Evaluation of the left atrial appendage with real-time 3-dimensional transesophageal echocardiography: implications for catheter-based left atrial appendage closure

A new braided model of the Amulet Amplatzer for accurate simulations of left atrial appendage occlusion procedures

Atrial Fibrillation (AF) is a cardiac disease altering the human heart rate. It is posing an increasing burden to society, with complications that lead to stroke and ischemic events from thromboembolisms, originating in the left atrial appendage (LAA). Percutaneous LAA occlusion (LAAO) is becoming an increasingly adopted preventive treatment option due to its minimally invasive nature. However, this treatment faces complex challenges: the heterogeneity of LAA morphologies limits the pre-operative planning and several procedures are associated with peri-device leakage from malposition and device-related thrombi. One of the two most commonly deployed LAAO devices (LAAODs) is the Amulet Amplatzer (AA), a mesh-like pacifier device. In-silico models have demonstrated their potential to serve as supporting tools for clinical planning, providing insight able to enhance the efficacy and safety of the intervention. Most of the computational studies approximate the AA to a closed surface model. In this work, we aimed to develop a more realistic and detailed structural model of the AA, capturing the mesh of wires. Experimental tests on the physical device were conducted to compare the behaviour of simplified closed surface models and the newly developed braided geometry. The results have demonstrated how closed surface models of the AA fail to capture the real deformation mechanism of the physical device. Conversely, the more realistic braided characterisation mimics more closely the changes in shape of the physical AA, by capturing the change in angles of the wires. Finally, the virtual deployment of the intertwined model into a patient-specific LAA resulted in a configuration similar to the clinically implanted AA.

Optimizing Imaging Techniques for Left Atrial Appendage Closure: Insights and Emerging Directions

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in adults and is associated with significant morbidity and mortality, including an increased risk of stroke, heart failure, dementia, and recurrent hospitalizations. As life expectancy rises, both the incidence and prevalence of AF continue to grow. Stroke prevention remains a cornerstone of AF management, with oral anticoagulation being the primary strategy to reduce thromboembolic risk. However, despite their advantages, direct oral anticoagulants do not completely eliminate the risk of bleeding complications. For patients in whom anticoagulation is contraindicated, poorly tolerated, or ineffective at preventing AF-related stroke, interventional alternatives have gained traction. The left atrial appendage (LAA), a primary site of thrombus formation in AF, can be occluded through a catheter-based procedure known as left atrial appendage closure (LAAC) or left atrial appendage occlusion (LAAO). This review aims to provide imaging specialists with a comprehensive understanding of their role in LAAC, underscoring the importance of a multidisciplinary approach to enhance patient selection, procedural success, and long-term efficacy.

Review of the Etiology, Diagnosis, and Therapy of Left Atrial Thrombus

Thrombi in the left atrial appendage (LAA) are an important cause of systemic thromboembolism in patients with atrial fibrillation. The gold standard for the diagnosis of LAA thrombi is a transesophageal echocardiogram, although cardiac multidetector computed tomography, intracardiac echocardiogram, and cardiac magnetic resonance imaging are alternative diagnostic imaging modalities. When an LAA thrombus is diagnosed, effective anticoagulation is recommended for at least 3 weeks or until thrombus resolution is confirmed on repeat transesophageal echocardiogram. Recent prospective research shows the efficacy of nonvitamin K oral anticoagulants in the treatment of LAA thrombus, which offers a promising alternative to vitamin K antagonists. As an alternative approach, left atrial aspiration thrombectomy has been described in case reports, though there is limited evidence comparing its efficacy to anticoagulation alone.

Advancements in 3D Transoesophageal Echocardiography (TOE) and Computed Tomography (CT) for Stroke Prevention in Left Atrial Appendage Occlusion Interventions

Left atrial appendage occlusion (LAAO) has emerged as a highly effective alternative to oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation. Precise pre-procedural planning and meticulous post-procedural follow-up are essential for achieving successful LAAO outcomes. This review explores the latest advancements in three-dimensional (3D) transoesophageal echocardiography (TOE) and computed tomography (CT) imaging modalities, which have considerably improved the planning, intra-procedural guidance, and follow-up processes for LAAO interventions. Innovations in 3D TOE and CT imaging have transformed the approach to LAAO by providing a more detailed and accurate assessment of the left atrial appendage, enabling clinicians to acquire comprehensive anatomical and morphological information, crucial for optimising device selection and positioning, thus reducing the risk of complications and enhancing the overall safety and efficacy of the procedure. Post-procedurally, CT and TOE imaging are invaluable in the monitoring of patients, ensuring that the device is correctly positioned and functioning as intended. Early detection of any complications (e.g., device-related thrombus and peri-device leaks) can help to risk-stratify patient at increased risk of stroke and initiate timely interventions, thereby improving long-term outcomes for patients.

Understanding the role of the left atrial appendage on the flow in the atrium

BACKGROUND

The exclusion/occlusion of the left atrial appendage (LAA) is a treatment option for atrial fibrillation (AF) patients who are at high risk of stroke and high risk of bleeding. As the role of the LAA is not well understood or explored, this study aims to assess its role on flow dynamics in the left atrium.

METHODS

Computational fluid dynamics (CFD) simulations were carried out for nine AF patients before and after LAA exclusion. The flow parameters investigated included the LA velocities, Time Averaged Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), Relative Residence Time (RRT), and Pressure in the LA.

RESULTS

This study shows that, on average, a decrease in TAWSS (1.82 ± 1.85 Pa to 1.27 ± 0.96 Pa, p < 0.05) and a slight increase in OSI (0.16 ± 0.10 to 0.17 ± 0.10, p < 0.05), RRT (1.87 ± 1.84 Pa-1 to 2.11 ± 1.78 Pa-1, p < 0.05), and pressure (-19.2 ± 6.8 mmHg to -15.3 ± 8.3 mmHg, p < 0.05) were observed in the LA after the exclusion of the LAA, with a decrease in low-magnitude velocities.

CONCLUSION

The exclusion of the LAA seems to be associated with changes in LA flow dynamics. Further studies are needed to elucidate the clinical implications of these changes.

Validation study of new left atrial appendage closure device measurement by two-dimensional and three-dimensional transesophageal echocardiography

BACKGROUND

In left atrial appendage closure using WATCHMAN FLX, accurate device measurement by transesophageal echocardiography (TEE) is important. We aimed to experimentally validate appropriate methods of device measurement with two-dimensional (2D) and three-dimensional (3D) TEE compared with actual size.

METHODS

We prepared a full range of device sizes (20, 24, 27, 31, 35 mm), each with five different compression rates. Each device was measured by 2D and 3D TEE at depths of 2, 4, and 6 cm in vitro using inner, outer, and middle line methods. We compared the difference between the actual size by caliper and measurements at each compression rate and depth by the three methods in 2D and 3D TEE.

RESULTS

A total of 450 patterns of measurements were analyzed. The differences using the middle line method were much less than those using the inner and outer line methods in 2D and 3D TEE (2D TEE: 0.45 ± 0.36 vs. 2.55 ± 0.99 vs. 2.59 ± 0.72 mm, p < 0.01; 3D TEE: 0.34 ± 0.27 vs. 2.38 ± 0.69 vs. 1.86 ± 0.77 mm, p < 0.01). Moreover, the differences in measurements by 3D TEE were more accurate than those of 2D TEE in the inner (2.47 ± 1.86 vs. 1.86 ± 0.77 mm, p < 0.01) and middle (0.58 ± 0.37 vs. 0.34 ± 0.27 mm, p < 0.01) line methods.

CONCLUSIONS

Middle line method by 3D TEE is the most reliable approach for device measurement at left atrial appendage closure using WATCHMAN FLX device.

Use of Computed Tomography for Left Atrial Appendage Occlusion Procedure Planning and Post-Procedure Assessment

Transcatheter left atrial appendage occlusion (LAAO) is an alternative to systemic anticoagulation in patients with non-valvular atrial fibrillation with increased risk for thromboembolic events. Pre- and post-procedural imaging is essential for technical success, allowing practitioners to identify contraindications, select appropriate devices, and recognize procedural complications. Although transesophageal echocardiography has traditionally served as the preeminent imaging modality in LAAO, cardiac computed tomography imaging has emerged as a noninvasive surrogate given its excellent isotropic spatial resolution, multiplanar reconstruction capability, rapid temporal resolution, and large field of view.

