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.

Does Morphology of the Shoulder Joint Play a Role in the Etiology of Rotator Cuff Tear?

BACKGROUND

The etiology of rotator cuff tears (RCTs) have been investigated for years and many underlying causes have been identified. Shoulder joint morphology is one of the extrinsic causes of RCTs.

AIM

Morphometric measurements on MRI sections determined which parameters are an important indicator of RCT in patients with shoulder pain. The aim of this study was to determine the risk factors in the etiology of RCTs by evaluating the shoulder joint morphology with the help of previously defined radiological parameters.

METHOD

Between January 2019-December 2020, 408 patients (40-70 years old) who underwent shoulder MRI and met the criteria were included in the study. There were 202 patients in the RCT group and 206 patients in the control group. Acromion type, acromial index (AI), critical shoulder angle (CSA), acromiohumeral distance (AHD), lateral acromial angle (LAA), acromial angulation (AA), acromion-greater tuberosity impingement index (ATI), and glenoid version angle (GVA) were measured from the MRI images of the patients.

RESULTS

AI (0.64 vs. 0.60, p = 0.003) CSA (35.3° vs. 32.4°, p = 0.004), ATI (0.91 vs. 0.83, P < 0.001), and AA (13.6° vs. 11.9°, p = 0.011) values were higher in the RCT group than in the control group and the difference was significant. AHD (8.1 mm vs. 9.9 mm, P < 0.001), LAA (77.2° vs. 80.9°, p = 0.004) and GVA (-3.9° vs. -2.5°, P < 0.001) values were lower in the RCT group than in the control group, and again the difference was significant. According to the receiver operating characteristic curve analysis, the cutoff values were 0.623 for AI and 0.860 for ATI.

CONCLUSION

Acromion type, AI, CSA, AHD, LAA, AA, ATI, and GVA are suitable radiological parameters to evaluate shoulder joint morphology. High AI, CSA, AA, ATI, GVA and low AHD and LAA are risk factors for RCT.

Expression of hes, iha, and tpsA codified in locus of adhesion and autoaggregation and their involvement in the capability of shiga toxin-producing Escherichia coli strains to adhere to epithelial cells

OBJECTIVES

Shiga toxin-producing Escherichia coli strains LAA-positive are important cause of human infection. The capability to adhere to epithelial cells is a key virulence trait, and genes codified in LAA pathogenicity island could be involved in the adhesion during the pathogenesis of LAA-positive STEC strains. Thus, our objectives were to compare hes-negative and hes-positive STEC strains in their adherence capability to epithelial cells (HEp-2) and to evaluate the expression levels of the hes, iha, and tpsA in the bacteria adhered and non-adhered to HEp-2 cells. These genes are encoded in LAA, and are virulence factors that participate in adhesion and autoaggregation.

RESULTS

We could not observe differences between the adhesion of strains but also in the expression level of of hes, iha, and tpsA. Genes encoded in LAA contribute to the adhesion phenotype though the expression of STEC adhesins is a coordinated event that depends not only the strain but also on the environment as well as its genetic background. Therefore, the results of this study suggest that LAA ,the most prevalent PAI among LEE-negative STEC strains, plays a role in pathogenesis.

Gross anatomic relationship between the human left atrial appendage and the left ventricular summit region: implications for catheter ablation of ventricular arrhythmias originating from the left ventricular summit

PURPOSE

The left ventricular summit (LVS) is a source of difficult-to-treat arrhythmias because of anatomical limitations. The aim of this study was to perform detailed research of the left atrial appendage (LAA) anatomy of cadaveric hearts to analyze their complex anatomy and coverage of the LVS.

METHODS AND RESULTS

Eighty human formalin fixed hearts (mean age 44.4 ± 15.5, 27.5% females) were investigated. Each LAA size, type, and its relationship to the LVS were analyzed, as well as possible access sites for mapping/ablating electrode. Four types of LAA were observed over two LVS sites that are either accessible or not. The highest coverage over an inaccessible LVS area was observed in the Broccoli type, followed by the Windsock then the Chicken Wing and finally the Cactus types; over the accessible area of the LVS was observed in the Windsock, then in the Chicken Wing, then in the Cactus, and finally in the Broccoli types. The attainable coverage for electrode access is diminished from 25 to 65% because of the complex pectinate muscles and sharp angles. The highest density of the LAA floor made by pectinate muscles can be found in the Broccoli type (p < 0.005), while the Chicken Wing had the highest number of paper-thin-like pouches.

