Left Atrial Appendage Anatomy Research Articles

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.

Left atrial, pulmonary vein, and left atrial appendage anatomy in Indigenous individuals: Implications for atrial fibrillation.

BackgroundIndigenous Australians experience a greater burden of AF. Whether this is in-part due to differences in arrhythmogenic structures that appear to contribute to AF differences amongst other ethnicities is not known.MethodsWe studied forty individuals matched for ethnicity and other AF risk factors. Computed tomography imaging was used to characterise left atrial (LA), pulmonary vein (PV), and left atrial appendage (LAA) anatomy.ResultsThere were no significant differences in LA diameters or volumes between Indigenous and non-Indigenous Australians. Similarly, we could not detect any consistent differences in PV number, morphology, diameters, or ostial characteristics according to ethnicity. LAA analyses suggested that Indigenous Australians may have a greater proportion of non chickenwing LAA type, and a tendency for eccentric, oval-shaped LAA ostia; however, there were no other differences seen with regards to LAA volume or depth. Indexed values for LA, PV and LAA anatomy corrected for body size were broadly similar.ConclusionsIn a cohort of individuals matched for AF risk factors, we could find no strong evidence of ethnic differences in LA, PV, and LAA characteristics that may explain a predisposition of Indigenous Australians for atrial arrhythmogenesis. These findings, in conjunction with our previous data showing highly prevalent cardiometabolic risk factors in Indigenous Australians with AF, suggest that it is these conditions that are more likely responsible for the AF substrate in these individuals. Continued efforts should therefore be directed towards risk factor management in an attempt to prevent and minimise the effects of AF in Indigenous Australians.

Assessment of the left atrial appendage morphology in patients after ischemic stroke — The ASSAM study

BackgroundThe ASSAM study was designed to evaluate the association between left atrial appendage (LAA) morphology and stroke risk in patients with atrial fibrillation (AF). MethodsThe study included 85 randomly chosen AF patients with acute ischemic stroke matched with 84 AF without stroke. All patients had left atrial (LA) computed tomography performed to analyze LAA anatomy. ResultsPatients in the stroke group had a larger LAA volume (10.22 [7.83–13.62] vs. 9.33 cm3 [7.33–11.47], p = 0.046], greater distance from LAA ostium to the first LAA bend (9.25 ± 3.85 vs. 7.23 ± 2.95 mm, p = 0.0002), and more frequently had round LAA ostium shape (11.8 vs. 1.2%, p = 0.005). According to a multivariable model, significant predictors of ischemic stroke were distance from LAA ostium to the first LAA bend (OR 1.202 [1.065–1.356], p = 0.003), LAA ostium round shape of (OR 16.813 [1.857–152.231], p = 0.012), LAA ostium surface area (OR 0.612 [0.457–0.819], p = 0.009), and cactus LAA morphology (OR 2.739 [1.176–6.380], p = 0.016). After adjusting for CHA2DS2-VASc score, only the distance from LAA ostium to the first LAA bend remained a significant risk factor for stroke (OR 1.154 [1.014–1.314], p = 0.03). ConclusionsThe distance from LAA ostium to the first bend of the LAA was independently associated with stroke risk in patients with AF. Whether this parameter may help improve identification of patients at risk of ischemic stroke, needs to be confirmed in larger studies.

Double device closure for large or bilobar left atrial appendage anatomy.

To assess the safety and feasibility of double device closure of large or bilobar left atrial appendages (LAAs). Procedural details and mid-term outcomes of 8 consecutive patients who underwent LAAO with double devices were described. Mean age was 75.9±6.0 years, mean CHA2DS2VASc score was 5.3±1.4, and mean HASBLED score was 3.0±1.5. The mean minimal and maximal diameters of the LAA orifice were 20.8±6.5mm and 26.7±6.7mm, respectively. The Watchman device was the first device in all cases. The second device was Watchman in 1 patient (12.5%), and Amplatzer vascular plug- II (AVP) in 7 (87.5%). Simultaneous deployment via 2 transseptal punctures was utilized in 3 patients, and sequential deployment via a single puncture was used in the other 5. Procedural success was achieved in 100%. There were no 30-day mortality or major complications. No device-related thrombus or major peri-device leak were detected on follow-up imaging. At mid-term follow up (median=142, range=67-539 days), 1 patient died due to intra-cranial hemorrhage while on dual antiplatelets. No other major adverse events were observed. Double device LAA occlusion may provide a feasible and effective alternative stroke prevention strategy for patients with challenging LAA anatomies that have no other feasible options.

