Impact of left atrial appendage flow velocity on thrombus resolution and clinical outcomes in patients with atrial fibrillation and silent left atrial thrombi: insights from the LAT study.

AIMS: Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear. METHODS AND RESULTS: The LAT study was a multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal echocardiography (TEE). Among 17 436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (P < 0.001). During 1 year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], P = 0.003). Despite limited predictive power (area under the curve, 0.659; P = 0.001), LAAFV ≤ 20.0 cm/s (best cut-off) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; P = 0.015). The incidence of adverse outcomes including ischaemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank P = 0.005). CONCLUSION: Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Prognostic Impact of Left Atrial Appendage Patency After Device Closure.

BACKGROUND: The prognostic impact of left atrial appendage (LAA) patency, including those with and without visible peri-device leak (PDL), post-LAA closure in patients with atrial fibrillation, remains elusive. METHODS: Patients with atrial fibrillation implanted with the WATCHMAN 2.5 device were prospectively enrolled. The device surveillance by cardiac computed tomography angiography was performed at 3 months post-procedure. Adverse events, including stroke/transient ischemic attack (TIA), major bleeding, cardiovascular death, all-cause death, and the combined major adverse events (MAEs), were compared between patients with complete closure and LAA patency. RESULTS: Among 519 patients with cardiac computed tomography angiography surveillance at 3 months post-LAA closure, 271 (52.2%) showed complete closure, and LAA patency was detected in 248 (47.8%) patients, including 196 (37.8%) with visible PDL and 52 (10.0%) without visible PDL. During a median of 1193 (787-1543) days follow-up, the presence of LAA patency was associated with increased risks of stroke/TIA (adjusted hazard ratio for baseline differences, 3.22 [95% CI, 1.17-8.83]; P=0.023) and MAEs (adjusted hazard ratio, 1.12 [95% CI, 1.06-1.17]; P=0.003). Specifically, LAA patency with visible PDL was associated with increased risks of stroke/TIA (hazard ratio, 3.66 [95% CI, 1.29-10.42]; P=0.015) and MAEs (hazard ratio, 3.71 [95% CI, 1.71-8.07]; P=0.001), although LAA patency without visible PDL showed higher risks of MAEs (hazard ratio, 3.59 [95% CI, 1.28-10.09]; P=0.015). Incidences of stroke/TIA (2.8% versus 3.0% versus 6.7% versus 22.2%; P=0.010), cardiovascular death (0.9% versus 0% versus 1.7% versus 11.1%; P=0.005), and MAEs (4.6% versus 9.0% versus 11.7% versus 22.2%; P=0.017) increased with larger PDL (0, >0 to ≤3, >3 to ≤5, or >5 mm). Older age and discontinuing antiplatelet therapy at 6 months were independent predictors of stroke/TIA and MAEs in patients with LAA patency. CONCLUSIONS: LAA patency detected by cardiac computed tomography angiography at 3 months post-LAA closure is associated with unfavorable prognosis in patients with atrial fibrillation implanted with WATCHMAN 2.5 device. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03788941.

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.

Evaluating the effectiveness of echocardiographic guidance in diminishing postoperative wound complications for left atrial appendage closure: A clinical retrospective study.

Echocardiographic guidance in left atrial appendage (LAA) closure procedures is increasingly recognized for its potential to enhance patient outcomes in atrial fibrillation (AF). This retrospective study assesses its impact on hospital stay duration, readmission rates and surgical site wound complications in 200 AF patients. Divided equally into an echocardiographically guided group (Group E) and a non-guided group (Group N), the analysis focused on detailed patient data encompassing hospital stay, 30-day readmission and wound complications. Findings revealed that Group E experienced a significantly shorter average hospital stay of 3.5 days, compared with 6.5 days in Group N, along with a lower 30-day readmission rate (5% vs. 18% in Group N). Furthermore, Group E showed a considerable reduction in surgical site wound complications, such as infections and hematomas. The study concludes that echocardiographic guidance in LAA closure procedures markedly improves postoperative wound outcomes, underscoring its potential as a standard practice in cardiac surgeries for AF patients. This approach not only optimizes patient safety and postoperative recovery but also enhances healthcare resource utilization.

Prevalence of left atrial appendage thrombus and spontaneous echo contrast on transesophageal echocardiography in patients scheduled for pulmonary vein isolation.

