Left Atrial Appendage Lobes Research Articles

Left atrial appendage geometry and function using transesophageal three-dimensional echocardiography in atrial fibrillation: a new approach to characterize left atrial thrombogenic milieu

Abstract Background Little data is available on the evaluation of left atrial appendage (LAA) geometry and function using three-Dimensional (3D) transoesophageal echocardiography (TEE). Purpose We hypothesized that 3D LAA geometry evaluated using dedicated TEE software could be integrated in the evaluation of the thromboembolic milieu in patients hospitalized for atrial fibrillation (AF). Methods We prospectively studied 206 hospitalized patients with AF with two-dimensional transthoracic echocardiography (TTE) and 3D TEE of the LAA within 24 hours of admission. 3D parameters were analysed off-line using Tomtec software (4D Cardio-View, Generic Volume, Philips) (Figure 1). Patients were divided into two groups according to the presence (n = 35) or absence (n = 171) of LAA sludge/thrombus on admission. Results Patients with LAA sludge/thrombus had more frequently a history of heart failure together with higher values of BNP, CRP and hemoglobin. These patients received less frequently angiotensin II receptor antagonist treatment on admission. Concerning the echocardiographic characteristics, patients with LAA sludge/thrombus exhibited higher left atrial (LA) volume, lower left ventricular ejection fraction (LVEF) and cardiac output. In the 2D TEE study they had lower LAA emptying and filling flow velocities compared to those without sludge/thrombus. 3D TEE showed overall higher 3D end-systolic (ES) and end-diastolic (ED) LAA measurements (ostium area, length, volume), and more frequently the absence of a chicken wing morphology. There were no intergroup differences regarding the number of LAA lobes (Table 1). Conclusion 3D characterization of LAA geometry and function depicts a degree of appendage remodeling in AF that appears to be associated with the degree of thrombogenicity. Further investigation is needed to determine the impact of this remodeling on outcomes in these patients.

Association Between Left Atrial Appendage Morphology and Function and the Risk of Ischaemic Stroke in Patients with Atrial Fibrillation.

AF is the most common cardiac arrhythmia and has been identified as an independent risk factor for stroke. The European Society of Cardiology guidelines recommend a thromboembolic event risk assessment based on the CHA2DS2-VASc score. However, stroke also occurs in some patients with a low CHA2DS2-VASc score. Therefore, it is necessary to find new factors to improve thromboembolic risk stratification in AF patients. Over 90% of embolic strokes are caused by thrombi originating from the left atrial appendage (LAA). Thus, certain anatomical or functional parameters of the LAA could potentially be used to predict cardioembolic stroke. Studies have suggested that some of these factors, such as LAA morphology, number of LAA lobes, LAA dimensions, LAA volume, distance from the LAA ostium to the first bend of LAA, LAA orifice diameter, extent of LAA trabeculations, LAA takeoff, LAA flow velocity and LAA strain rate, are independently associated with a higher risk of stroke in a population of patients with AF and improve the performance of the CHA2DS2-VASc score. However, the results are conflicting and, so far, no new parameter has been added to the CHA2DS2-VASc score.

Relations between left atrial appendage contrast retention and thromboembolic risk in patients with atrial fibrillation.

Left atrial appendage (LAA), a blind pouch, accounts for more than 90% of the source of cardiac thrombus formation. Contrast retention (CR) in the LAA has been frequently observed during left atrial appendage occlusion (LAAO) procedures, especially in patients with stroke history. This study was designed to assess the relations between LAA contrast retention and thrombogenesis risk of the LAA in patients with non-valvular atrial fibrillation. A total of 132 consecutive patients who underwent LAAO were enrolled. The data collected from computed tomography (CT), transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and blood samples were analyzed. Univariate and multivariate logistic regression models were constructed to assess the association between CR, left atrial appendage thrombus (LAAT) and other factors. Contrast retention was observed in 33 patients, accounting for 25% of the population. Compared to the non-CR group, patients in the CR group had a larger left atrium anteroposterior diameter (49.64 ± 11.57 vs. 42.42 ± 7.04, P = 0.002), higher CHADS2 (3.88 ± 0.99 vs. 2.97 ± 1.35, P = 0.001) and CHA2DS2-VASc scores (5.79 ± 1.14 vs. 4.89 ± 1.56, P = 0.003), a higher rate of prior stroke (90.9% vs. 66.7%, P = 0.007), more LAA lobes (3.13 ± 1.18 vs. 2.64 ± 1.12, P = 0.038), and a higher prevalence of LAAT (63.6% vs. 13.1%, P < 0.001). After having adjusted the logistic model, only contrast retention, LAA cauliflower morphology and left ventricular ejection fraction (LVEF) were independently associated with LAAT. Patients with LAA contrast retention have a higher risk of left atrial appendage thrombosis. Contrast retention may be a cardiac factor strongly associated with cardiogenic stroke.

