Incidence, progression, and predictors of left atrial appendage sealing after Watchman FLX device implantation with computed tomographic assessment.

BACKGROUND: Limited data exists regarding incidence, progression, and predictors of left atrial appendage (LAA) sealing after transcatheter LAA closure. We aimed to evaluate the incidence, progression, and predictive factors associated with LAA sealing after LAA closure. METHODS: This study includes patients who underwent successful LAA closure with Watchman FLX device and had both pre- and postprocedural computed tomography (CT). Postprocedural CT was performed 45 days after LAA closure and used to evaluate residual LAA patency. Patient who had residual LAA patency at 45 days underwent 1-year follow-up CT. RESULTS: A total of 105 patients (mean age: 75.2 ± 9.6 years; 53.3% female) who underwent successful LAA closure with Watchman FLX device and had pre- and postprocedural CT at 45 days were included. Residual patency was observed in 35 (33.3%) patients: 21 (20.0%) patients showed complete contrast opacification in LAA (complete LAA patency) while 14 (13.3%) patients showed contrast opacification only in the distal LAA (distal LAA patency). Among patients with residual LAA patency at 45 days, the rate of LAA sealing at 1 year was significantly higher in the distal LAA patency group than in the complete LAA patency group (75.0% vs. 16.7%; p = 0.019). Increased depth oversizing was associated with both distal LAA patency and complete LAA patency. CONCLUSION: Postprocedural CT at 45 days detected patent LAA in one-third of patients after LAA closure. LAA sealing was more frequently observed at 1 year among the distal LAA patency group than the complete LAA patency group.

Percutaneous left atrial appendage occlusion in mitral valve disease: A Nationwide Readmission Database analysis.

BACKGROUND: Percutaneous left atrial appendage occlusion (LAAO) has emerged as a non-pharmacologic alternative to oral anticoagulation in reducing stroke risk in AF patients. However, patients with mitral valve disease (MVD), who are expected to have a significantly greater risk of left atrium (LA) thrombus formation and embolic stroke were excluded from randomized trials examining percutaneous LAAO. To address this gap, we present a national registry analysis of the use of LAAO among patients with MVD. METHODS: Using the National Readmissions Database, we performed a retrospective review of all hospitalizations for LAAO identified between September 2015 and November 2019. Of these, patients with ICD-10 codes for MVD were identified. Propensity matched (PSM) analysis was used to compare patients with MVD with a matched sample of patients undergoing LAAO with non-valvular AF. Outcomes examined included all-cause mortality, stroke, major bleeding, pericardial effusion (PE), and tamponade. RESULTS: 51,540 patients who underwent LAAO without a history of MVD and 3777 with a history of MVD were identified. Crude analysis demonstrated the odds of mortality, PE, and cardiac tamponade during index hospitalization to be higher in the MVD group. The length of stay and cost of index hospitalization were also slightly greater for the MVD group. A sample of 7649 patients (MVD: 3777 MVD and no MVD: 3872) were selected for PSM analysis with similar comorbidities across the two groups. In the PSM comparison, MVD was associated with higher risk of PE. The MVD group had a slightly higher rate of readmissions the association with PE remained at 30-day readmission (OR: 2.099 [1.360-3.238], p-value: <0.001). CONCLUSION: To our knowledge, this is the first study examining the use of LAAO among MVD patients. Our findings suggest that patients with MVD who underwent LAAO had a higher risk of post-procedural PE without an increase in mortality, stroke, or major bleeding. These results provide a rationale for considering LAAO as part of the stroke prevention strategy among patients with valvular AF.

Preclinical Assessment of a Novel Conformable Foam-Based Left Atrial Appendage Closure Device.