CONCLUSIONS

The LAA appears to be a promising entry for ablation-qualified patients with the LV summit originate arrhythmias. The complex internal structure of the LAA may complicate ablation procedures. More prominent appendages are promising in more extensive mapping areas over the LVS.

Associations Between Morphological Phenotypes of COPD and Clinical Characteristics in Surgically Resected Patients with COPD and Concomitant Lung Cancer

Purpose

The associations between morphological phenotypes of COPD based on the chest computed tomography (CT) findings and clinical characteristics in surgically resected patients with COPD and concomitant lung cancer are unclear. The purpose of this study was to clarify the differences in clinical characteristics and prognosis among morphological phenotypes based on the chest CT findings in these patients.

Patients and Methods

We retrospectively reviewed the medical records of 132 patients with COPD and concomitant lung cancer who had undergone pulmonary resection for primary lung cancer. According to the presence of emphysema and bronchial wall thickness on chest CT, patients were classified into three phenotypes: non-emphysema phenotype, emphysema phenotype, or mixed phenotype.

Results

The mixed phenotype was associated with poorer performance status, higher score on the modified British Medical Research Council (mMRC) dyspnea scale, higher residual volume in pulmonary function, and higher proportion of squamous cell carcinoma than the other phenotypes. Univariate and multivariate Cox proportional hazards regression analyses showed that the extent of emphysema on chest CT, presented as a low attenuation area (LAA) score, was an independent determinant that predicted prognosis. In the Kaplan-Meier analysis, the Log rank test showed significant differences in survival between the non-emphysema and mixed phenotypes, and between the emphysema and mixed phenotypes.

Conclusion

The cross-sectional pre-operative LAA score can predict the prognosis in surgically resected patients with COPD and concomitant lung cancer. The COPD phenotype with both emphysema and bronchial wall thickness on chest CT was associated with poorer performance status, greater extent of dyspnea, greater impairment of pulmonary function, and worse prognosis.

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.

Association Between Air Pollution and Lung Lobar Emphysema in COPD

The development of emphysema has been linked to air pollution; however, the association of air pollution with the extent of lobar emphysema remains unclear. This study examined the association of particulate matter <2.5 μm in aerodynamic diameters (PM_2.5) (≤2.5 μm), nitrogen dioxide (NO₂), and ozone (O₃) level of exposure with the presence of emphysema in 86 patients with chronic obstructive pulmonary disease (COPD). Exposure to the air pollution estimated using the land-use regression model was associated with lung function, BODE (a body mass index, degree of obstruction, dyspnea severity, and exercise capacity index) quartiles, and emphysema measured as low-attenuation areas on high-resolution CT (HR-CT) lung scans. Using paraseptal emphysema as the reference group, we observed that a 1 ppb increase in O₃ was associated with a 1.798-fold increased crude odds ratio of panlobular emphysema (p < 0.05). We observed that PM_2.5 was associated with BODE quartiles, modified Medical Research Council (mMRC) dyspnea score, and exercise capacity (all p < 0.05). We found that PM_2.5, NO₂, and O₃ were associated with an increased degree of upper lobe emphysema and lower lobe emphysema (all p < 0.05). Furthermore, we observed that an increase in PM_2.5, NO₂, and O₃ was associated with greater increases in upper lobe emphysema than in lower lobe emphysema. In conclusion, exposure to O₃ can be associated with a higher risk of panlobular emphysema than paraseptal emphysema in patients with COPD. Emphysema severity in lung lobes, especially the upper lobes, may be linked to air pollution exposure in COPD.