Abstract 17421: Use of a Novel Septal Occluder Device for Left Atrial Appendage Closure in Patients With Post-Surgical and Post-Lariat Leaks or Anatomies Unsuitable for Conventional Percutaneous Occlusion

Introduction: Interventional therapies aiming at excluding the left atrial appendage (LAA) from systemic circulation have been established as a valid alternative to oral anticoagulation (OAC) in patients at high thromboembolic (TE) risk. However, their efficacy on stroke prophylaxis may be compromised owing to incomplete LAA closure. Additionally, the need for an alternative TE prevention may remain unmet in patients with contraindications to OAC whose appendage anatomy is unsuitable for some conventional devices commercially available. Hypothesis: We aimed at evaluating the feasibility of LAA closure with the novel Gore® Cardioform Septal Occluder (CSO) in patients with incomplete appendage ligation or anatomical features which do not meet the manufacturer’s requirements for Watchman deployment. Methods: Twenty-one consecutive patients (mean age: 72±6 years; 85.7% males; CHA 2 DS 2 -VASc: 4.5±1.4; HAS-BLED: 3.6±1.0) were included. Trans-esophageal echocardiography (TEE) was performed within 2 months to assess for residual LAA patency. Results: Fourteen patients had incomplete LAA closure following surgical (n=6) or Lariat ligation (n=8). In 7 patients with an appendage anatomy unsuitable for Watchman deployment, the mean maximal landing zone size and LAA depth were 14.4±1.3mm and 18.6±2.8mm. Successful CSO deployment was achieved in all patients. No peri-procedural complications were documented.Procedure and fluoroscopy times were 46±13min and 14±5min. Follow-up TEE after 58±9 days revealed complete LAA closure in all patients. Conclusions: Transcatheter LAA closure via a CSO device might be a valid alternative in patients with residual leaks following failed appendage ligation or whose LAA anatomy does not meet the minimal anatomical criteria to accommodate a Watchman device.

Use of a Novel Septal Occluder Device for Left Atrial Appendage Closure in Patients With Postsurgical and Postlariat Leaks or Anatomies Unsuitable for Conventional Percutaneous Occlusion.

Interventional therapies aiming at excluding the left atrial appendage (LAA) from systemic circulation have been established as a valid alternative to oral anticoagulation in patients at high thromboembolic risk. However, their efficacy on stroke prophylaxis may be compromised owing to incomplete LAA closure. Additionally, the need for an alternative thromboembolic prevention may remain unmet in patients with contraindications to oral anticoagulation whose appendage anatomy is unsuitable for some conventional devices commercially available. We aimed at evaluating the feasibility of LAA closure with the novel Gore Cardioform Septal Occluder in patients with incomplete appendage ligation or anatomic features which do not meet the manufacturer's requirements for Watchman deployment. Twenty-one consecutive patients (mean age: 72±6 years; 85.7% males; CHA2DS2-VASc: 4.5±1.4; HAS-BLED: 3.6±1.0) were included. Transesophageal echocardiography was performed within 2 months to assess for residual LAA patency. Fourteen patients had incomplete LAA closure following surgical (n=6) or Lariat ligation (n=8). In 7 patients with an appendage anatomy unsuitable for Watchman deployment, the mean maximal landing zone size and LAA depth were 14.4±1.3 and 18.6±2.8 mm. Successful Cardioform Septal Occluder deployment was achieved in all patients. No peri-procedural complications were documented. Procedure and fluoroscopy times were 46±13 and 14±5 minutes. Follow-up transesophageal echocardiography after 58±9 days revealed complete LAA closure in all patients. Transcatheter LAA closure via a Cardioform Septal Occluder device might be a valid alternative in patients with residual leaks following failed appendage ligation or whose LAA anatomy does not meet the minimal anatomic criteria to accommodate a Watchman device. Graphic Abstract: A graphic abstract is available for this article.

