Efficiency of optimal fluoroscopic projection angle defined by computed tomography angiography for left atrial appendage closure

Left atrial appendage (LAA) closure (LAAC) procedures are conventionally performed using empirical fluoroscopic viewing angles. However, because the LAA is a highly variable anatomical structure, these angles cannot depict the LAA in the optimal position. The present study aimed to assess the efficiency of using a novel optimal fluoroscopic projection angle (OPA) for LAAC and to validate its feasibility. The OPAs of the derivation cohort were acquired using cardiac computed tomography angiography (CCTA) to assess its superiority for depicting LAA depth versus traditional working angles (TAs) of RAO 30°, CAU 20°. The practicability of OPA-guided LAAC was demonstrated by comparison between clinical data from the validation cohort and those from a propensity-score matched (PSM) control group, as well as randomized controlled studies investigating LAAC. Of 705 patients in the derivation cohort, the median OPA was RAO 46°, CAU 31°. Compared with TA, the OPA depicted a longer mean (± SD) LAA depth (5.1±4.4) mm and a larger orifice diameter (1.1±1.1 mm), (P<0.0001 for both). All 38 OPA-guided LAACs were successful, with a shorter mean procedure duration (42.9 ± 12.3 min versus [vs.] 107.2 ± 41.5 min; P<0.0001) and reduced device consumption (1.08 vs. 1.5 per case), compared with the PSM control group. At the 3-month follow-up, the incidence of peri-device leak was 52.6% (20/38) detected by CCTA, with a mean leakage of 1.6±0.8 mm. By unfolding the LAA depth and orifice diameter to a better view, OPA demonstrated the potential to optimize LAAC procedural efficiency, although further larger-scale studies are required to confirm this.