Custom Made Fenestrated Stent Graft Collapse after Thoracic Endovascular Aortic Repair: A Case Report

We present a case of stent graft collapse after performing thoracic endovascular aortic repair with a custom-made fenestrated stent graft. The patient was a 70-year-old woman with an asymptomatic aneurysm of the distal aortic arch, and thoracic endovascular aortic repair was performed. The patient showed a blood pressure difference between the left arm and the right arm on postoperative day (POD) 17 prompting the performance of a chest computed tomography scan which revealed stent graft collapse. She then underwent staged debranching of thoracic endovascular aortic repair. Stent graft collapse is a rare but well-described complication of thoracic endovascular repair. Therefore, patients who undergo such a procedure should be carefully monitored for signs and symptoms, which suggest the possibility of stent collapse.

Fenestrated and branched stent-grafts： present and future

The goals of future development of endovascular aortic stent grafting were towards. extension of the proximal seal, preservation of vital branches, deployment, and low profile delivery ease of systems. Fenestrated aortic stent graft is a viable option for treating aortic aneurysms with short necks, and more than 5000 grafts have been implanted worldwide. The first device available, the Zenith fenestrated graft （Cook Medical, USA）, involved placing a proximal tube fenestrated component, then accessing each target vessels from the contralateral side with a sheath, and bridging the connection with a covered stent. A bifurcated distal component is then placed to complete the endovascular repair.

Optimization of fenestrated technique in application to aortic aneurysms with an attached branch

Background:The fenestrated stent technique has been developed for the treatment of aneurysms with branches.However,the hole size and type,which are the key factors for optimal treatment outcomes,are still controversial in clinical application.Therefore,a hemodynamics investigation in terms of the size and type of the hole was performed with the objective of providing evidence for optimization of this technique.Method:Six cases were modeled for comparison:cases 1 and 2 corresponded to suprarenal aortic aneurysm(SRAA)models with no stent and a multilayer stent(MS),respectively;cases 3–6 represented the SRAA models treated with fenestrated stent grafts(FSGs)including a small-sized hole(SSH,3 mm),middle-sized hole(MSH,6 mm),large-sized hole(LSH,9 mm),and multiple holes(MH,which included the features of both the MS and stent graft,6 mm),respectively.The total stent area in cases 4 and 6 was equal to the cross-section of the branch.Results:As opposed to cases 1 and 2,the pressure on the aneurysmal wall reduced more significantly with FSG intervention(cases 3–6),and the area of low wall shear stress(WSS)on the aneurysmal wall was unexpectedly large in case 5 owing to jet flow deflection.The branch flux increased with the increase of the hole size,and normal blood flow in the branch was only observed in case 5.Interestingly,the weakest jet flow was found in case 5.Conclusion:Our findings indicate that the diameter of the hole should be slightly larger than that of the branch to achieve better aneurysm isolation and preserve branch patency.