The left atrial appendage morphology and gender differences by multi-detector computed tomography in an Egyptian population

BackgroundThe left atrial appendage (LAA) is the main source of thromboembolism in patients with non-valvular atrial fibrillation. Unique LAA morphologies have been associated with the risk of thromboembolism. This study investigates the LAA anatomy in the Egyptian population using cardiac multi-detector computed tomography (MDCT).ResultsWe included 252 consecutive patients presenting for coronary computed tomography angiography in 2 tertiary centers in Egypt in the period from January to July 2017. Patients with atrial fibrillation, valvular affection, or left ventricular dysfunction were excluded. Two and three-dimensional cardiac MDCT images were assessed for LAA morphology, volume, length, and orifice position. The distribution of LAA morphologies was windsock (32.5%), chicken wing (25.4%), cauliflower (22.6%), and cactus (19.4%). Differences in the LAA dimensions in the 4 morphological variants were described. Females were less likely to have a chicken wing LAA morphology compared to males (7.9% vs 34.7%, p value < 0.01), and had a larger LAA volume, smaller LAA length, and a higher prevalence of high LAA orifice position.ConclusionsThe most common LAA morphology in our study population is windsock, which may represent the Egyptian population or patients in sinus rhythm. Females were less likely to have a chicken wing LAA morphology, and had a larger LAA volume, smaller length, and higher incidence of high orifice position. Clinical correlation into the translation of these differences into thromboembolic risk is required.

Left Atrial Appendage Anatomy: Implications for Endocardial Catheter-based Device Closure.

This clinical review focuses on both current devices approved by the United States Food and Drug Administration and investigational devices available for left atrial appendage (LAA) closure. Specifically, the article describes the anatomical considerations that are particularly relevant from a procedural standpoint. In addition, we have also focused on the technical aspects of the procedure.

Personalized Fluoroscopic Angles in Watchman™ Left Atrial Appendage Closure Landing Zone Assessment: A Three-Dimensional Printed Simulation Study.

BackgroundAtrial fibrillation causes ischemic stroke when thrombi dislodge from a cardiac outpouching, the left atrial appendage (LAA), and embolize to the brain. LAA occlusion with the Watchman™ device (Boston Scientific Corporation, MA, USA), which prevents stroke, requires accurate LAA measurements for device sizing. We explore whether standard fluoroscopic LAA measurements improve when obtained at CT-derived viewing angles personalized to LAA anatomy while concurrently referring to three-dimensional (3D) CT.MethodsLeft atrial 3D reconstructions created from contrast CT (n=28) were analysed to identify personalized viewing angles wherein LAA dimensions (LAA maximum landing zone diameter and LAA length) were best observed. The 3D-CT reconstructions were then 3D printed with stands. Fluoroscopy of anatomically oriented models in the catheter lab simulated LAA angiography. Fluoroscopic images were acquired at standard (caudal 20˚/right anterior oblique 30˚) and personalized viewing angles. Repeated measurements of LAA dimensions were taken from CT (Control), fluoroscopy at standard angles (Standard), personalized angles (Blinded), and personalized angles while concurrently referring to 3D CT (Referred).ResultsControl measurements correlated and agreed better with Referred and Blinded measurements than with Standard measurements (diameter correlation and agreement: Control/Standard r=.554, limits of agreement [LOAs]=6.83/-5.91; Control/Blinded r=.641, LOA =5.67/-5.54; Control/Referred r=.741, LOA=4.69/-4.14; length correlation and agreement: Control/Standard rs=.829, LOA=9.61/-3.02; Control/Blinded rs=0.789, LOA=7.13/-4.94; Control/Referred rs=.907, LOA=4.84/-4.13). Personalized angles resulted in hypothetical device size predictions more consistent with Control (device size correlation: Control/Standard rs=.698, Control/Blinded rs=.731, Control/Referred rs=.893, P<0.001). False ineligibility rates were Standard=6/28, Blinded=6/28, and Referred=2/28.ConclusionThis simulation suggests that personalized fluoroscopic viewing angles with in-procedural reference to 3D CT may improve the accuracy of LAA maximum landing zone diameter and length measurements at the Watchman landing zone. This improvement may result in more consistent device size selection and procedural eligibility assessment. Further clinical research on these interventions is merited.

