Assessment of Pull-out Forces in TEVAR and ANACONDA FEVAR Combination and Early Clinical Results: Creation of a Proximal Landing Zone for FEVAR in Patients with Extent I and Extent IV TAAAs.

BACKGROUND

Although recent data on the treatment of thoracoabdominal aortic aneurysms (TAAAs) are promising, in some cases, the paravisceral segment of the aorta may not be suitable for a branched endograft due to space restrictions. A combination of a fenestrated aneurysm repair (FEVAR) with a thoracic aneurysm repair (TEVAR) 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 30-mm thoracic tube grafts (oversizing of at least 2 mm: 13.3-21.4; minimum overlap of 15 mm). Continuously increasing longitudinal pull forces of up to 100 N were applied on an Instron Tensile Tester. Initial break point and damage to the endografts were documented. Clinical results of patients treated with such an FEVAR/TEVAR combination at our institution are presented as a second part of this study.

RESULTS

Median pull-out forces ranged from 2.38 N to 55.0 N. The highest stability was achieved with 34-mm Anaconda devices in 28-mm thoracic tube grafts. Grafts with either thinner Dacron material or those featuring a polytetrafluorethylene membrane seemed especially vulnerable to punctures and tears caused by the downward-looking hooks of the Anaconda device. Between April 1, 2013 and December 31, 2018, in 28 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. Although 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 were 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. Although pull-out testing has shown good stability with most assessed grafts, the thoracic devices with thicker Dacron membranes seemed to be especially suitable.