Left Atrial Appendage Anatomy Research Articles

A comparison of conventional and advanced 3D imaging techniques for percutaneous left atrial appendage closure.

Understanding complex cardiac anatomy is essential for percutaneous left atrial appendage (LAA) closure. Conventional multi-slice computed tomography (MSCT) and transesophageal echocardiography (TEE) are now supported by advanced 3D printing and virtual reality (VR) techniques for three-dimensional visualization of volumetric data sets. This study aimed to investigate their added value for LAA closure procedures. Ten patients scheduled for interventional LAA closure were evaluated with MSCT and TEE. Patient-specific 3D printings and VR models were fabricated based on MSCT data. Ten cardiologists then comparatively assessed LAA anatomy and its procedure relevant surrounding structures with all four imaging modalities and rated their procedural utility on a 5-point Likert scale questionnaire (from 1 = strongly agree to 5 = strongly disagree). Device sizing was rated highest in MSCT (MSCT: 1.9 ± 0.8; TEE: 2.6 ± 0.9; 3D printing: 2.5 ± 1.0; VR: 2.5 ± 1.1; p < 0.01); TEE, VR, and 3D printing were superior in the visualization of the Fossa ovalis compared to MSCT (MSCT: 3.3 ± 1.4; TEE: 2.2 ± 1.3; 3D printing: 2.2 ± 1.4; VR: 1.9 ± 1.3; all p < 0.01). The major strength of VR and 3D printing techniques was a superior depth perception (VR: 1.6 ± 0.5; 3D printing: 1.8 ± 0.4; TEE: 2.9 ± 0.7; MSCT: 2.6 ± 0.8; p < 0.01). The visualization of extracardiac structures was rated less accurate in TEE than MSCT (TEE: 2.6 ± 0.9; MSCT: 1.9 ± 0.8, p < 0.01). However, 3D printing and VR insufficiently visualized extracardiac structures in the present study. A true 3D visualization in VR or 3D printing provides an additional value in the evaluation of the LAA for the planning of percutaneous closure. In particular, the superior perception of depth was seen as a strength of a 3D visualization. This may contribute to a better overall understanding of the anatomy. Clinical studies are needed to evaluate whether a more comprehensive understanding through advanced multimodal imaging of patient-specific anatomy using VR may translate into improved procedural outcomes.

Left Atrial Appendage Closure: What Do We Know?

Atrial fibrillation (AF) is the most common arrhythmia in the United States and the most common cause of embolic cerebrovascular events, with the majority of these thrombi originating in the left atrial appendage. The left atrial appendage (LAA) has separate developmental, ultrastructural, and physiological characteristics from the left atrium. Although LAA anatomy is highly variable, it can be categorized into 4 types: cactus, cauliflower, chicken wing, and windsock. The cauliflower type is associated with higher stroke risk in patients with nonvalvular AF. Although the cornerstone of therapy to prevent embolic strokes from AF has been anticoagulation with thrombin inhibitors, a large group of patients are unable to tolerate anticoagulation due to bleeding. This has led to the development and advancement of multiple surgical and percutaneous LAA closure devices to prevent embolic cerebrovascular accidents without the need for anticoagulation. In this article, we discuss the outcomes of major studies that utilized surgical LAA occlusion and its effectiveness. Furthermore, we summarize nonsurgical methods of LAA closure and future directions regarding LAA closure.

Left atrial appendage volume is an independent predictor of atrial arrhythmia recurrence following cryoballoon pulmonary vein isolation in persistent atrial fibrillation.