Cell penetration and chondrogenic differentiation of human adipose derived stem cells on 3D scaffold

The ability of cells to penetrate the scaffold and differentiate into chondrocyte is important in cartilage engineering. The aim of this research was to evaluate the use of silk fibroin 3D scaffold in facilitating the growth of stem cell and to study the role of L-ascorbic acid and platelet rich plasma (PRP) in proliferation and differentiation genes. Cell penetration and type II collagen content in the silk fibroin scaffold was analyzed by confocal microscopy. Relative expressions of CDH2, CCND1, CTNNB1 and COL2A1 were analyzed by reverse transcription-quantitative PCR (RT-qPCR). The silk fibroin 3D scaffold could facilitate cell penetration. L-ascorbic acid and PRP increased the expression of CDH2 and COL2A1 on the 21st day of treatment while PRP inhibited CTNNB1 and CCND1.

Determination of pre-arthropathy scapular anatomy with a statistical shape model: part I-rotator cuff tear arthropathy

HYPOTHESIS AND BACKGROUND

Rotator cuff tear arthropathy (RCTA) is a pathology characterized by a massive rotator cuff tear combined with acromiohumeral and/or glenohumeral arthritis. The severity of RCTA can be staged according to the Hamada classification. Why RCTA develops in some patients is unknown. Furthermore, in RCTA patients, distinctly different articular damage patterns can develop on the glenoid side as categorized by the Sirveaux classification (glenoid erosion). The goal of this study was to determine whether an association exists between scapular anatomy and RCTA and different severity stages of RCTA, as well as the associated glenoid erosion types.

METHODS

A statistical shape model of the scapula was constructed from a data set of 110 computed tomography scans using principal component analysis. Sixty-six patients with degenerative rotator cuff pathology formed the control group. The computed tomography scan images of 89 patients with RCTA were included and grouped according to the Hamada and Sirveaux classifications. A complete 3-dimensional scapular bone model was created, and statistical shape model reconstruction was performed. Next, automated 3-dimensional measurements of glenoid version and inclination, scapular offset, the critical shoulder angle (CSA), the posterior acromial slope (PAS), and the lateral acromial angle (LAA) were performed. All measurements were then compared between controls and RCTA patients.

RESULTS

The control group had a median of 7° of retroversion (variance, 16°), 8° of superior inclination (variance, 19°), and 106 mm of scapular offset (variance, 58 mm). The median CSA, PAS, and LAA were 30° (variance, 14°), 65° (variance, 60°), and 90° (variance, 17°), respectively. In terms of inclination, version, scapular offset, and the PAS, we found no statistically significant differences between the RCTA and control groups. For RCTA patients, the median CSA and median LAA were 32° (P ≤ .01) and 86° (P ≤ .01), respectively. For all investigated parameters, we did not find any significant difference between the different stages of RCTA. Patients with type E3 erosion had a different pre-arthropathy anatomy with increased retroversion (12°, P = .006), an increased CSA (40°, P ≤ .001), and a reduced LAA (79°, P ≤ .001).

DISCUSSION

Our results seem to indicate that a 4° more inferiorly tilted and 2° more laterally extended acromion is associated with RCTA. RCTA patients in whom type E3 erosion develops have a distinct pre-arthropathy scapular anatomy with a more laterally extended and more inferiorly tilted acromion and a more retroverted glenoid in comparison with RCTA patients with no erosion. The pre-arthropathy scapular anatomy does not seem to differ between patients with different stages of RCTA.

Left atrial appendage occlusion in COVID-19 times

The coronavirus disease 2019 pandemic is having a major impact on healthcare systems worldwide. Several months after the COVID-19 outbreak, waiting lists of non-urgent structural heart (SH) interventions continue to increase. Limitations in terms of ICU beds and anesthesiology represent a major limitation to conduct non-urgent SH interventions and are a valid reason to move towards less invasive approaches. The field of left atrial appendage occlusion (LAAO) reflects this challenging situation perfectly. The aim of this paper is to describe the possibilities for pre-procedural LAA assessment, performance of the LAAO procedure and post-procedural surveillance in these challenging times.

