Left Atrial Appendage Dimensions Predict the Risk of Stroke/TIA in Patients With Atrial Fibrillation

Malignant left atrial appendage morphology and embolization risk in atrial fibrillation

BackgroundAs an integral part of the left atrium (LA), the left atrial appendage (LAA) plays an important role in atrial fibrillation (AF). However, the relationship between LAA remodeling and AF has not been clearly defined. This retrospective case-control study aimed to assess the morphological and functional features of the LA and the LAA in AF patients using images obtained by computed tomography angiography (CTA).MethodsA total of 140 AF patients and 64 patients without AF or other cardiovascular diseases who underwent CTA scans between September 2016 and August 2017 were enrolled in this observational study as the experimental and the control groups, respectively. The major and minor axes, area, and perimeter of the LAA orifice, the LAA depth, and the volume of both the LAA and LA were analyzed. The data of the AF group and the control group were compared. The t-test was used to analyze the normally distributed data, and the Wilcoxon rank-sum test was used for abnormally distributed data. The best critical value of predictors of AF was calculated using receiver operating characteristic (ROC) curve analysis. The correlation of the LAA volume change with the major and minor axes, area, and perimeter of the LAA orifice, and the LAA depth were analyzed using the Pearson correlation coefficient.ResultsThe LAA orifice’s minor axis, LAA volume, and LA volume were significantly greater (P=0.004, P=0.010, and P<0.001, respectively) in patients with AF than in those without AF. The LAA volume [95% confidence interval (CI): 1.01 to 1.30; P=0.038] and LA volume (95% CI: 1.03 to 1.07; P<0.001) were significantly independent predictors of AF. An LAA volume of 8.75 mL had the highest predictive value for AF [area under the curve (AUC), 0.612], with a sensitivity of 76.6% and a specificity of 48.6%. In contrast, an LA volume of 97.15 mL had the highest predictive value for AF (AUC, 0.771), with a sensitivity of 90.6% and a specificity of 53.6%. The change of LAA volume was positively weakly correlated with the area and perimeter of the LAA orifice (r=0.1703 and r=0.1378, respectively). The LAA emptying fraction was negatively correlated with the major axis and the area of the LAA orifice. The major and minor axes, area, and perimeter of the LAA orifice, and LAA depth were significantly greater in female than in male patients (P=0.003, P=0.003, P=0.001, P=0.019, and P<0.001, respectively).ConclusionsThe AF patients had a longer minor axis of the LAA orifice than that of the control group, resulting in a more circular LAA orifice. The LAA orifice area and perimeter were positively correlated with LAA volume change. The LAA orifice major and minor axes, area, and perimeter, and the LAA depth of the female patients were significantly greater than those of their male counterparts in AF patients.

Contemporary left atrial appendage management during adult cardiac surgery

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.

Pulmonary Artery Perforation by Plug Anchoring System After Percutaneous Closure of Left Appendage

Left atrial appendage morphology and dynamic parameters differ between patients with and without atrial fibrillation

POSTER PRESENTATIONS

Analysis of the left atrial appendage by magnetic resonance angiography in patients with atrial fibrillation

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.

BNP elevation in patients with AF is observed in the absence of heart failure; however, prior mechanistic studies have not included direct left atrial pressure measurements. This study sought to understand how emptying function of the left atrial appendage (LAA) and LAA dimension contributes to brain-natriuretic peptide elevations (BNP) in atrial fibrillation (AF) accounting for left atrial pressure (LAP). 132 patients referredfor left atrial appendage occlusion (LAAO) were prospectively enrolled in this study. BNP levels and LAP were measured just before LAAO. Statistical analysis considered BNP, rhythm at time of procedure, LAP, LAA morphology, LAA size (ostial diameter, depth, volume), LAA emptying velocity, CHADS2-VASc score, body mass index (BMI), left ventricular ejection fraction (LVEF), estimated glomerular filtration rate (eGFR), and obstructive sleep apnea (OSA) diagnosis as covariates. Bivariate statistical analysis demonstrated positive associations with age, LAA ostial diameter, depth, and volume, LAP, AF status at time of measurement, OSA, and CHADS2-VASc score. BNP was negatively associated with LVEF, eGFR, LAA emptying velocity and BMI. With multivariate logistic regression including LAP as covariate, significant relationships between BNP and AF/AFL(OR 1.99 [1.03, 3.85]), LAP (OR 1.13 [1.06, 1.20]), LAA diameter (OR 1.14 [1.03, 1.27]), LAA depth (OR 1.14 [1.07, 1.22]), and LAA emptying velocity (OR 0.97 [0.96,0.99]) were observed; however, no significant associations were seen with LAA morphology or CHADS2-VASc score. BNP elevations in AF are associated with LAA size and function, but not CHADS2-VASc score or appendage morphology after accounting for changes in LAP.