BACKGROUND: To avoid causing a thromboembolic event in patients undergoing catheter ablation for atrial fibrillation (AF), patients are treated with oral anticoagulants (OAC) prior to the procedure. Despite being on anticoagulants, some patients develop a left atrial appendage thrombus (LAAT). To exclude the presence of LAAT, transesophageal ultrasound (TEE) is performed in all patients prior to the procedure. We hypothesized continuous treatment with anticoagulants would result in a low prevalence of LAAT, in patients with low CHA2DS2-VASc score. METHOD: Medical records of consecutive patients planned to undergo AF ablation at Lund University Hospital during the years 2018-2020 were reviewed retrospectively. Examination protocols from transesophageal and transthoracic echocardiography were examined for LAAT and spontaneous echo contrast (SEC). Patients with LAAT and SEC were compared to patients without using Mann-Whitney U-test and Pearson Chi-squared analysis to test for correlation. RESULTS: Of 553 patients, three patients (0.54%) had LAAT, and 18 (3.25%) had spontaneous contrast (SEC). Patients with LAAT or SEC had a higher CHA2DS2-VASc score, more often presented in AF at TEE and less often had a normal sized left atrium. CONCLUSION: There is a low prevalence of LAAT and SEC in patients with AF scheduled for pulmonary vein isolation. Patients with SEC or LAAT tend to have paroxysmal AF less often and more often presented in AF at admission. No patients with CHA2DS2-VASc 0, paroxysmal AF, normal sized left atrium and sinus rhythm at TEE were found to have LAAT or SEC.

Contrast-free left atrial appendage occlusion in patients using the LAMBRE™ device.

BACKGROUND: Advances in imaging have led to procedural optimization of left atrial appendage closure (LAAC). Contrast-free approaches, guided merely by echocardiography, have been established, however data on this topic remains scarce. In this analysis, we assessed contrast-free procedural results with the LAMBRE LAAC device. METHODS: The multicenter retrospective BoBoMa (Bonn/Bordeaux/Mainz)-Registry included a total of 118 patients that underwent LAAC with LAMBRE devices omitting contrast-dye. Baseline and echocardiographic characteristics as well as intra- and postprocedural complications and outcomes were assessed. RESULTS: Patients were at a mean age of 77.5 ± 7.5 years with high thromboembolic and bleeding risk (CHADS-VASc-score 4.6 ± 1.4, HAS-BLED-score 3.7 ± 1.0, respectively). Renal function was impaired with a mean glomerular filtration rate (GFR) of 50 ± 22 ml/min. Mean procedural time was 47.2 ± 37.5  minutes with a mean radiation dose of 4.75 ± 5.25 Gy*cm2. Device success, defined as proper deployment in a correct position, was achieved in 97.5% (115/118) of cases with repositioning of the occluder in 7.6% (9/118) and resizing in 3.4% (4/118) of cases. No relevant peri-device leakage (>3 mm) was observed with 42% of occluders being implanted in an ostial position. Periprocedural complications occurred in 6.8% (8/118) of cases, including two cases of device embolization and one case of clinically-relevant pericardial effusion requiring surgical intervention. Other complications included pericardial effusion (2.5%, 3/118) and vascular access site complications (1.7%, 2/118). CONCLUSION: Echocardiography-guided contrast-free LAAC using the LAMBRE device is safe and feasible. Further prospective studies including the direct comparison of devices as well as imaging techniques are warranted in contrast-free LAAC.

Lights and shadows on left atrial appendage occlusion: mind the gap in knowledge and think twice on long-term outcomes.

Ischemic stroke prevention represents a crucial concern in health systems, being associated with high morbidity and mortality. Atrial fibrillation is associated with 15-20% of ischemic strokes, in the presence of thrombus in the left atrial appendage in 90% of patients with nonvalvular atrial fibrillation. Oral anticoagulation represents the standard of care. However, left atrial appendage occlusions have been developed for selected patients with nonvalvular atrial fibrillation. With regard to the latter, particularly, some important concerns have been raised on the selection of patients potentially amenable to the procedure, seemingly emphasizing a gap in knowledge, real-life clinical practice, and current management guidelines. In light of the recent evidence regarding the current indications for management of left atrial appendage in presence of nonvalvular atrial fibrillation, the purpose of this critical review is to highlight the blind spots of left atrial appendage occlusion indications, taking into account the evidence-based mid- to long-term outcomes. Apparently, many unsolved concerns and problems are still present, mainly including mid- and long-term device-related potential complications, the possibility of concurrent sources of embolization, ethical and economic issues. Furthermore, larger, well designed, long-term, multicentric, and more inclusive studies, as well as shared/integrated registries are needed, aiming at comparing direct oral anticoagulation with left atrial appendage occlusion in the long run.

