Antithrombotic Therapy Following Structural Heart Disease Interventions: Current Status and Future Directions.

Interventions in structural heart disease cover many catheter-based procedures for congenital and acquired conditions including valvular diseases, septal defects, arterial or venous obstructions, and fistulas. Among the available procedures, the most common are aortic valve implantation, mitral or tricuspid valve repair/implantation, left atrial appendage occlusion, and patent foramen ovale closure. Antithrombotic therapy for transcatheter structural heart disease interventions aims to prevent thromboembolic events and reduce the risk of short-term and long-term complications. The specific approach to antithrombotic therapy depends on the type of intervention and individual patient factors. In this review, we synopsize contemporary evidence on antithrombotic therapies for structural heart disease interventions and highlight the importance of a personalized approach. These recommendations may evolve over time as new evidence emerges and clinical guidelines are updated. Therefore, it's crucial for healthcare professionals to stay updated on the most recent guidelines and individualize therapy based on patient-specific factors and procedural considerations.

Interventional closure of an iatrogenic LAA-perforation by means of a PFO-occluder.

Atrial fibrillation (AF) is the most common rhythm disorder with a high risk for cardioembolic strokes. Interventional occlusion of the left atrial appendage (LAA) is an alternative to the widely established stroke prevention with oral anticoagulation. Complications through LAA closure (LAAC) are rare and usually occur periinterventional. We present a case of an 87-year-old patient who presents for elective LAAC. After placement of the LAA occluder (Amplatzer Amulet device 25 mm) in the LAA and partial resheathing, the patient developed a pericardial effusion (PE), became hemodynamically unstable and went into cardiac arrest with the need for cardiopulmonary resuscitation (CPR). After drainage of the PE, we closed the causative LAA-perforation using a persistent foramen ovale (PFO)-occluder device (Amplatzer Talisman, 25 mm). Thereby we were able to successfully seal the perforation and stabilize the patient. The patient was monitored at our intensive care unit for 2 days and left the hospital in good condition a few days after. Procedural complications during interventional LAAC are rare but can be serious. The most common complication, PE, requires percutaneous drainage and often cardiac surgery. We present a case in which a perforation and following PE with hemodynamic relevance and need for CPR was resolved with an interventional strategy through implantation of a PFO-occluder into the perforation. With this approach we were able to show that in the right setting even serious complications can be treated by interventional measures, thereby not only saving the patient's life, but also avoiding cardiac surgery.

Safety and efficacy of the second-generation cryoballoon for left atrial appendage electrical isolation in canines.

AIMS: Left atrial appendage electrical isolation (LAAEI) has demonstrated a significant enhancement in the success rate of atrial fibrillation (AF) ablation. Nevertheless, concerns persist about the safety of LAAEI, particularly regarding alterations in left atrial appendage (LAA) flow velocity and the potential risks of thrombus. This study aimed to assess the efficacy and safety of LAAEI, investigating changes in LAA flow velocity in canines. METHODS AND RESULTS: The study comprised a total of 10 canines. The LAAEI procedure used by a 23 mm cryoballoon of the second generation was conducted at least 180 s. Intracardiac ultrasonography (ICE) was employed to quantify the velocity flow of the LAA both prior to and following LAAEI. Following a 3-month period, subsequent evaluations were performed to assess the LAA velocity flow and the potential reconnection. Histopathological examination was conducted. Left atrial appendage electrical isolation was effectively accomplished in all canines, resulting in a 100% acute success rate (10/10). The flow velocity in the LAA showed a notable reduction during LAAEI as compared with the values before the ablation procedure (53.12 ± 5.89 vs. 42.01 ± 9.22 cm/s, P = 0.007). After the follow-up, reconnection was observed in four canines, leading to a success rate of LAAEI of 60% (6/10). The flow velocity in the LAA was consistently lower (53.12 ± 5.89 vs. 44.33 ± 10.49 cm/s, P = 0.006), and no blood clot development was observed. The histopathological study indicated that there was consistent and complete injury to the LAA, affecting all layers of its wall. The injured tissue was subsequently replaced by fibrous tissue. CONCLUSION: The feasibility of using cryoballoon ablation for LAAEI was confirmed in canines, leading to a significant reduction of LAA flow velocity after ablation. Some restoration of LAA flow velocity after ablation may be linked to the passive movement of the LAA and potential reconnecting. However, this conclusion is limited to animal study; more clinical data are needed to further illustrate the safety and accessibility of LAAEI in humans.

