Pararenal or abdominal aortic aneurysms require grafts and stents. The patients undergo chimney endovascular aneurysm repair (chEVAR). These grafts are lined with stents to exclude the aneurysm while allowing visceral blood flow. This study analyzes the performance of flexible nitinol stents to improve surgical outcomes.

The retrospective study, done at a single center, involved 116 patients. They had chEVAR and V12/iCAST CGs with Endurant stent-graft during 2009-2017. A total of 32 patients had chimney graft (CG) lining with nitinol stents in 43 target vessels. Freedom from reintervention (FFR) and primary CG patency were estimated by the Kaplan-Meier method.

The participants had a radiological follow-up with a mean of 27.3 months. During this period, 6 out of 8 CG occlusions had stent lining. Patency was restored in 3 out of 4 symptomatic occluded stents. The first-year primary patency and FFR for the unlined group were 96.9% and 87.6%, respectively. For the lined group, they were 77.1% and 83.4%. The odds ratio for CG occlusion due to the lining as an independent risk factor was 9.9.

CG lining was significantly associated with occlusion, principally in angulated renal arteries during chEVAR. The distal part of the CG should not impinge on the target vessel’s angulated segment.