Three-Dimensional Transesophageal Echocardiography in Percutaneous Catheter-Based Cardiac Interventions

Cardiac structural and valve interventions have remained surgical procedures for several decades. The ability to directly visualize the region of interest during surgery made imaging of these structures pre- and postsurgery a secondary tool to compliment surgical visualization. The last two decades, however, have seen rapid advances in catheter-based percutaneous structural heart interventions (SHIs). Due to the "blind" nature of these interventions, imaging plays a crucial role in the success of these procedures. Fluoroscopy is used universally in all percutaneous cardiac SHIs and helps primarily in the visualization of catheters and devices. However, success of these procedures requires visualization of intracardiac soft tissue structures. Due to its portable nature and rapid ability to show cardiac structures online, transesophageal echocardiography (TEE) has become an integral tool for guidance for all percutaneous SHI. Transcatheter aortic valve replacement-one of the earliest catheter-based procedures-while initially dependent on TEE, has largely been replaced by preprocedural cardiac CT for accurate assessment of valve sizing. Developments in echocardiography now allow live three-dimensional (3D) visualization of cardiac structures mimicking surgical anatomy during TEE. Besides showing actual 3D intracardiac structures, 3D-TEE allows visualization of the interaction of intracardiac catheters and devices with soft tissue cardiac structures, thereby becoming a "second pair of eyes" for the operator. Real-time 3D-TEE now plays an important role complementing multiplane two dimensional and biplane TEE during such interventions. In this review, we discuss the incremental role of 3D-TEE during various SHIs performed today.

Echocardiographic Imaging in Transcatheter Structural Intervention: An AAE Review Paper

Transcatheter structural heart intervention (TSHI) has gained popularity over the past decade as a means of cardiac intervention in patients with prohibitive surgical risks. Following the exponential rise in cases and devices developed over the period, there has been increased focus on developing the role of "structural imagers" amongst cardiologists. This review, as part of a growing initiative to develop the field of interventional echocardiography, aims to highlight the role of echocardiography in myriad TSHIs available within Asia. We first discuss the various echocardiography-based imaging modalities, including 3-dimensional echocardiography, fusion imaging, and intracardiac echocardiography. We then highlight a selected list of structural interventions available in the region-a combination of established interventions alongside novel approaches-describing key anatomic and pathologic characteristics related to the relevant structural heart diseases, before delving into various aspects of echocardiography imaging for each TSHI.

Cardiac magnetic resonance imaging for preprocedural planning of percutaneous left atrial appendage closure

Introduction

Percutaneous closure of the left atrial appendage (LAA) facilitates stroke prevention in patients with atrial fibrillation. Optimal device selection and positioning are often challenging due to highly variable LAA shape and dimension and thus require accurate assessment of the respective anatomy. Transesophageal echocardiography (TEE) and x-ray fluoroscopy (XR) represent the gold standard imaging techniques. However, device underestimation has frequently been observed. Assessment based on 3-dimensional computer tomography (CTA) has been reported as more accurate but increases radiation and contrast agent burden. In this study, the use of non-contrast-enhanced cardiac magnetic resonance imaging (CMR) to support preprocedural planning for LAA closure (LAAc) was investigated.

Methods

CMR was performed in thirteen patients prior to LAAc. Based on the 3-dimensional CMR image data, the dimensions of the LAA were quantified and optimal C-arm angulations were determined and compared to periprocedural data. Quantitative figures used for evaluation of the technique comprised the maximum diameter, the diameter derived from perimeter and the area of the landing zone of the LAA.

Results

Perimeter- and area-based diameters derived from preprocedural CMR showed excellent congruency compared to those measured periprocedurally by XR, whereas the respective maximum diameter resulted in significant overestimation (p < 0.05). Compared to TEE assessment, CMR-derived diameters resulted in significantly larger dimensions (p < 0.05). The deviation of the maximum diameter to the diameters measured by XR and TEE correlated well with the ovality of the LAA. C-arm angulations used during the procedures were in agreement with those determined by CMR in case of circular LAA.

Discussion

This small pilot study demonstrates the potential of non-contrast-enhanced CMR to support preprocedural planning of LAAc. Diameter measurements based on LAA area and perimeter correlated well with the actual device selection parameters. CMR-derived determination of landing zones facilitated accurate C-arm angulation for optimal device positioning.

Left Atrial Thrombus-Are All Atria and Appendages Equal?

Although the left atrial appendage (LAA) seems useless, it has several critical functions that are not fully known yet, such as the causes for being the main origin of cardioembolic stroke. Difficulties arise due to the extreme range of LAA morphologic variability, making the definition of normality challenging and hampering the stratification of thrombotic risk. Furthermore, obtaining quantitative metrics of its anatomy and function from patient data is not straightforward. A multimodality imaging approach, using advanced computational tools for their analysis, allows a complete characterization of the LAA to individualize medical decisions related to left atrial thrombosis patients.

Appropriate Use Criteria of Left Atrial Appendage Closure Devices: Latest Evidences

Atrial fibrillation is the most common arrythmia and it is linked to an increased risk of stroke. Even if anticoagulation therapy reduces the rate of stroke the benefits of this therapy have to been balanced with the increased risk of hemorrhagic event. Left atrial appendage closure is a valid alternative to long term anticoagulation in patients with atrial fibrillation and high hemorrhagic risk. Actually new devices with different features have been tested and introduced progressively in the clinical practice. Improvements preprocedural imaging evaluation and the learning curve of the operators led to percutaneous left atrial appendage closure a safe and effective procedure. A good knowledge of different devices and the technique of implant is necessary for optimization percutaneous left atrial appendage closure and the reduction of complications during the acute phase and follow up.

FEops HEARTguide Patient-Specific Computational Simulations for WATCHMAN FLX Left Atrial Appendage Closure: A Retrospective Study

Background

Three-dimensional transesophageal echocardiography (3D-TEE) is the primary imaging tool for left atrial appendage closure planning. The utility of cardiac computed tomography angiography (CCTA) and patient-specific computational models is unknown.

Objectives

The purpose of this study was to evaluate the accuracy of the FEops HEARTguide patient-specific computational modeling in predicting appropriate device size, location, and compression of the WATCHMAN FLX compared to intraprocedural 3D-TEE.

Methods

Patients with both preprocedural and postprocedural CCTA and 3D-TEE imaging of the LAA who received a WATCHMAN FLX left atrial appendage closure device were studied (n = 22). The FEops HEARTguide platform used baseline CCTA imaging to generate a prediction of device size(s), device position(s), and device dimensions. Blinded (without knowledge of implanted device size/position) and unblinded (implant device size/position disclosed) simulations were evaluated.

Results

In 16 (72.7%) patients, the blind simulation predicted the final implanted device size. In these patients, the 3D-TEE measurements were not significantly different and had excellent correlation (Pearson correlation coefficient (r) ≥ 0.90). No patients had peridevice leak after device implant. In the 6 patients for whom the model did not predict the implanted device size, a larger device size was ultimately implanted as per operator preference. The model measurements of the unblinded patients demonstrated excellent correlation with 3D-TEE.

Conclusions

This is the first study to demonstrate that the FEops HEARTguide model accurately predicts WATCHMAN FLX device implantation characteristics. Future studies are needed to evaluate if computational modeling can improve confidence in sizing, positioning, and compression of the device without compromising technical success.

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 299 patients (mean age: 67 ± 13 years) who underwent transesophageal echocardiography (TEE) were included. Patients were classified into non-AF (n = 64), 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 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 was increased with the progression of AF.