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation in persistent AF (persAF), and cryoballoon PVI emerged as an initial ablation strategy. Symptomatic atrial arrhythmia recurrence following successful PVI in persAF is observed more frequently than in paroxysmal AF. Predictors for arrhythmia recurrence following cryoballoon PVI for persAF are not well described, and the role of left atrial appendage (LAA) anatomy is uncertain. Patients with symptomatic persAF and pre-procedural cardiac computed tomography angiography (CCTA) images undergoing initial second-generation cryoballoon (CBG2) were enrolled. Left atrial (LA), pulmonary vein (PV) and LAA anatomical data were assessed. Clinical outcome and predictors for atrial arrhythmia recurrence were evaluated by univariate and multivariate regression analysis. From May 2012 to September 2016, 488 consecutive persAF patients underwent CBG2-PVI. CCTA with sufficient quality for measurements was available in 196 (60.4%) patients. Mean age was 65.7 ± 9.5 years. Freedom from arrhythmia was 58.2% after a median follow-up of 19 (13; 29) months. No major complications occurred. Independent predictors for arrhythmia recurrence were LAA volume (HR 1.082; 95% CI, 1.032 to 1.134; p = 0.001) and mitral regurgitation ≥ grade 2 (HR, 2.49; 95% CI 1.207 to 5.126; p = 0.013). LA volumes ≥110.35 ml [sensitivity: 0.81, specificity: 0.40, area under the curve (AUC) = 0.62] and LAA volumes ≥9.75 ml (sensitivity: 0.56, specificity 0.70, AUC = 0.64) were associated with recurrence. LAA-morphology, classified as chicken-wing (21.9%), windsock (52.6%), cactus (10.2%) and cauliflower (15.3%), did not predict outcome (log-rank, p = 0.832). LAA volume and mitral regurgitation were independent predictors for arrhythmia recurrence following cryoballoon ablation in persAF. LA volume was less predictive and correlated with LAA volume. LAA morphology did not predict the clinical outcome. To improve outcomes in persAF ablation, further studies should focus on treatment strategies for persAF patients with large LAA and mitral regurgitation.

Centerline depth world for left atrial appendage orifice localization using reinforcement learning.

Left atrial appendage (LAA) occlusion (LAAO) is a minimally invasive implant-based method to prevent cardiovascular stroke in patients with non-valvular atrial fibrillation. Assessing the LAA orifice in preoperative CT angiography plays a crucial role in choosing an appropriate LAAO implant size and a proper C-arm angulation. However, accurate orifice localization is hard because of the high anatomic variation of LAA, and unclear position and orientation of the orifice in available CT views. With the major research focus being on LAA segmentation, the only existing computational method for orifice localization utilized a rule-based decision. Nonetheless, using such a fixed rule may yield high localization error due to the varied anatomy of LAA. While deep learning-based models usually show improvements under such variation, learning an effective localization model is difficult because of the tiny orifice structure compared to the vast search space of CT volume. In this paper, we propose a centerline depth-based reinforcement learning (RL) world for effective orifice localization in a small search space. In our scheme, an RL agent observes the centerline-to-surface distance and navigates through the LAA centerline to localize the orifice. Thus, the search space is significantly reduced facilitating improved localization. The proposed formulation could result in high localization accuracy compared to the expert annotations. Moreover, the localization process takes about 7.3s which is 18 times more efficient than the existing method. Therefore, this can be a useful aid to physicians during the preprocedural planning of LAAO.

Left atrial dimensions and left atrial appendage morphology: differences in paroxysmal versus persistent atrial fibrillation patients

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is an effective treatment strategy in symptomatic atrial fibrillation (AF) patients. However, this approach shows worse long-term results in individuals suffering from persistent compared to the paroxysmal type. Purpose The objective was to investigate differences of left atrial (LA) as well as left atrial appendage (LAA) anatomy in persistent AF (persAF) and paroxysmal (PAF) and patients. Methods An observational single center study with a blinded retrospective analysis of cardiac computed tomography angiography (CCTA) images was conducted. Dimensions of LA, posterior wall box, pulmonary veins (PV) as well as LAA size and morphology were assessed and statistically analyzed. All important measures are depicted in the attached figure. Results From 2012 to 2016 a total of 1.103 patients underwent second generation cryoballoon PVI. Prior to PVI, CCTA was available for 725 (65.7%) patients with sufficient quality for measuring in 473 (65.2%). Mean age was 66.3±9.5 years; PAF was present in 277 (58.6%) participants. In persAF LA volume [mL] (111.8; 128.8; p&amp;lt;0.001), posterior wall box area [cm2] (11.9; 13.3; p&amp;lt;0.001) and pulmonary vein ostial dimensions were significantly larger compared to PAF. LAA volume [mL] (9.0; 10.0; p=0.01) and LAA ostial perimeters (66.5; 70.0; p=0.003) were also identified to be larger in persAF. However, there was no difference in LAA morphology (overall distribution: "windsock" 51%; "chicken-wing" 20%; "cauliflower" 15% and "cactus" 13%). Conclusion Compared to PAF, persAF patients had significantly larger LA volumes, posterior wall box areas, PV ostial dimensions as well as LAA volumes and LAA ostial perimeters. LAA morphological types were distributed equally in both groups.