Should left atrial appendage closure be considered in resistant left atrial appendage thrombus cases? 'Former Foe, New Ally'.

BACKGROUND: The study explores left atrial appendage closure (LAAC) as a safe and effective alternative to anticoagulation for atrial fibrillation (AF) patients at high bleeding risk. Complications, such as cardioembolic events due to left atrial appendage thrombus (LAAT), highlight the need for alternative stroke prevention strategies. AIMS: This research assesses LAAC's safety and efficacy in patients with LAAT, aiming to offer valuable insights into its potential as a viable option for stroke prevention in such cases. METHODS: The study included 205 patients who underwent LAAC using specific devices between September 2015 and February 2023. Among them, 32 patients had persistent LAAT. Baseline characteristics, antithrombotic medications, risk scores, and LAAC indications were documented. Patients were followed to monitor significant clinical events like stroke, cardiovascular mortality, and all-cause mortality. RESULTS: The mean age was 71.9 and mostly female. Indications for LAAC were ischemic cerebrovascular events (CVE) despite anticoagulation (25%), bleeding complications (major/minor, 37.5% each), or both. Successful LAA closure was achieved in all cases, with minimal pericardial effusion in one. One-month follow-up showed no major events or device-related issues. Median follow-up of 16.5 months saw 21.9% non-cardiac deaths. The study underscores LAAC's efficacy for stroke prevention in patients with persistent LAAT. CONCLUSIONS: The LAAC in cases of LAAT, whether pursued initially or as a deferred approach, demonstrates feasibility and safety, exhibiting notable procedural success and minimal incidence of periprocedural complications.

Diagnostic Accuracy of Left Atrial/Left Atrial Appendage Thrombus in Patients with Atrial Fibrillation: A Systematic Review and Network Meta-Analysis.

Background: This paper aimed to appraise the diagnostic precision of assorted methodologies to identify left atrial/left atrial appendage (LA/LAA) thrombus through a network meta-assessment. Methods: Methodologically, we conducted a comprehensive literature search across multiple databases. Utilizing the risk of bias tool from the Cochrane Collaboration, methodological quality of included studies was critically assessed and potential publication bias was examined via funnel plots. The subsequent data analysis was executed using Stata software, with the most efficacious diagnostic modalities being determined based on cumulative ranking curve (SUCRA) values. Results: We scrutinized a sum of 18 papers, comprising 4102 subjects and utilizing 10 different diagnostic techniques. The hierarchical results derived from the network meta-analysis indicated that in regards to sensitivity, the dual-source cardiac computed tomography (DSCT) was superior (with a SUCRA value of 71.7%), it was succeeded by 3-minute delayed cardiac computed tomography (CCT) (scoring 66.8%), which surpassed the transesophageal echocardiography (TEE) (holding a SUCRA value of 57.5%). In terms of specificity, DSCT was the best (SUCRA value of 84.3%), followed by three dimensional (3D) cardiac magnetic resonance imaging (3D-CMRI) (SUCRA value of 78.0%), which was better than TEE (SUCRA value of 66.6%). In terms of positive likelihood ratio (PLR), 6-minute delayed CCT (SUCRA value of 85.6%) was superior to 3-minute delayed CCT (SUCRA value of 80.1%), both of which were superior to TEE (SUCRA value of 69.1%). DSCT (SUCRA value of 89.3%) had the best negative likelihood ratio (NLR), while DSCT (SUCRA value of 79.9%) had the highest accuracy. Conclusions: This study demonstrated that DSCT outperformed TEE in sensitivity, specificity, NLR, and accuracy in identifying thrombus of LA/LAA among patients suffering from atrial fibrillation. Our conclusion is that DSCT is the best in diagnosing LA/LAA. In addition, 3D-CMRI and 3-minute delayed CCT are expected to replace TEE.

