Anatomic feasibility of endovascular treatment of abdominal aortic aneurysms in emergency in the era of the chimney technique: impact on an emergency endovascular kit.

BACKGROUND

Despite promising results, endovascular aortic repair (EVAR) of ruptured/painful abdominal aortic aneurysms (RPAAA) continues to have limited use due to anatomic constraints linked to RPAAA morphology. Currently, EVAR for RPAAA is reserved for patients presenting with a long infrarenal aortic neck, because commercially available fenestrated stent grafts are not available in an emergency setting. Recently, the chimney technique (ChT) has been utilized to treat infrarenal abdominal aortic aneurysms (AAA) with short necks, but this technique requires specific materials. The aim of this study was to determine the rate of RPAAA eligible for EVAR since the advent of the ChT and to ascertain the standard materials needed in this context.

METHODS

We carried out a retrospective study of patients operated on for RPAAA (<24 hours after admission) at our center between 2006 and 2011. Patients' computed tomography (CT) scans were analyzed by two independent operators using 3-dimensional reconstruction software with a centerline of flow. To perform standard EVAR, the anatomic criteria used were those provided by the manufacturer (proximal neck diameter 18-32 mm with length >15 mm, angulation <60°, iliac diameter >7 mm). ChT anatomic feasibility criteria were: (1) a healthy aortic area >15 mm between the renal arteries and celiac trunk; (2) caudal orientation of renal arteries; and (3) a healthy descending thoracic aorta. Patients were classified according to the feasibility or nonfeasibility of standard EVAR and ChT.

RESULTS

In total, over the period of study, 55 patients were operated on for RPAAA. In 5 patients (9%), CT scan quality was unsatisfactory and thus 50 patients (mean age 76 years, 75% men) were analyzed. Among them, 35 (70%) had a ruptured aneurysm and 17 (34%) were unstable. Anatomically, 22 (44%) patients were eligible for standard EVAR. Taking the ChT into consideration, an additional 11 (22%) patients were eligible for EVAR. Among these EVAR-eligible patients, mean proximal neck diameter was 23 ± 3 mm and stent grafts with 24-, 28-, and 32-mm diameters could fit in 33% (11 of 33), 51% (17 of 33), and 12% (4 of 33) of the cases, respectively. These results enabled us to determine the material that should be made available in the emergency setting in centers treating RPAAA. Among the 17 patients who were not eligible for EVAR, an iliac pathology (calcifications, stenosis) and a very hostile proximal neck (angulation, thrombus), respectively, were involved in 88% (15 of 17) and 12% (2 of 17) of the cases.

CONCLUSIONS

The ChT increases EVAR feasibility by 50% in RPAAA. Taking into consideration our results, we recommend continued availability of emergency kits, including suitable aortouni-iliac stent grafts and basic material for performing ChT to allow surgeons to provide EVAR to the greatest number of RPAAA cases.