Real-time 3D echocardiographic transilluminated imaging combined with artificially intelligent left atrial appendage measurement for atrial fibrillation interventional procedures.

Aims: This study investigated the feasibility and accuracy of real-time three-dimensional (3D) echocardiographic transilluminated imaging (TrueVue Glass) in left atrial appendage (LAA) anatomical morphology and artificial intelligence (AI)-assisted 3D automated LAA measurement (3D Auto LAA) software in the preoperative evaluation of LAA occlusion (LAAO) in patients with atrial fibrillation (AF). Method and results: Thirty-seven patients with AF were selected. Two-dimensional (2D) and real-time 3D transesophageal echocardiography (RT3D-TEE) were performed preoperatively, using conventional 3D, the new 3D TrueVue Glass mode, and cardiac computed tomography angiography (CCTA) to assess and type the morphology of LAA. Physiological parameters were measured using traditional 2D and 3D manual (3D Manual LAA), 3D Auto LAA, and CCTA. TrueVue Glass for LAA outer contour display was compared with CCTA. Comparisons were based on correlation and consistency in measuring the maximum diameter (LZ max), minimum diameter (LZ min), area (LZ area), and circumference (LZ cir) of LAA landing zone (LZ). Times and variabilities were compared. The concordance rate for external shape of LAA was 97.14% between TrueVue Glass and CCTA. 3D Auto LAA and 3D Manual LAA have a stronger correlation and higher consistency in all parameters. 3D Auto LAA showed higher intra- and interobserver reproducibility and allowed quicker analysis (p < 0.05). LAAO was performed in 35 patients (94.59%), and none of which had serious adverse events. Conclusion: TrueVue Glass is the first non-invasive and radiation-free visualization of the overall external contour of LAA and its adjacent structures. 3D Auto LAA simplifies the measurement, making the preoperative assessment more efficient and convenient while ensuring the accuracy and reproducibility. A combination of the two is feasible for accurate and rapid assessment of LAA anatomy and physiology in AF patients and has practical application in LAAO.

First-in-Human Experience of Using a Universal Steerable Sheath in Implanting Left Atrial Appendage Closure Devices.

Left atrial appendage (LAA) closure (LAAC) device implantation may be challenging in cases with difficult LAA anatomy. A deflectable sheath to approach multiple LAA positions may be helpful. We used a deflectable sheath to implant LAAC devices in 20 patients and included 60 cases using the standard sheaths for comparison. The procedures were successful in all patients without peri-procedural complications. After a median follow-up of 1.52 (IQR: 0.76-2.33) years, none of the patients in the deflectable sheath group had peri-device leak≥3mm and experienced thromboembolic stroke. In the standard sheath group, after follow-up of 2.03 (IQR: 0.87-3.19) years, 2 had peri-device leak≥3mm and 1 experienced thromboembolic stroke. We first proved the idea of using a universal steerable sheath for LAAC device implantation in difficult LAA anatomy, which also allows rapid switching of different LAAC devices.

Atrial fibrillation ablation: the position of computed tomography in pre-procedural imaging

