Assessment of Pull-out Forces in TEVAR & ANACONDA FEVAR Combination and early clinical results: Creation of a Proximal Landing Zone for FEVAR in Patients with Extent I and Extent IV TAAAs

Abstract Objective While recent data on the treatment of thoracoabdominal aortic aneurysms (TAAA) are promising, in some cases, the paravisceral segment of the aorta may not be suitable for a branched endograft due to space restrictions. A FEVAR/TEVAR combination may represent a feasible treatment option. The current investigation was performed to assess the stability of a fenestrated Anaconda device implanted into a set of thoracic endografts from different manufacturers. We then assessed our clinical results with the FEVAR/TEVAR combination. Methods Pull-out forces were measured in-vitro after docking a fenestrated Anaconda graft within the distal end of different TEVAR devices. Anaconda devices were implanted in 28 or 30mm thoracic tube grafts (oversizing of at least 2mm: 13.3 – 21.4; minimum overlap of 15mm). Continuously increasing longitudinal pull forces of up to 100 Newton were applied on an Instron Tensile Tester. Initial break point and damage to the endografts were documented. Clinical results of patients treated with such a FEVAR/TEVAR combination at our institution are presented as a second part of this study. Results Median pull-out forces ranged from 2.38N to 55.0N. The highest stability was achieved with 34mm Anaconda devices in 28mm thoracic tube grafts. Grafts with either thinner dacron material or those featuring a PTFE membrane seemed especially vulnerable to punctures and tears caused by the downward-looking hooks of the Anaconda device. Between April 1st 2013 and December 31st 2018, in 28 out of 172 patients treated with a fenestrated Anaconda device, prior implantation of a thoracic tube graft was necessary to create a sufficient proximal landing zone. In 25 cases (89.3%), the aneurysm was successfully treated. While the 30-day reintervention rate in this subgroup was relatively high at 28.6%, none of these was due to a failure of the FEVAR/TEVAR combination. Upon an average follow-up of 15 months, no failure of the graft connection and no Type III endoleak due to membrane damage was observed. Conclusions The combination of a thoracic tube graft and a fenestrated Anaconda device is a viable option for the treatment of patients with Extent I or IV TAAAs with no adequate landing zone above the celiac trunk. While pull-out testing has shown good stability with most assessed grafts, the thoracic devices with ticker dacron membranes seemed to be especially suitable.