Early mid-term results of the first 103 cases of multilayer flow modulator stent done under indication for use in the management of thoracoabdominal aortic pathology from the independent global MFM registry.

AIM: We report mid-term results from the Global Independent multilayer flow modulator (MFM) registry using a uni-modular multilayer flow modulator stent technology.

METHODS: We present the first 103 cases out of the 380 cases implanted in Europe under indications for use. All were done on a compassionate basis, in 12 countries, and were fully analyzed through the MFM registry. Primary endpoints were: one-year freedom from rupture and aneurysm-related death, one year all cause mortality, patency of visceral branches at one year, and one year incidence of stroke and paraplegia. Primary technical endpoints were aneurysm sac volume modulation at one year. Secondary technical endpoints were technical success and one-year freedom from reintervention. Mean age of 69.2 years (16-93 years), mean aneurysm diameter was 6.4±1.66 cm and mean length was 12.96 cm. They were 75 Crawford thoracoabdominal aortic aneurysms (TAAA) (11 Type I, 14 Type II, 26 Type III, and 24 Type IV), 7 arch aneurysms, 15 suprarenal aortic aneurysms and 6 type B dissections. The mean number of side branches covered for a total number of 378 branches is 3.7 side branches per case. Total numbers of stents used was 176 with a mean of 1.71 MFM stents per case; 77.77 were ASA IV E, 72.7% had previous thoracic endovascular aortic repair or open TAAA repair.

RESULTS: Thirty-day morbidity was 5.4% with zero mortality. Aneurysm related survival was 91.7% at one year. No rupture occurred. Four cases of consumptive coagulopathy were observed, two of which resulted in death from hemorrhagic cerebrovascular stroke and one of which resulted in death from a gastrointestinal bleed. Technical success was 97.3%. One-year all-cause survival was 86.8%. At 12 months 95.1% of all visceral branches were patent. There were no stent fractures. One-year intervention free survival was 89.4%. At six months the mean rate of sac volume increase was 0.57%% per month, resulting in a mean volume increase of 2.56%. At 12 months the rate of increase had slowed to 0.33% per month, resulting in a total average increase in sac volume of 5.07%. Mean base line thrombus volume was 297.54 cm3. At one year the mean thrombus volume was 361.38 cm3 with mean volume change of 63.45 cm3. However, mean base line total volume was 332.79 cm3. At one year the mean total volume was 355.4 cm3 with a mean total volume change of 22.61 cm3. The mean base line maximum diameter was 6.27 cm. At one year mean maximum diameter was 7.06 cm with mean total change of 0.79 cm3. The mean baseline residual flow volume was 71.75 cm3. At one year, mean residual flow volume had decreased to 63.3cm3 with mean volume change of 8.4 cm3.

CONCLUSION: Increasing sac volume, thrombus or diameter size was not associated with rupture. MFM implantation instigates a process of aortic remodeling involving initial thrombus deposition, which slows between six and twelve months. This Global MFM Registry data has demonstrated the proof of concept of this disruptive technology.