To find out the most successful surgical technique to obliterate left atrial appendage (LAA) in atrial fibrillation (AF) patients who had undergone concomitant cardiac surgery. About 10%-65% of patients develop AF following cardiac surgery [Rho 2009; Mathew 2004; Maesen 2012]. Cerebral cardio-embolic stroke remains the most serious complication in AF patients. LAA is the main anatomical source for thromboembolic events. The use of oral anticoagulants (OAG) is considered to be an effective method for reduction of thromboembolic complications [Johnson 2000]. The use of oral anticoagulants is faced by two important facts which are the therapy duration is still unknown [Kirchhof 2017] and importantly that between 30-50% of patients are not candidates for oral anticoagulants due to the high bleeding risk or other contraindications [Johnson 2000; Kirchhof 2017; Kirchhof 2014]. In such patients, LAA obliteration would be an optimal alternative technique as it will reduce the stroke risk by 50% [Go 2014]. Several surgical techniques with variable degrees of success rates have been used. It still is unclear which surgical technique is optimum to achieve a successful obliteration of the LAA and a considerable reduction of the postoperative stroke events in AF patients. A total of 100 patients have been subjected to surgical LAA exclusion from April 2017 to April 2019 in two different centers. All patients had postoperative transesophageal echo (TEE) examination to confirm the success of LAA occlusion. All patients included in our study suffered from AF at the time of surgery or in past history, which was confirmed by ECG examination in their previous medical files. A variety of surgical techniques to close the LAA have been utilized, including surgical excision by means of scissors, patch exclusion by means of an endocardial patch, suture exclusion and finally stapler exclusion. TEE examination 16 months postoperatively divided our patients into four groups as follows: successful LAA occlusion, Patent LAA, excluded LAA with persistent flow into LAA, and remnant LAA with a stump connection with LAA more than 1 cm. Out of 100 patients, 30 patients (30%) underwent surgical LAA excision, 24 patients (24%) underwent surgical epicardial suture ligation, eight patients (8%) underwent patch exclusion using autologous pericardial patch, 33 patients (33%) underwent LAA internal orifice purse string suture obliteration, and five patients (5%) underwent stapler exclusion. Forty-two patients out of 100 (42%) showed successful LAA closure. The successful LAA occlusion occurred mostly in LAA excision patients 87%, 24% in LAA internal orifice purse string suture obliteration patients, 21% in epicardial suture ligation patients, and 37.5% in patch exclusion patients. The stapler exclusion was very disappointing as we did not record a single case out of the five patients who showed a successful LAA occlusion. Stroke events were recorded in all surgical techniques except the LAA excision technique. The stroke rate after two years follow up was zero in the surgical excision group, 49% in the suture exclusion group, 20% in the patch exclusion group, and 40% in stapler exclusion group. Surgical LAA excision is the most successful technique for LAA occlusion and represents a promising technique for the reduction of thromboembolic events in AF patients who undergo a concomitant cardiac surgery.