BACKGROUND: Left atrial appendage (LAA) occlusion has been established as an alternative to systemic anticoagulation for stroke prevention in patients with atrial fibrillation; however, limitations of current devices have slowed adoption. We present preclinical evaluations of a novel device, the Conformal Left Atrial Appendage Seal (CLAAS). METHODS: An in vitro assessment of conformability was conducted to evaluate the two CLAAS devices (regular 27 mm and large 35 mm) and a Watchman 2.5 (27 mm). Devices were placed within silicone tubes and compressed in a vise submerged in a water bath at 37°C. Changes in device diameter and visual seal were noted. Acute (n = 1) and chronic 60-day (n = 6) canine studies with gross and histologic assessment were performed. RESULTS: Conformability bench tests demonstrated that the regular CLAAS implant was able to seal oval orifices from 20 × 30 mm to 15 × 33 mm and the large from 30 × 35 mm to 20 × 40 mm. As the CLAAS implant was compressed in the minor diameter, it increased in the major diameter, thereby filling the oval space, whereas the Watchman 2.5 showed gaps and maintained its round configuration when compressed in one direction. Seven devices were successfully implanted in the canine model with complete seal without thrombus. Histologic examination showed complete neointima covering with minimal inflammation at 60 days. CONCLUSIONS: Preclinical testing demonstrated the conformability of the CLAAS implant and its ability to seal the LAA. Clinical studies are ongoing to characterize the utility of the CLAAS implant in the treatment of patients with atrial fibrillation.

Incremental diagnostic role of left atrial strain analysis in thrombotic risk assessment of nonvalvular atrial fibrillation patients planned for electrical cardioversion.

During the COVID-19 pandemic, transesophageal echocardiography (TEE) for left atrial appendage thrombosis (LAAT) detection should be limited to situations of absolute necessity. We sought to identify the main conventional and functional echocardiographic parameters associated with LAAT on TEE in non-valvular atrial fibrillation (NVAF) patients planned for electrical cardioversion (ECV). This retrospective study included 125 consecutive NVAF patients (71.5±7.8 yrs, 75 males), who underwent TEE at our Institution between April 2016 and January 2020, to exclude LAAT before scheduled ECV. All patients underwent a transthoracic echocardiography (TTE) implemented with speckle tracking echocardiography (STE) analysis of left atrial (LA) strain and strain rate (SR) parameters. 28% of patients were diagnosed with LAAT, while 72% without LAAT. Compared to controls, patients with LAAT had significantly higher CHA2DS2-Vasc Score and average E/e' ratio, and significantly lower left ventricular ejection fraction (LVEF). Moreover, LA-peak positive global atrial strain (GSA+) and LA-SR parameters were significantly reduced in patients with LAAT. Multivariate logistic regression revealed that, differently from CHA2DS2-Vasc Score, LVEF (OR 0.88, 95%CI 0.81-0.97, p = 0.01), average E/e' ratio (OR 2.36, 95%CI 1.41-3.98, p = 0.001), and LA-GSA+ (OR 0.57, 95%CI 0.36-0-90, p = 0.01) were independently associated with LAAT. LA-GSA+ (optimal cut-off ≤ 9.1%, AUC 0.95) showed the highest diagnostic performance. Finally, a strong linear correlation of LA peak-to-peak SR with both LA appendage filling (r = 0.86) and emptying (r = 0.83) velocities was demonstrated. TTE implemented with STE analysis of LA mechanics improves thrombotic risk assessment of NVAF patients.

Left Atrial Appendage Occlusion: Past, Present and Future.

There are several situations whereby oral anticoagulation may be unsuitable for stroke prevention in patients with atrial fibrillation (AF). Percutaneous left atrial appendage (LAA) occlusion has received much attention in this area. Various devices have already been developed and tested for this purpose. Data from registries and cohort studies have indicated favourable short- and long-term outcomes with LAA occlusion, and several international guidelines recommend its use in AF patients with contraindications to oral anticoagulation. However, prospective controlled trials in this very population are lacking. Furthermore, while modelling studies on cost analyses have suggested that LAA occlusion may be a cost-effective strategy compared with standard medical therapy, these have not been performed in high-risk patients who may have limited survival in the medium to long term. Thus, while LAA occlusion offers promise, there is a strong need for additional research to investigate its exact role, its long-term outcomes and cost efficacy.

Simultaneous Functional and Morphological Assessment of Left Atrial Appendage by 3D Virtual Models.

Purpose: The left atrial appendage (LAA) is responsible for thrombus formation in patients with atrial fibrillation. The evaluation of both LAA function and morphology is crucial for the patient characterization and the preprocedural planning of LAA closure intervention. Despite the availability of 3D imaging modalities, the current standard image analysis is based on manual delineation of the LAA contours on 2D views. Methods: In this study, a comprehensive approach based on a full 3D analysis of the tomographic dataset by surface extraction and processing (3D-S) is presented. The proposed method allows extracting functional and morphologic information in the entire cardiac cycle by minimalizing manual user interaction. The proposed methodology has been validated on ten computer tomography datasets. Results: The proposed 3D-S method was feasible in all cases. Reproducibility was improved with respect to the reference 2D manual procedure (2D-S) (coefficient of variation 2.9 vs. 4.1% for diastolic ostium area; 3.8 vs. 6.1% for systolic ostium area; 2.4 vs. 5.3% for diastolic LAA volume; 2.7 vs. 5.9% for systolic LAA volume; and 7.7 vs. 17.1% for LAA ejection fraction). No significant differences were found between 2D-S and 3D-S measurements. Conclusions: In this study, we introduced a fully 3D approach for LAA characterization, allowing the simultaneous assessment of LAA function and geometry. The proposed approach could be used to improve the patient selection and the best sizing of the device for LAA closure and to allow a patient-specific 3D printing.

