P1799 The importance of 3D imaging techniques in left atrial appendage closure: landing zone eccentricity influence on peri-device leak incidence and its implication in long-term clinical outcomes
Authors: Italiano G , Maltagliati A , Mantegazza V , Gasperetti A , Fusini L , Arioli L , Susini F , Brusoni D , Fassini G , Tondo C , Pepi M 
Published: January 2020

Abstract

Background
A complex left atrial appendage (LAA) morphology and a non-circular landing zone (LZ) are frequently encountered in patients undergoing percutaneous LAA occlusion (LAAO). Three-dimensional (3D) imaging modalities as 3D transoesophageal echocardiography (3D TOE) and cardiac computed tomography (CCT) should be preferred over two dimensional techniques for better evaluation of LAA diameters, especially for the LZ. In fact, non-circular shape could impair the choice of occluder device size and may be implicated in the occurrence of residual leaks. Incomplete LAA occlusion is recognized to be associated with thromboembolic events.

Purpose
The aim of the study was to evaluate the utility of 3D imaging techniques to predict LAA device size and the landing zone eccentricity index as a potential predictor of residual peri-device leaks and to assess their clinical implications on long-term follow-up.

Methods
It was a retrospective, single-center study including 137 consecutive patients undergoing successful LAAO from January 2010 to July 2018. Pre-procedural 3D TOE and CCT were used to predict device size based upon LZ diameters and quantify LAA orifice eccentricity. Leaks were defined as the presence of peri-device flow at 2D TOE immediately after the device implantation and at 3 months follow-up. Leaks were classified as significant (color jet width ≥4 mm) or minor (&lt;3 mm). A clinical evaluation of thromboembolic events was performed at 48 ± 27 months from the procedure.

Results
LAAO closure was performed implanting either Amulet or Watchman devices (n = 98 and n = 40, respectively). The assessment of LZ measurements with 3D TOE and CCT showed a significant correlation with the device size selected on the basis of 2D techniques (r = 0.82 and r = 0.74, respectively). As concerns the peri-device leaks, the presence of an eccentric LZ (eccentricity index &gt;0.20) was not associated to the development of post-procedural leaks in the overall population; a significant correlation was detected only in the subgroup of patients treated with the Amulet device (p = 0.045). Residual leaks included only 1 significant leak (0.7%) after Amulet device implantation, which was related to a major neurological event (stroke) and 47 (34%) minor leaks (n = 28 in the Amulet group, n = 19 in the Watchman group). In this last population, 2 patients (1.5%) developed minor neurological events (transient ischemic attack).

Conclusions
3D TOE and CCT better predict device size overcoming the limit of 2D imaging techniques undersizing. In eccentric LAA, Watchman device may reduce the incidence of peri-device leaks. The presence of significant residual leaks is uncommon but associated with major clinical events, whilst minor leaks are relatively frequent but do not seem to be related to life-threatining thromboembolic accidents.