Endotension after EVAR: diagnosis by fluoro-guided translumbar approach and \'relining\' treatment

Clinical History

A male patient, 75 years old, underwent EVAR treatment (Excluder-Gore stent-graft) for an abdominal aortic aneurysm in 2003. He had a normal CT-follow-up in 2005 (Fig.1a), but in June 2012 a CT examination performed as follow-up revealed a focal increase of the aneurysmatic sac without visible endoleak suggestive for endotension (Fig.1b)(type 5 endoleak).

Imaging Findings

After a diagnostic angiography which excluded type 2 endoleak the patient underwent endovascular treatment by "relining technique" with deployment of one proximal cuff and two limb extensions (Excluder-Gore) in perfect alignment with the previous deployed stent-graft. Furthermore to confirm "endotension" diagnosis 3 weeks later we decided to proceed to direct puncture of the aneurysmatic sac using a method of image needle guidance (XperGuide-Philips Medical Systems) which allows to perform percutaneous needle procedures in the interventional cath-lab. This application overlays live-fluoroscopy and 3D soft-tissue imaging data from previously-acquired XperCT (Fig.2a), providing information on the needle path and target (Fig.2b, c). The procedure was done under mild sedation with the patient in the prone position. The needle used was a 5F catheter-needle (Optimed). Once the needle reached the target, aspiration was done and a yellow dense fluid was drawn, confirming the diagnosis of "endotension" (Fig.2d). The tract was occluded with a coil (Fig.3).

Discussion

Endotension is defined as increased intrasac pressure after EVAR without visualized endoleak on delayed contrast CT scans. Some authors define this abnormality as sac hygroma [1]. Several reports indicate a significant percentage of enlarging AAAs after EVAR without evidence of endoleak with what was known as the “original” Excluder stent-graft [2-5]. Complications related to sac enlargement in the absence of endoleak appear to be uncommon, but rupture, loss of proximal seal zone, and conversion to open repair or other secondary interventions have been reported[3, 5, 6]. Partly because of the low number of reported complications, the true nature of endotension and its natural history is not entirely clear. Examination of fluid withdrawn from the sac by direct puncture, reports on the sac at the time of conversion, and explanted devices have all indicated that in many cases enlargement in the absence of endoleak with the original Excluder is due to material permeability: no blood is found but rather a hygroma or gelatinous substance [1, 4-6]. The problem appears to have been corrected by changing the graft material in the newer low-permeability ExcluderLP-stent-graft [4] but this has not solved the problem of endotension in patients with the original Excluder. The problem may be solved by conversion to open repair, but this carries a significant risk to the patient. Less invasive options such as laparoscopic sac fenestration and suction of the sac have been performed but have not been successful[1]. Fortunately, this sac expansion appears to be arrested by relining the original permeability device with low-permeability Excluder endoprosthesis components. Logically, the relining procedure only needs to involve the components that are exposed to the aneurysm sac itself. The case shown here is original for the fact that sac expansion had a focal pattern that was significant. For this reason we decided to treat it using the “relining” strategy as proposed by Goodney[7]. Furthermore, once the sac was protected by the relining low-permeability cuffs we decided to try to confirm the diagnosis of endotension by direct fluoroguided puncture using the new tool available in the Integris FD20 equipment (Philips Medical Systems). The tool demonstrated to be easy to use and effective and at the first attempt we were able to advance the catheter needle in the sac and draw a dense yellow fluid confirming the diagnosis of hygroma or endotension. A CT done after one month did not reveal any complication due to this manoeuvre(Fig. 3).

Differential Diagnosis List

Final Diagnosis

Diagnosis and endovascular treatment of endotension post-EVAR

URL:	https://www.eurorad.org/case/10356
DOI:	10.1594/EURORAD/CASE.10356
ISSN:	1563-4086