Assessment of peri-device leaks after interventional left atrial appendage closure using standardized imaging by cardiac computed tomography angiography.

Cardiac computed tomography angiography (cCTA) has recently been proposed for evaluation of successful interventional left atrial appendage closure (LAA/LAAC). This prospective longitudinal observational study aims to assess this proposal by applying a standardized imaging protocol to detect and quantify peri-device leaks (PDL) after LAAC. cCTA datasets of consecutive patients 6 months after successful LAAC were acquired on a third generation dual-source computed tomography system and reconstructed with a slice thickness of 0.5 mm. The standardized multi-planar reconstruction LAA occluder view for post-implantation evaluation (LOVE) algorithm was used to assess PDL in relation to LAA morphology and implanted LAAC devices. A total of 49 patients (median age 80 years, 24% female) were included consecutively. Overall PDL rate was 31%. Leak rates among different left atrial appendage morphologies varied largely. Windsock type had the highest incidence of PDL (47%). AMPLATZER™ AMULET™ device type revealed slightly higher PDL rates than WATCHMAN™ type and showed larger leaks. However, no statistical differences were found. PDL can be sized best in LOVE sagittal views, whereas a synopsis of LOVE sagittal, axial and coronal views allows further examination and detection of small leaks. PDL are common after successful interventional LAAC, which can be accurately detected and sized by standardized cCTA imaging protocols.

Cost-Effectiveness of Left Atrial Appendage Closure With the WATCHMAN Device Compared With Warfarin or Non-Vitamin K Antagonist Oral Anticoagulants for Secondary Prevention in Nonvalvular Atrial Fibrillation.

BACKGROUND AND PURPOSE: Once a patient with atrial fibrillation experiences an embolic event, the risk of a recurrent event increases 2.6-fold. New treatments have emerged as viable treatment alternatives to warfarin for stroke risk reduction in secondary prevention populations. This analysis sought to assess the cost-effectiveness of left atrial appendage closure (LAAC) compared with warfarin and the non-vitamin K antagonist oral anticoagulants dabigatran 150 mg, apixaban and rivaroxaban in the prevention of stroke in nonvalvular atrial fibrillation patients with a prior stroke or transient ischemic attack. METHODS: A Markov model was constructed using data from the secondary prevention subgroup analyses of the non-vitamin K antagonist oral anticoagulant and LAAC pivotal trials. Costs were from 2016 US Medicare reimbursement rates and the literature. The cost-effectiveness analysis was conducted from a US Medicare perspective over a lifetime (20 years) horizon. The model was populated with a cohort of 10 000 patients aged 70 years with a CHA2DS2-VASc score of 7 (annual stroke risk=9.60%) and HAS-BLED score of 3 (annual bleeding risk=3.74%). RESULTS: LAAC achieved cost-effectiveness relative to dabigatran at year 5 and warfarin and apixaban at year 6. At 10 years, LAAC had more quality-adjusted life years (4.986 versus 4.769, 4.869, 4.888, and 4.810) and lower costs ($42 616 versus $53 770, $58 774, $55 656, and $58 655) than warfarin, dabigatran, apixaban, and rivaroxaban, respectively, making LAAC the dominant (more effective and less costly) stroke risk reduction strategy. LAAC remained the dominant strategy over the lifetime analysis. CONCLUSIONS: Upfront procedure costs initially make LAAC higher cost than warfarin and the non-vitamin K antagonist oral anticoagulants, but within 10 years, LAAC delivers more quality-adjusted life years and has lower total costs, making LAAC the most cost-effective treatment strategy for secondary prevention of stroke in atrial fibrillation.

Incidence, Prevention, and Management of Periprocedural Complications of Left Atrial Appendage Occlusion.