Left Atrial Appendage Occlusion: Current Stroke Prevention Strategies and a Shift Toward Data-Driven, Patient-Specific Approaches

The left atrial appendage (LAA) is a complex structure with unknown physiologic function protruding from the main body of the left atrium. In patients with atrial fibrillation, the left atrium does not contract effectively. Insufficient atrial and LAA contractility predisposes the LAA morphology to hemostasis and thrombus formation, leading to an increased risk of cardioembolic events. Oral anticoagulation therapies are the mainstay of stroke prevention options for patients; however, not all patients are candidates for long-term oral anticoagulation. Percutaneous occlusion devices are an attractive alternative to long-term anticoagulation therapy, although they are not without limitations, such as peri-implant leakage and device-related thrombosis. Although efforts have been made to reduce these risks, significant interpatient heterogeneity inevitably yields some degree of device-anatomy mismatch that is difficult to resolve using current devices and can ultimately lead to insufficient occlusion and poor patient outcomes. In this state-of-the-art review, we evaluated the anatomy of the LAA as well as the current pathophysiologic understanding and stroke prevention strategies used in the management of the risk of stroke associated with atrial fibrillation. We highlighted recent advances in computed tomography imaging, preprocedural planning, computational modeling, and novel additive manufacturing techniques, which represent the tools needed for a paradigm shift toward patient-centric LAA occlusion. Together, we envisage that these techniques will facilitate a pipeline from the imaging of patient anatomy to patient-specific computational and bench-top models that enable customized, data-driven approaches for LAA occlusion that are engineered specifically to meet each patient's unique needs.

Clinical Characteristics of Non-Valvular Atrial Fibrillation Patients With a Large Left Atrial Appendage Ostium-Limiting Percutaneous Closure

BACKGROUND

The left atrial appendage (LAA) is a therapeutic target for preventing cardioembolic stroke in patients with non-valvular atrial fibrillation (NVAF). A large LAA ostium limits percutaneous LAA closure. This study investigated the characteristics and factors associated with a large LAA ostium in Japanese patients with NVAF.

METHODS AND RESULTS

In 1,102 NVAF patients, the maximum LAA diameter was measured using transesophageal echocardiography (TEE). A large LAA ostium was defined by a maximum diameter of >30 mm. Forty-four participants underwent repeated TEEs, and changes in LAA size under lasting AF were assessed. A large LAA ostium was observed in 3.1% of all participants and 8.9% of patients with long-standing persistent AF (LSAF). The large LAA group had greater CHA2DS2-VASc (P=0.024) and HAS-BLED scores (P=0.046) and a higher prevalence of LAA thrombus (P=0.004) than did the normal LAA group. LSAF, moderate or severe mitral regurgitation, left atrial volume ≥42 mL/m2, E/E' ratio ≥9.5, and left ventricular mass ≥85 mg/m2were independently associated with a large LAA ostium (P<0.001, P<0.001, P=0.009, P=0.009, and P=0.032, respectively). In 44 patients with lasting AF, the LAA ostial diameter increased over time (P<0.001).

CONCLUSIONS

NVAF patients with a large LAA ostium may have a higher risk of stroke and bleeding. LSAF and factors leading to LA overload may be closely associated with LAA ostial dilatation and can promote it.

Changes in left atrial appendage orifice following percutaneous left atrial appendage closure using three-dimensional echocardiography

Percutaneous left atrial appendage (LAA) occlusion is increasingly performed in patients with atrial fibrillation and long-term contraindications for anticoagulation. Our aim was to evaluate the effects of LAA occlusion with the Watchman device on the geometry of the LAA orifice and assess its impact on the adjacent left upper pulmonary vein (LUPV) hemodynamics. We included 50 patients who underwent percutaneous LAA occlusion with the Watchman device and had acceptable three-dimensional transesophageal echocardiography images of LAA pre- and post-device placement. We measured offline the LAA orifice diameters in the long axis, and the minimum and maximum diameters, circumference, and area in the short axis view. Eccentricity index was calculated as maximum/minimum diameter ratio. The LUPV peak S and D velocities pre- and post-procedure were also measured. Patients were elderly (mean age 76 ± 8 years), 30 (60%) were men. There was a significant increase of all LAA orifice dimensions following LAA occlusion: diameter 1 (pre-device 18.1 ± 3.2 vs. post-device 21.5 ± 3.4 mm, p < 0.001), diameter 2 (20.6 ± 3.9 vs. 22.1 ± 3.6 mm, p < 0.001), minimum diameter (17.6 ± 3.1 vs. 21.3 ± 3.4 mm, p < 0.001), maximum diameter (21.5 ± 3.9 vs. 22.4 ± 3.6 mm, p = 0.022), circumference (63.6 ± 10.7 vs. 69.6 ± 10.5 mm, p < 0.001), and area (3.1 ± 1.1 vs. 3.9 ± 1.2 cm2, p < 0.001). Eccentricity index decreased after procedure (1.23 ± 0.16 vs. 1.06 ± 0.06, p < 0.001). LUPV peak S and D velocities did not show a significant difference (0.29 ± 0.15 vs. 0.30 ± 0.14 cm/s, p = 0.637; and 0.47 ± 0.19 vs. 0.48 ± 0.20 cm/s, p = 0.549; respectively). LAA orifice stretches significantly and it becomes more circular following LAA occlusion without causing a significant impact on the LUPV hemodynamics.

Evaluating left atrial appendage function in a subtype of non-valvular atrial fibrillation using transesophageal echocardiography combined with two-dimensional speckle tracking

BACKGROUND

The use of transesophageal echocardiography (TEE) is a clinically feasible method for quantitative analysis of left atrial appendage (LAA) function. LAA dysfunction is closely associated with atrial fibrillation (AF)-related stroke. However, there are few studies on the changes in LAA function in patients with different types of AF. This study aimed to observe changes in LAA systolic motion and function in patients with different types of AF by using speckle-tracking echocardiography (STE).

METHODS

A retrospective study of 216 patients with non-valvular AF was conducted. The LAA was divided into three parts: the basal segment (B), middle segment (M), and top segment (A). Speck -racking technology was used to measure and record the forward strain values of the basal segment (B), middle segment (M), and top segment (A) of the LAA, and the peak positive strain dispersion of the LAA was calculated. The left atrial appendage mechanical dispersion (LAAMD) was defined as the standard deviation (SD) of the peak positive strain at each segment of the R-R interval.

RESULTS

Partial speckle-tracking parameters of the LAA showed statistical significance between the two groups. The peak strain on the top segment of the LAA was reduced in the persistent atrial fibrillation (per-AF) group compared to the paroxysmal atrial fibrillation (par-AF) group [11.87 (6.47-20.12) vs. 16.02 (9.76-24.50); 12.66 (6.66-21.22) vs. 20.16 (14.16-30.56); both P<0.01]. In the group with lower LAAMD, the proportion of patients with persistent AF (per-AF) was higher (66.3% vs. 33.7%; P<0.001), the left atrial dilatation was more significant (45.80±5.656 vs. 42.85±4.867; P<0.001), the LAA filling velocity and LAA empty velocity were lower (42.35±20.354 vs. 51.0±20.599; 38.71±24.39 vs. 51.62±21.282; both P<0.001), the LAA ejection fraction was significantly lower (52.16±25.538 vs. 70.85±20.741; P=0.000), and the peak positive strains of the M and A of the LAA were lower than those in the higher LAAMD group.

CONCLUSIONS

The deformability of the LAA is decreased diffusely in per-AF, especially in the A of the LAA. Compliance with LAA was worse in patients with per-AF than in those with par-AF.

Computed tomography-based selection of transseptal puncture site for percutaneous left atrial appendage closure

BACKGROUND

An inferoposterior transseptal puncture (TSP) is generally recommended for percutaneous left atrial appendage (LAA) closure. However, the LAA is a highly variable anatomical structure. This may have an impact on the preferred TSP site.

AIMS

This study aimed to determine the optimal TSP site for percutaneous LAA closure in different LAA morphologies.

METHODS

In this prospective study, 182 patients undergoing percutaneous LAA closure were included. The spatial relationship of the LAA to the fossa ovalis and its consequence for TSP was assessed at preprocedural cardiac computed tomography (CCT).