Are Three Weeks of Oral Anticoagulation Sufficient for Safe Cardioversion in Atrial Fibrillation?

Background and Objectives: Patients with atrial fibrillation (AF), lasting >48 h, considered for cardioversion, are recommended ≥3 weeks of oral anticoagulation before sinus rhythm restoration because of high risk of development of left atrial thrombosis (LAT) and stroke. However, the optimal duration of anticoagulation in the presence of overt LAT is unknown. Materials and Methods: An open-label study aimed to investigate the prevalence of spontaneous echo contrast (SEC) and LAT before and after 3 weeks of direct oral anticoagulant (DOAC) treatment. We included 51 consecutive patients (50.9% males), mean age 69.3 ± 7.4 years with paroxysmal/unknown duration of AF, considered for cardioversion, who agreed to have transesophageal echocardiography at enrollment and 3 weeks later. Results: At baseline SEC was present in 26 (50.9%) and LAT in 10 (19.6%) of 51 patients. After 3 weeks on DOAC, SEC persisted in 12 (25.0%) and LAT in 7 (14.5%) of 48 patients, p < 0.05 vs. baseline. Factors, associated most strongly with persistence of SEC/LAT, were left atrial appendage (LAA) emptying velocity <20 cm/s (OR = 2.82), LAA lobes >2 (OR = 1.84), and indexed left atrial volume ≥34 mL/m2 (OR = 1.37). Conclusions: In our study the incidence of SEC/LAT, particularly in AF with unknown duration, was not as low as we expected. The prevalence of SEC/LAT seemed to be dependent on factors not routinely evaluated in AF patients planned for cardioversion (indexed LA volume, LAA morphology and number of lobules, LAA emptying velocity, etc.). Our data suggested an individualized approach for DOAC duration in AF patients before an attempt for restoration of sinus rhythm is made, taking into consideration the LAA morphology and function.

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 appendage morphology and the risk of stroke

Abstract In patients with non-valvular atrial fibrillation (AF) the risk of stroke is five times higher than in patients with sinus rhythm. Moreover, stroke is likely to be more severe in the AF patient population. Left atrial appendage (LAA) is the most common source of emboli in AF-related stroke. LAA thrombus is present in 15% of AF patients. Therefore, numerous studies aimed to evaluate the role of LAA structure and function in stroke formation. Higher LAA volume and bigger LAA orifice have been reported to be associated with increased risks of stroke. Moreover, not only the size, but also the shape of the LAA influences thrombus formation. The presence of an obvious bend in the proximal part of the dominant LAA lobe, described as chicken wing LAA morphology has been reported to be protective against stroke. However, other studies are not consistent with this finding and there is no consensus about LAA morphology categories. LAA has reservoir, contractile, electric and endocrine functions, that can provide essential information about the risk of clot formation and embolic events. Decreased LAA flow velocity, reflecting lower LAA contractility has been described to be associated with higher stroke risk. All in all, even if the LAA plays an important role in stroke formation, there are controversial literature data, therefore further studies are needed to evaluate the underlying mechanisms.

Left Atrial Appendage Morphology and Left Atrial Wall Thickness Are Associated with Cardio-Embolic Stroke.

