Multilayer Flow Modulator Stent for Aortic Pathology: A Meta-Analysis and Additional Data from a Single-Centre Retrospective Cohort

Abstract

Background: Thoracoabdominal aneurysms and aortic dissections are a challenge for vascular surgeons. Open surgery, fenestrated or branched endograft, and the chimney technique are not possible in some patients, because of comorbidities or anatomical restrictions. However, the multilayer flow modulator (MFM) can be implanted in some of these patients. In this systematic review, we will describe the experience with the multilayer stent. To augment the limited number of studies available, we will include a cohort of patients from our hospital.

Methods: We retrieved data on all consecutive patients treated using the MFM between May 2013 and August 2020. This included patients with type B dissections and thoracoabdominal or thoracic aneurysms who were unfit for open surgery. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included all the studies that used the MFM in the aortic segment. Single-arm meta-analyses were performed using OpenMeta (Brown University, Providence, RI, USA).

Results: A total of 37 patients were treated in our hospital during the study period. The technical success was 97.3% and the 30-day mortality was 5.4%. In 40.5% of the included patients, the instructions for use were not followed. Off-label implantation was associated with a higher aneurysm-related mortality. A total of 12 studies were included in the meta-analysis and the technical success was 97.8%. In 68.5%, the aneurysm sack or false lumen remained perfused, 97% of all the covered side branches remained patent. After a follow-up period of 1 year, five patients in the meta-analysis presented with a ruptured aneurysm.

Conclusions: The overall quality of evidence is poor because long-term results are lacking, patients are frequently lost during follow-up and all the studies were non-comparative. Our retrospective study suggests a relatively low incidence of perioperative complications, although there was a high incidence of persistent perfusion in the aneurysm sac (102 of 149 patients). The risk of rupture at the 1-year follow-up was 2.1%.

Keywords: flow modulator; multilayer stent; thoracic aneurysm; thoracoabdominal aneurysm; type B aortic dissection.

Fig. 1.

All-cause and aneurysm-related mortality. (a) All-cause mortality. (b) Aneurysm-related mortality. (c) All-cause mortality: within and outside IFU. (d) Aneurysm-related mortality: within and outside IFU. IFU, instructions for use.

Fig. 2.

Study flow chart. MFM, multilayer flow modulator.

Fig. 3.

Meta-analyses. (a) Technical success. (b) Mesenteric ischemia at 30 days. (c) Neurological complications at 30 days. (d) Patency of side branches at maximal follow-up. (e) Complete thrombosis of the aneurysm sac at maximal follow-up. (f) Reinterventions at 1 year. (g) Reinterventions at maximal follow-up. (h) Rupture at 1 year. (i) Rupture at maximal follow-up. (j) All-cause mortality at 30 days. (k) All-cause mortality at 1 year. (l) All-cause mortality at maximal follow-up. Ev, event; Trt, treated patient.