Cath Lab Digest

Abstract

We report the case of a ruptured abdominal aortic aneurysm (AAA) related to a Type III endoleak which occurred 3 years after treatment of the AAA with a Zenith Cook stent graft. This report will also discuss the mechanism of occurrence and means of detection.

An 81-year-old female underwent elective treatment of a 55 mm AAA using a right aorto-uni-iliac Zenith Cook stent graft. During follow-up, a Type II endoleak was detected and was responsible for a 4 mm aneurysm sac diameter increase. At 30 months, the patient experienced a secondary AAA rupture due to a large Type III endoleak which was caused by a separation of the main body of the stent graft and the right leg extension. A close reinterpretation of the anterior follow-up scans shows a progressive decrease of the overlap between the main body and the extension. Progressive shortening of the overlap between the main body of the graft and the limbs leads to limb disconnection. Enlargement of the aneurysm due to Type II endoleak may be a favoring factor in shortening the overlap. This case demonstrates the need for close scrutiny of all components of an endograft during follow-up.

VASCULAR DISEASE MANAGEMENT 2010;7:E142–E146

Key words: abdominal aortic aneurysm, morbidity, aneurysm repair, aortic aneurysm stent graft

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Introduction

Rupture following endovascular aneurysm repair (EVAR) is a dramatic event that occurs at a rate of about 1% per year or less.¹ Aortic rupture is mainly due to acute pressurization of the aneurysm sac secondary to stent-graft migration, graft erosion or limb disconnection.² Graft-related deteriorations were mostly observed with the first-generation stent grafts. Technological improvements included thicker fabric, better anchorage with hooks or strong radial forces and longer overlap between the main body and the limbs of the grafts. With the latest stent-graft generation, failures appear to occur less frequently. The Cook Zenith device (Cook, Inc., Bloomington, Indiana) was introduced on the European market in 2000. Our group reported placement of 217 Zenith stent-grafts with a 4-year follow-up.³ Component separations in these series were rare and never led to rupture.

We report the case of limb disconnection of a Zenith stent graft, which led to acute AAA rupture despite a thorough surveillance protocol. We discuss the mechanisms of occurrence and means of detection.

Case Report

An 81-year-old female was referred to our department for the treatment of a 55 mm AAA. The patient was free of major comorbidities, however, considering her age, an endovascular option was chosen. A right aorto-uni-iliac procedure was performed due to the existence of a 90° angle from the longitudinal axis of the aneurysm to the left common iliac artery associated with 30 mm aneurysms of both common iliac arteries which was without a 15 mm fixation site above the iliac bifurcation. The right common iliac angulation was 60°. Assuming that preservation of internal iliac artery flow may be particularly important in endovascular repair since there is no opportunity to inspect the sigmoid colon or to reimplant the inferior mesenteric artery,⁴ the plan was to treat the aortic aneurysm and the bilateral common iliac aneurysms using a right aorto-uni-iliac endograft with a distal fixation site 15 mm into the right external iliac artery and an aortic occluder above the left iliac bifurcation (exclusion of the right internal iliac artery and conservative treatment of the left internal iliac artery). To reach the external iliac fixation zone, we added a 12 x 55 mm right-leg extension to the main endograft body. As recommended by Cook Zenith aorto-uni-iliac graft instructions for use, the overlap between the main body and the iliac leg extension was 1 stent length (15 mm). The early outcome of the intervention was uneventful. Follow-up consisted of a computed tomographic (CT) scan the day of the patient’s discharge, 6 months and 12 months and then yearly if no complication was detected. Images were viewed using Netvantage Windows volume show 3 software. Sagittal and coronal reconstructions were performed to assess the aorto-iliac angles. Maximum diameter was measured at the level of the third lumbar vertebra. All CT scans were reviewed for the purpose of this study. Postoperatively, no endoleak was detected and the sac diameter was 55 mm. At 6 months and 12 months, a Type II endoleak was observed whose origin was thought to be the lumbar arteries. Since the sac diameter shrunk to 52.8 mm, no further treatment was undertaken (Figure 1A).