Choosing Appropriate Candidates for Left Atrial Appendage Occlusion.

Atrial fibrillation (AF) is one the most prevalent arrhythmias globally and is associated with a significantly higher risk of morbidity and mortality, including an up to five-fold increase in risk of stroke. While oral anticoagulation therapy remains the standard approach for stroke prevention in nonvalvular AF, left atrial appendage occlusion (LAAO) has emerged as a viable alternative for patients who are intolerant to long-term oral anticoagulation therapy. However, selecting appropriate candidates for LAAO requires a comprehensive evaluation that considers various clinical factors, although this presents a challenge in clinical practice. This review aims to provide an overview of the current recommendations for patient selection in LAAO procedures and the key factors that need to be considered both before and after the procedure, as well as the ongoing advancements in this field that may facilitate the selection of patients for LAAO.

Implementation and first outcomes of a novel standard operating procedure for preprocedural transoesophageal echocardiography screening in course of atrial arrhythmia ablation.

AIMS: Preprocedural transoesophageal echocardiography (TEE) screening for left atrial (LA) thrombi is the standard of care in many centres performing atrial fibrillation (AF) ablation. However, TEE imposes procedural risks for patients and is often challenging to implement in daily practice, besides causing patient discomfort. At our centre, a novel standard operating procedure (SOP) was implemented, aiming to identify patients that can be exempt from TEE screening. We aimed to assess whether this screening approach may reduce preprocedural TEEs without imposing patients of higher risks for cerebrovascular events (CVEs). METHODS AND RESULTS: Data of 1874 consecutive patients treated by catheter ablation of LA arrhythmias between 2018 and 2022 were retrospectively analysed. A cohort of 937 patients, where decision to perform TEE screening was based on a new SOP (considering rhythm at admission, CHA2DS2-VASc score, and sufficient anticoagulation), was compared to a matched cohort receiving TEE before every procedure. Number of performed TEEs and incidences of CVEs were compared. Implementation of the new SOP led to a 67% reduction in TEEs performed (old SOP: 933 vs. new SOP: 305). No significant differences between the groups were detected regarding transitory ischaemic attack (old SOP: 5 vs. new SOP: 3; P = 0.48) and stroke (no events). No solid thrombi were detected during TEE screening. CONCLUSION: The number of preprocedural screening TEEs before AF ablation procedures can be safely reduced by applying risk stratification based on rhythm at admission and CHA2DS2-VASc score, if anticoagulation was performed properly.

Linear Antenna Array Sectorized Beam Scanning Approaches Using Element Position Perturbation in the Azimuth Plane.

In this paper, two sector beam scanning approaches (BSAs) based on element position perturbations (EPPs) in the azimuth plane are introduced. In EPP-BSA, the elements' excitations are kept constant and the elements' positions in the direction normal to the array line are changed according to a predetermined EPP pattern. The magnitude and repetition rate of the selected EPP pattern determines the steering angle of the main beam. However, EPP-BSA results in a wide scanning range with a significant increase in the side lobe level (SLL). To mitigate this drawback, a reduction in the SLL of the array pattern is firstly performed using the single convolution/genetic algorithm (SC/GA) technique and then perturbing the elements' positions in the azimuth plane. This combination between SLL reduction and EPP-BSA (SLL/EPP-BSA) results in a smaller scanning range with a relatively constant half power beamwidth (HPBW) and a much lower SLL. In addition, keeping the synthesized excitation coefficients constant without adding progressive phase shifters facilitates the manufacturing process and reduces the cost of the feeding network. Furthermore, a planar antenna array thinning approach is proposed to realize the EPP-BSA. The results are realized using the computer simulation technology (CST) microwave studio software package, which provides users with an optimized modeling environment and results in realizable and realistic designs.

Prognostic Value of Galectin-3 after Left Atrial Appendage Occlusion for Predicting Peri-Device Leakage.