Abstract Atrial fibrillation (AF) is the most common supraventricular arrhythmia. Despite significant advances in its treatment, it still remains one of the leading causes of cardiovascular morbidity and mortality. In the last two decades, pulmonary vein isolation (PVI) was developed as the most effective treatment option. The reported effectiveness of a single ablation procedure ranges from 40% to 69% with single, and up to 88% with repeated procedures, with acceptable safety profile. The PubMed database was searched, using terms including ‘atrial fibrillation ablation’, ‘pulmonary vein isolation’, ‘computed tomography’, ‘pulmonary vein anatomy’ and ‘ovality index’. Papers were reviewed for relevance and scientific merit. Different imaging techniques are used for pre-procedural assessment of left atrial (LA) anatomy, of which computed tomography (CT) is the most common. It allows assessing pulmonary vein (PV) anatomy, the LA wall thickness in different regions and the left atrial appendage (LAA) anatomy, together with excluding the presence of intracardiac thrombi. Pre-procedural PVs imaging is important regardless of the selected ablation technique, however, cryoballoon (CB) ablation seems to be particularly anatomy-dependent. Additionally, CT also permits assessment of several PVs characteristics (geometry, dimensions, angulations, the ostium area, orientation and ovality index (OI), which are essential for the patients’ qualification and designing the strategy of AF ablation. In this paper, we have reviewed the role of CT imaging in patients undergoing ablation procedure due to recurrent/symptomatic atrial fibrillation. Moreover, we discussed the relevant literature.

474 Watchman Flx Device Sizing Based On CT Left Atrial Appendage Area And Perimeter

Introduction: Left atrial appendage (LAA) closure devices offer alternatives to systemic anticoagulation in patients with atrial fibrillation. Device selection is determined by LAA ostial size, morphology and depth. Traditionally, transesophageal echo (TEE) has been utilized for assessing LAA anatomy. This study aims to evaluate if using cardiac computed tomography (CT) area and perimeter better predicts final device selection.

Apêndice Atrial Esquerdo: Anatomia, Função e Importância na Formação de Trombos

The left atrial appendage (LAA) is an extension of the left atrium (LA) and has complex anatomical structure and unique pathophysiological properties. The LAA functions as a decompression chamber during left ventricular (LV) systole and under increased left atrial pressure conditions. Despite previously being considered a relatively insignificant portion of the cardiac anatomy, the LAA has been highlighted as an important structure involved in the genesis of thrombus formation and thromboembolic events. With the recent development of percutaneous closure devices, LAA morphology assessments have become increasingly important. This article aims to describe LAA anatomy and morphology, function assessment parameters, thrombus diagnostic challenges, and the main imaging modalities, particularly transesophageal echocardiography.

Real-world experience with the new Watchman FLX device: Data from two high-volume Sicilian centers. The FLX-iEST registry.

The Watchman-FLX left atrial appendage closure (LAAC) device presents innovative features: higher conformability, reduced length, closed distal "flex-ball" during deployment, and flattened surface. We report our real-world experience with the Watchman-FLX device in two centers with consolidated LAAC expertise. We enrolled 200 consecutive Watchman-FLX patients (2019-2021) in a nonrandomized double-center registry; procedural data and follow-up for midterm clinical outcomes were collected. A control group of 100 patients treated with first-generation Watchman (2.5) was included. According to mean CHAD2 DS2 -VASc (5 ± 1.40) and HAS-BLED (3.8 ± 1.01) scores, the population included in this study was at high risk: 29% had a previous stroke and 56.5% a bleeding event. Main LAAC indications were symptomatic hemorrhage (39.5%), need for triple antithrombotic therapy (39%), gastrointestinal bleeding (32%), and oral anticoagulation intolerance (18%). Transesophageal echocardiography guidance was followed in 93% of cases (48% in general anesthesia and 45% under conscious sedation). Repositioning an FLX device was required in 20% of cases and no complication occurred. In 96% of patients, the first selected device was delivered, while in 4% a device size change was required after the first choice (7% with Watchman 2.5). Peridevice leaks (<5 mm) were found postimplant in two cases (1%). Overall, the procedural success rate was 99.5%. One patient's procedure was unsuccessful (0.5%), due to left atrial appendage(LAA) anatomy; differently, the mean failure rate with Watchman 2.5 was 2%. No device embolization was reported. Complications (8.5%) were mainly related to the access site (3%); major bleedings (1%), and in-hospital death (0.5%) rarely occurred. After a follow-up of 272 ± 173 days, 2.3% of cases experienced a non-device-relatedstroke and 0.6% fatal bleeding. Our registry showed a high procedural success rate of the Watchman-FLX in a high-risk population. According to our experience, the main advantages include easy implanting and repositioning, absence of embolization, good LAA sealing, and low rate of complications in the follow-up period.