Major procedural complications related to left atrial appendage occlusion (LAAO) are relatively infrequent but may be associated with major morbidity and mortality. LAAO operators should be knowledgeable about these potential complications. Prompt recognition and treatment are necessary to avoid rapid deterioration and dire consequences. With stringent guidelines on operator training, competency requirements, and procedural-technical refinements, LAAO can be performed safely with low complication rates. This article focuses on commonly used devices, as well as prevention, treatment, and management of complications of LAOO.

Assessment of left atrial appendage function by transthoracic pulsed Doppler echocardiography: Comparing against transesophageal interrogation and predicting echocardiographic risk factors for stroke.

AIMS: Transesophageal echocardiographic (TEE) findings of left atrial appendage (LAA) thrombus, spontaneous echo contrast (SEC), and LAA dysfunction are established risk factors of cardioembolic stroke. The semi-invasive nature of TEE limits its utility as a routine risk stratification tool. We aim to correlate TEE and transthoracic echocardiography (TTE) pulsed Doppler measurements of LAA flow velocities and use TTE measurements to predict TEE findings. METHODS AND RESULTS: We prospectively measured pulsed Doppler LAA flow velocities in 103 consecutive patients on TEE and TTE. There was a strong correlation between TEE and TTE LAA emptying velocity (LAA E) (r = .88, P < .001) and a moderate correlation between LAA filling velocities (r = .50, P < .001). TTE LAA E predicted the presence of thrombus or SEC independent of atrial fibrillation (AF). To predict the presence of thrombus or SEC, the optimal TTE LAA E cutoff was ≤30 cm/s in all patients (75% sensitive, 90% specific) and ≤31 cm/s in AF patients (80% sensitive, 79% specific). To predict LAA dysfunction (TEE E ≤ 20 cm/s), the optimal TTE LAA E cutoff was ≤27 cm/s (100% sensitive, 89% specific in all patients and 100% sensitive, 74% specific in AF patients). CONCLUSIONS: TTE assessment of LAA function is feasible and correlates well with the more invasive TEE method. It predicts the presence of thrombus, SEC, and LAA dysfunction on TEE. TTE LAA assessment has incremental value in thromboembolic risk stratification and should be utilized more frequently.

Assessment of the left atrial appendage structure and morphology: comparison of real-time three-dimensional transesophageal echocardiography and computed tomography.

In this study, the left atrial appendage (LAA) structure and morphology were assessed using real-time three-dimensional transesophageal echocardiography (RT3D-TEE) and enhanced cardiac computed tomography (CT) scanning, and the two measurements obtained using these different techniques were compared. Two hundred nonvalvular atrial fibrillation (NVAF) patients who were prepared to undergo radiofrequency ablation were enrolled, and 62 controls were enrolled prospectively. RT3D-TEE and CT were performed, and the following parameters were measured: LAA orifice diameter, area, depth, maximum volume, and emptying velocity. The differences between the NVAF patients and controls were compared, and the differences and correlations in the LAA parameters between the two imaging techniques were assessed. The NVAF patients had significantly bigger orifice sizes, orifice areas, and maximum volumes, and lower emptying rates. The AF cohort had roughly equal proportions of the four morphological types, whereas the controls predominantly had the windsock type. A Bland-Altman analysis demonstrated that the LAA measurements obtained using RT3D-TEE were lower than those obtained with the CT. However, linear regression analysis showed the good correlations between the RT3D-TEE and CT measurements of the LAA orifice area, depth and volume (r = 0.86, 0.63, and 0.75, respectively). The use of RT3D-TEE for the visualization and quantitative analysis of LAA parameters is feasible, and the obtained measurements correlate well with those obtained with cardiac CT. This technique may be an ideal tool for guiding LAA occlusion procedures, and combining these two methods may enhance the accuracy of LAA measurements.

Assessment of left atrial appendage function during sinus rhythm in patients with obstructive sleep apnea.