RESULTS

Based on CCT analysis, it was predicted that coaxial alignment between the delivery sheath and the LAA would be obtained by an inferoposterior, inferocentral, or inferoanterior TSP in 75%, 16% and 8% of cases, respectively. This was also confirmed by procedural LAA angiogram in 175 cases (96%) with <30° angle between the delivery sheath and the LAA central axis. Multivariate logistic regression analysis identified reverse chicken wing LAA (odds ratio [OR] 6.36 [1.85-29.3]; p=0.005) and posterior bending of the proximal LAA (OR 17.2 [3.3-96.2]; p<0.001) as independent predictors of a central or anterior TSP - this to increase the chance of obtaining coaxial alignment between the delivery sheath and the LAA.

CONCLUSIONS

An inferoposterior TSP is recommended in the majority of percutaneous LAA closure procedures in order to obtain coaxial alignment between the delivery sheath and the LAA. An inferior but more central/anterior TSP should be recommended in case of a reverse chicken wing LAA or posterior bending of the proximal LAA, which occurs in 20-25% of cases.

Left Atrial Thrombus-Are All Atria and Appendages Equal?

Although the left atrial appendage (LAA) seems useless, it has several critical functions that are not fully known yet, such as the causes for being the main origin of cardioembolic stroke. Difficulties arise due to the extreme range of LAA morphologic variability, making the definition of normality challenging and hampering the stratification of thrombotic risk. Furthermore, obtaining quantitative metrics of its anatomy and function from patient data is not straightforward. A multimodality imaging approach, using advanced computational tools for their analysis, allows a complete characterization of the LAA to individualize medical decisions related to left atrial thrombosis patients.

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.

TrueVue transillumination volume rendering for three-dimensional transoesophageal echocardiography in interventional imaging

AIMS

The aim of the present article is to address the advantages of real-time TrueVue transillumination rendering for three-dimensional transoesophageal echocardiography in the context of echocardiographic procedural guidance for structural interventions for several procedural concerns.

METHODS

Procedures in which transillumination imaging was used during at least one step of the whole intervention were retrospectively collected; the loops were reviewed by an experienced imaging specialist and the most important concerns imaged in the loops were listed. The apparent added value of transillumination for each of these concerns was scored independently by two imager specialists, and their agreement was derived.

RESULTS

Between January and June 2019, 50 procedures were performed in our centre. Transillumination imaging was used in 64% of these cases. Considering all the loops the added value of transillumination compared with the conventional rendering was scored greater than 3 in a Likert scale in 87% of analysed loops by both the operators with a good agreement (κ  = 0.47, P  = 0.001). A different level of perceived advantage and agreement was observed between three image features that improved: substantial agreement (κ  = 0.652, P  = 0.001) for enhancing the contrast between structures and cavities (n  = 24 loops); good agreement for the contrast between different structures (κ  = 0.588, P  = 0.002) (n  = 37 loops); moderate agreement for the perception of interaction between the device and structures (κ  = 0.3, P  = 0.027) (n  = 7 loops).

CONCLUSION

The use of new volume-rendering techniques in interventional imaging may be useful especially for solving the concerns regarding the cavity-structure contrast.

Feasibility and Accuracy of Automated Three-Dimensional Echocardiographic Analysis of Left Atrial Appendage for Transcatheter Closure

BACKGROUND

Procedural success of transcatheter left atrial appendage closure (LAAC) is dependent on correct device selection. Three-dimensional (3D) transesophageal echocardiography (TEE) is more accurate than the two-dimensional modality for evaluation of the complex anatomy of the left atrial appendage (LAA). However, 3D transesophageal echocardiographic analysis of the LAA is challenging and highly expertise dependent. The aim of this study was to evaluate the feasibility and accuracy of a novel software tool for automated 3D analysis of the LAA using 3D transesophageal echocardiographic data.

METHODS

Intraprocedural 3D transesophageal echocardiographic data from 158 patients who underwent LAAC were retrospectively analyzed using a novel automated LAA analysis software tool. On the basis of the 3D transesophageal echocardiographic data, the software semiautomatically segmented the 3D LAA structure, determined the device landing zone, and generated measurements of the landing zone dimensions and LAA length, allowing manual editing if necessary. The accuracy of LAA preimplantation anatomic measurement reproducibility and time for analysis of the automated software were compared against expert manual 3D analysis. The software feasibility to predict the optimal device size was directly compared with implanted models.

RESULTS

Automated 3D analysis of the LAA on 3D TEE was feasible in all patients. There was excellent agreement between automated and manual measurements of landing zone maximal diameter (bias, -0.32; limits of agreement, -3.56 to 2.92), area-derived mean diameter (bias, -0.24; limits of agreement, -3.12 to 2.64), and LAA depth (bias, 0.02; limits of agreement, -3.14 to 3.18). Automated 3D analysis, with manual editing if necessary, accurately identified the implanted device size in 90.5% of patients, outperforming two-dimensional TEE (68.9%; P < .01). The automated software showed results competitive against the manual analysis of 3D TEE, with higher intra- and interobserver reproducibility, and allowed quicker analysis (101.9 ± 9.3 vs 183.5 ± 42.7 sec, P < .001) compared with manual analysis.

CONCLUSIONS

Automated LAA analysis on the basis of 3D TEE is feasible and allows accurate, reproducible, and rapid device sizing decision for LAAC.

Left Atrial Appendage Function Assessment by Tissue Doppler Transesophageal Echocardiography in Acute Ischemic Stroke Patients

Background: Strokes due to Cardioembolic causes are the most severe in ischemic stroke subtypes. LAA flow patterns and function could be assessed accurately by TEE. The study aimed to present the importance of Transesophageal echocardiography in the assessment of LAA function and its relation to cardioembolic stroke. Methods: 120 patients were enrolled in the study and were subdivided into 3 subgroups, each group included 40 patients. Group A; patients had a stroke with normal sinus rhythm, Group B; patients had a stroke with atrial fibrillation, and Group C; normal control subjects. The study participants were evaluated by medical history, physical examination, standard 12-leads electrocardiogram, a transesophageal echocardiographic detailed evaluation of the LAA, and brain CT and/or MRI for patients with stroke. Results: both stroke patients with AF and sinus rhythm had significantly higher LAA mean orifice diameter and higher LAA length than control patients, significantly lower mean LAA medial wall tissue Doppler upward and downward motion velocities than control patients and that patients with stroke and AF had significantly lower mean LAA pulsed wave emptying and filling velocities than both patients with stroke and sinus rhythm and control patients. Presence of LAA thrombi, spontaneous echo contrast, and stroke recurrence were higher in stroked AF patients than stroke patients with sinus rhythm. Conclusion: increased LAA orifice diameter, LAA length, and reduced filling and emptying velocities and upward and downward motion velocities of the medial wall of LAA as detected by TEE are associated with stroke and cardio embolization.  

Additive Value of Preprocedural Computed Tomography Planning Versus Stand-Alone Transesophageal Echocardiogram Guidance to Left Atrial Appendage Occlusion: Comparison of Real-World Practice

Background

Transesophageal echocardiogram is currently the standard preprocedural imaging for left atrial appendage occlusion. This study aimed to assess the additive value of preprocedural computed tomography (CT) planning versus stand‐alone transesophageal echocardiogram imaging guidance to left atrial appendage occlusion.

Methods and Results

We retrospectively reviewed 485 Watchman implantations at a single center to compare the outcomes of using additional CT preprocedural planning (n=328, 67.6%) versus stand‐alone transesophageal echocardiogram guidance (n=157, 32.4%) for left atrial appendage occlusion. The primary end point was the rate of successful device implantation without major peri‐device leak (>5 mm). Secondary end points included major adverse events, total procedural time, delivery sheath and devices used, risk of major peri‐device leak and device‐related thrombus at follow‐up imaging. A single/anterior‐curve delivery sheath was used more commonly in those who underwent CT imaging (35.9% versus 18.8%; P<0.001). Additional preprocedural CT planning was associated with a significantly higher successful device implantation rate (98.5% versus 94.9%; P=0.02), a shorter procedural time (median, 45.5 minutes versus 51.0 minutes; P=0.03) and a less frequent change of device size (5.6% versus 12.1%; P=0.01), particularly device upsize (4% versus 9.4%; P=0.02). However, there was no significant difference in the risk of major adverse events (2.1% versus 1.9%; P=0.87). Only 1 significant peri‐device leak (0.2%) and 5 device‐related thrombi were detected in follow‐up (1.2%) with no intergroup difference.