Accuracy of contrast-enhanced computed tomography for thrombus detection prior to atrial fibrillation ablation and role of novel Left Atrial Appendage Enhancement Index in appendage flow assessment

AIMS

To evaluate diagnostic accuracy of different protocols of contrast enhanced computed tomography venogram (CTV) for LAA thrombus detection in patients undergoing AF ablation and study the correlation of the novel LAA enhancement index (LAA-EI) to LAA flow velocity obtained using transesophageal echocardiography (TEE).

METHODS

Study comprised of patients undergoing CTV and TEE on the same day from October 2016 to December 2017. Three CTV scanning protocols (described in results), were evaluated wherein ECG gating was used only for those with sinus rhythm on day of CTV. LAA-EI was calculated as Hounsfield Unit (HU) in the LAA divided by the HU unit in the center of the LA. The diagnostic accuracy for CTV was calculated in comparison to TEE. The LAA-EI was compared to LAA emptying velocities as obtained from TEE.

RESULTS

590 patients with 45.6% non-ECG-gated without delayed imaging, 26.9% non-ECG-gated with delayed imaging and 27.5% ECG-gated with delayed imaging, were included in the study. All three protocols had 100% negative predictive value with improvement in specificity from 61.8% to 98.1% upon adding delayed imaging. The LAA-EI correlated significantly with reduced LAA flow velocities (r = 0.45, p < .0001). The mean LAA emptying velocity in patients with LAA-EI of ≤ 0.6 was significantly lower than in those with LAA-EI of >0.6 (36.2 cm/s [95% CI: 32.6-39.7] vs, (58 cm/s [95% CI 55.3-60.8]), respectively (p < .0001).

CONCLUSION

CTV with delayed imaging (with or without ECG gating) is highly specific in ruling out LAA thrombus. The novel LAA-EI can detect low LAA flow velocities.

Rationale and design of a randomized clinical trial to compare two antithrombotic strategies after left atrial appendage occlusion: double antiplatelet therapy vs. apixaban (ADALA study)

BACKGROUND

Data on antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO) is scarce and no randomized evaluation has been performed to demonstrate what is the best antithrombotic strategy. Up to date, different antithrombotic regimens with variable durations are currently used. In fact, the use of oral anticoagulation (OAC) or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel during the initial phase (∓ 3 months post-LAAO) has been proposed as valid strategies. However, antiplatelet and OAC therapies have never been compared in a randomized study after left atrial appendage closure (LAAC). The purpose of the present study is to ascertain an optimal antithrombotic strategy after LAAC in terms of safety and efficacy. The study will compare a novel OAC (NOAC) with a highly safety profile like apixaban 5 mg/12 h or 2.5 mg/12 h (after dose adjustment or in high-risk patients) with standard antiplatelet therapy with DAPT. The aim of the study was to compare a strategy of anticoagulation with apixaban 5 mg/2.5 mg bid to the current standard of care (DAPT with aspirin and clopidogrel) after LAAO in patients with non-valvular atrial fibrillation (AF).

METHODS

This is a phase IV multicenter randomized, open-label, controlled trial comparing the efficacy and safety of apixaban vs. DAPT after LAAO, both for 3 months. The primary endpoint is a combined endpoint of death, myocardial infarction, stroke, thromboembolic complications, and major or significant bleeding at 3 months of follow-up. Approximately 160 subjects will be enrolled and followed 12 months from randomization.

CONCLUSIONS

Considering the high risk of both thromboembolic and hemorrhagic events of patients undergoing LAAO, establishment of an appropriate antithrombotic therapy in terms of efficacy and safety after LAAO is of vital importance.

TRIAL REGISTRATION

EudraCT number: 2018-001013-32.

