Disruptive endovascular technology with multilayer flow modulator stents as a therapeutic option in the management of thoracoabdominal aortic aneurysms. Early results from the global independent MFM registry

Abstract

Aim. Patients with thoracoabdominal aortic aneurysm (TAAA) have been classically managed by open surgical repair since 1955 but despite advances in surgical technique and the introduction of less invasive endovascular techniques, morbidity and mortality rates remain high. We report outcome using a novel uni-modular multi-layer stent technology. Methods. Out of 172 cases implanted worldwide we present the first 26 cases, in 7 countries, that were fully analyzed through the MFM registry. All were Crawford Thoraco-abdominal aortic aneurysms (11 type II, 9 type III, and 6 type IV); 75% were male; median age was 73years (57-91); 79.7% were ASA IV E; 62% were reintervention after previous TEVAR; mean aneurysm diameter was 67 mm and mean length was 167 mm. Primary endpoints are freedom from rupture and aneurysm-related death, aneurysm sac and lumen volume modulation, patency of visceral branches, and freedom from stroke and paraplegia. Secondary endpoints were technical success and all-cause mortality. Finite element analyses was performed on aortic sac pressure, shear stress, wall displacement and blood flow velocities. Results. All stents were deployed to their intended target. No aneurysm-related death occurred within 6 months. No peri-operative visceral or renal insult occurred. There were no cerebrovascular accidents, paraplegia or loss of visceral branches patency during follow-up. At 6 months, mean sac volume shrunk by 8% with lumen volume reduction of 14%. Average thrombus volume increased but thrombus to lumen ratio decreased by 23%. Finite element analysis post-MFM documented dampening of wall displacement by 80%. Wall pressure fell to 200 Pa with immediate depressurization of the aortic sac and dissipation of the maximum pressure zone. There was 55% immediate reduction in wall stress. MFM carries no risk of critical shuttering or loss of native side branches. With physiological modulation of the aneurysm, volume sac reduction was documented in 65% of cases. Conclusion. MFM offers immense promise for resolution of complex TAAA. A Global MFM Registry is required and long-term follow-up is mandatory.