Background. New markers for stroke risk stratification in patients with atrial fibrillation (AF) are on demand. Hence, we aimed to investigate the association of left atrial appendage (LAA) and left atrium (LA) morphological parameters in patients with cardio-embolic (CE) stroke due to AF in comparison to controls without stroke. Methods: A retrospective analysis of cardiac computed tomography angiography (CTA) examinations performed between 2006 and 2017 for clinical indications in 158 patients (median age 65 (54–73) years, 48.7% females) was conducted: 56 patients with CE stroke were compared to 102 controls not differing in gender, body mass index (BMI) and CHA2DS2-VASc score. Results: On multivariable regression analysis adjusted for CHA2DS2-VASc score and LA diameter CE stroke was independently associated with the following parameters: windsock LAA type (OR 2.55; CI: 1.04–6.26, p = 0.041), a greater lobe number (OR 1.54; CI: 1.13–2.10, p = 0.006), a greater LAA ostium area (OR 1.88; CI: 1.38–2.55, p < 0.001) and a greater left atrium wall thickness (LAWT) in the middle and right part, measured along the anterior LA wall in the axial plane (respectively, OR 1.94; CI: 1.26–3.0, p = 0.003 and OR 1.57; CI: 1.07–2.31, p = 0.021). Conclusions: The windsock LAA type, a greater LAA lobe number, a larger LAA ostium and a greater LAWT are associated with CE stroke. These CTA parameters could improve risk stratification for thromboembolic stroke.

A collective European experience with left atrial appendage suture ligation using the LARIAT+ device.

We report the collective European experience of percutaneous left atrial appendage (LAA) suture ligation using the recent generation LARIAT+ suture delivery device. A total of 141 patients with non-valvular atrial fibrillation and contraindication to oral anticoagulation (OAC), thrombo-embolic events despite OAC or electrical LAA isolation were enrolled at seven European hospitals to undergo LAA ligation. Patients were followed up by clinical visits and transoesophageal echocardiography (TOE) following LAA closure. Left atrial appendage ligation was completed in 138/141 patients (97.8%). Three patients did not undergo attempted deployment of the LARIAT device due to pericardial adhesion after previous epicardial ventricular tachycardia ablation (n = 1), a pericardial access-related complication (n = 1), and multiple posterior LAA lobes (n = 1). Serious 30-day procedural adverse events occurred in 4/141 patients (2.8%). There were two device-related LAA perforations (1.4%) not resulting in any corrective intervention as the LAA was completely sealed with the LARIAT. Minor adverse events occurred in 19 patients (13.5%), including two pericardial effusions due to procedure-related pericarditis requiring pericardiocentesis. Transoesophageal echocardiography was performed after LAA ligation in 103/138 patients (74.6%) after a mean of 181 ± 72 days. Complete LAA closure was documented in 100 patients (97.1%). Two patients (1.8% of patients with follow-up) experienced a transient ischaemic attack at 4 and 7 months follow-up, although there was no leak observed with TOE. There were two deaths during long-term follow-up which were both not device related. Initial experience with the LARIAT+ device demonstrates feasibility of LAA exclusion. Further larger prospective studies with longer follow-up are warranted.

P3383Left atrial appendage and left atrial morphology is associated with cryptogenic stroke