Background/Introduction The volume of the left atrial appendage (LAA), as measured in contrast-enhanced cardiac computed tomography (CCTA), has been previously reported as a predictor of long-term recurrence of atrial fibrillation (AF) following cryoballoon ablation procedures. Unfortunately manual assessment of LAA volume, is tedious and time-consuming, making it impractical for clinical practice. The recent advent of artificial intelligence (AI)-based methods offers a potential solution to this limitation. Purpose This study aims to evaluate the utility of LAA volume, as automatically measured by a state-of-the-art AI model for the fully automatic segmentation of LAA in CCTA, in predicting AF recurrence following cryoballoon ablation procedures. Methods We retrospectively analyzed a cohort of patients who underwent cryoballoon ablation for pulmonary vein isolation at our facility between 2010 and 2016. AF recurrence was determined through in-person visits and Holter monitoring at 3, 6, and 12 months post-ablation, followed by annual visits. The first three months post-ablation were considered a blanking period. An open-source deep neural network AI model [1] was utilized to perform automatic segmentation and calculation of LAA and left atrium (LA) volumes in. Receiver-operating characteristic curves were used to obtain optimal cut-off values for increased LAA and LA volumes. We then assessed the association of increased LAA and LA volume, and the LAA to LA volume ratio with recurrence-free survival using the Cox regression model. Results The cohort consisted of 212 patients (median age 62, inter-quartile range [IQR]: 55–65), with 25% having persistent AF before the procedure. Subjects were observed for a median period of 12 months (IQR: 12–36), with 70 of them (33%) experiencing a documented recurrent AF episode. The optimal thresholds for predicting AF recurrence were established as 9.8ml for LAA volume, 124ml for LA volume, and 0.086 for the LAA to LA volume ratio, respectively. An increased LAA volume demonstrated the strongest association with AF recurrence (hazard ratio [HR]: 2.6, 95% confidence interval [CI]: 1.55–4.2), followed by an increased LA volume (HR: 2.1, 95% CI: 1.3–3.4), persistence of AF (HR: 2, 95% CI: 1.2–3.3), and increased LAA to LA volume ratio (HR: 1.9, 95% CI: 1.1–3). Kaplan-Meier plots illustrating AF-free survival, are presented in Figure 1. After adjusting for age, persistent AF, left ventricular ejection fraction, and body surface area, all AI measurements remained significantly associated with a higher AF recurrence (Table 1). Conclusions Increased LAA volume, as assessed automatically by AI in CCTA, is a useful predictor of AF recurrence after catheter ablation for atrial fibrillation. The use of freely available, AI-assisted analysis of CCTA could be instrumental in assessing LAA volume, among other predictors, for long-term ablation success.Figure 1.

Pulmonary vein isolation (PVI) is effective in treating atrial fibrillation (AF), but outcomes are worse for persistent AF (persAF) patients than paroxysmal AF (PAF) patients. The study aimed to identify differences in left atrial (LA) and left atrial appendage (LAA) anatomy in different AF types. In a single-center observational study, a blinded retrospective analysis of preprocedural cardiac computed tomography angiography (CCTA) images was performed. The study evaluated the dimensions of the LA and pulmonary veins (PV), as well as the size and morphology of the LAA using a 3D electroanatomical mapping system. Between 2012 and 2016, a total of 1103 patients underwent second-generation cryoballoon PVI. Of these, 725 patients (65.7%) had CCTA available, and 473 of these (65.2%) had sufficient quality for measurements. The mean age of the patients was 66.3 ± 9.5 years, and PAF was present in 277 (58.6%) participants. The study found that in persAF patients, LA dimensions such as LA volume [mL] (108; 125; p < .001) or PV ostial dimensions were significantly larger than in those with PAF. LAA volume [mL] (8.3; 9.2; p = .005) and LAA ostial area [mm2] (325; 353; p = .01) were enlarged in persAF. There were no significant differences regarding LAA morphology, with the overall distribution being "windsock" (51%), "chicken-wing" (20%), "cauliflower" (15%), and "cactus" (13%). Compared to PAF, persAF patients had significantly larger LA as well as LAA dimensions. LAA morphological types were distributed equally in both groups suggesting that LAA morphology may not be associated with the underlying AF type.

