Predicting the Size of Left Atrial Appendage Occluder Using a Printed MDCT 3D Model – A Feasibility Study

Background: LAA occlusion is an effective alternative to oral anticoagulation in non valvular atrial fibrillation patients. The LAA varies significantly in size, morphology and spatial orientation making percutaneous occlusion challenging. MDCT provides three dimensional (3D) datasets allowing accurate imaging. Our objective was to evaluate the ability of printed 3D LAA models based on MDCT datasets in predicting LAA occluder size.

Methods: Patients planned for LAA occluder implantation were included. All patients underwent MDCT before implantation; this data was used for creating and printing 3D LAA models. Three cardiologists ( informed which type of occluder was inserted) were asked to use the 3D models in vitro to predict the size of the device by fitting the device into the model. The chosen device size was compared with the actual device implanted during the procedure.

Results: This retrospective study cohort included 29 patients (78±7 years, 64% males). Watchman™ and Amplazer™ devices were deployed in 15 and 11 patients, respectively. Three procedures were aborted, all three physicians predicted it. There was poor agreement between the 3D models and the inserted device for Watchman™ devices; concordance correlation coefficient 0.3 (95% CI -0.13, 0.76) as compared with a very good correlation between the 3D models and the inserted device for Amplazer devices concordance correlation coefficient 0.8 (95% CI 0.5, 1.0). Intra-observer and inter-observer variability were tested for 6 cases (2 physicians evaluating each case twice) .Average interclass correlation was 0.97 (95% CI 0.9, 0.99) and 0.8 (95% CI -0.2, 0.97) for the two physicians, respectively.

Conclusions: LAA printed 3D models were accurate in predicting both device size for Amplazer™ device and procedure failures. However, no such correlation was demonstrated for predicting Watchman™ device size. Further studies are required in order to evaluate the potential role of printed 3D LAA models in assisting LAA occluder procedures