Left atrial appendage orifice dimensions in Japanese atrial fibrillation population measured by multiplane transesophageal echocardiography.

Successful implantation of the WATCHMAN device requires an accurate understanding of left atrial appendage (LAA) anatomy and orifice dimensions. Racial differences are observed in LAA size when comparing Asians with non-Asians. A total of 170 patients (123 male, 67.4 ± 9.2years) with paroxysmal or persistent atrial fibrillation (AF) underwent transesophageal echocardiography before catheter ablation or cardioversion (September 2018 to September 2019). As per the recommendations of the WATCHMAN device, the maximal LAA ostial diameters were measured at multiplane angles of 0°, 45°, 90°, and 135°. The majority of patients (121/170, 71%) had an LAA orifice size within 17-25mm. Fifteen (8.8%) patients had undersized (< 17mm) and eight (0.5%) had oversized (> 31mm) LAA. One patient in this population had no LAA. LAA size was significantly larger in patients with persistent AF than in those with paroxysmal AF (23.3 ± 4.2mm vs. 20.0 ± 3.0mm, p < 0.001) and in male patients than in female patients (22.4 ± 4.2 vs. 20.9 ± 3.7mm, p = 0.03). LAA orifice dimension was significantly correlated with CHADS2 score, the left atrial volume (LAV), E/e', and the left ventricular ejection fraction. Persistent AF, body mass index, and LAV were independently associated with LAA orifice dimension in multivariate analysis. This study demonstrated the distribution of LAA orifice dimension in the Japanese AF patients. This finding should be used as a reference to understand the racial characteristics of LAA size for the WATCHMAN procedure.

Gross anatomic relationship between the human left atrial appendage and the left ventricular summit region: implications for catheter ablation of ventricular arrhythmias originating from the left ventricular summit.

The left ventricular summit (LVS) is a source of difficult-to-treat arrhythmias because of anatomical limitations. The aim of this study was to perform detailed research of the left atrial appendage (LAA) anatomy of cadaveric hearts to analyze their complex anatomy and coverage of the LVS. Eighty human formalin fixed hearts (mean age 44.4 ± 15.5, 27.5% females) were investigated. Each LAA size, type, and its relationship to the LVS were analyzed, as well as possible access sites for mapping/ablating electrode. Four types of LAA were observed over two LVS sites that are either accessible or not. The highest coverage over an inaccessible LVS area was observed in the Broccoli type, followed by the Windsock then the Chicken Wing and finally the Cactus types; over the accessible area of the LVS was observed in the Windsock, then in the Chicken Wing, then in the Cactus, and finally in the Broccoli types. The attainable coverage for electrode access is diminished from 25 to 65% because of the complex pectinate muscles and sharp angles. The highest density of the LAA floor made by pectinate muscles can be found in the Broccoli type (p < 0.005), while the Chicken Wing had the highest number of paper-thin-like pouches. The LAA appears to be a promising entry for ablation-qualified patients with the LV summit originate arrhythmias. The complex internal structure of the LAA may complicate ablation procedures. More prominent appendages are promising in more extensive mapping areas over the LVS.

Morphometric topography of the left atrial appendage in human adult heart

Topography of the left atrial appendage is of importance for supraventricular arrhythmias surgery and sealing of the appendage orifice to prevent thromboembolism in cryptogenic strokes. The aim was to explore the common position of the appendage and delineate variants of its adjacent anatomy in human adults by means cadaveric morphometrics. Material and methods . We studied 54 silicone-filled heart specimens of 200–400 g. With the caliper, we measured the distances from the base of the left atrial appendage to the cardiac apex, to the structures of the atrial complex, nearest large blood vessels, as well as to the left coronary artery. Results. The base of the appendage was 87 ± 13.1 mm from the cardiac apex and 49.7 ± 7.0 mm from the right appendage. The distance from the appendage to the superior caval vein (36.4 ± 8.1 mm) was 16 % longer than the distance to the ascending aorta (30.4 ± 6.4 mm), 1.25 times less than the distance to the oval fossa (45.2 ± 6.0 mm), 1.5 times less than the distance to the inferior caval vein (55.5 ± 8.7). The smallest median value (9.6 mm) and the largest variation (1.4–15.2 mm) were found for the distance to the pulmonary trunk. Four pulmonary veins inflowed to the atrium at different distances from the appendage opening. In 59.6 %, we revealed the left upper pulmonary vein to be closest to the auricle. The mouth of that was 43 % higher and 57 % at the same level with the appendage opening ( p = 0.07). The left coronary artery ran 2.63–18.74 mm inferiorly to the appendage. Interrelations of average strength were found for the parameters of atrial complex. The study showed the length of the ventricular complex as being an unpredictable parameter for determining the adjacent anatomy of left atrial appendage. Conclusions. The morphometric parameters and their interrelations are proposed to use as reference values and criteria for determining the normal atrial complex.

