Mechanical Performance of Two Left Atrial Appendage Occlusion Systems: In Vitro Comparison of Tug Force, Radial Force, Sealing and Deformation.

Abstract

The aim of this study was to establish in vitro bench-tests of left atrial appendage occlusion (LAAo) devices regarding tug force, radial force and sealing capacity. Two LAAo devices, namely the WATCHMAN™ and the Occlutech^®, of three different sizes underwent testing in novel dedicated in vitro setups. Radial force was assessed in a commercial radial force tester. At baseline, tug force of the WATCHMAN™ was significantly higher when compared to Occlutech^® for all devices. Repeated resheathing resulted in a reduction of device-diameter in the WATCHMAN™ devices of max. 7.9%, whereas diameters of Occlutech^® occluders remained unchanged. Tug force was not significantly impacted by resheathing in both devices. At baseline, sealing capacity in a bench-test using silicone LAA-models did not differ between the devices. Resheathing lead to an in vitro loss of sealing capacity of the WATCHMAN™ devices, increasing with resheathing and resulting in a max. peridevice leak of 91.1 ± 7.9%. Radial force was higher for the Occlutech^® devices and decreased for WATCHMAN™ occluders after resheathing. The WATCHMAN™ occluder series showed progressive deformation, increased peridevice leakage and decreased radial force after resheathing, presumably as a result of diameter reduction. Tug force of the WATCHMAN™ was not impaired by resheathing and was significantly higher than that of the Occlutech^® device.