Echocardiographic detection of residual peri-device leakage (PDL) after percutaneous left atrial appendage occlusion (LAAO) is crucial for managing anticoagulation. Galectin-3, a protein involved in tissue-foreign body interactions, may hold significance in understanding PDL and cardiac tissue remodeling after LAAO. This study aimed to analyze galectin-3 serum levels in relation to PDL using a novel echo-morphological classification. LAAO eligible patients were included in the study. Galectin-3 serum levels were measured before LAAO, at 45 days (45D), and at 6 months (6M) after the procedure. Transesophageal echocardiography was used to assess LAAO success. A new echo-morphological classification categorized the degree of LAAO into three different types (A: homogenous echodensity, indicating completely thrombosed device; B: inhomogeneous echolucencies (<50% of device); and C: partially thrombosed device with echolucencies > 50%). Among 47 patients, complete LAAO was achieved in 60% after 45D and in 74% after 6M. We observed a significant increase and distribution of serum levels of galectin-3 [ng/mL] after 45D among the three types (baseline: 13.1 ± 5.8 ng/mL; 45D: 16.3 ± 7.2 ng/mL (Type A) vs. 19.2 ± 8.6 ng/mL (Type B) vs. 25.8 ± 9.4 ng/mL (Type C); p = 0.031), followed by a drop in galectin-3 for Types A and B after 6M toward and below the baseline levels (6M: 8.9 ± 3.1 ng/mL (Type A) vs. 12.4 ± 5.5 ng/mL (Type B)), whereas Type C persisted in showing elevated galectin-3 levels compared to all other types (6M: 17.5 ± 4.5 ng/mL (Type C); p < 0.01). Increased galectin-3 serum levels after LAAO likely reflect the transition from thrombus formation to fibrotic scar development in the LAA lumen. Successful occlusion is associated with a time-restricted decrease in galectin-3 levels after 6 months, while relevant PDL leads to persistently elevated levels, making galectin-3 a potential predictor of occlusion success.

Metabolic effects of the left atrial appendage exclusion (the heart hormone study).

INTRODUCTION: The effect of epicardial left atrial appendage (LAA) occlusion therapy on lipid and glucose metabolism in atrial fibrillation (AF) patients over the long-term follow-up are unclear. METHODS: In a single-center prospective observational study, 60 patients with longstanding persistent AF with cardiovascular risk factors had undergone an epicardial exclusion procedure. Anthropometric parameters and glucose, glycated hemoglobin (HbA1c), insulin, leptin, adiponectin, free fatty acids, beta-hydroxybutyrate, and total cholesterol levels were evaluated on fasting at baseline before the procedure and compared with levels at 24 h, 7 days, 1, 3, 6, and 24 months follow the procedure. RESULTS: The mean age of the patients was 67.5 ± 8.1. Insulin levels significantly increased at 7 days, 1, 3, 6, 12, and 24 months follow-up. The leptin levels showed a significant increase in 6, 12, and 24 months when compared to baseline. Whereas the adiponectin levels showed a significant decrease at 3, 6, 12, and 24 months when compared to baseline levels. In patients with the epicardial procedure, when compared to baseline, glucose, glycated hemoglobin, total cholesterol, and beta-hydroxybutyrate levels did not show any significant changes at baseline and 24 months follow-up. CONCLUSION: The epicardial exclusion ligation in AF patients was associated with significant changes in insulin, leptin, and adiponectin over long follow-up.

Association of air pollution exposure with exercise-induced oxygen desaturation in COPD.

