A New Transseptal Solution For Enabling Left Atrial Access Of Large Delivery Sheaths

Background Transseptal access for large sheaths may be encumbered by tissue resistance against the sheath-dilator stepped interface. The ExpanSure Large Access Transseptal Dilator (Baylis Medical) is designed as a single introducer and dilation device with a smooth sheath-dilator transition to support transseptal puncture. It may facilitate ease and efficiency of interatrial crossing.Methods This study experimentally evaluated the crossing force of ExpanSure relative to a conventional 8.5 F Swartz SL1 transseptal sheath and dilator in a benchtop septum model. Its ability to reduce the subsequent crossing force of a 14 F WATCHMAN delivery sheath was also tested. The clinical use of ExpanSure, including procedure time, was then validated in a series of left atrial appendage closure (LAAC) procedures.Results In a benchtop septum model (N = 12), less peak force (1.90 +/- 0.08 N vs. 2.36 +/- 0.09 N; p < .001) and overall work (17.3 +/- 1.2 mJ vs. 28.0 +/- 1.9 mJ; p < .001) were required to advance ExpanSure relative to a conventional SL1 transseptal sheath and dilator system. Peak force (2.34 +/- 0.24 N vs. 2.65 +/- 0.21 N; p < .003) and overall work (28.5 +/- 3.9 mJ vs. 35.4 +/- 2.1 mJ; p < .001) to advance a WATCHMAN sheath were also significantly lower after using ExpanSure than after using a conventional transseptal system. In 19 LAAC procedures, ExpanSure crossed the septum smoothly and integrated readily, which enabled efficient procedure completion (mean total procedure time 37.6 +/- 13.5 min), with 100% success and no procedure-related complications.Conclusion Experimental force measurements, combined with early clinical experience using ExpanSure, suggest that the tapered design with smooth transition without dilator-sheath step-up and the larger diameter, both facilitated ease and efficiency of interatrial crossing.