5 GHz Band LTE-LAA Signal Selection for Use as the Unintended Signal in ANSI C63.27 Wireless Coexistence Testing

This article details the experimental work conducted at the Electromagnetic Compatibility and Wireless Laboratory, U.S. Food and Drug Administration, to investigate the use of LAA signals for wireless coexistence testing. A software defined radio platform was deployed to generate realistic LAA signals and measure the wireless coexistence impact on the LAA communication link. The equipment under test (EUT) used IEEE 802.11ac as an example incumbent technology in the 5 GHz band. The standardized radiated anechoic chamber method was used for testing. Results highlight the mutual coexistence impact of LAA in the 5 GHz band and suggest that selecting an LAA signal with the maximum possible channel time occupancy and the highest possible modulation and coding scheme (MCS) yields the most impactful coexistence situation on both the EUT and the LAA system. Additionally, an analysis of the internal LAA system states during coexistence testing is presented to document the inverse relationship between LAA transmit and wait times during coexistence and the adverse impact of challenging coexistence scenarios on successful channel access. Finally, the risk management process of wireless coexistence for medical devices is summarized and associated with coexistence testing.

Beyond Pulmonary Vein Isolation in Nonparoxysmal Atrial Fibrillation: Posterior Wall, Vein of Marshall, Coronary Sinus, Superior Vena Cava, and Left Atrial Appendage

The optimal ablation strategy for non-paroxysmal atrial fibrillation remains controversial. Non-PV triggers have been shown to have a major arrhythmogenic role in these patients. Common sources of non-PV triggers are: posterior wall, left atrial appendage, superior vena cava, coronary sinus, vein of Marshall, interatrial septum, crista terminalis/Eustachian ridge, and mitral and tricuspid valve annuli. These sites are targeted empirically in selected cases or if significant ectopy is noted (with or without a drug challenge), to improve outcomes in patients with non-paroxysmal atrial fibrillation. This article focuses on summarizing the current evidence and the approach to mapping and ablation of these frequent non-PV trigger sites.

Left Atrial Appendage Occlusion in Patients With Thrombus in Left Atrial Appendage

BACKGROUND

Atrial appendage (LAA) occlusion is a therapeutic option for thromboembolic prevention in atrial fibrillation (AF) patients who have contraindications to oral anticoagulation (OAC) or high risk of bleeding. Traditionally, thrombus in the LAA has been considered a contraindication for LAA occlusion. Recently, resistant thrombus formation in patients using OACs was suggested as an indication for LAA occlusion.

METHODS AND RESULTS

In this single-center study, we evaluated the safety and efficacy of LAA occlusion in patients with a thrombus in the LAA. Twelve non-valvular AF patients who had a thrombus in the LAA were enrolled. The mean age was 71.8 years (range, 62-83 years). Permanent AF was present in all patients. Mean CHA2DS2-VASc score was 4.9 (range, 2-8) and mean HAS-BLED score was 4.8 (range, 3-6). Thrombi in the LAA were classified as type 1 (proximal to mid) and type 2 (distal) in 3 and 9 patients, respectively. Median follow-up duration was 12 months (interquartile range, 6-24 months). LAA occlusion was performed successfully with Amplatzer Amulet device without any significant periprocedural adverse events in all 12 patients. Transesophageal echocardiography (TEE) was performed at 1 and 6 months post procedure. Cardiovascular and all-cause mortality, significant ischemic cerebrovascular events, worsening heart failure, and major bleeding events did not occur during follow-up. Device-related thrombus was not observed with TEE in any patient.

CONCLUSION

Our study showed that percutaneous LAA closure could be a therapeutic option for patients with resistant LAA thrombus.

Persistent atrial fibrillation in the setting of pulmonary vein isolation-Where to next?

Catheter ablation for atrial fibrillation (AF) is indicated in symptomatic patients who are intolerant or refractory to antiarrhythmic therapy. However, outcomes from catheter ablation remain suboptimal in patients with persistent AF. Pulmonary vein antral isolation (PVAI) is established as the cornerstone of AF ablation strategies. The landmark STAR AF II study demonstrated a lack of incremental benefit with adjunctive linear and complex fractionated electrogram ablation beyond PVAI. Randomized studies thus far have failed to consistently show favorable outcomes from other trigger/substrate-based ablation approaches over PVAI alone. In this issue of the journal, we pose an interesting clinical scenario-of a middle-aged female who presents with recurrent persistent AF but was found to have enduring PVAI on repeat electrophysiologic study. Which approach should be undertaken next? In this review article, we aim to provide an overview of ablation strategies beyond PVAI. Finally in light of scant randomized data to guide decision making we have approached leading experts in the field to provide their approach to this scenario.