Abstract Background Stroke causes a high burden of morbidity and mortality worldwide. Approximately 30% of stroke cases remain cryptogenic (CS), of which one third is due to occult atrial fibrillation (AF) with left atrial appendage (LAA) being the most frequent thrombus source. Hence, aim of our study was to assess if LAA morphological parameters analysed by computed tomography angiography (CTA) are associated with CS. Methods and materials In 184 patients (Table 1), 82 CS patients and 102 controls (age median 62 (52,2–72), 40.2% females), matched for BMI, a CTA was performed, and LAA morphology evaluated retrospectively. LAA morphology was classified into 5 types (Figure 1): Cactus, Cauliflower, Chicken-wing, Windsock and the new “Seahorse” with a distinctive tip angulation of ≤90° and 2 bends (Z-shape). Further measurements included: LAA tip angulation (≤90°, 91–110°, &gt;110°), LAA lobe number, LAA ostium size (length) and angulation, left atrium wall thickness (LAWT). Results LAA and left atrium (LA) parameters associated with CS on multivariable analysis after adjusting for CHA2DS2-VASc score were: Chicken-wing type (OR 2.15; 95% CI: 1.01–4.56, p=0.046), a greater lobe number (OR 2.01; 95% CI: 1.52–2.64, p&lt;0.001), a greater middle and mean LAWT (respectively, OR 2.13; 95% CI: 1.49–3.05, p&lt;0.001, OR 2.64; 95% CI: 1.63–4.29, p&lt;0.001), a larger (length, OR 1.08; 95% CI: 1.0–1.16, p=0.039) and a less bent LAA ostium (OR 1.02; 95% CI: 1.01–1.03, p=0.006). In contrast, a sharp-angled LAA tip (≤90°) was protective from CS (OR 0.43; 95% CI: 0.23–0.83, p=0.012) on multivariable analysis. Table1. Clinical patient characteristics CS (n=82) Non-stroke (n=102) p value Females 21 (25.6%) 53 (52%) p&lt;0.001 Age, y 66.5 (57–73) 57.5 (50–70) 0.001 BMI, kg/m2 25.6 (23.9–28.2) 26 (23.3–30.1) 0.320 CHA2DS2-VASc score 2 (1–3) 2 (1–3) 0.387 AF (paroxysmal/permanent) 0 4 0.071 Hypertension 68 (82.9%) 54 (56.3%) p&lt;0.001 Diabetes mellitus, type 2 16 (19.8%) 11 (11.5%) 0.145 Values are given in median ± IQR. AF, atrial fibrillation; BMI, body mass index. LAA and LA morphology in CTA. Conclusion In CS, a Chicken-wing LAA, a greater number of lobes and a thicker LA wall are independently associated with CS while a sharp LAA tip (≤90°) mostly seen in Seahorse type LAA is protective. Such “high-risk” LAA and LA morphology could help to select CS patients benefiting from extended rhythm-monitoring to detect an occult AF, however, further prospective studies are needed to confirm this hypothesis.

Percutaneous closure of the left atrial appendage: The value of real time 3D transesophageal echocardiography and the intraoperative change in the size of the left atrial appendage.

The aim of this study was to investigate the value of real time three-dimensional transesophageal echocardiography (RT3DTEE) in percutaneous closure of the left atrial appendage (LAAC). In addition, this study also explored the change in the size of the left atrial appendage (LAA) from 24hours before the operation to just before implantation during the operation. In a retrospective study, 32 patients underwent two-dimensional transesophageal echocardiography (2DTEE) and RT3DTEE 24hours prior to operation and during operation. The maximal LAA orifice diameter (by 2DTEE, 22.7±2.7 vs 24.6±2.2mm, P<0.01; by RT3DTEE, 24.2±2.9 vs 25.8±2.7mm, P<0.01), the maximal landing zone diameter (by 2DTEE, 19.0±2.8 vs 20.4±2.8mm, P<0.01; by RT3DTEE, 20.4±2.7 vs 22.6±3.0mm, P<0.01), and the maximal depth diameter (by 2DTEE, 25.2±3.2 vs 26.5±3.0mm, P<0.01; by RT3DTEE, 26.4±3.2 vs 27.5±3.7mm, P<0.01) all increased significantly during the operation. The highest correlation (R) between the maximal landing zone diameter and the compressed occluder diameter was determined for RT3DTEE measurements during the operation (R=0.90), whereas the landing zone diameter (R=0.80) measured by 2DTEE was less correlated. In addition, our study showed that RT3DTEE was of great value in discriminating the LAA orifice shape, allowing differentiation of the LAA morphology and identification of the number of LAA lobes. A certain amount of intravenous rehydration just before and during operation increased the LAA size significantly. The measurements by RT3DTEE showed a closer correlation to LAA occluder size than those by 2DTEE. The LAA displayed by RT3DTEE was more visible than that by 2DTEE.

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.

