20–40 % of patients suffering from acute thoraco-abdominal type B aortic dissection present with aneurysmal dilatation of the false lumen during follow up [1, 3]. Both conventional open and hybrid open-endovascular surgery are valid therapeutic alternatives but can be associated with high morbidity and mortality even in experienced surgical centers [2, 4].
Complete endovascular treatment of chronic abdominal aortic dissection with aneurysmal degeneration using fenestrated or branched stents has a number of limitations. The small diameter of the TL and often immobile septum make endovascular repair challenging with conventional stent grafts. Moreover, sealing the re-entry tears in the FL that often involve the celiac trunk and the lower renal artery is often not possible [5].
The use of endovascular occluders to try to seal the re-entry into the FL has been associated with poor outcomes by some; notably the persistence of endoleaks and the absence of remodelling of the aortic lumen [6, 7].
The SETA MUG® is a non-tapered endoprosthesis, full stented, with no bare metal proximal stents (‘free flow’) and consisting of a multilayer membrane and hybrid stent design with 2 types of cells. It is mounted on a 25 mm diameter balloon, for this case. The high porosity of the multilayer membrane allows for in situ fenestration thus allowed us to seal the FL re-entry tear at the level of the left renal artery and restore true lumen flow to the kidney. Importantly, this membrane is easily visible and permits one orient the crossing wire/catheter precisely at the level of the renal ostia and thus puncture the membrane and accurately deploy the bridging stent-graft without using 3D image fusion. Regarding the long-term evolution of FL, in a recent meta-analysis, P Qui et al. reported the results of 8 observational studies in which 914 patients participated, where the PETTICOAT technique does not favor aortic remodeling due to the absence of false lumen thrombosis [8].
We believe that the SETA MUG® device would also be favorable for the remodeling of the abdominal aorta, similar to that reported with the E-PETTICOAT technique [9].
During the 8-month follow-up, the patient remained asymptomatic and the CTA showed patency of all branches as well as the left hypogastric artery with complete occlusion and reduction in the size of the FL (Fig. 4).
We did not find previous reports in the international literature regarding a stent with such characteristics. As an antecedent to this endoprosthesis, we carried out a research work in 7 sheep at the Veterinary University of Zaragoza, the results of which are in the process of being published.
To guarantee blood flow to the superior mesenteric artery and right renal artery covered stents were used (chimney technique), taking into consideration that we expected no endoleak due to the fact that the lumen of the suprarenal aorta was non-aneurysmal [10] and also, due to the initial learning curve with the SETA MUG® device.
Creatinine levels immediately after the intervention and the previous control prior to the performance of the computed tomography revealed no changes.
While cardiac and renal morbidity is relatively low, the risk of spinal cord ischemia remains significantly high during endovascular repair of thoraco-abdominal aneurysms, and therefore highlights the importance of staging these procedures when possible [11].
In conclusion, this first case demonstrates the feasibility of the SETA MUG device design in which in-situ fenestration of the stent graft membrane can be performed to treat aortic dissection with persistent false lumen flow. Pending further studies, this may soon become a new option in the endovascular therapy for patients with chronic abdominal aortic dissection such as our patient, as well as those patient anatomies with difficult landing zones (short and/or conical necks, etc.) or those with type1 A endoleaks, who might otherwise require fenestrated stent grafts or fenestrated cuffs. Larger studies with longer follow-up are essential to fully evaluate the safety and effectiveness of this technology and the need of possible secondary procedures.
Approved by Leben Clinic ethics committee.