Conclusions

Additional preprocedural planning using CT in Watchman implantation was associated with a higher successful device implantation rate, a shorter total procedural time, and a less frequent change of device sizes.

EACVI recommendations on cardiovascular imaging for the detection of embolic sources: endorsed by the Canadian Society of Echocardiography

Cardioaortic embolism to the brain accounts for approximately 15-30% of ischaemic strokes and is often referred to as 'cardioembolic stroke'. One-quarter of patients have more than one cardiac source of embolism and 15% have significant cerebrovascular atherosclerosis. After a careful work-up, up to 30% of ischaemic strokes remain 'cryptogenic', recently redefined as 'embolic strokes of undetermined source'. The diagnosis of cardioembolic stroke remains difficult because a potential cardiac source of embolism does not establish the stroke mechanism. The role of cardiac imaging-transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), cardiac computed tomography (CT), and magnetic resonance imaging (MRI)-in the diagnosis of potential cardiac sources of embolism, and for therapeutic guidance, is reviewed in these recommendations. Contrast TTE/TOE is highly accurate for detecting left atrial appendage thrombosis in patients with atrial fibrillation, valvular and prosthesis vegetations and thrombosis, aortic arch atheroma, patent foramen ovale, atrial septal defect, and intracardiac tumours. Both CT and MRI are highly accurate for detecting cavity thrombosis, intracardiac tumours, and valvular prosthesis thrombosis. Thus, CT and cardiac magnetic resonance should be considered in addition to TTE and TOE in the detection of a cardiac source of embolism. We propose a diagnostic algorithm where vascular imaging and contrast TTE/TOE are considered the first-line tool in the search for a cardiac source of embolism. CT and MRI are considered as alternative and complementary tools, and their indications are described on a case-by-case approach.

Evidence and Challenges in Left Atrial Appendage Management

This review aimed to discuss the anatomical properties of the left atrial appendage (LAA), its relationship with atrial fibrillation (AF), effectiveness of LAA occlusion (LAAO), techniques, and new devices used to perform this procedure. An electronic search was performed to identify studies, in the English language, on LAA management. Searches were performed on PubMed Central, Scopus, and Medline from the dates of database inception to February 2020. For the assessed papers, data were extracted from the reviewed text, tables, and figures, by two independent authors. Anticoagulant therapy for patients with AF has proven beneficial and is highly recommended, but it is challenging for many patients to maintain optimal treatment. Surgery is the most cost-effective option; surgical methods include simple LAA resection, thoracoscopic surgery, and catheter treatment. Each procedure has its advantages and disadvantages, and many prospective studies have been conducted to evaluate various treatment methods. In managing the LAA, dissection of the LAA, such as changes in its shape and size due to remodeling during AF, changes in autonomic nerve function, and thrombosis, must be understood anatomically and physiologically. We believe that early treatment intervention for the LAA should be considered particularly in cases of recurrent AF.

Conclusion: SLET under artificial pneumothorax is feasible and safe in minimally invasive McKeown esophagectomy.

Clinical Impact of Preprocedural CT-Based 3D Computational Simulation of Left Atrial Appendage Occlusion with Amulet

Aims

Standard of care (SoC) device size selection with transoesophageal echocardiography (TOE) and computed tomography (CT) in LAAO can be challenging due to a certain degree of variability at both patient and device levels. The aim of this study was to prospectively evaluate the clinical impact of 3D computational modelling software in the decision-making of left atrial appendage occlusion (LAAO) with Amplatzer Amulet.

Methods and Results

SoC preprocedural assessments as well as CT-based 3D computational simulations (FEops) were performed in 15 consecutive patients scheduled for LAAO with Amulet. Preprocedural device size selection and degree of confidence were determined after SoC and after FEops-based assessments and compared to the implanted device. FEops-based preprocedural assessment correctly selected the implanted device size in 11 out of 15 patients (73.3%), compared to 7 patients (46.7%) for SoC-based assessment. In 4 patients (26.7%), FEops induced a change in device size initially selected by SoC. In the 7 patients (46.7%) in which FEops confirmed the SoC device size selection, the degree of confidence of the size selection increased from 6.4 ± 1.4 for SoC to 8.1 ± 0.7 for FEops. One patient (6.7%) could not be implanted for anatomical reason, as correctly identified by FEops.

Conclusions

Preprocedural 3D computational simulation by FEops impacts Amulet size selection in LAAO compared to TOE and CT-based SoC assessment. Operators could consider FEops computational simulation in their preprocedural device size selection.

Percutaneous Left Atrial Appendage Occlusion: An Emerging Option in Patients with Atrial Fibrillation at High Risk of Bleeding

Atrial fibrillation (AF) is a common cardiac arrhythmia with an estimated prevalence of 1% in the general population. It is associated with an increased risk of ischemic stroke, silent cerebral ischemia, and cognitive impairment. Due to the blood flow stasis and morphology, thrombus formation occurs mainly in the left atrial appendage (LAA), particularly in the setting of nonvalvular AF (NVAF). Previous studies have shown that >90% of emboli related to NVAF originate from the LAA, thus prevention of systemic cardioembolism is indicated. According to the current guidelines, anticoagulant therapy with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs), represents the standard of care in AF patients, in order to prevent ischemic stroke and peripheral embolization. Although these drugs are widely used and DOACs have shown, compared to VKAs, non-inferiority for stroke prevention with significantly fewer bleeding complications, some issues remain a matter of debate, including contraindications, side effects, and adherence. An increasing number of patients, indeed, because of high bleeding risk or after experiencing life-threatening bleedings, must take anticoagulants with extreme caution if not contraindicated. While surgical closure or exclusion of LAA has been historically used in patients with AF with contradictory results, in the recent years, a novel procedure has emerged to prevent the cardioembolic stroke in these patients: The percutaneous left atrial appendage occlusion (LAAO). Different devices have been developed in recent years, though not all of them are approved in Europe and some are still under clinical investigation. Currently available devices have shown a significant decrease in bleeding risk while maintaining efficacy in preventing thromboembolism. The procedure can be performed percutaneously through the femoral vein access, under general anesthesia. A transseptal puncture is required to access left atrium and is guided by transesophageal echocardiography (TEE). Evidence from the current literature indicates that percutaneous LAAO represents a safe alternative for those patients with contraindications for long-term oral anticoagulation. This review summarizes scientific evidences regarding LAAO for stroke prevention including clinical indications and an adequate patient selection.

Pre- and Postprocedural CT of Transcatheter Left Atrial Appendage Closure Devices

Transcatheter left atrial appendage (LAA) closure is an alternative to long-term anticoagulation therapy in selected patients with nonvalvular atrial fibrillation who have an increased risk for stroke. LAA closure devices can be implanted by means of either an endocardial or a combined endocardial and epicardial approach. Preprocedural imaging is key to identifying contraindications, accurately sizing the device, and minimizing complications. Transesophageal echocardiography (TEE) has been the reference standard imaging modality to assess the anatomy for LAA closure and to provide intraprocedural guidance. However, CT has emerged as a less-invasive alternative to TEE for pre- and postprocedural imaging. CT is comparable to TEE for exclusion of thrombus but is superior to TEE for the delineation of complex LAA anatomy, measurement for device sizing, and evaluation of pulmonary venous and extracardiac structures. CT provides accurate measurements of the LAA ostial diameter, landing zone diameter, and LAA length, which are vital for accurate sizing of the device. CT allows evaluation of the relationship with the pulmonary veins and other adjacent structures that can be injured during the procedure. CT also simulates procedural fluoroscopic angles and provides evaluation of the interatrial septum, which is punctured during LAA closure. CT also provides a more convenient method for the evaluation of postprocedural complications such as incomplete closure, peridevice leaking, device-related thrombus, and device dislodgement. Online supplemental material is available for this article. ^©RSNA, 2021.