Single antiplatelet therapy following Amplatzer left atrial appendage occlusion.

BACKGROUND: The optimal antithrombotic therapy following left atrial appendage occlusion (LAAO) remains debated. Ideally, this therapy should effectively prevent device-related thrombosis (DRT) while minimising the associated bleeding risk. AIMS: We aimed to evaluate the long-term safety and efficacy of a postprocedural single antiplatelet therapy (SAPT) strategy following Amplatzer LAAO in a large consecutive cohort. METHODS: This retrospective, single-centre, observational study included all patients discharged on SAPT after LAAO with the Amplatzer Cardiac Plug (ACP) or Amplatzer Amulet between March 2010 and December 2021 at Aarhus University Hospital, Denmark. Baseline, procedural, and imaging data were obtained locally, while clinical outcomes and medication data were extracted from the Danish national health registries. RESULTS: A total of 553 patients underwent Amplatzer LAAO during the specified time frame. Of these, 431 (77.9%) high bleeding risk patients were discharged on SAPT with either acetylsalicylic acid (n=403, 72.9%) or clopidogrel (n=28, 5.1%). At 6 months, 173 (41.7%) patients were not on any antithrombotic therapy. The mean CHA2DS2-VASc and HAS-BLED scores were 3.9±1.5 and 3.4±1.1, respectively. DRT was detected in 6 (1.5%) patients on 8-week follow-up imaging using cardiac computed tomography (n=386, 89.6%) or transoesophageal echocardiography (n=27, 6.3%). The 1-year ischaemic stroke rate was 2.2% (95% confidence interval [CI]: 1.1-4.2). One-year rates for major bleeding and cardiovascular death were 5.9% (95% CI: 4.0-8.9) and 2.9% (95% CI: 1.6-5.1), respectively. CONCLUSIONS: SAPT following Amplatzer LAAO displayed rates of DRT and stroke comparable to those reported with more intensive antithrombotic regimens. Meanwhile, we observed low rates of major bleeding.

A device-related fistula between coronary artery and left atrial appendage following left atrial appendage closure: Case presentation.

INTRODUCTION: Left atrial appendage (LAA) closure (LAAC) is considered a viable alternative to anticoagulation therapy for stroke prevention in nonvalvular atrial fibrillation, we report a case with a less common shunt resulting from a device-related coronary artery-appendage fistula (CAAF) following LAAC. METHODS AND RESULTS: A 67-year-old male with a history of LAAC was referred to our emergency room with recurrent chest pain and palpitations and was diagnosed with ischemic angina pectoris. Subsequent coronary angiography (CAG) revealed 70% in-stent restenosis and an abnormal shunt of contrast originating from the left circumflex artery (LCA) to the LAA tip which did not exist before. The restenosis was successfully dilated using a drug-coated balloon, the procedure was safely completed without pericardial effusion. The patient had been implanted with a LAmbre occluder (Lifetech Scientific Corp.) in the previous LAAC procedure. This occluder had a lobe-disk design, and the distal umbrella was not fully opened after release, particularly in the lower portion. This could make the hooks embedded on the umbrella contact the LAA wall more tightly, possibly resulting in microperforation and coincidental impingement of the LCA. The epicardial adipose and hyperplastic tissue then chronically wrapped the perforated site, prevented blood outflow into the epicardium, and ultimately formed a CAAF. CONCLUSION: CAAF is a rare complication after LAAC but may be underestimated, especially for lobe-disk designed occluders. Therefore, CAG is perhaps necessary to detect this complication.

The role of the pulmonary veins on left atrial flow patterns and thrombus formation.

Atrial fibrillation (AF) is the most common human arrhythmia, forming thrombi mostly in the left atrial appendage (LAA). However, the relation between LAA morphology, blood patterns and clot formation is not yet fully understood. Furthermore, the impact of anatomical structures like the pulmonary veins (PVs) have not been thoroughly studied due to data acquisition difficulties. In-silico studies with flow simulations provide a detailed analysis of blood flow patterns under different boundary conditions, but a limited number of cases have been reported in the literature. To address these gaps, we investigated the influence of PVs on LA blood flow patterns and thrombus formation risk through computational fluid dynamics simulations conducted on a sizeable cohort of 130 patients, establishing the largest cohort of patient-specific LA fluid simulations reported to date. The investigation encompassed an in-depth analysis of several parameters, including pulmonary vein orientation (e.g., angles) and configuration (e.g., number), LAA and LA volumes as well as their ratio, flow, and mass-less particles. Our findings highlight the total number of particles within the LAA as a key parameter for distinguishing between the thrombus and non-thrombus groups. Moreover, the angles between the different PVs play an important role to determine the flow going inside the LAA and consequently the risk of thrombus formation. The alignment between the LAA and the main direction of the left superior pulmonary vein, or the position of the right pulmonary vein when it exhibits greater inclination, had an impact to distinguish the control group vs. the thrombus group. These insights shed light on the intricate relationship between PV configuration, LAA morphology, and thrombus formation, underscoring the importance of comprehensive blood flow pattern analyses.