Predictive value of left atrial appendage lobes on left atrial thrombus or spontaneous echo contrast in patients with non-valvular atrial fibrillation

BackgroundLeft atrial appendage morphology has been proved to be an important predictor of left atrial thrombus (LAT) and left atrial spontaneous echo contrast (LASEC) and stroke in patients with non-valvular atrial fibrillation (NVAF). However, the relation between left atrial appendage (LAA) lobes and LAT or LASEC is still unknown. The aim of this study is to investigate the correlation between the number of left atrial appendage lobes and LAT/LASEC in patients with NVAF.MethodsThis monocentric cross-sectional study enrolled 472 consecutive patients with non-valvular atrial fibrillation, who had transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) prior to cardioversion or left atrial appendage closure (LAAC) from July 2009 to August 2015 in department of cardiology of Shanghai Tenth People’s Hospital. Patients who had significant mitral or aortic valve disease, previous cardiac valvular surgery and other complicated cardiac diseases were excluded. Individuals were divided into two groups:the LAT/LASEC group (16.95%), which comprised patients with LAT or LASEC, as confirmed by TEE; and a negative control group (83.05%).Baseline overall group characterization with demographic, clinical, laboratory data and echocardiographic parameters, alongside with information on medication was obtained for all patients. Subgroup analysis with line chart was applied for exploring the association between LAA lobes and LAT/LAESC. Receptor-operating curves (ROC) were used to test the value of LA anteroposterior diameter detected by different echocardiography methods predicting LAT or LASEC. Multivariable logistic regression analysis was used to investigate independent predictors of LAT/LASEC.ResultsAmong 472 patients, 23 (4.87%) had LA/LAA thrombus and 57 (12.1%) had LA spontaneous echo contrast. Compared to the negative group, patients in LAT/LASEC group had higher CHA2DS2-VASc score (3.79 ± 1.75 vs 2.65 ± 1.76, p < 0.001), larger LAD (measured by TTE, 48.1 ± 7.7 vs 44.6 ± 6.5, P < 0.001; measured by TEE, 52.2 ± 6.2 vs 46.7 ± 7.1, P < 0.001), lower left upper pulmonary venous flow velocity (LUPVFV) (0.54 ± 0.17 m/s vs 0.67 ± 0.26 m/s, CI 95% 0.05–0.22, P = 0.003), more left atrial appendage lobes (1.67 ± 0.77 vs 1.25 ± 0.50, p < 0.001). There was a good discriminative capacity for LAD detected by TTE (area under the curve (AUC), 0.67, CI 95% 0.61–0.73, p < 0.001) and LAD detected by TEE (AUC, 0.73, CI 95% 0.67–0.79, p < 0.001). The subgroup analysis based on gender and different LAA lobes yielded similar results (male group: p < 0.001;female group: p = 0.004) that the number of LAA lobes were significantly associated with LA thrombus or SEC. In multivariable logistic regression analysis, both the number of LAA lobes (odds ratio: 2.37; CI 95% 1.37–4.09; p = 0.002) and the persistent AF (odds ratio: 3.57; CI 95% 1.68–7.57; p = 0.001) provided independent and incremental predictive value beyond CHA2DS2-VASc score.ConclusionThe number of LAA lobes is an independent risk factor and has a moderate predictive value for LAT/LASEC among NVAF patients in China.

Abstract 11638: Angiographic Efficacy of the Atriclip Left Atrial Appendage (LAA) Exclusion Device Placed by Minimally Invasive Thoracoscopic Approach

Introduction: Closure of the LAA with an endocardial device is associated with a low risk for AF related embolic stroke. The Atriclip exclusion device (Atricure, Inc., West Chester, OH, USA) allows epicardial closure of the LAA, avoiding the need for oral anticoagulation (OAC) post procedure. We sought to assess long-term LAA closure efficacy of the Atriclip applied via totally thoracoscopic (TT) approach. Hypothesis: LAA closure efficacy will be high. Methods: We performed a prospective CT angiography (CTA) study of all TT placed Atriclips at Vanderbilt Medical Center implanted June 13, 2011 to October 6, 2015. All subjects provided informed consent under Vanderbilt IRB approved protocol. Intra-op TEE was performed in all cases to confirm procedural success. At a minimum of 90 days postimplant, 3-D volumetric two phase CTA was performed to assess the presence of contrast leak, exposed trabeculations, residual stump and clip position. All CTA interpretation and data was obtained by chest radiologists. Results: As of June 1, 2016, 63 patients completed CTA. The mean age was 64.8 ± 8.87 years and 77.8% were male. The majority of patients had persistent AF (82.5%). Mean CHADS2VASC score was 2.43 ± 1.44 and HASBLED was score 2.21 ± 1.23. Adequate LAA closure was defined as complete exclusion of the trabeculated LAA, which was confirmed in 59 subjects (93.6%). Cases without complete closure (n=4) include: 2 malpositioned clip not addressing a secondary LAA lobe, and 2 clips placed too distal leaving a stump with exposed trabeculae. Of the patients with complete closure, 30 (50.8%) had a smooth proximal stump. There were no major complications associated with TT placed Atriclips. Prospective follow-up over 143 observed patient-years reveals 1 stroke in a patient with documented complete LAA closure and no thrombus (hypertensive CVA). Conclusions: Angiographic LAA closure efficacy with a TT placed Atriclip is high (93.6%). The clinical significance of a remnant stump is unknown.