Percutaneous left atrial appendage closure using the TrueFusion™ fusion-imaging technology

OBJECTIVE

To describe percutaneous left atrial appendage closure (LAAc) in a patient with recurrent gastric ulcer bleeding with the help of the TrueFusion™ fusion-imaging system.

METHOD AND RESULTS

In a patient with paroxysmal atrial fibrillation, the need for an effective oral anticoagulation and recurrent gastrointestinal bleeding, left atrial appendage closure (LAAc) was performed under guidance of the TrueFusion™ fusion-imaging technology (Siemens Healthineers, Erlangen, Germany) to enhance procedural precision, save radiation time and contrast dye. Left atrial appendage closure was performed with the use of a 20 mm Amplatzer Amulet™ (Abbott Laboratories, Chicago, IL, USA) using the TrueFusion™ system under mild sedation with minimal use of contrast. Intraprocedural transesophageal echocardiography revealed complete LAA occlusion without residual flow. The patient was uneventfully discharged on the second postoperative day.

CONCLUSION

LAAc using an integrated approach combining ultrasound and live fluoroscopy, as provided by the TrueFusion™, is safe and feasible. Target-oriented device navigation and synchronized image orientation as provided by fusion imaging may potentially be beneficial regarding radiation time, contrast dye and periprocedural risk of suboptimal device positioning.

Biomarkers for ischemic stroke subtypes: A protein-protein interaction analysis

According to the Trial of Org 10172 in Acute Stroke Treatment, ischemic stroke is classified into five subtypes. However, the predictive biomarkers of ischemic stroke subtypes are still largely unknown. The utmost objective of this study is to map, construct and analyze protein-protein interaction (PPI) networks for all subtypes of ischemic stroke, and to suggest the predominant biological pathways for each subtypes. Through 6285 protein data retrieved from PolySearch2 and STRING database, the first PPI networks for all subtypes of ischemic stroke were constructed. Notably, F2 and PLG were identified as the critical proteins for large artery atherosclerosis (LAA), lacunar, cardioembolic, stroke of other determined etiology (SOE) and stroke of undetermined etiology (SUE). Gene ontology and DAVID analysis revealed that GO:0030193 regulation of blood coagulation and GO:0051917 regulation of fibrinolysis were the important functional clusters for all the subtypes. In addition, inflammatory pathway was the key etiology for LAA and lacunar, while FOS and JAK2/STAT3 signaling pathways might contribute to cardioembolic stroke. Due to many risk factors associated with SOE and SUE, the precise etiology for these two subtypes remained to be concluded.

Wireless Coexistence Testing in the 5 GHz Band with LTE-LAA Signals

Exploiting unlicensed spectrum bands for cellular communication is a rapidly embraced trend by industry stakeholders. Accordingly, the specifications of Long Term Evolution (LTE) were extended in Release 13 to allow unlicensed spectrum operation, also known as LTE-Licensed Assisted Access (LAA). LTE is widely adopted, and there is a potential for significant coexistence impact of LTE-LAA on users of unlicensed spectrum including wireless medical devices, whether adopters of the new technology or incumbents. Therefore, work was initiated to revise and update the American National Standards Institute (ANSI) C63.27 standard for evaluation of wireless coexistence. This paper details the experimental work conducted at the Electromagnetic Compatibility and Wireless Laboratory, U.S. Food and Drug Administration, to investigate the use of LAA signals for wireless coexistence testing. A software defined radio platform was deployed to generate realistic LAA signals and measure the wireless coexistence impact on the LAA communication link. The equipment under test (EUT) used IEEE 802.11ac as an example incumbent technology in the 5 GHz band. The standardized radiated anechoic chamber method was used for testing. Results highlight the mutual coexistence impact of LAA in the 5 GHz band and suggest that selecting an LAA signal with the maximum possible channel time occupancy and the highest possible modulation and coding scheme (MCS) yields the most impactful coexistence situation on both the EUT and the LAA system.