BACKGROUND: There is a link between exposure to air pollution and the increased prevalence of chronic obstructive pulmonary disease (COPD) and declining pulmonary function, but the association with O2 desaturation during exercise in COPD patients with emphysema is unclear. Our aims were to estimate the prevalence of O2 desaturation during exercise in patients with COPD, and determine the association of exposure to air pollution with exercise-induced desaturation (EID), the degree of emphysema, and dynamic hyperinflation (DH). METHODS: We assessed the effects of 10-year prior to the HRCT assessment and 7 days prior to the six-minute walking test exposure to particulate matter with an aerodynamic diameter of < 10 µm (PM10) or of < 2.5 µM (PM2.5), nitrogen dioxide (NO2), and ozone (O3) in patients with emphysema in this retrospective cohort study. EID was defined as a nadir standard pulse oximetry (SpO2) level of < 90% or a delta (△)SpO2 level of ≥ 4%. Ambient air pollutant (PM2.5, PM10, O3, and NO2) data were obtained from Taiwan Environmental Protection Administration (EPA) air-monitoring stations, usually within 10 km to each participant's home address. RESULTS: We recruited 141 subjects with emphysema. 41.1% of patients with emphysema exhibited EID, and patients with EID had more dyspnea, worse lung function, more severe emphysema, more frequent acute exacerbations, managed a shorter walking distance, had DH, and greater long-term exposure to air pollution than those without EID. We observed that levels of 10-year concentrations of PM10, PM2.5, and NO2 were significantly associated with EID, PM10 and PM2.5 were associated with the severity of emphysema, and associated with DH in patients with emphysema. In contrast, short-term exposure did not have any effect on patients. CONCLUSION: Long-term exposure to ambient PM10, PM2.5 and NO2, but not O3, was associated with EID.

Usefulness of a novel sizing chart for left atrial appendage occlusion with the Amplatzer Amulet.

PURPOSE: The present article aims to compare a novel sizing chart based on both maximum and minimum diameters (novel MATRIX) with the current sizing recommendation instructions for use (IFU) based on the maximum diameter. BACKGROUND: Current IFU with the Amulet device are still based on the maximum left atrial appendage (LAA) diameter, which might lead to inappropriate oversizing, especially in elliptic appendages. METHODS: This was a retrospective analysis of patients undergoing LAA occlusion in two high-volume centers. Two hundred patients were included (100 patients with baseline cardiac computed tomography angiography [CCTA] and 100 with baseline 2D and 3D-transesophageal echocardiography [TEE]). The degree of concordance between the predicted device size recommendation and the actual device selection was the primary outcome. RESULTS: The novel MATRIX showed a higher level of concordance between the predicted and implanted device size, regardless of imaging modalities. CCTA showed the strongest, and 2D-TEE the weakest concordance between the predicted and implanted device for both MATRIX and IFU charts. The percentage of patients in whom the disagreement among the predicted and implanted device represented >1 size was higher when using the IFU chart. In elliptical LAA anatomies, the differences favoring the use of MATRIX compared to the IFU in terms of predicted/implanted agreement were higher. Finally, no significant differences in clinical or imaging endpoints were observed between the two different sizing charts. CONCLUSIONS: Incorporating both the LAA maximum and minimum diameters, as opposed to just maximum diameter, appears to improve sizing accuracy. The proposed MATRIX sizing chart offered a higher level of concordance between predicted and implanted device compared to the current IFU.

Adverse events and stroke prevention by interventional left atrial appendage occlusion in patients with low CHA2 DS2 -VASc score-results from the multicenter German LAARGE registry.

BACKGROUND: Interventional left atrial appendage occlusion (LAAO) is routinely performed in patients with nonvalvular atrial fibrillation and contraindications to standard anticoagulation. AIMS: We investigated its role in patients at low stroke risk, and compared the effectiveness and safety in patients with low versus high risk. METHODS: LAARGE is a prospective registry depicting the clinical reality of LAAO. LAAO was conducted with different standard commercial devices, and follow-up period was 1 year. Patients with started procedure and documented CHA2 DS2 -VASc score were selected from the whole database. RESULTS: A total of 638 patients from 38 centers were divided into CHA2 DS2 -VASc score ≤2, i.e., low-risk group (10.2%), and >2, i.e., high-risk group (89.8%). The latter had a pronounced cardiovascular risk profile and preceding strokes (0% vs. 23.9%; p < 0.001). Implantation success was consistently high (97.6%), frequencies of intrahospital major adverse cardiac and cerebrovascular events (0% vs. 0.5%) and other major complications (4.6% vs. 4.0%) were low (each p = not significant [NS]). Numerous moderate complications were also observed in the low-risk patients (12.3% vs. 9.4%; p = NS). Frequencies of nonfatal strokes (0% vs. 0.7%) and severe bleedings (0% vs. 0.7%) were low (each p = NS). In a specific analysis, patients at very high risk of stroke (i.e., CHA2 DS2 -VASc score >4) did not have increased rates of complications or nonfatal strokes in the first year after the procedure. CONCLUSIONS: Low-risk patients had no nonfatal strokes and major bleedings within 1 year after hospital discharge but had unexpectedly high rates of moderate procedural complications. The indication in these patients should be strictly defined based on an individual benefit-risk assessment.