OBJECTIVE: Obstructive sleep apnea (OSA) is associated with thromboembolic events. Compromised left atrial appendage (LAA) function due to left ventricular (LV) performance abnormality, often present in patients with OSA, may play an important role. The purpose of this study is to evaluate LV and LAA mechanical functions during sinus rhythm (SR) in patients with OSA. METHODS: LV and LAA functions were assessed in 43 OSA patients and compared with that of 20 control patients in SR. Tissue Doppler velocities of the LAA apex and emptying velocities (EV) of LAA were obtained on parasternal short-axis view. RESULTS: The baseline clinical characteristics were similar except for AHI (apnea-hypopnea index), minimal SaO2, mean SaO2, hypertension, and body-surface area. Most of the LV echocardiographic parameters significantly deteriorated in OSA patients in comparison with those in the control group. LAA EV, LAA systolic relaxation velocity (SM), LAA early-diastolic velocity (EM), LAA contraction velocity (AM), left atrial (LA) minimum volume index, LA ejection fraction, LA conduit volume index, and LA reservoir volume index were lower in OSA patients compared with those in the control group (p<0.05). LAA AM was negatively correlated with AHI and the ratio of peak early diastolic flow velocity (E) to early-diastolic (E') and positively correlated with LA conduit volume (p<0.05). Multiple predictors for LAA AM were AHI, presence of diastolic dysfunction, and E/E' values (p<0.05). CONCLUSION: LAA mechanical function is significantly depressed in patients with OSA and SR. LAA dysfunction may predispose these patients to thromboembolic events. The evaluation of LAA mechanical function by tissue Doppler study using transthoracic echocardiography (TTE) may become an alternative for routine work-up in OSA patients.

Relevance of transthoracic left atrial appendage wall velocity measurement in addition to left atrial volume for noninvasive and quantitative assessment of left atrial thrombogenesis in patients with atrial fibrillation and normal D-dimer levels.

PURPOSE: This study examined the role of left atrial (LA) appendage wall velocity (LAAWV) measurement in addition to LA size for the noninvasive assessment of thrombogenesis in patients with atrial fibrillation (AF) and normal plasma D-dimer levels. METHODS: In 58 non-valvular AF patients, LAAWV and the LA volume index (LAVI) were determined by transthoracic echocardiography. LA appendage flow velocity and severity of spontaneous echo contrast (SEC) were determined by transesophageal echocardiography. RESULTS: LAAWV was strongly correlated with LA appendage flow velocity (r = 0.82), and LAVI was weakly correlated with LA appendage flow velocity (r = -0.37). As SEC severity increased, LAAWV decreased (p < 0.001) and LAVI increased (p < 0.001). Among 52 patients with normal D-dimer levels, LAAWV < 10 cm/s had 71 % sensitivity and 94 % specificity for diagnosing severe SEC. Severe SEC was not found in 18/32 large LAVI patients (>34 mL/m(2)), but 17 of the 18 patients (94 %) had LAAWV < 10 cm/s. Severe SEC was found in 3/20 patients with normal LAVI, but all of them showed LAAWV < 10 cm/s. CONCLUSION: The noninvasive measurement of transthoracic LAAWV in addition to LA volume is clinically relevant for quantitatively assessing thrombogenesis in AF patients with normal D-dimer levels.

Assessment of Left Atrial Appendage Morphology and Function in Patients with Non-valvular Paroxysmal Atrial Fibrillation with Different Rhythms Using Real-Time 3D Transesophageal Echocardiography.

The aim of this study was to evaluate the morphology and function of the left atrial appendage (LAA) in different rhythms of paroxysmal atrial fibrillation (PaAF) patients using real-time 3D transesophageal echocardiography. This study included 46 patients with PaAF-24 with PaAF with sinus rhythm (PaAF-S) and 22 with PaAF with fibrillation (PaAF-F)-and 23 healthy volunteers. Real-time 3D transesophageal echocardiography images of the LAA were acquired in all patients. LAA end-diastolic volume increased in PaAF-S and PaAF-F, whereas LAA end-systolic volume increased only in PaAF-F. LAA emptying index, end-diastolic volume and end-systolic volume were strongly negatively correlated. LAA emptying index was positively correlated with percentage changes in LAA area and diameter, as well as flow velocity. The co-occurrence of spontaneous echo contrast and thrombus gradually increased in the PaAF-F group, compared with the PaAF-S group. The morphology and change in function of the LAA in patients with paroxysmal PaAF can be evaluated with superior feasibility and reproducibility using real-time 3D transesophageal echocardiography. Morphologic changes in the LAA appeared earlier than changes in LAA function during the course of PaAF. Spontaneous echo contrast and thrombus co-occurred more often in PaAF-F than in PaAF-S.

Percutaneous interventions for left atrial appendage exclusion: options, assessment, and imaging using 2D and 3D echocardiography.