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.&#x0D; 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.&#x0D; 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.&#x0D; 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.

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.

To study the anatomy and function of left atrial appendage and its correlation with the incidence of left atrial and appendage thrombus formation in patients with rheumatic mitral stenosis

To study the anatomy and function of left atrial appendage and its correlation with the incidence of left atrial and appendage thrombus formation in patients with rheumatic mitral stenosis

Feasibility of preprocedural LAA occluder sizing

Abstract Background Implantation of occluders in the left atrial appendage (LAA) has been established to prevent patients with atrial fibrillation (AF) from stroke and embolisation. Currently, the individual occluder sizing will be done intraprocedurally using fluoroscopy and/or transesophageal echo (TEE) imaging. Purpose Development of a new approach allowing preprocedural occluder sizing and its validation by conventional intraprocedural methods. Methods The CARTO electro-anatomical mapping system was used in 62 consecutive patients (40 m, 22 f, age: 69.8±8.4 years) to preprocedurally predict the size of Watchman (n=34) or Amplatzer Amulet (n=28) devices. During device implantation, 23 of the patients (37.1%) were in AF. LAA morphologies were Chicken Wing (40.0%), Cauliflower (31.7%), Windsock (20.0%) and Cactus (8.3%). CHA2DS2-VASc Score was 3.7±1.9 and HAS-BLED-Score was 3.6±1.3. Preprocedurally, routine cardiac CT scans were imported into the CARTO segmentation tool for segmentation of the left atrium. The resulting volume images (VI) and slice images (SI) were adjusted in their 3-dimensional orientation to fit the manufacturer's sizing recommendations. Subsequently, the match between pre- and intraprocedural sizing was compared with the actually implanted device size. Results In the Watchman group, preprocedural VI corresponded with 38.1% (8/21) and SI with 42.3% (11/26), while intraprocedural fluoroscopy corresponded with 29.6% (8/27) and TEE with 40.0% (12/30) of all actually implanted devices. According to clinical routine an aberration of one size is common practice. After including one additional size to the estimation, VI corresponded with 81.0% (17/21), SI with 84.6% (22/26), while fluoroscopy corresponded with 85.2% (23/27) and TEE with 80.0% (24/30) of all actually implanted occluders. In the Amplatzer Amulet group, VI corresponded with 37.0% (10/27), SI with 57.1% (16/28) and fluoroscopy with 71.4% (20/28) of all actually implanted devices. After including one additional size to the estimation, VI corresponded with 66.7% (18/27), SI with 85.7% (24/28) and fluoroscopy with 100% (28/28) of all actually implanted occluders. The remaining were selected empirically. Conclusion In this study cohort of 62 patients, feasibility of a preprocedural sizing using the CARTO segmentation tool was demonstrated for Watchman occluders providing results comparable with conventional intraprocedural fluoroscopy and/or TEE based intraprocedural sizing. Possibly due to the different manufacturer measuring recommendation, 10 to 12 mm away from the LAA ostium, results for the Amplatzer Amulet system were found to be less accurate. Nevertheless, the proposed approach offers the advantage of preoperative visualisation of the individual LAA anatomy and morphology. Funding Acknowledgement Type of funding sources: None.

