Endovascular management of pararenal aortic aneurysms with multiple overlapping uncovered stents

Abstract

An alternative method of management of complicated aortic aneurysm appears to be feasible using overlapping bare stents, which may prevent aneurysm growth while preserving vital branches. The short-term outcome of our study seems encouraging but is not sufficient to draw a robust conclusion. Further hemodynamic and clinical studies are warranted to evaluate long-term efficacy.

Total Endovascular Repair of Thoracoabdominal Aortic Aneurysms With Non-Customized Stent Grafts

“…A larger D/N ratio could lead to a more significant decrease in wall shear stress within the aneurysm sac. This theory is in accordance with our previous clinical investigation [13], in which we found that the aneurysm SE length could influence the thrombosis process within the sac. While the dome length is fixed for a given aneurysm, the neck length could be shortened by a stent graft covering part of it.…”

“…For a TAAA that mainly affected the infrarenal aorta rather than the thoracic aorta (type Ⅳ TAAA), a "reversed procedure" could be considered, in which the stent graft (Hercules-B, MicroPort) could be placed at the infrarenal aorta to cover the distal aneurysm SE, while the multiple bare stents were deployed above it to cover the proximal aneurysm residual SE (Fig 3B). The aneurysm sac entrance was defined as the threshold between the normal laminar flow of the native aorta and the turbulent flow of aneurysm sac (A: sac entrance for saccular aneurysms; B: sac entrance for fusiform aneurysms), whose length could exert an influence on the thrombosis process of the aneurysm sac according to our previous study [13]. The length of the aneurysm sac entrance could be artificially shortened by a stent graft covering part of it.…”

“…imported into CT-imaging process software (Aquarius Workstation, Version 3.7.0.13; TeraRecon, Foster City, CA) for three-dimensional reconstruction of the aortic contour and measurement (Figs 4A, 4B). Preoperative ( Fig 4C) and postoperative aneurysm maximum diameters ( Fig 4D) were measured on the cross-sectional images on the same aortic level referring to the vertebrae, as utilized in previous studies [13,16]. The visceral branches covered by the bare stents were noted during surgery, and the patency of each was assessed during follow-up.…”

“…In a pilot study using multiple overlapping uncovered stents as an alternative to the commercial Cardiatis multilayer stents in the treatment of pararenal aortic aneurysms [13], we have demonstrated that aneurysm morphologic characteristics, such as the aneurysm "sac entrance (SE)" (defined as the threshold between the normal laminar flow of the native aorta and the turbulent flow entering the aneurysmal sac; Figs 1A, 1B) could impact on the thrombosis process after stenting. Short-SE aneurysms were observed to have a better clinical prognosis compared with wide-SE ones.…”

Is Multiple Overlapping Uncovered Stents Technique Suitable for Aortic Aneurysm Repair?

“…This observation also supports clinical studies that use three to four MOUS stents and reported encouraging short-term outcomes (25). In the clinical setting, the number of uncovered stents implanted can be determined by intraoperative angiography with the criterion of velocity reduction in aneurysm sac achieved on fluoroscopy (22,23,26). To avoid perfect overlapping of stents, the alignment of stent can be adjusted circumferentially during deployment by referring to the radiopaque markers located at both proximal and distal end of the stent.…”