“By failing to prepare, you are preparing to fail.” Benjamin Franklin

In this Issue of the Journal of Interventional Cardiac Electrophysiology, Nirmalan, et al. report a retrospective analysis of 150 patients undergoing left atrial appendage occlusion (LAAO) with an Abbott Amulet™ device who had pre-procedure CT scans comparing the accuracy of novel sizing based on calculating the landing zone diameter from the mean, perimeter or area of the landing zone as compared to conventional maximum diameter measurements [1]. Using these different calculated or measured diameters, they compared the accuracy of these in predicting the actual device used at the time of implant as well as peri-device leaks (PDLs).

The results of the study showed that the measurement that had the greatest prediction error, calculated as the difference between the implanted device size and the predicted device size, was using the maximum landing zone diameter (− 2.55 mm) when compared to the calculated values of mean, perimeter derived, or area derived diameters. Among the calculated diameters, the mean diameter performed the best followed by the area-derived and then the perimeter-derived diameters, with values of 0.08 mm, 0.3 mm, and − 0.39 mm, respectively. There were no significant differences in PDLs between the different landing zone measurement strategies. The authors calculated an eccentricity index [2] (1-minimum diameter/maximum diameter) to determine if the calculated diameter values performed better in low or high-eccentricity landing zones. The results showed that the value of the calculated diameters was greatest in the landing zones with the most eccentricity. This would be expected, since in a more circular landing zone, the calculated values would all be very similar as the landing zone approximated a more circular shape.

Current pre-procedure planning for LAAO is primarily transesophageal echocardiography and CT scans. Both options have limitations and may lead to suboptimal planning [3, 4]. This may result in longer procedures if multiple devices are attempted or suboptimal closure, PDLs, or increased risk of device-related thrombus. CT scanning has multiple advantages due to being noninvasive, not needing sedation, and offering post-image analysis in multiplanar views. However, cost, gating in atrial fibrillation, and the need for contrast make widespread availability difficult.

The anatomy of the left atrial appendage is complex and varied. Frequently, there is a discrepancy between different modalities of landing zone measurements (TEE vs CT) and a difference between the minimal and maximal diameters, owing to the eccentric shape of many LAA device landing zones. This discrepancy may result in difficulty choosing the properly sized device and require multiple devices or repeated attempts to place the device properly. These factors can increase procedure times, risk from repeated device recaptures, deployments, removals and replacement, and cost.

Newer 3-D modeling software, such as FEOPS™, or proprietary software, such as TruPlan™, can utilize CT scanning to model and predict proper device selection. These impressive and helpful tools are currently available at added cost (FEOPS) or are linked to a particular company/device (TruPlan) [5,6,7,8].

The authors are commended on providing a tool that would be easily available to implanters who have access and utilize CT scanning routinely. In this study, intracardiac echo was the primary guide for implantation (89.7%), which may reduce the generalizability of these results since there could be a difference in the device chosen that was a result of the procedural imaging modality, and this discrepancy could have been less or more if compared to a TEE-guided implant strategy. Despite these limitations, the results of this study add another useful tool to pre-procedure planning that is easily implemented at low incremental cost. As the number of LAAO cases continues to increase, increased efficiency is a worthy and necessary goal without increasing procedural risk. With this intriguing study, a prospective study validating this strategy seems warranted.