Contemporary strategies for repair of complex thoracoabdominal aortic aneurysms: real-world experiences and multilayer stents as an alternative

Late surgical conversion of failed Multilayer Flow Modulator stenting in thoraco-abdominal aneurysms

OBJECTIVES

The aim of this study was to report the outcomes of open or hybrid repair of failed thoraco-abdominal aortic aneurysm endovascular treatment with Multilayer Flow Modulator (MFM) stents.

METHODS

All patients who underwent open or hybrid repair of a failed MFM aortic treatment were retrospectively analysed. Perioperative and postoperative data, as well as midterm survival, were assessed.

RESULTS

Between 2013 and 2020, 39 patients received an open or hybrid conversion after endovascular treatment. Five of them [13%; 4 males; median age 68 years (interquartile range 66-76)] were previously treated with aortic MFM stents (Cardiatis, Isnes, Belgium). Among these, the median interval between index repair and conversion was 84 months (interquartile range 75-84). The median aneurysm diameter was 9.6 cm (interquartile range 8-10). Renovisceral vessels steno-occlusion was highly prevalent: 2 renal arteries were occluded; 3 coeliac trunks, 2 renal arteries and 1 superior mesenteric artery had a >70% ostial stenosis. Open standard thoraco-abdominal aneurysm conversion was performed in 3 fit patients, while a hybrid approach with visceral debranching and tube endografting was performed in 2 high-risk patients. Two patients (2 open repairs) died intraoperatively, and 1 (hybrid repair) postoperatively. The 2 successfully treated patients are alive at 4- and 34-month follow-up, respectively, with patent visceral branches.

CONCLUSIONS

Open or hybrid thoraco-abdominal aortic aneurysm treatment after failed endovascular aortic repair with MFM stents might be the only surgical option to address sac enlargements and ruptures or branch-related failures. However, both procedures had a poor prognosis due to both the impaired preoperative patient's status and the surgical complexity in the presented series.

A systematic review and meta-analysis of the streamliner multilayer flow modulator stent for treatment of complex aortic lesions

OBJECTIVE

We evaluated the safety and efficacy of multilayer flow modulator (MFM) stents (Cardiatis, Isnes, Belgium) for the treatment of complex aortic lesions.

METHODS

A systematic electronic research was conducted for studies reported from December 2008 to May 2020. Data extracted from 15 eligible case series (CS) were appropriately pooled and analyzed in a meta-analysis. The patient baseline characteristics were recorded, and 16 outcomes of interest were studied. The primary end points included 30-day all-cause and aneurysm-related mortality, aneurysm-related mortality at 1 year, vessel patency, and any endoleaks, ruptures, reinterventions, and aneurysm exclusion at the end of follow-up.

RESULTS

A total of 39 studies (15 CS and 24 case reports), involving 429 patients, met the inclusion criteria. Overall, 436 lesions were treated, and 1521 aortic branches were covered by the multilayer stent. The mean follow-up for the 15 CS with 404 patients was 14.6 months. Compliance with the instructions for use was reported by eight CS, with 75% of the procedures performed within the instructions for use. However, 41% of the patients reported by 12 CS had undergone a previous aortic intervention. The pooled 30-day all-cause and 30-day aneurysm-related mortality rates were 0.56% (95% confidence interval [CI], 0.00%-2.54%) and 0.00% (95% CI, 0.00%-0.80%), respectively. The pooled aneurysm-related mortality at 1 year of follow-up was 5.25% (95% CI, 0.07%-14.91%). The pooled vessel patency at the end of follow-up was 99.12% (95% CI, 97.73%-99.93%). The pooled reintervention and endoleak rates at the end of follow-up were 10.94% (95% CI, 3.64%-20.67%) and 10.70% (95% CI, 4.45%-18.66%), respectively. The crude spinal cord ischemia and renal failure rates were 0.69% and 1.8%, respectively.

CONCLUSIONS

The results from the present review and meta-analysis have indicated the safety and efficacy of MFM stents for treating challenging aortic pathologic lesions when used as first-line treatment and within the instructions for use. The almost zero pooled 30-day all-cause and aneurysm-related mortality rates combined with the low crude spinal cord ischemia and renal failure rates indicate the use of MFM stents is a good treatment option for complex aortic lesions in the short- and mid-term periods. The lack of long-term follow-up warrants further research concerning the efficacy of the device in the long term.

Current status on aortic endografts

Endovascular treatment has become widespread to treat aneurysmal disease, especially located in the aorta. The modern era of abdominal aortic aneurysm repair started between 1986 and 1991, and in the last 30 years, Endovascular Treatment for abdominal aortic aneurysms evolved both due to the development of new materials and devices and the increasing appeal and effectiveness of the endovascular therapy itself. Vascular surgeons are using nowadays different solutions of Endovascular Treatment to treat all the expressions of aortic pathology (aneurysms, dissections and trauma) both in the acute and elective setting. Despite its use in every location of the aorta (the ascending aorta, the aortic arch, the thoracic aorta, thoraco-abdominal aorta, pararenal, iuxtarenal and infrarenal aortic aneurysms and iliac aneurysms), its safety and efficiency, endovascular treatment for aortic aneurysms presents some drawbacks: despite a lower short-term morbi-mortality, reinterventions and long-term patency are higher compared to open repair. In this review, we detail the most used types of endografts according to location, their performances and durability for each device. We conclude by discussing options to overcome ET limitations. Therefore, an obvious question arises: what we need in the future? What can the technological progress gives to physicians to further improve this new way of treating aorta?

Challenges and experience of setting up an aortic service

Aortic surgery is a complex procedure posing high risks in comparison to other adult cardiac surgeries. Novel surgical approaches including minimally invasive procedures, sutureless aortic valve replacement, and transcatheter aortic valve implantation have been found to be acceptable alternatives to conventional surgeries. In addition, novel endovascular repair techniques and hybrid procedures have been introduced for the management of patients with thoracoabdominal aortic pathologies. However, these modalities are not readily available in every center, and such novel procedures impose a learning curve for surgeons and high costs for affected patients. In this review, we discuss the challenges of setting up an aortic service, having regard to the Iranian experience.

Aortic Remodeling After Total Endovascular Aortic Repair With Multilayer Stents: Computational Fluid Dynamics Analysis of Aortic Remodeling Over 3 Years of Follow-up

PURPOSE

To report Multilayer Flow Modulator (MFM) implantation from the sinotubular junction to the distal infrarenal aorta in the treatment of type B aortic dissection (TBAD) and demonstrate aortic remodeling using computational fluid dynamics (CFD) analysis over the course of 3-year follow-up.

CASE REPORT

A hypertensive patient with complicated TBAD required thoracic endovascular aortic repair due to severe thoracic pain associated with rapid progression of the false lumen aneurysm toward the distal aortic arch. Under general anesthesia, 2 aortic multilayer stents were placed over a 0.035-inch stiff guidewire in the compressed true lumen. The aorta was covered with 2 MFM stents between the sinotubular junction and the distal infrarenal aorta. Serial computed tomography scans showed progressive remodeling of the entire dissected aortic wall, with an excellent result at 24 months. Morphological and CFD vascular analysis confirmed the aortic remodeling, with a false lumen index drop from a preoperative 4.04 to 0.01 at 36 months.

CONCLUSION

Endovascular aortic repair with multilayer stents is a promising treatment for complicated TBAD due to the unique ability of these devices to stabilize the entire aortic wall without compromising the flow in the major aortic side branches.