The multilayer flow modulator stent for the treatment of arterial aneurysms

The purpose of this manuscript was to: 1) report our experience with the Multilayer Flow Modulator (MFM) for the treatment of peripheral, visceral and aortic aneurysms; 2) review the published literature regarding the outcomes of patients treated with the MFM; and 3) develop initial treatment guidelines regarding the MFM.

We reviewed our clinical experience with the MFM in 58 high surgical risk patients. Thirty-one peripheral (PAAs), 9 visceral (VAAs) and 18 aortic aneurysms (10 thoracoabdominal [TAAA]; 8 abdominal) were treated. In addition, the PubMed database through April 2013, along with relevant websites and scientific presentations at international meetings, were quered regarding the MFM. Seventeen articles and 3 presentations were identified. Data regarding 178 patients treated with the MFM were included for analysis including 57 PAAs, 31 VAAs and 90 complex degenerative aortic lesions. Outcomes including technical success, 30-day mortality, endoleak rate and aneurysm-related survival were studied.

In our experience, there were 47 males and the mean age was 62 years (16-80). In patients with PAAs and VAAs, technical success with the MFM was 100%. At 30 days, there were no deaths. Initial MFM patency was 97.5% (39/40) with patency of the thrombosed MFM successfully restored. Longer-term follow-up (mean 16 ± 8 months) demonstrated progressive thrombosis and shrinkage of the aneurysm sacs and all side-branches were patent. In patients with aortic aneurysms, technical success was 100%, with no complications and no deaths at 30 days. Longer-term follow-up (8 ± 7 months) demonstrated aneurysm-related survival of 100%, all-cause survival of 83.3%, intervention-free survival of 100% and 100% patency of the side branches. The longest duration for aneurysm sac thrombosis was 18 months. A significant mean diameter reduction was observed at 6 months (17.3 mm for the transversal maximal diameter and 13.83 mm for the antero-posterior diameter) in the TAAA group. In the literature review, there was 100% technical success and a 97.7% 30-day survival rate in patients with PAAs and VAAs treated with the MFM. In follow-up (range 5-26 months), there were no aneurysm-related deaths or aneurysm ruptures and the overall survival was 95.5%. Complete aneurysm exclusion was observed in 94.3% of the patients with significant aneurysm shrinkage in 83% of the patients. Nine (10%) MFMs occluded with most occlusions resulting from pre-existing conditions. Patency of 5 occluded MFMs were restored and 4 occluded MFMs were not treated and were asymptomatic. All covered side branches were patent except in a patient with thrombophilia who also had an occluded MFM. The treatment of complex aortic degenerative lesions with MFM demonstrates a 95.5% 30-day survival with 2 aneurysm ruptures for contrindicated use (previously ruptured aneurysm; mycotic aneurysm). Over the follow-up (range 3-28 months), all-cause survival was 87.8% and aneurysm-related survival was 96.7% (1 late rupture due to a type 1 endoleak). Side branches were patent for 97.7% of the treated cases and a 13.3% endoleak rate was reported. There were no neurological, renal or respiratory complications. Complete exclusion and size stability were achieved for most of the cases.

Clinical experience with the MFM is increasing. The MFM has been used to treat many types of aneurysms including peripheral, visceral and aortic. Early results suggest that use of the MFM can help prevent aneurysm-related mortalities while maintining branch vessel patency. Additional study and investigation is needed.