Left atrial appendage closure in patients with prohibitive anatomy: Insights from PINNACLE FLX

Watchman 2.5 (Boston Scientific Inc, Marlborough, MA) implant success approaches 95% in registries, yet many patients are not attempted because of complex left atrial appendage (LAA) anatomy. Watchman FLX can expand the range of ostium width (14-31.5 mm) and depth available for LAA closure. The purpose of this study was to evaluate the safety and efficacy of Watchman FLX in patients with a failed Watchman 2.5 attempt or prohibitive LAA anatomy. The roll-in (n = 58) and primary effectiveness (n = 400) cohorts of the PINNACLE FLX trial comprised the study population. Subjects were identified who previously failed implantation of Watchman 2.5 (n = 11) or were not attempted because of prohibitive LAA anatomy (n = 88). Demographic characteristics, implant procedure details, and TEE follow-up data were compared to controls composed of enrollees not meeting these criteria (n = 359). Watchman FLX LAA closure was successfully implanted in all subjects with a prior failed Watchman 2.5 attempt (n = 11 of 11). Subjects with previously failed Watchman 2.5 were more likely to receive a 35 mm FLX device than controls (27.3% vs 7.3%; P = .047). Patients with prohibitive anatomy had smaller LAA dimensions than did controls (diameter 18.0 ± 4 mm vs 20.4 ± 3 mm; P < .001 and length 23.7 ± 5 mm vs 28.9 ± 5 mm; P < .001). There was no difference in age, sex, CHA2DS2-VASc score, HAS-BLED score, or primary efficacy between cohorts. Transesophageal echocardiography (TEE) at 12 months showed zero leak in 90.9% in the failed Watchman 2.5 cohort, 91.3% in the prohibitive anatomy cohort, and 89.5% in the control cohort (P = .84). Overall and cardiovascular mortality was lower in the prohibitive anatomy cohort (1.2% vs 8.8% in controls; P = .02). Watchman FLX implantation in patients with a prior failed Watchman 2.5 attempt or prohibitive LAA anatomy remained safe and highly effective. The association of reduced overall mortality with smaller LAA dimension warrants future study.

3D transesophageal echocardiography assists in evaluating the morphology, function, and presence of thrombi of left atrial appendage in patients with atrial fibrillation

BackgroundLeft atrial appendage (LAA) is significantly more likely to form thrombi in patients with atrial fibrillation (AFib). Two-dimensional transesophageal echocardiography (2D TEE) is considered the gold standard for assessing and studying LAA morphology and anatomy. However, 2D TEE can only visualize one plane at any given time. Real-time three-dimensional echocardiography (RT-3D TEE) imaging can preserve spatial and temporal resolution, which is a safe, accurate, and reproducible imaging modality. There are few reports of the usage of RT-3D TEE to study LAA in AFib patients. In our research, RT-3D TEE helps to provide detailed LAA information and identifying the presence or absence of thrombi from pectinate muscles in paroxysmal and long-standing AFib patients.MethodsLAA morphology was analyzed in detail by 2D TEE and RT-3D TEE in 320 patients with paroxysmal or long-standing AFib. The LAA flow pattern, as maximal LAA emptying flow velocity (LAAeV), was retrieved from 2D and 3D TEE imaging. LAA morphological parameters, spontaneous echo contrast (SEC), and thrombi were also detected by 2D and 3D TEE in all patients. In addition, LAA lobes and types were classified according to the morphology by 3D TEE, and the relationship between LAA types and the incidence of thrombi was evaluated.ResultsLong-standing AFib had greater enlargement of LAAs (orifice diameters and area), significantly more severe SEC, and a higher thrombi clot incidence rate by 3D-TEE compared with paroxysmal AFib patients (P<0.05). In addition, cauliflower morphology in long-standing AFib patients was associated with a higher LAA thrombus (OR 2.1, 95% CI: 1.1–8.5, P=0.031) and increased prevalence of SEC. Moreover, the uncertainty of thrombi detection was significantly decreased by 3D TEE compared with 2D TEE (P<0.001), and the certainty of thrombi detection by 3D TEE also decreased slightly (P=0.06).ConclusionsRT-3D TEE is a safe and real-time option for the evaluation of LAA morphology and function. Long-standing AFib has greater LAA and SEC, as well as a higher incidence of thrombi than the paroxysmal group. Cauliflower LAA type was associated with a higher prevalence of SEC and thrombi.