Challenging Left Atrial Appendage Closure Using Intraprocedural Cardiac CT Guidance

Percutaneous left atrial appendage (LAA) closure has become an attractive alternative to long-term anticoagulation for prevention of stroke in patients with atrial fibrillation ([1][1]). However, there is great variability in LAA anatomy among patients ([2][2]). Therefore, advanced cardiac imaging

Left Atrial Appendage Closure: Technical Considerations of Endocardial Closure.

Left atrial appendage closure (LAAC) is a safe and effective therapy for the prevention of stroke in patients with nonvalvular atrial fibrillation and high bleeding risk with oral anticoagulants. Multimodality imaging with transesophageal echocardiography and computed tomography angiography to define the anatomy and its implications on endocardial exclusion is becoming increasingly important. The only LAAC device currently approved for clinical use in the United States is the WATCHMAN device. Systematic assessment of the transseptal crossing site, left atrial appendage anatomy, adequate device size selection, and device postdeployment evaluation is essential for the safety and efficacy of the procedure.

CRT-600.34 Are There Gender Disparities in Presentation and Left Atrial Anatomy in Adults With Atrial Fibrillation Undergoing Watchman Left Atrial Appendage Occlusion?

Left atrial appendage (LAA) occlusion has become the mainstay for treatment in adults with atrial fibrillation (AF) and a high bleeding risk. While accurate device sizing is critical for successful LAA occlusion and optimal clinical outcomes, it is unknown whether gender impacts LAA anatomy and

701 Left Atrial, Pulmonary Vein, and Left Atrial Appendage Anatomy in Indigenous Individuals: Implications for Atrial Fibrillation

701 Left Atrial, Pulmonary Vein, and Left Atrial Appendage Anatomy in Indigenous Individuals: Implications for Atrial Fibrillation

Anatomic Considerations for Epicardial and Endocardial Left Atrial Appendage Closure

Left atrial appendage closure is an increasingly used means of achieving thromboprophylaxis in atrial fibrillation, particularly in patients with contraindications to anticoagulation. Left atrial appendage anatomy is highly variable, and preprocedural imaging is critical to choosing the correct device and approach for left atrial appendage closure. This article reviews the common endocardial and epicardial closure systems, including anatomic considerations, advantages and disadvantages, as well as complications to be avoided.

Lifetech LAmbre: a new promising and novel device in the interventional stroke prevention.

The advances in the left atrial appendage closure as a stroke prevention method in patients with atrial fibrillation and contraindications to oral anticoagulants made a huge revolution offering a great alternative for patients with a high risk of bleeding. The nitinol-based, self-expanding LAmbre closure system shows promising initial results in terms of efficacy and safety in worldwide different clinical trials offering an alternative to the known Amulet and Watchman closure systems. Lifetech received CE Mark approval for the LAmbre closure system on 15 June 2016. Different studies have shown encouraging results in terms of feasibility and efficacy of the novel occluder. The favorable device design gives a big advantage in the occlusion of difficult left atrial appendage anatomy.

Photorealistic imaging of left atrial appendage occlusion/exclusion.

Recent improvements in 3D TEE post processing rendering techniques referred to as TrueVue (Philips Medical Systems, Andover, MA, USA). It allows for novel photorealistic imaging of cardiac structures including left atrial appendage (LAA) and its closure devices. Here we present TrueVue images of the LAA prior to and after LAA exclusion/occlusion using various percutaneous and surgical techniques. TrueVue may improve delineation of LAA anatomy prior to occlusion as well as visualization of occluder device position within the LAA.