--LAA Occluder View for post-implantation Evaluation (LOVE)--standardized imaging proposal evaluating implanted left atrial appendage occlusion devices by cardiac computed tomography.

BackgroundA standardized imaging proposal evaluating implanted left atrial appendage (LAA) occlusion devices by cardiac computed tomography angiography (cCTA) has never been investigated.MethodscCTA datasets were acquired on a 3rd generation dual-source CT system and reconstructed with a slice thickness of 0.5 mm. An interdisciplinary evaluation was performed by two interventional cardiologists and one radiologist on a 3D multi-planar workstation. A standardized multi-planar reconstruction algorithm was developed in order to assess relevant clinical aspects of implanted LAA occlusion devices being outlined within a pictorial essay.ResultsThe following clinical aspects of implanted LAA occlusion devices were evaluated within the most appropriate cCTA multi-planar reconstruction: (1) topography to neighboring structures, (2) peri-device leaks, (3) coverage of LAA lobes, (4) indirect signs of neo-endothelialization. These are illustrated within concise CT imaging examples emphasizing the potential value of the proposed cCTA imaging algorithm: Starting from anatomical cCTA planes and stepwise angulation planes perpendicular to the base of the LAA devices generates an optimal LAA Occluder View for post-implantation Evaluation (LOVE). Aligned true axial, sagittal and coronal LOVE planes offer a standardized and detailed evaluation of LAA occlusion devices after percutaneous implantation.ConclusionsThis pictorial essay presents a standardized imaging proposal by cCTA using multi-planar reconstructions that enables systematical follow-up and comparison of patients after LAA occlusion device implantation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12880-016-0127-y) contains supplementary material, which is available to authorized users.

The use of real-time three-dimensional transesophageal echocardiography in percutaneous left atrial appendage occlusion

Objective To evaluate the role of real-time three-dimensional transesophageal echocardiography(RT-3D TEE) in left atrial appendage (LAA) occlusion. Methods Consecutive 10 atrial fibrillation (AF) patients (CHADS2≥2) with high risk bleeding underwent LAA occlusion under the guidance of TEE. The LAA orifice shape and characteristics of lobes were assessed, the size of LAA with RT-3D TEE wee measured before closer implanation, and the position of the LAA occlusion device were evaluated by RT-3D TEE.The correlational analysis between LAA diameter and occluder size was conducted. Results Among 10 patients, the test results revealed 8 cases with complete LAA occlusion and 1 case with incomplete occlusion, and 1 case with failed occlusion. Five cases showed approximate round LAA ostium, and the other 5 showed approximate oval ostium. The average number of LAA lobes were 2.2±0.7. LAA ostium long diameter were larger by 3D TEE compared with 2D TEE[(21.8±5.1)mm vs (20.8±4.1)mm], and ostium short diameter were smaller by 3D TEE compared with 2D TEE[(16.1±3.0)mm vs (17.0±2.6)mm], however there were no significant differences between 2D and 3D TEE measurements, and the mean ostium diameter and LAA depth were comparable between two methods. LAA ostium long diameter, short diameter, average diameter and LAA depth assessed by 3D TEE and 2D TEE showed good correlation with occluder diameter (3D TEE: r=0.719, 0.690, 0.791, 0.711, and P=0.029, 0.040, 0.011, 0.032, respectively; 2D TEE: r=0.887, 0.894, 0.932, 0.896, and P=0.001, 0.001, 0.000, 0.000, respectively). LAA occlusion device position assessed by RT-3D: 6 cases with appropriate position, acceptable position with 2 cases, and 1 case with malposition. Conclusions RT-3D TEE can play important role in evaluating the morphology of LAA, accurately judging LAA ostium shape and size and position of the occlusion device. Key words: Echocardiography, transesophageal; Echocardiography, real-time three-dimensional; Left atrial appendage; Occlusion