Clinical Characteristics of Non-Valvular Atrial Fibrillation Patients With a Large Left Atrial Appendage Ostium-Limiting Percutaneous Closure.

BACKGROUND: The left atrial appendage (LAA) is a therapeutic target for preventing cardioembolic stroke in patients with non-valvular atrial fibrillation (NVAF). A large LAA ostium limits percutaneous LAA closure. This study investigated the characteristics and factors associated with a large LAA ostium in Japanese patients with NVAF.Methods and Results: In 1,102 NVAF patients, the maximum LAA diameter was measured using transesophageal echocardiography (TEE). A large LAA ostium was defined by a maximum diameter of >30 mm. Forty-four participants underwent repeated TEEs, and changes in LAA size under lasting AF were assessed. A large LAA ostium was observed in 3.1% of all participants and 8.9% of patients with long-standing persistent AF (LSAF). The large LAA group had greater CHA2DS2-VASc (P=0.024) and HAS-BLED scores (P=0.046) and a higher prevalence of LAA thrombus (P=0.004) than did the normal LAA group. LSAF, moderate or severe mitral regurgitation, left atrial volume ≥42 mL/m2, E/E' ratio ≥9.5, and left ventricular mass ≥85 mg/m2were independently associated with a large LAA ostium (P<0.001, P<0.001, P=0.009, P=0.009, and P=0.032, respectively). In 44 patients with lasting AF, the LAA ostial diameter increased over time (P<0.001). CONCLUSIONS: NVAF patients with a large LAA ostium may have a higher risk of stroke and bleeding. LSAF and factors leading to LA overload may be closely associated with LAA ostial dilatation and can promote it.

Diagnostic efficacy of visual subtypes and low attenuation area based on HRCT in the diagnosis of COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease. Current gold standard criteria, pulmonary function tests (PFTs) may result in underdiagnosis of potential COPD patients. Therefore, we hypothesize that the combination of high-resolution computed tomography (HRCT) and clinical basic characteristics will enable the identification of more COPD patients. METHODS: A total of 284 patients with respiratory symptoms who were current or former smokers were included in the study, and were further divided into 5 groups of GOLD grade I-IV and non-COPD according to PFTs. All patients underwent inspiratory HRCT scanning and low attenuation area (LAA) was measured. Then they were divided into seven visual subtypes according to the Fleischner Society classification system. Non-parametric tests were used for exploring differences in basic characteristics and PFTs between different groups of enrolled patients and visual subtypes. Binary logistic regression was to find the influencing factors that affected the patients' outcome (non-COPD vs GOLD I-IV). The area under the receiver operating characteristic curve (AUC-ROC) was to explore the diagnostic efficacy of LAA, visual subtypes, and combined basic characteristics related to COPD for COPD diagnosis. Finally, based on the cut-off values of ROC analysis, exploring HRCT features in patients who do not meet the diagnostic criteria but clinically suspected COPD. RESULTS: With the worsening severity of COPD, the visual subtypes gradually progressed (p < 0.01). There was a significant difference in LAA between GOLD II-IV and non-COPD (p < 0.0001). The diagnostic efficacy of LAA, visual subtypes, and LAA combined with visual subtypes for COPD were 0.742, 0.682 and 0.730 respectively. The diagnostic efficacy increased to 0.923-0.943 when basic characteristics were added (all p < 0.001). Based on the cut-off value of ROC analysis, LAA greater than 5.6, worsening of visual subtypes, combined with positive basic characteristics can help identify some potential COPD patients. CONCLUSION: The heterogeneous phenotype of COPD requires a combination of multiple evaluation methods. The diagnostic efficacy of combining LAA, visual subtypes, and basic characteristics achieves good consistency with current diagnostic criteria.

