A Comparison of the Accuracy of WATCHMAN and WATCHMAN FLX Device Sizing between CT, TEE, and Patient Specific 3D Models

Background and Hypothesis: In patients with Atrial fibrillation (AF), the Left Atrial Appendage (LAA) is the most common site of thrombus formation. The LAA occlusion procedure using the WATCHMAN device implant is an alternative for stroke prevention in AF patients. Transesophageal echocardiogram (TEE) and Computed tomography (CT) scans aid in measuring the LAA to predict implant device sizes. However, due to varying LAA anatomy and limited spatial resolution, the current imaging techniques often predict one of two sized devices. The objective of this retrospective study is to compare the accuracy of measurements made preoperatively of the LAA with those on 3D models to determine if they can be used in preoperative planning. We hypothesize 3D models will be more accurate in predicting device size and any anatomical impediments than traditional TEE planning. Project Methods: There were 21 subjects selected who underwent the WATCHMAN FLX procedure at Parkview Heart Institute in 2021. 3D models of LAA were created from CT scans using a Form 2 3D printer. The device sizes predicted for the procedure were determined from Boston Scientific FLX guidelines based on the maximum LAA orifice diameter from TEE, CT, and 3D models. Results: Two-proportion z-test between the 3D model predicted sizes to the actual size deployed demonstrated no statistical significance (p=0.298) demonstrating no difference between 3D model predicted sizes and actual size deployed. Two-proportion z-test between TEE vs actual size and CT vs actual size demonstrated statistical significance, suggesting a difference between the group's predictions. 3D models predicted the accurate device size for 20/21(95%) subjects. TEE measurements of maximum orifice diameter were, on average, lower compared to CT and 3D model measurements. Conclusion and Potential Impact: 3D printed models provide the most accurate device size predictions and can be used to optimize presurgical planning while reducing intraoperative complications.

475 Is left atrial appendage device compression rate a predictor of incomplete occlusion in patients undergoing watchman device implantation?

Aims Transesophageal echocardiography (TEE) is a standard peri-procedural imaging modality in patients undergoing percutaneous left atrial appendage (LAA) occlusion. An accurate device sizing is pivotal to assess stability and achieve successful closure. In this prospective study, we sought to evaluate the correlation between Watchman device compression rates (DCRs) and risk of incomplete LAA occlusion at follow-up in patients undergoing Watchman device implantation. Methods and results Two-dimensional TEE via a commercially available transducer (Vivid, Philips) was performed during the procedure and within 3 months after the procedure. LAA size, morphology, and DCRs [(original device size—size after deployment)/original device size; %] were assessed in a mid-oesophageal view at 0°, 45°, 90° and 135°, according to company recommendations. Residual leaks ≥ 3 mm were classified as significant. Between 2016 and 2018, 116 patients underwent LAA occlusion with a Watchman device at our institution. The mean age was 74 ± 9 years and 60.4% (n = 70) were males. The average CHA2DS2-VASc and HAS-BLED scores were 4.7 ± 1.7 and 2.5 ± 1.1, respectively. The final device size was 21 mm in 11 (9.5%) patients, 24 mm in 28 (24.1), 27 mm in 27 (23.3%), 30 mm in 26 (22.4%), and 33 mm in 24 (20.7). At follow-up TEE, 16 (13.8%) patients were found to have a significant (≥3 mm) residual leak. The average DCRs measured at different angles in patients with and without leak were not significantly different (24 ± 8% vs. 26 ± 7% at 0°, P = 0.47; 23 ± 9% vs. 25 ± 7% at 45°, P = 0.58; 23 ± 8% vs. 23 ± 6% at 90°, P = 0.61; 22 ± 8% vs. 21 ± 7% at 135°, P = 0.61). At receiver operating characteristic (ROC) analysis, the areas under the curve to discriminate between patients with/without leak were 0.58, 0.57, 0.55, and 0.46 for DCRs measured at 0°, 45°, 90°, and 135° angles. Conclusions Peri-procedural assessment of DCRs does not appear to be an accurate method to predict LAA complete occlusion in patients undergoing Watchman device implantation.