Morphological and volumetric analysis of left atrial appendage and left atrium: cardiac computed tomography-based reproducibility assessment.

ObjectivesLeft atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments.MethodsA total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N = 40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A = Cactus, B = ChickenWing, C = WindSock, D = CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa.ResultsThe intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC = 0.954) and LA (ICC = 0.945) volume measurements were comparable between 2CV and TV. Morphological classification (ĸ = 0.24) and assessments of LAA opening height (ĸ = 0.1), number of LAA lobes (ĸ = 0.16), trabeculation (ĸ = 0.15), and orientation of the LAA tip (ĸ = 0.37) was only slightly to fairly reproducible.ConclusionsLA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers.

Complex Left Atrial Appendage Morphology and Left Atrial Appendage Thrombus Formation in Patients With Atrial Fibrillation

In patients with atrial fibrillation (AF), most thrombus forms in the left atrial appendage (LAA). However, the relation of LAA morphology with LAA thrombus is unknown. We prospectively enrolled 633 consecutive patients who were candidates for catheter ablation for symptomatic drug-resistant AF. Transesophageal echocardiography (TEE) was performed to assess LAA thrombus. LAA structure was assessed by 3-dimensional TEE. LAA orifice area, depth, volume, and number of lobes were measured on reconstructed 3-dimensional images. Clinical characteristics and echocardiographic measures were compared to determine variables predicting LAA thrombus. Excluded were 69 (10.9%) patients who met the exclusion criteria. Finally, this study comprised 564 patients, of whom LAA thrombus was observed in 36 (6.4%) patients. Multivariate analysis revealed CHADS2 (Congestive heart failure, Hypertension Age>75, Diabetes mellitus and prior Stroke or transient ischemic attack) score (P=0.002), left ventricular ejection fraction (P=0.01), degree of spontaneous echo contrast (P=0.02), left atrial volume (P=0.02), and number of LAA lobes (P<0.001) to be independently associated with thrombus formation. Most patients with LAA thrombus (32/34, 94.4%) had ≥3 LAA lobes, whereas LAA thrombus was observed in only 2 (0.7%) of 296 patients with 1 or 2 lobes. LAA volume significantly decreased in patients maintaining sinus rhythm after catheter ablation (P=0.0009). Number of LAA lobes did not change in any patient. Complex LAA morphology characterized by an increased number of LAA lobes was associated with the presence of LAA thrombus independently of clinical risk and blood stasis. This study suggests that LAA morphology might be a congenital risk factor for LAA thrombus formation in patients with AF.

The Morphology of Left Atrial Appendage Lobes: A Novel Characteristic Naming Scheme Derived through Three-Dimensional Cardiac Computed Tomography

Objectives: This study used cardiac CT to identify and name the different shapes of individual left atrial appendage (LAA) lobes and identified correlations between the size and shape of the LAA ostium and the volume of the LAA in a population of normal individuals. Background: The anatomy of the LAA appendage has become the subject of current research, because appendage occlusion devices have emerged for patients with atrial fibrillation. The development of cardiac computed tomography (CT) allows researchers to identify and observe cardiac anatomy, including various shapes of the LAA lobes. Methods: This study was a retrospective review of 102 consecutive patients from March 2009 to November 2010 who underwent cardiac CT using the GE 64-slice Light Speed VCT CT scanner. For each patient, the LAA ostium was measured, and the shape of the ostium was observed and described. After the LAAs were reconstructed 3-dimensionally, each LAA was categorized by its shape and number of lobes. Results: No significant difference was observed between the average LAA volume between males and females. LAA appendages with circular ostium (n = 61) were observed to have a larger mean volume than those with elliptical ostium (n = 39). Predictors of LAA volume were identified. The most common number of lobes was 2 (n = 61), followed by 1 (n = 27), 3 (n = 10), and 4 (n = 2). Eight unique LAA morphologies were identified and a name was assigned to each morphology. Based on the shape and number of lobes observed, the most common LAA lobe shape was hook (n = 55), followed by wing, arrowhead, flame, double wing, finger, sea horse, double hook, knob, spiral, and double knob. Conclusion: This study used 3D cardiac CT to identify and name the morphology of individual LAA lobes as one of eight different types. The Beutler-Loli naming system formulates a basis to improve understanding of the complex structure of LAA anatomy and to facilitate a system for researchers and clinicians to communicate more precisely about the LAA.