Percutaneous left atrial appendage (LAA) exclusion is an evolving treatment to prevent embolic events in patients with nonvalvular atrial fibrillation. In the past few years multiple percutaneous devices have been developed to exclude the LAA from the body of the left atrium and thus from the systemic circulation. Two- and 3-dimensional transesophageal echocardiography (TEE) is used to assess the LAA anatomy and its suitability for percutaneous closure to select the type and size of the closure device and to guide the device implantation procedure in conjunction with fluoroscopy. In addition, 2- and 3-dimensional TEE is also used to assess the effectiveness of device implantation acutely and on subsequent follow-up examination. Knowledge of the implantation options that are currently available along with their specific characteristics is essential for choosing the appropriate device for a given patient with a specific LAA anatomy. We present the currently available LAA exclusion devices and the echocardiographic imaging approaches for evaluation of the LAA before, during, and after LAA occlusion.

Left atrial appendage flow velocity after successful ablation of persistent atrial fibrillation: clinical perspective from transesophageal echocardiographic assessment during sinus rhythm.

BACKGROUND: Left atrial appendage flow velocity (LAAFV) is a predictor of thromboembolism in atrial fibrillation (AF) patients, as well as CHA2DS2-VASc score. However, little is known about LAAFV in sinus rhythm (SR) after catheter ablation. The aim of this study was to determine clinical predictors of low LAAFV in patients in whom stable SR had been maintained after catheter ablation for persistent AF. METHODS: The study comprised 104 patients with persistent AF (median AF duration 24 months) in whom SR had been achieved and maintained for at least 6 months after the final ablation procedure. Transesophageal echocardiography was performed to assess LAAFV during SR after ablation. Lower LAAFV was defined as ≤40 cm/s. RESULTS: Mean LAAFV before ablation was 29 ± 11 cm/s (range 10-67 cm/s). In 23 (22%) patients, LAAFV remained low even after being in SR for at least 6 months. Multiple logistic regression analysis showed that CHA2DS2-VASc scores of ≥2 (odds ratio 2.18, 95% CI 1.19-3.99, P = .012) was an independent predictor of lower LAAFV after successful ablation. Seventeen (74%) of the 23 patients with low LAAFV during SR presented CHA2DS2-VASc scores of ≥2 complicated by spontaneous echo contrast during AF. CONCLUSIONS: Long-term maintenance of SR after catheter ablation for persistent AF does not guarantee LAAFV recovery. The CHA2DS2-VASc score appears to predict poor recovery of LAAFV. Further studies are necessary to confirm the usefulness of LAAFV during SR as a surrogate marker predicting thromboembolism in patients after AF ablation.

Utilization and adverse outcomes of percutaneous left atrial appendage closure for stroke prevention in atrial fibrillation in the United States: influence of hospital volume.

BACKGROUND: Safety data on percutaneous left atrial appendage closure arises from centers with considerable expertise in the procedure or from clinical trial, which might not be reproducible in clinical practice. We sought to estimate the frequency and predictors of adverse outcomes and costs of percutaneous left atrial appendage closure procedure in the US. METHODS AND RESULTS: The data were obtained from the Nationwide Inpatient Sample from the years 2006 to 2010. The Nationwide Inpatient Sample is the largest all-payer inpatient data set in the US. Complications were calculated using patient safety indicators and International Classification of Diseases-Ninth Revision, Clinical Modification codes. Annual hospital volume was calculated using unique hospital identifiers. Weights provided by the Nationwide Inpatient Sample were used to generate national estimates. A total of 268 (weighted=1288) procedures were analyzed. The overall composite rate of mortality or any adverse event was 24.3% (65), with 3.4% patients required open cardiac surgery after procedure. Average length of stay was 4.61±1.05 days and cost of care was 26,024±34,651. Annual hospital procedural volume was significantly associated with reduced complications and mortality (every unit increase: odds ratio, 0.89; 95% confidence interval, 0.85-0.94; P<0.001), decrease in length of stay (every unit increase: hazard ratio, 0.95; 95% confidence interval, 0.92-0.98; P<0.001) and cost of care (every unit increase: hazard ratio, 0.96; 95% confidence interval, 0.93-0.98; P<0.001). CONCLUSIONS: Our study demonstrates that the frequency of inhospital adverse outcomes associated with percutaneous left atrial appendage closure is higher in the real-world population than in clinical trials. We also demonstrate that higher annual hospital volume is associated with safer procedures, with lower length of stay and cost.