Impact of ultrasound contrast agent during transoesophageal echocardiography on the sizing of the left atrial appendage

INTRODUCTION

Interventional closure of the left atrial appendage closure (LAAC) has been established as an alternative treatment in patients with atrial fibrillation (AF) and an increased risk of stroke. So far it is unknown whether the use of ultrasound contrast agent (UCA) would influence the correct sizing of the LAA and thereby have an impact on device selection during interventional LAAC.

METHODS

Between January 2017 and April 2018, 223 transoesophageal echocardiography (TOE) examinations were prospectively performed in adult patients with non-valvular AF (Impact of the use of ultrasound contrast agent on the detection of thrombi in the left atrial appendage during transesophageal echocardiography (CONDOR) study). LAA was examined both with and without the use of UCA. The following measurements were taken at 0^o, 45^o, 90^o and 135^o: diameter of LAA ostium, maximal depth of the LAA, maximal available depth of the LAA orthogonal to the ostial plane and area of the LAA.

RESULTS

The use of UCA had no relevant influence on the size determination of the LAA. Additionally, Bland-Altman blots demonstrate a high degree of correlation between the measurements with and without UCA with no evidence for a systematic effect arising from the use of UCA. When comparing the measurements of two independent investigators, the use of UCA rather leads to a higher variability than to an improved precision.

DISCUSSION

Despite the fact that the use of UCA during TOE leads to an improved rule out of thrombi, our study shows that there is no advantageous effect of UCA on the size determination of the LAA and should therefore not be used for this purpose.

Prevalence of left atrial thrombus by real time three-dimensional echocardiography in patients undergoing electrical cardioversion of atrial fibrillation: A contemporary cohort study

BACKGROUND

The prevalence of left atrial thrombi in patients scheduled for electrical cardioversion (ECV) of atrial fibrillation (AF) remains unknown in contemporary real-life practice.

METHODS AND RESULTS

Patients scheduled for ECV underwent transesophageal echocardiography (TEE) regardless of AF duration and type of anticoagulant. Of 277 consecutive patients (65% men, mean age 71 ± 10 years, CHA₂ DS₂ -VASc 3.1 ± 1.4), 92 were on direct oral anticoagulants (DOACs) and 99 on antivitamin K (AVK) oral agents for at least 3 weeks before and 4 after ECV. Eighty-five patients with paroxysmal AF on low-molecular-weight heparin were also considered. Real time three-dimensional TEE detected left atrial appendage (LAA) thrombus in 7% of patients, without significant difference among three groups (P = .334). Anticoagulation was ineffective in eight patients on AVK oral agents, two of them had thrombus. Eight patients assumed incorrectly DOACs, four of them had thrombus. Among the 175 patients on effective anticoagulation, five showed thrombus, three on AVK oral agents, and two on DOACs (P = .716). Effective anticoagulation was associated with reduced risk of thrombosis (OR: 0.16, 95%CI: 0.06-0.45, P = .001). In patients with correct anticoagulation, predictors of thrombus were CHA₂ DS₂ VASc (for each point of increment OR: 1.97, 95%CI: 1.08-3.61, P = .029), low left ventricular ejection fraction (OR: 0.92, 95%CI: 0.86-0.99, P = .026), and degree of spontaneous echo-contrast (for each point increase OR: 10, 95%CI: 2-39, P < .0001).

CONCLUSION

Patients with AF, on effective anticoagulation, had a prevalence of thrombus not negligible regardless of type of anticoagulant. TEE is prudent before ECV and mandatory if unsuccessful anticoagulation is proved or suspected.

Multimodality Approach for Endovascular Left Atrial Appendage Closure: Head-To-Head Comparison among 2D and 3D Echocardiography, Angiography, and Computer Tomography

Background: Percutaneous left atrial appendage closure (LAAC) requires accurate pre- and intraprocedural measurements, and multimodality imaging is an essential tool for guiding the procedure. Two-dimensional (2D TOE) and three-dimensional (3D TOE) transoesophageal echocardiography, cardiac computed tomography (CCT), and conventional cardiac angiography (CCA) are commonly used to evaluate left atrial appendage (LAA) size. However, standardized approaches in measurement methods by different imaging modalities are lacking. The aims of the study were to evaluate the LAA dimension and morphology in patients undergoing LAAC and to compare data obtained by different imaging modalities: 2D and 3D TOE, CCT, and CCA. Methods: A total of 200 patients (mean age 70 ± 8 years, 128 males) were examined by different imaging techniques (161 2D TOE, 103 3D TOE, 98 CCT, and 200 CCA). Patients underwent preoperative CCT and intraoperative 2D and 3D TOE and CCA. Results: A significant correlation was found among all measurements obtained by different modalities. In particular, 3D TOE and CCT measurements were highly correlated with an excellent agreement for the landing zone (LZ) dimensions (LZ diameter: r = 0.87; LAA depth: r = 0.91, p < 0.001). Conclusions: Head-to-head comparison among imaging techniques (2D and 3D TOE, CCT, and CCA) showed a good correlation among LZ diameter measurements obtained by different imaging modalities, which is a parameter of paramount importance for the choice of the LAAC device size. LZ diameters and area by 3D TOE had the best correlation with CCT.

The differences of atrial thrombus locations and variable response to anticoagulation in nonvalvular atrial fibrillation with ventricular cardiomyopathy

OBJECTIVES

This study aims to research the clinical features of atrial thrombi in patients with nonvalvular atrial fibrillation (AF).

METHODS

This study included 191 patients of AF who had atrial thrombi. One hundred and twenty-eight of them were assigned into nonventricular cardiomyopathy group (non-VCM), and the remaining 63 into ventricular cardiomyopathy group (VCM). After atrial thrombi diagnosed, all patients had taken oral anticoagulant therapy. The resolution rates of thrombi within 12 months were compared between the two groups, as well as the locations of thrombi.

RESULTS

Of all 191 patients, 161 had thrombi only detected in left atrial appendage (LAA), 20 in both left atrium (LA) and LAA, six in LA only, and four in right atrium only. More patients had thrombi out of LAA in the VCM group than in the non-VCM group (30.2% vs 8.6%, P < .001). After propensity score matching, the atrial thrombi were resolved faster in the non-VCM group than in the VCM group (mean time length: 22 ± 2 weeks vs 30 ± 3 weeks, P = .038), and the resolution rate within 12 months was higher in the non-VCM group than in the VCM group (88.7% vs 61.4%, Log-rank, P = .038). In Cox proportional hazards model, absence of ventricular cardiomyopathy was an independent predictor for the resolution of atrial thrombus (hazard ratio: 1.76; P = .035).

CONCLUSIONS

The patients of atrial fibrillation with ventricular cardiomyopathies have higher incidence of thrombosis in the body of left atrium or right atrium. And the resolution rate was lower in these patients.

Left atrial appendage size in patients with atrial fibrillation in Japan and the United States

Left atrial appendage (LAA) evaluation is important to select the optimal LAA closure device for patients with atrial fibrillation (AF). The LAA characteristics of Japanese patients remain uninvestigated. We compared the LAA size and morphology between 212 Japanese AF patients before catheter ablation and 119 AF patients undergoing LAA closure in the United States (US). We measured the LAA ostial dimension and depth by transesophageal echocardiography in all patients and determined the LAA morphology types of Japanese patients by multidetector cardiac computed tomography and those of US patients by LAA angiography. The maximum LAA ostial dimension was significantly larger in Japanese patients than in US patients (22.6 ± 4.1 mm vs. 21.5 ± 3.5 mm, P = 0.02). Also, Japanese patients had larger maximum dimension and depth corrected by body surface area than US patients in both paroxysmal and nonparoxysmal AF groups. The angle showing the maximum dimension was 0° or 135° in approximately 75% of patients in both groups. The common LAA morphology types were "cauliflower" and "chicken wing" in Japanese patients and "cactus" and "windsock" in US patients. In this study, Japanese patients had a larger LAA size than US patients. Because the maximum LAA dimension was obtained at the same angles, the LAA measurement method for US patients can be applicable to Japanese patients.