337-I * THORACOSCOPIC LEFT ATRIAL APPENDECTOMY

Objectives: In patients with non-rheumatic atrial fibrillation, the most common place for thrombosis is the left atrial appendage (LAA). The efficacy of stroke prevention with oral anticoagulant therapy (OAC) has been proved, but there are patients who are not candidates for long-term OAC, namely patients with a high risk of bleeding complications or previous haemorrhagic stroke. In those patients, percutaneous closure of the LAA has been demonstrated to be safe and efficacious in preventing cardioembolic events. However, some LAAs are too large or too fragile and they may not be suitable for occlusion. Methods: We present a film showing videothoracoscopic LAA excision in an 82-year-old male patient with lone atrial fibrillation, in whom the need to suppress OAC became obvious after an intracerebral haemorrhagic event. Percutaneous closure of LAA also failed because an additional LAA lobe precluded tight occlusion. Results: Following right selective pulmonary intubation, the patient was placed in a right anterolateral decubitus position. Transoesophageal echocardiography confirmed the absence of LAA thrombus. Three thoracoscopic incisions were made to introduce the video-assisted thoracoscopic instruments. The pericardial cavity was entered 1 cm above the phrenic nerve and the pericardial incision was enlarged to visualize the LAA. Then, a gentle traction was performed to show the appendiceal base where a row of staples was placed. The duration of the procedure was 40 min and the patient was discharged after four days without postoperative complications. Conclusions: This approach demonstrated feasibility, safety and effectiveness and should be considered as a possible alternative to percutaneous closure of the LAA. However, its effect on long-term prevention of stroke needs to be evaluated.

Abstract 17795: Left Atrial Appendage Volume Reflects Severity of Mitral Regargitation: A Three-Dimensional Transesophageal Echocardiography Study

Background: Left atrial (LA) size is well known to reflect volume overload condition such as mitral regurgitation (MR). However, the effects to left atrial appendage (LAA) have not been well defined. LAA structure has multilobed complicated three-dimensional structures. Recent development of real-time 3-dimensional transesophageal echocardiography (RT3D-TEE) has enabled us to examine morphology and determine absolute volumes of LAA without geometrical assumptions. We investigated the relationship between MR severity and LAA volume. Methods: Seventy-four patients with MR who underwent RT3D-TEE were studied. All measurements were performed off-line software. Maximal LAA orifice area, depth and volume, and the number of LAA lobes were assessed (Figure). We also measured LAA emptying flow velocity (LAAev) as the average of 3 consecutive cardiac cycles in patients in normal sinus rhythm and 5 consecutive cardiac cycles in patients with atrial fibrillation. MR grade was evaluated by vena contracta width (VCW). In 58 patients, we also determined the maximal LA volume by the Simpson method from apical views by 2-dimensional transthoracic echocardiography. Pulsed Doppler E, tissue Doppler E' and E/E' were also measured. Results: Mean LAA orifice area was 5.0±3.8 cm 2 , LAA volume was 11±10 ml, LA volume was 116±57ml, and LAAev was 41±23 cm/sec. Patients with moderate to severe MR had larger LAA orifice area, LAA volume, and LA volume than patients with mild MR (Table). In contrast, there were no relationship between MR severity, the number of LAA lobes and LAAev. 3D derived LAA volume was correlated with VCW significantly (r=0.51, p&lt;0.01). Conclusion: LAA volume was associated with MR severity.