Bi-Criteria Radio Spectrum Sharing With Subspace-Based Pareto Tracing.

Radio spectrum is a scarce resource. To meet demands, new wireless technologies must operate in shared spectrum over unlicensed bands (coexist). We consider coexistence of Long-Term Evolution (LTE) License-Assisted Access (LAA) with incumbent Wi-Fi systems. Our scenario consists of multiple LAA and Wi-Fi links sharing an unlicensed band; we aim to simultaneously optimize performance of both coexistence systems. To do this, we present a technique to continuously estimate the Pareto frontier of parameter sets (traces) which approximately maximize all convex combinations of network throughputs over network parameters. We use a dimensionality reduction approach known as active subspaces to determine that this near-optimal parameter set is primarily composed of two physically relevant parameters. A choice of two-dimensional subspace enables visualizations augmenting explainability and the reduced-dimension convex problem results in approximations which dominate random grid search.

Thickness of the left atrial wall surrounding the left atrial appendage orifice.

INTRODUCTION: The aim of this study was to investigate the thickness of the left atrial wall surrounding the left atrial appendage (LAA) orifice. METHODS AND RESULTS: The tissue thickness around the LAA orifice was measured at four points (superior, inferior, anterior, and posterior) in 200 randomly selected autopsied human hearts. The thickest tissue was observed at the anterior point (3.17 ± 1.41 mm), followed by the superior (2.47 ± 1.00 mm), inferior (2.22 ± 0.80 mm) and posterior (2.22 ± 0.83 mm). The chicken wing LAA type was associated with the lowest thickness at the superior point compared to the cauliflower and arrowhead shapes (p = .024). In hearts with an oval LAA orifice, the atrial wall was significantly thicker in all points than in specimens with a round LAA orifice (p > .05). Both the LAA orifice anteroposterior diameter and orifice surface area were negatively correlated with the tissue thickness in the anterior (r = -.22, p = .004 and r = -.23, p = .001) and posterior points (r = -.24, p = .001 and r = -.28, p = .005). Endocardial surface roughness was commonly in the inferior pole of the LAA orifice (75.5% of cases), while they are much less prevalent in other sectors around the orifice (anterior: 17.5%), superior: 4.0%, and posterior: 1.5%). CONCLUSIONS: Although a significant heterogeneity in the atrial wall thickness around the LAA orifice was observed, the thickness in the respective points is quite conservative and depends only on LAA orifice size and shape, as well as LAA body shape. Thin atrial wall and endocardial surface roughness might challenge invasive procedures within this region.

Biofilm formation by LEE-negative Shiga Toxin-Producing Escherichia coli strains.

Shiga toxin-producing Escherichia coli (STEC) include several serotypes isolated from cases of hemorrhagic colitis and, hemolytic uremic syndrome. Although O157:H7 is the most predominant STEC serotype, more than 100 non-O157 serogroups cause diseases in humans. Some STEC carry a Locus of Enterocyte Effacement (LEE-positive); however, STEC that do not carry LEE (LEE-negative) have also been associated with illness, mainly those harbouring the Locus of Adhesion and Autoaggregation (LAA). LAA carry some genes such as hes, iha, tpsA, and agn43, related with pathogenicity. One of them is the ability to form biofilms on different environments, which can contaminate food and generate infections while protecting themselves against adverse conditions. Considering that LAA could be responsible for some adherence mechanisms, the aims of this study were to compare different serogroup of LEE-negative STEC strains in their ability to form biofilms and to evaluate the participation of some genes encoding in LAA. A total of 348 LEE-negative STEC strains was analyzed. The presence of hes, iha, tpsA and agn43 were determined by monoplex PCR. From them, 48 STEC strains belonging to serogroups O113, O130, O171, O174 and, O178 were assayed for their ability to form biofilm. The most prevalent genes detected were agn43 (72.1%) and tpsA (69.5%). The iha and hes genes were present in 63.7% and 54% of the strains, respectively. Although all STEC strains were able to form biofilm, it was found a high variability between them. The relation between the biofilm formation and the presence of each gene was not statistically significant, suggesting that biofilm formation is independent of the presence of those genes. Highlighting that there is no treatment for HUS, it is once again notable that prevention measures and control strategies to prevent biofilm formation are important factors in reducing STEC transmission.