Overcoming barriers for left atrial appendage thrombus: a systematic review of left atrial appendage closure.

BACKGROUND: Approximately 90% of intracardial thrombi originate from the left atrial appendage in non-valvular atrial fibrillation patients. Even with anticoagulant therapy, left atrial appendage thrombus (LAAT) still occurs in 8% of patients. While left atrial appendage closure (LAAC) could be a promising alternative, the current consensus considers LAAT a contraindication to LAAC. However, the feasibility and safety of LAAC in patients with LAAT have yet to be determined. METHODS: This systematic review synthesizes published data to explore the feasibility and safety of LAAC for patients with LAAT. RESULTS: This study included a total of 136 patients with LAATs who underwent successful LAAC. The Amulet Amplatzer device was the most frequently utilized device (48.5%). Among these patients, 77 (56.6%) had absolute contraindications to anticoagulation therapy. Cerebral protection devices were utilized by 47 patients (34.6%). Transesophageal echocardiography (TEE) is the primary imaging technique used during the procedure. Warfarin and novel oral anticoagulants were the main anticoagulant medications used prior to the procedure, while dual antiplatelet therapy was primarily used post-procedure. During a mean follow-up period of 13.2 ± 11.5 months, there was 1 case of fatality, 1 case of stroke, 3 major bleeding events, 3 instances of device-related thrombus, and 8 cases of peri-device leakage. CONCLUSIONS: This review highlights the preliminary effectiveness and safety of the LAAC procedure in patients with persistent LAAT. Future large-scale RCTs with varied LAAT characteristics and LAAC device types are essential for evidence-based decision-making in clinical practice.

Left atrial strain time integral evaluated by two-dimensional speckle tracking predicts left atrial appendage dysfunction in patients with acute ischemic stroke.

Cardioembolic stroke is a serious disease with poor prognosis, whose main embolic source is the left atrial appendage (LAA). Left atrial (LA) strain evaluated by the two-dimensional (2D) speckle tracking technique has been proposed. However, the commonly used peak LA strain reflects only LA reservoir function. The LA strain also includes indicators of the other LA functions, such as booster pump function, which reflects active contraction of the LA. This study aimed to investigate whether a newly developed parameter, the left atrial strain time integral (LASTI), can evaluate LAA dysfunction more accurately in patients with acute stroke. We measured LA strain using a 2D speckle tracking method in 168 patients with acute stroke and 20 age-matched control subjects. LASTI was calculated as the area under the LA strain curve in one cardiac cycle. LAA dysfunction was defined as LAA thrombus and/or severe spontaneous echo contrast by transesophageal echocardiography. LASTI was significantly lower in patients with LAA dysfunction than those without. LASTI was a better correlation with LAA blood flow velocity measured by transesophageal echocardiography than peak LA strain. Multivariate logistic regression analysis showed that LASTI was an independent predictor of LAA dysfunction after adjustment for conventional risk factors. LASTI can be a feasible parameter for predicting LAA dysfunction in patients with acute stroke.

Late device-related thrombus associated with occult malignancy years after left atrial appendage closure.

INTRODUCTION: The use of Left Atrial Appendage (LAA) occluder devices has been on the rise in patients with atrial fibrillation. Studies regarding the long-term risks of occluder devices remain sparse. MATERIALS & METHODS: In this brief report, we discuss the unusual case of an 85-year-old female with long-term complication from Left Atrial Appendage (LAA) closure: Device-Related Thrombus (DRT) about two years after insertion. RESULTS: Compared to the expected stroke rate without anticoagulation, patients with DRT on their LAAO device still had a 28 % relative reduction in ischemic stroke. This suggests that these strokes may have emanated from alternate etiologies other than the DRT. CONCLUSIONS: Patients with active or known history of cancer appears to have a higher risk of DRT. More data is needed on this topic to augment awareness and understanding of LAAO complications and DRT management strategies.