Why Follow-up Examinations After Left Atrial Appendage Closure Are Important: Detection of Complications During Follow-up and How to Deal with Them

PURPOSE OF REVIEW

Device-related thrombus (DRT) formation and incomplete left atrial appendage closure (LAAC) are the two major complications that can occur after LAAC and can potentially limit the success of such a procedure. This review discusses the incidence, clinical and/or prognostic significance, detection methods, treatment options, and potential strategies to prevent these complications.

RECENT FINDINGS

It has recently been proven that the presence of a DRT represents an independent predictor for ischemic stroke after LAAC. Continued need for anticoagulation due to incomplete LAAC is clinically relevant to the patient. The appearances of a DRT or an incompletely closed LAA after a LAAC procedure are not rare complications. Due to the clinical and/or prognostic significance of these complications, it is important to detect them in a timely manner during follow-up by using the appropriate diagnostic imaging techniques. Since a DRT is associated with an increased risk of stroke, the therapy should be aggressive. In the case of incomplete LAA closure, an additional closure device may be used to complete occlusion and avoid lifelong anticoagulation therapy.

Left atrial appendage occlusion with the Amplatzer Amulet: update on device sizing

PURPOSE

The present paper analyzes the role of different imaging modalities for left atrial appendage (LAA) assessment and the recommended specific measurements to improve device selection with regard to the Amulet device.

BACKGROUND

Morphological LAA assessment is one of the pivotal factors to achieve proper LAA sealing and potentially reduce the risk of complications by minimizing manipulation inside the appendage.

METHODS

Eight experienced physicians in LAAO were asked to contribute in the preparation of a device sizing consensus manuscript after comprehensive assessment of previous published data on LAA imaging/measurement.

RESULTS

LAA morphology is often complex and requires more detailed spatial resolution and 3-dimensional assessments to reduce the risk of mis-sizing. Traditionally, upsizing of devices based upon the largest measured LAA diameters have been used. However, this may lead to oversizing in markedly elliptical appendages. Thus, when 3D imaging modalities are available, utilizing the LAA mean diameters might be a better alternative. Operators should also note the systematic biases in differences in measurements obtained with different imaging modalities, with CT giving the largest measurements, followed by 3D-TEE, and then 2D-TEE and angiography. In fact, for 2D imaging techniques (2D-TEE and angiography), LAA diameters tend to be underestimated, and therefore, LAA largest diameters seem to be still the best option for device sizing. Some specific anatomies such as proximal chicken-wing or conic LAAs may require different measurements and implantations to achieve implant success.

CONCLUSIONS

In conclusion, LAA mean diameters might be a better alternative to largest diameters when 3D imaging modalities are available.

Transesophageal echocardiography complications associated with interventional cardiology procedures

BACKGROUND

Although there have been several reports documenting complications related with transesophageal echocardiography (TEE) manipulation following cardiac surgery, there is a paucity of data regarding the safety of TEE used to guide catheter-based interventions. The aim of this study was to determine the prevalence, types and risk factors of complications associated with procedures requiring active TEE guidance.

METHODS

This study included 1249 consecutive patients undergoing either transcatheter aortic valve implantation (TAVI), Mitraclip, left atrial appendage occlusion (LAAO) or paravalvular leak closure (PVLC). Patients were divided into 2 cohorts based on the degree of probe manipulation required to guide the procedure and the risk of developing a TEE-related complication: low-risk (TAVI, n = 1037) and high-risk (Mitraclip, LAAO and PVLC, n = 212). Patients were further analyzed according to the occurrence of major and minor TEE-related complications.

RESULTS

The overall incidence of TEE-related complications was 0.9% in the TAVI group and 6.1% in the rest of the cohort (P < .001). Patients in the high-risk cohort had also a higher incidence of major-complications (2.8% vs 0.6%, P = .008), and factors associated with an increased risk were being underweight, having a prior history of gastrointestinal bleeding and the use of chronic steroids/immunosuppressive medications. Procedural time under TEE-manipulation was longer in patients exhibiting complications and was an independent predictor of major complications (OR = 1.13, 95% CI 1.01-1.25, for each 10 minutes increments in imaging time). Patients with major complications undergoing Mitraclip had the longest median time under TEE-manipulation (297 minutes) and a risk of developing a major-complication that was 10.64 times higher than the rest of the cohort (95% CI 3.30-34.29, P < .001).

CONCLUSION

The prevalence of TEE-related complications associated with interventional procedures is higher than previously reported. Undergoing a prolonged procedure, particularly in the setting of Mitraclip, was the main factor linked to TEE-related complications.

Periprocedural Imaging for Left Atrial Appendage Closure: Computed Tomography, Transesophageal Echocardiography, and Intracardiac Echocardiography

Percutaneous left atrial appendage closure is increasingly performed for stroke prevention for patients with nonvalvular atrial fibrillation with contraindications to oral anticoagulation. The success and complication rates with left atrial appendage closure have dramatically improved with maturing experience, growing procedural familiarity, and preprocedural planning. Multimodality imaging involving cardiac computer tomography angiography, transesophageal echocardiography, or intracardiac echocardiography in conjunction with fluoroscopy has improved the efficacy, procedural success, and safety of left atrial appendage closure in recent years. Proceduralists need to familiarize themselves with the various modalities and understand their complimentary roles and their limitations.

Systematic review on left atrial appendage closure with the LAmbre device in patients with non-valvular atrial fibrillation

BACKGROUND

Percutaneous closure (LAAC) of the left atrial appendage (LAA) is an efficacious preventive procedure for patients with non-valvular atrial fibrillation (NVAF) and considerable bleeding risk. We sought to systematically review the available LAAC data on the novel occluder device LAmbre™.

METHODS

For this systematic review, a search of the literature was conducted by 3 independent reviewers, reporting the safety and therapeutic success of LAAC in patients being treated with a LAmbre™. Publications reporting the safety and therapeutic success of LAAC using LAmbre™ in n > 5 patients were included.

RESULTS

The literature search retrieved n = 10 publications, encompassing n = 403 NVAF patients treated with a LAmbre™ LAAC, with relevant data regarding safety and therapeutic success of the procedure. The mean CHA₂DS₂-VASc Score was 4.0 + 0.9, and the mean HAS-BLED score was 3.4 + 0.5. The implantation success was 99.7%, with a mean procedure time of 45.4 ± 18.7 min, and a fluoroscopy time of 9.6 ± 5.9 min, and a contrast agent volume of 96.7 ± 0.7 ml. The anticoagulation regimen was switched to DAPT post procedure in the majority of the patients (96.8%). Partial and full recapture were done in 45.5% and in 25.6%, respectively. Major complications were reported in 2.9%, with 0.3% mortality, 1.7% pericardial tamponade, 0.3% stroke, and 0.6% major bleeding complications; no device embolization was observed. During follow up at 6 or 12 months, major adverse cardiovascular events were reported in 3.3%: Stroke or TIA in 1.7%, thrombus formation on the device in 0.7%, and residual flow > 5 mm in 1.0%. In some publications, the favorable implantion properties of the LAmbre™ for difficult anatomies such as shallow or multilobular LAA anatomies were described.

CONCLUSIONS

This systematic review on the LAmbre™ LAA-occluder including n = 403 NVAF patients demonstrates an excellent implantion success rate, promising follow-up clinical data, and favorable properties for also challenging LAA anatomies,. While its design seems to be helpful in preventing device embolization, pericardial tamponade may not be substantially reduced by the LAmbre™ as compared with other established LAAC devices. Further larger prospective multicenter registries and randomized trials are needed to scrutinize the value of the LAmbre™ compared with established LAAC devices.