Pre-procedural determination of device size in left atrial appendage occlusion using three-dimensional cardiac computed tomography

The complex structure of the left atrial appendage (LAA) brings limitations to the two-dimensional-based LAA occlusion (LAAO) size prediction system using transesophageal echocardiography. The LAA anatomy can be evaluated more precisely using three-dimensional images from cardiac computed tomography (CT); however, there is lack of data regarding which parameter to choose from CT-based images during pre-procedural planning of LAAO. We aimed to assess the accuracy of measurements derived from cardiac CT images for selecting LAAO devices. We retrospectively reviewed 62 patients with Amplatzer Cardiac Plug and Amulet LAAO devices who underwent implantation from 2017 to 2020. The minimal, maximal, average, area-derived, and perimeter-derived diameters of the LAA landing zone were measured using CT-based images. Predicted device sizes using sizing charts were compared with actual successfully implanted device sizes. The mean size of implanted devices was 27.1 ± 3.7 mm. The perimeter-derived diameter predicted device size most accurately (mean error = − 0.8 ± 2.4 mm). All other parameters showed significantly larger error (mean error; minimal diameter = − 4.9 ± 3.3 mm, maximal diameter = 1.0 ± 2.9 mm, average diameter = − 1.6 ± 2.6 mm, area-derived diameter = − 2.0 ± 2.6 mm) than the perimeter-derived diameter (all p for difference < 0.05). The error for other parameters were larger in cases with more eccentrically-shaped landing zones, while the perimeter-derived diameter had minor error regardless of eccentricity. When oversizing was used, all parameters showed significant disagreement. The perimeter-derived diameter on cardiac CT images provided the most accurate estimation of LAAO device size regardless of landing zone eccentricity. Oversizing was unnecessary when using cardiac CT to predict an accurate LAAO size.

Left Atrial Appendage Morphology With The Progression of Atrial Fibrillation

Left atrial appendage (LAA) size is crucial for determining the indication of transcatheter LAA closure. The aim of this study was to evaluate the differences in LAA morphology according to the types of atrial fibrillation (AF). A total of 340 patients (mean age: 65 ± 15 years) who underwent transesophageal echocardiography (TEE) were included. Patients were classified into non-AF (n = 105), paroxysmal AF (n = 86), persistent AF (n = 87), or long-standing persistent AF (n = 62). LAA morphology, including LAA ostial diameter and depth, was assessed using TEE. Patients with long-standing persistent AF had larger LAA ostial diameter and depth, greater LAA lobes, and lower LAA flow velocity. The maximum LAA ostial diameter was 19 ± 4 mm in patients with non-AF, 21 ± 4 mm in patients with paroxysmal AF, 23 ± 5 mm in patients with persistent AF, and 26 ± 5 mm in patients with long-standing persistent AF. LAA ostial diameter was increased by 2 or 3 mm with the progression of AF. LAA ostial diameter was correlated with LA volume index (r = 0.37, p < 0.01) and the duration of continuous AF (r = 0.30, p < 0.01), but not with age or the period from the onset of AF. In conclusion, LAA size, which is the determinant for selecting device size of transcatheter LAA closure, was increased with the progression of AF. Our findings have potential implications for therapeutic strategy of transcatheter LAA closure.