Key Findings▪Percutaneous left atrial appendage (LAA) occlusion has emerged as an alternative strategy to oral anticoagulants in selected patients with atrial fibrillation.▪The landmark trials comparing LAA occlusion to an oral anticoagulation strategy enrolled patients with no apparent contraindications to the use of warfarin.▪LAA occlusion has limited head-to-head comparison against the direct-acting oral anticoagulants.▪Observational data to date have generally shown specific adverse events after LAA occlusion in specific subgroups of patients (women, patients with kidney disease and heart failure, patients belonging to racial/ethnic subgroups and with advanced age), but further large-scale studies are necessary to elucidate reasons for increased adverse events associated with LAA occlusion in these subgroups of patients before recommending this modality as first-line therapy in all patient groups. ▪Percutaneous left atrial appendage (LAA) occlusion has emerged as an alternative strategy to oral anticoagulants in selected patients with atrial fibrillation.▪The landmark trials comparing LAA occlusion to an oral anticoagulation strategy enrolled patients with no apparent contraindications to the use of warfarin.▪LAA occlusion has limited head-to-head comparison against the direct-acting oral anticoagulants.▪Observational data to date have generally shown specific adverse events after LAA occlusion in specific subgroups of patients (women, patients with kidney disease and heart failure, patients belonging to racial/ethnic subgroups and with advanced age), but further large-scale studies are necessary to elucidate reasons for increased adverse events associated with LAA occlusion in these subgroups of patients before recommending this modality as first-line therapy in all patient groups.

Background and objective: Decreased peak flow velocity (PFV) of the left atrial appendage (LAA) measured by transesophageal echocardiography (TEE) was reported to be associated with atrial fibrillation (AF) and thrombus formation in LAA. This study aimed to elucidate the association between flow, volume and ejection fraction (EF) of LAA measured by real-time three dimensional TEE (3D-TEE) and the presence of paroxysmal atrial fibrillation (PAF) in acute stroke. Methods: 3D-TEE was performed using an iE 33 Ultrasound Machine and X7-2t TEE transducer (Philips Healthcare) in acute stroke patients with sinus rhythm at the examination. Patients were divided into those with a history or later documentation of PAF (PAF group) and others (sinus group). PFV was measured by pulse Doppler and LAA volume was measured off-line using QLAB software. LAA volume was measured twice before p wave (maximum LAA volume) and after p wave (minimum LAA volume) to calculate EF of LAA. Results: Of a total 97 patients (26 women, 72.7±10.6 years), 20 were allocated to the PAF group and the remaining 77 to the sinus group. LAA volume and EF were correlated with PFV (r=0.378, p=0.0002 and r = 0.374, p=0.0002; respectively). Patients in the PAF group had lower PFV (39.0cm/s, 29.4-57.0 vs. 63.9cm/s, 38.3-81.8, p=0.0006), larger LAA volume (median 7.6ml, IQR 3.6-10.45 vs. 2.3ml, 1.6-6.2, p=0.0033) and lower EF (38.2%, 21.4-49.8 vs. 58.1%, 44.1-71.8, p=0.0006) than those in the sinus group. Using receiver operating characteristic curve analysis, the optimal cutoff of PFV to predict PAF patients was ≤39cm/s, with a sensitivity of 58%, a specificity of 89%, and a c-statistic of 0.756. The cutoff of LAA volume was ≥7.5ml, with a sensitivity of 55%, a specificity of 84%, and a c-statistic of 0.714. The cutoff of EF was ≤47.9%, with a sensitivity of 75%, a specificity of 75%, and a c-statistic of 0.751. Using the combination of LAA volume ≥7.5ml or EF ≤47.9%, patients with PAF were detected with a sensitivity of 85% and a specificity of 67%. Conclusions: Because EF of LAA was associated with FV, it is a promising marker of LAA function. LAA enlargement and reduced LAA contraction, measured by 3-dimensional techniques, in addition to lower FV may help us to detect those with PAF in acute stroke.