New Measurements Using Computed Tomography Predict Success of Left Atrial Appendage Closure

BACKGROUND: Preprocedural screening using transesophageal echocardiography (TEE) and computed tomography (CT) is widely performed in patients undergoing left atrial appendage (LAA) closure (LAAC). However, established methods for accurately predicting procedural device success (DS) remain unclear. AIMS: This study aimed to evaluate whether a novel preprocedural CT-based assessment focusing on the landing zone and presence of an internal septum could improve DS prediction. METHODS: We analyzed 560 patients from a Japanese multicenter registry who underwent LAAC with Watchman FLX (Boston Scientific, USA). Preprocedural CT multiplanar reconstruction measured the diameter of the LAA landing zone (Dland), LAA length (L), and major lobe ostium diameter (Dlobe), if present. Based on these measurements, a ratio calculation (Rcal), defined as L/(Dland-Dlobe), was used to predict DS. The predictive performance of this ratio was evaluated using receiver operating characteristic (ROC) curve analysis and compared with that of conventional CT- and TEE-derived depth-to-ostium ratios. RESULTS: DS was achieved in 95.5% (535/560) of patients. The mean Rcal was significantly lower in the failure group than in the success group (0.66 ± 0.25 vs. 1.00 ± 0.28; p < 0.001). Rcal predicted DS with an area under the ROC curve (AUC) of 0.872 (p < 0.001). An optimal Rcal cutoff of 0.77 demonstrated 80.0% sensitivity and 83.4% specificity. Rcal showed superior predictive performance compared with CT depth/ostium ratio (AUC: 0.552) and TEE depth/ostium ratio (AUC: 0.456). CONCLUSIONS: The novel CT-derived metric, Rcal, which accounts for LAA landing zone dimensions and internal septa, predicts the DS of Watchman FLX. Rcal may improve pre-LAAC patient selection and procedural planning.