Atrial Fibrillation in Heart Failure: Left Atrial Appendage Management

Atrial fibrillation is common in patients with congestive heart failure (CHF). Due to reduced left atrial appendage (LAA) emptying velocities and increased sludge formation, a higher rate of stroke and embolism are seen with CHF. Up to 50% of CHF patients are inadequately covered for stroke protection with anticoagulation, and, even while on therapy, CHF patients are at risk for failure to clear LAA or left ventricular (LV) thrombus. Device-based LAA closure (LAAC) alternatives exist. Following intracardiac device closure, an increased rate of device-related thrombus is seen in heart failure patients, which warrants further study to optimize LAAC benefits.

CT sizing for left atrial appendage closure is associated with favourable outcomes for procedural safety

Aims

We evaluated the utility of computerized tomography (CT) with respect to sizing work-up for percutaneous left atrial appendage (LAA) closure, and implications for procedural safety and outcomes.

Methods and results

Contrast-enhanced multi-detector CT was routinely conducted to guide sizing for LAA closure in addition to transoesophageal echocardiography (TOE). Procedural safety and efficacy were prospectively assessed. Across 73 consecutive cases there were no device-related procedural complications, and no severe leaks. Systematic bias in orifice sizing by TOE vs. CT was significant on retrospective analysis (bias -3.0 mm vs. maximum diameter on CT; bias -1.1 mm vs. mean diameter on CT). Importantly, this translated to an altered device size selection in more than half of all cases, and median size predicted by CT was one interval greater than that predicted by TOE (27 mm vs. 24 mm). Of particular note, gross sizing error by TOE vs. CT was observed in at least 3.4% of cases. Degree of discrepancy between TOE and CT was correlated with LAA orifice eccentricity, orifice size, and left atrial volume. Mean orifice size by CT had the greatest utility for final Watchman device-size selection.

Conclusions

In this single-centre registry of LAA closure, routine incorporation of CT was associated with excellent outcomes for procedural safety and absence of major residual leak. Mean orifice size may be preferable to maximum orifice size. A particular value of CT may be the detection and subsequent avoidance of gross sizing error by 2D TOE that occurs in a small but important proportion of cases.

Echocardiographic Imaging for Left Atrial Appendage Occlusion: Transesophageal Echocardiography and Intracardiac Echocardiographic Imaging

Left atrial appendage occlusion (LAAO) is a rapidly evolving technology. Multi-modality imaging and understanding of left atrial appendage anatomy are sure to advance. Two-dimensional and 3-dimensional transesophageal echocardiography with fluoroscopy are the mainstay for LAAO image-guided therapy. Key to successful LAAO is an understanding of the transseptal puncture, LAAO size selection for the device-specific landing zone, and postdeployment evaluation for leak and complications. With advancements in computed tomography, there may be a greater role for intracardiac echocardiographic imaging in specific types of LAAO anatomy and devices.

Expression of Rho Kinase and Its Mechanism in the Left Atrial Appendage in Patients with Atrial Fibrillation

AIM

To study the expression of Rho kinase (Rho associated coil forming protein kinase-1, ROCK-1) and its substrate myosin phosphatase target subunit 1 (myosin phosphatase target subunit-1, MYPT-1), connexin 40 (Cx40) and connexin 43 (Cx43) in the left atrial appendage of patients with atrial fibrillation, and explore the role of ROCK signaling pathway in patients with atrial fibrillation and its underlying mechanism. Methods: 40 patients undergoing open heart surgery were divided into two groups; atrial fibrillation group (AF group) and sinus rhythm group (SR group). About 100 mg of left atrial appendage tissue was taken during surgery and quickly frozen in liquid nitrogen. Immunohistochemistry and western blot were performed to evaluate the expression and location of ROCK-1, MYPT-1, Cx40 and Cx43 in the left atrial appendage tissue. Results: The results indicated that the expression of ROCK-1, MYPT-1, and Cx40 in the left atrial appendage in patients with atrial fibrillation was significantly upregulated (P < .01), the difference in the two groups was statistically significant, and ROCK-1, Cx40, and MYPT-1 expression in the AF group were higher than those in sinus rhythm group; there was a weakly positive expression of Cx43 protein in the AF group and sinus rhythm group, the difference was not statistically significant, and ROCK-1 and MYPT-1 expression showed a significant positive correlation (r = 0.968, P < .05), MYPT 1 and Cx40 protein expression was also positively correlated (r = 0.983, P < .05). Evidence in the left atrial appendage tissue of patients with atrial fibrillation showed that some proteins in Rho/ROCK pathway were upregulated, and MYPT-1 and Cx40 protein expression in AF group were significantly higher than that of SR group, which was also positively correlated; Cx43 showed a weak positive expression in both the SR group and AF group, which indicates that Rho kinase may induce expression of Cx40 by phosphorylation of MYPT-1; Cx43 may not be involved, suggesting that Rho kinase signaling pathway may activate and play an important role in the pathogenesis of atrial fibrillation lesions.