Impact of individual stroke risk on outcome after Amplatzer left atrial appendage closure in patients with atrial fibrillation.

OBJECTIVES: To investigate periprocedural and long-term outcome of left atrial appendage closure (LAAC) using Amplatzer occluders with respect to individual pre-procedural stroke risk. BACKGROUND: LAAC is a proven strategy for prevention from stroke and bleeding in patients with nonvalvular atrial fibrillation not amenable to oral anticoagulation. Whether individual pre-procedural stroke risk may affect procedural and long-term clinical outcome after LAAC is unclear. METHODS: Multicenter study of consecutive patients who underwent Amplatzer-LAAC. Using pre-procedural CHADS2 score, outcomes were compared between a low (0-2 points) and a high stroke risk group (3-6 points). RESULTS: Five hundred consecutive patients (73.9 ± 10.1 years) who underwent Amplatzer-LAAC. Two hundred and forty eight had preprocedural CHADS2 score ≤ 2 points (low-risk group) and the remaining 252 patients had 3-6 points (high-risk group). Periprocedural complication rates (6.0% vs. 5.6%, p = .85), procedural success (LAAC without major periprocedural or device-related complications or major para-device leaks: 89.4% vs. 87.9%, p = .74), and 30-day-mortality (2.4% vs. 2.6%, p = .77) were comparable. After 1,346 patient-years (PY), the long-term composite efficacy endpoint (stroke, systemic embolism, cardiovascular, and unexplained death) was reached in 23/653 (3.5/100 PY) versus 52/693 (7.5/100 PY); HR = 2.13; 95%-CI, 1.28-3.65, p = .002) with stroke rates 67% and 68% lower than anticipated by preprocedural CHADS2 score. Combined safety endpoint (major periprocedural complications and major, life-threatening or fatal bleedings) occurred in 22/653 (3.4/100 PY) versus 28/693 (4.0/100 PY); HR = 1.20; 95%-CI, 0.66-2.20, p = .52). CONCLUSIONS: Compared with patients at low risk of stroke, LAAC with Amplatzer devices is associated with similar safety and efficacy in high-risk patients in our study.

Stroke and left atrial thrombi after cryoballoon ablation of atrial fibrillation: incidence and predictors. Results from a long-term follow-up.

Stroke after catheter ablation (CA) of atrial fibrillation (AF) is a potential complication with long term consequences. Aim of this study was to determine incidence and potential predictors of stroke and left atrial appendage (LAA) thrombi after AF ablation with cryo-energy. Two hundred nine consecutive patients with symptomatic drug refractory AF (65% male; 61 ± 11 yo, 69% paroxysmal AF, mean CHA2DS2-VASc score 2 ± 1.4) were enrolled between October 2012 until December 2015. Long term follow-up was performed with outpatient clinic visits at 6-month intervals. Incidence of stroke after CA was 1.4% (3/209 pts) at long term follow-up. Two out of 3 pts experienced stroke during the first 3 month after CA and one after 36 months. At long term follow-up LAA thrombi were found in two patients (1%) that were on therapeutic oral anticoagulation. Recurrence of AF was found in 4 out of 5 pts with stroke or LAA thrombi. Patients with stroke or LAA thrombi did not differed from those without in term of age, gender, CV risk factors, LA size and AF type. They differed only for EHRA score (2.4 vs 1.3, p = 0.01) before CA. At multivariate analysis after correction for age, gender, LA size, LVEF and AF type, only EHRA score (ß 1.92, 95% C.I. 1.3-35 p = 0.02), was an independent predictor of stroke/LAA thrombi. Incidence of stroke after cryoablation is low, with a relative higher prevalence during the first 3 months after CA. Prospective, multicenter long-term registries are needed for a better stroke risk stratification.