The association between epicardial adipose tissue thickness around the right ventricular free wall evaluated by transthoracic echocardiography and left atrial appendage function

Epicardial adipose tissue (EAT) is associated with the development of atrial fibrillation (AF). EAT thickness identified on transthoracic echocardiography (TTE). The relationship between EAT volume and left atrial appendage (LAA) function is not well-known. We aimed to investigate the associations between EAT thickness and LAA emptying flow velocity and LAA orifice area. This single-center retrospective study enrolled 202 patients who underwent both TTE and transesophageal echocardiography (TEE). EAT thickness was measured on TTE in parasternal long-axis view. We measured LAA orifice areas in 41 patients with 3-dimensional TEE data. Spearman's correlation coefficient was used to determine the relationships between EAT thickness and LAA emptying flow velocity and LAA orifice area. We created a receiver operating characteristic curve for low LAA emptying flow velocity (< 20 cm/s) and determined the best cutoff for EAT thickness according to the maximum Youden index. There was a significant negative correlation between EAT thickness and LAA emptying flow velocity (ρ = - 0.56, P < 0.001) and a significant positive correlation between EAT thickness and LAA orifice area (ρ = 0.38, P = 0.014). The best EAT thickness cutoff value for low LAA emptying flow velocity was > 5.1 mm (c-statistics, 75.7%). A thickened EATT was associated with low LAA emptying flow velocity, which increases the risk of thromboembolic phenomena in the presence of AF.

Difference in left atrial appendage remodeling between diabetic and nondiabetic patients with atrial fibrillation

Background

Diabetes mellitus (DM) is a common and increasingly prevalent condition in patients with atrial fibrillation (AFib). The left atrium appendage (LAA), a small outpouch from the LA, is the most common location for thrombus formation in patients with AFib.

Hypothesis

In this study, we examined LAA remodeling differences between diabetic and nondiabetic patients with AFib.

Methods

This retrospective study analyzed data from 242 subjects subdivided into two subgroups of 122 with DM (diabetic group) and 120 without DM (nondiabetic group). The study group underwent real‐time 3‐dimensional transesophageal echocardiography (RT3DTEE) for AFib ablation, cardioversion, or LAA device closure. The LAA dimensions were measured using the “Yosefy rotational 3DTEE method.”

Results

The RT3DTEE analysis revealed that diabetic patients display larger LAA diameters, D1‐lengh (2.09 ± 0.50 vs 1.88 ± 0.54 cm, P = .003), D2‐width (1.70 ± 0.48 vs 1.55 ± 0.55 cm, P = .024), D3‐depth (2.21 ± 0.75 vs 1.99 ± 0.65 cm, P = .017), larger orifice areas (2.8 ± 1.35 and 2.3 ± 1.49 cm², P = .004), and diminished orifice flow velocity (37.3 ± 17.6 and 43.7 ± 19.5 cm/sec, P = .008).

Conclusions

Adverse LAA remodeling in DM patients with AFib is characterized by significantly LAA orifice enlargement and reduced orifice flow velocity. Analysis of LAA geometry and hemodynamics may have clinical implications in thrombotic risk assessment and treatment of DM patients with AFib.

Novel Echocardiographic Biomarkers in the Management of Atrial Fibrillation

Purpose of Review

Atrial fibrillation (AF) is the most common arrhythmia in adults. The number of patients with AF is anticipated to increase annually, mainly due to the aging population alongside improved arrhythmia detection. AF is associated with a significantly elevated risk of hospitalization, stroke, thromboembolism, heart failure, and all-cause mortality. Echocardiography is one of the key components of routine assessment and management of AF. Therefore, the aim of this review is to briefly summarize current knowledge on “novel” echocardiographic parameters that may be of value in the management of AF patients.

Recent Findings

Novel echocardiographic biomarkers and their clinical application related to the management of AF have been taken into consideration. Both standard parameters such as atrial size and volume but also novels like atrial strain and tissue Doppler techniques have been analyzed.

Summary

A number of novel echocardiographic parameters have been proven to enable early detection of left atrial dysfunction along with increased diagnosis accuracy. This concerns particularly experienced echocardiographers. Hence, these techniques might improve the prediction of stroke and thromboembolic events among AF patients and need to be further developed and disseminated. Nonetheless, even the standard imaging parameters could be of significant value and should not be discontinued in everyday clinical practice.

Comparison of echocardiographic and fluoroscopic sizing of the left atrial appendage prior to percutaneous closure

PURPOSE

Sizing of the left atrial appendage (LAA) ostium prior to occlusion (LAAO) is routinely performed with transesophageal echocardiography (TEE). We sought to compare the utility of sizing via fluoroscopy to TEE for percutaneous LAAO.

METHODS

We retrospectively evaluated all patients undergoing percutaneous LAAO at our institution from April 2015 through January 2018 (n = 195). We evaluated baseline characteristics, maximum measured ostium size (for both TEE and fluoroscopy), and differences in measured size to device size for both techniques.

RESULTS

Of the total cohort, 185 (95%) had both intraoperative TEE and fluoroscopic images available for analysis and were included in the final analysis. The mean age was 74 years and 64% were male. Hypertension was present in 89%, diabetes in 30%, and stroke in 32% of patients. The mean ejection fraction was 51%. The most common LAA morphology was "wind sock" (52%). Measured ostial diameter on fluoroscopy was larger compared with TEE (2.04 ± 3.43 mm larger on fluoroscopy, p < 0.001). Ostium diameter on TEE was more closely correlated to the size of the device implanted compared with fluoroscopy (0.76 vs. 0.61, p = 0.001).

CONCLUSIONS

Fluoroscopy results in larger estimated LAA ostium diameter compared with TEE. Despite this, TEE was more strongly correlated to operator choice in device sizing, which may reflect practice patterns. Because compression of the ostium on the device is necessary for long-term procedural success, under-sizing may lead to a higher rate of leaks. Prospective evaluation of the utility of routine fluoroscopic sizing compared with TEE is warranted.

Roles of Transesophageal Echocardiography and Cardiac Computed Tomography for Evaluation of Left Atrial Thrombus and Associated Pathology: A Review and Critical Analysis

Evaluation of the left atrium and left atrial appendage for the presence of thrombus prior to cardioversion and pulmonary vein isolation, and of the entire heart for embolic sources in the setting of cryptogenic stroke, has long been standard medical care. Guidelines have uniformly recommended transesophageal echocardiography (TEE) to accomplish these goals. In recent years, computed tomographic angiography has demonstrated diagnostic accuracy similar to that of TEE for the detection of thrombus. Analysis of the pertinent data and relative merits of the 2 technologies leads to the conclusions that: 1) both modalities have some unique, nonoverlapping capabilities that may dictate their use in specific situations; 2) computed tomographic angiography is a reasonable alternative to TEE when the primary aim is to exclude left atrial and left atrial appendage thrombus and in patients in whom the risks associated with TEE outweigh the benefits; and 3) both options should be discussed with the patient in the setting of shared decision making.

Morphologic and functional features of left atrial appendage in Iranian population: an echocardiographic study

Introduction: Cardioembolic events are accompanied by left atrial appendage (LAA) in patients suffering from atrial fibrillation (AF); therefore, the LAA closure is implemented as a preventive strategy. The detection of LAA morphologies and function is a paramount step before establishing the LAA closure. Herein, we sought to determine the morphologic features of the LAA in an Iranian population using echocardiographic evaluation.

Methods: Seventy-two near-normal heart patients were investigated by conducting a cross-sectional study. All patients were examined using the 2-dimensional and 3-dimensional transesophageal echocardiography (2D- and 3D-TEE) method. The anatomical features and functions of LAA were examined. All images were stored and analyzed offline.

Results: The patients’ mean age was 39 ± 15.5 year and 33 (45.8%) were female. The most frequent shape of LAA was wind sock . More LAA lobes was observed in patients with AF compared to those with NSR. In comparison with AF group, the NSR had higher LAA flow velocity (P < 0.01). The paroxysmal AF had greater LAA flow velocity and LAA ejection fraction in comparison with the chronic AF (39 ± 19 vs. 75 ± 22, P < 0.01; and 49±4 vs. 72±14, P < 0.003; respectively). The paroxysmal AF had smaller systolic LAA orifice area in comparison with the chronic AF (P < 0.02).

Conclusion: The morphologic features of LAA in Iranian population were within the range of other studies and LAA length and orifice diameters in 2D- and 3D-TEE were consistent. In addition, AF influenced the morphologies and functions of LAA compared to sinus rhythm.