, and associated with high morbidity due to repressurisation of the sac. As endografts are used in patients with longer life expectancy, late type IIIb endoleaks are to be expected. This is a report of a giant common iliac aneurysm resulting from a misdiagnosed type IIIb endoleak. REPORT: An 85 year old man with history of right common iliac artery aneurysm, treated in 2003 with an EXCLUDER AAA Endoprosthesis (WL Gore, Flagstaff, AZ, USA) with iliac limb extension into the external iliac artery, presented at the emergency department with abdominal pain, hypotension, and syncope. He had a known endoleak, unsuccessfully treated by relining the right iliac stent graft overlap zones for a suspected type IIIa endoleak (2009), coil embolisation, and computed tomography (CT) guided thrombin injection of the aneurysmatic sac for a type II (2010), none of which managed to treat the cause with continuous aneurysm growth. The patient refused further treatments, but agreed to maintain surveillance. At admission, CT angiography showed common iliac aneurysm (185 × 134 mm) sac rupture without a visible endoleak. Resuscitative endovascular balloon occlusion of the aorta (REBOA) technique was performed to obtain haemodynamic control, then the aneurysm was approached through a midline incision. A type IIIb endoleak was identified due to a fabric tear on the right iliac limb extension. Suture was attempted without success, then relining of the lesion with an Endurant II Limb (Medtronic, Minneapolis, MN, USA) was performed, which managed to repair the endoleak. DISCUSSION: Type IIIb endoleaks are uncommon and underdiagnosed due to fabric defects being too small or leaking intermittently. They can mimic other types of endoleaks and may cause aneurysm growth and rupture. One should consider this type of endoleak if previous treatments for other types were unsuccessful.