SP5.1.8 Long term outcomes of laparoscopic magnetic sphincter augmentation for gastro-oesophageal reflux disease: High patient satisfaction with low dysphagia rates

Aims Laparoscopic magnetic sphincter augmentation (MSA) or LINX® procedure is gaining popularity as a treatment for gastro-oesophageal reflux disease. We looked at the long-term outcomes of this procedure with regards to its efficacy, in particular studying the dysphagia rate in relation to the LINX® device size. Methods Postal questionnaires were sent to all patients who underwent MSA procedure between 2012-2019 at a single institution. Patients were asked to quantify, as a percentage, their symptom resolution, proton pump inhibitor (PPI) intake and side effects. Results 124 patients (male:female ratio was 45:55) underwent MSA procedure, with 82 responding to the questionnaire. Patients' age range was 18-71 years (median 49). Over 90% of patients reported improvements in reflux symptoms with 75% reporting complete resolution. 67% of patients no longer required PPI medication, whilst 21% of patients had &gt;50% reduction in their medication. Post-operative dysphagia occurred in 59% of patients at 3 months, which decreased to 16% at 1 year. There was no significant difference in size of LINX® device used between patients with dysphagia at ≥ 1 year versus those without dysphagia at ≥ 1 year (p = 0.554). In total 3 patients (2%) required explantation of the LINX® device. Overall 86% of patients rated their outcomes as satisfactory or very satisfactory. Conclusions Our 7 years of experience with laparoscopic MSA has demonstrated that this procedure is safe with high patient satisfaction rates. Dysphagia, although common in the early post-operative period, usually resolves within 3-6 months and is unrelated to LINX® device size.

Left atrial appendage perimeter ostium evaluation by cardiac CT utilizing 3mensio technology for watchman implantation

Background Left atrial appendage occlusion (LAAO) with Watchman device traditionally relies on accurate left atrial appendage ostium diameter measurement by 2D or 3D transesophageal echocardiogram (TEE). Alternate methods of ostium measurement including area-derived diameter and perimeter-derived diameter using cardiac computed tomography (CT) have been proposed. Methods We performed a retrospective analysis of 92 patients with atrial fibrillation (Afib) who underwent LAAO with WATCHMAN implantation with pre-procedural TEE and CT between May 2015 and December 2018. LAA characteristics including ostial or landing zone perimeter, minimum and maximum diameters were acquired utilizing 3mensio Structural Heart Imaging Program. Proposed device size was estimated utilizing ostium perimeter by CT and compared to the current standard utilizing ostium diameter by 2D-TEE. Both measurements were then compared to actual final device size that satisfying release criteria. Results CT had a very high correlation with the actual implanted device size (Pearson coefficient r=0.94, p&lt;0.001), while TEE based sizing had a lower correlation (Pearson coefficient r=0.66, p&lt;0.001). CT predicted size had a significantly higher agreement compared to standard TEE based sizing (93.4% vs 47.8%), and higher interrater agreement (Cohen's kappa = 0.91 vs Cohen's kappa = 0.32, p&lt;0.001, p&lt;0.001 respectively). Bland-Altman analysis also showed better correlation with CT-based sizing. Procedural complications were 0, and 0 patients had a leak recorded at 45-days post implant. Conclusion CCT LAA perimeter sizing is superior to the current standard TEE based Watchman sizing. Larger, multi-center studies may be necessary to further validate results. FUNDunding Acknowledgement Type of funding sources: None. 3mensio after CT upload

Optimized design for illusion device by genetic algorithm

The illusion device developed from the scattering cancellation employs very simple homogeneous and isotropic materials, but this device is only valid for electrically small objects. In this paper, we prove that the illusion device optimized by genetic algorithm can be applied to large-scale occasions. For an electrically small target, an optimized core–shell illusion device can achieve better illusion effect than the analytical design based on the scattering cancellation. With the increase of the device size, the ability of the single-layered shell to manipulate the scattering is very limited. For a moderate-size target, two optimized multi-layered examples are presented: one is to make a dielectric cylinder appear as another dielectric target, and the other is to make a conducting cylinder behave like a double-negative-material target. The full-wave simulations are carried out to visualize the similar field distributions of the target and the optimized multi-layered design. This optimized design greatly widens the size application range of the illusion device and can also improve the illusion performance with simple material parameters.