Traffic Offloading in Unlicensed Spectrum for 5G Cellular Network: A Two-Layer Game Approach

Licensed Assisted Access (LAA) is considered one of the latest groundbreaking innovations to provide high performance in future 5G. Coexistence schemes such as Listen Before Talk (LBT) and Carrier Sensing and Adaptive Transmission (CSAT) have been proven to be good methods to share spectrums, and they are WiFi friendly. In this paper, a modified LBT-based CSAT scheme is proposed which can effectively reduce the collision at the moment when Long Term Evolution (LTE) starts to transmit data in CSAT mode. To make full use of the valuable spectrum resources, the throughput of both LAA and WiFi systems should be improved. Thus, a two-layer Coalition-Auction Game-based Transaction (CAGT) mechanism is proposed in this paper to optimize the performance of the two systems. In the first layer, a coalition among Access Points (APs) is built to balance the WiFi stations and maximize the WiFi throughput. The main idea of the devised coalition forming is to merge the light-loaded APs with heavy-loaded APs into a coalition; consequently, the data of the overloaded APs can be offloaded to the light-loaded APs. Next, an auction game between the LAA and WiFi systems is used to gain a win–win strategy, in which, LAA Base Station (BS) is the auctioneer and AP coalitions are bidders. Thus, the throughput of both systems are improved. Simulation results demonstrate that the proposed scheme in this paper can improve the performance of both two systems effectively.

LAA occluder device for stroke prevention: Data on WATCHMAN and other LAA occluders

NOAC therapy has become the standard for stroke prevention in patients with atrial fibrillation. Yet some patients suffer extracranial bleeding events or have other reasons to seek non-pharmacologic stroke protection. LAA occlusion with the WATCHMAN device has been proven safe and effective for such patients and is now recommended in current guidelines for this patient group; other devices also seek approval.

Antiplatelet and Anticoagulation Therapy in Structural Heart Disease Interventions Beyond TAVI

Transcatheter interventions for structural heart disease represent an emerging field in interventional cardiology. Undoubtedly, there is an absolute necessity for antiplatelet and/or anticoagulation treatment prior, during and post such interventions. However, currently administered regimens are mainly based in expert consensus recommendations. In the present review we aim to summarize data regarding anti platelet and/or anticoagulation treatment in the following transcatheter structural heart interventions: left atrial appendage closure, atrial septal defect closure, patent foramen oval closure, paravalvular leak closure.

Coexisting COPD in elderly asthma with fixed airflow limitation: Assessment by DLco %predicted and HRCT

BACKGROUND

Asthma patients with fixed airflow limitation (FL) are theoretically classified into two phenotypes, that is, coexisting chronic obstructive pulmonary disease (COPD) and asthmatic airway remodeling. However, the precise percentages of such patients are not known.

OBJECTIVE

To assess the prevalence of patients with both FL and COPD components in elderly asthma.

METHODS

We evaluated patients by lung diffusion impairment and emphysematous findings in high-resolution computed tomography (HRCT) as candidates for COPD components, as a multicenter, cross-sectional survey. Asthma outpatients ≥ 50 years of age were enrolled from Tohoku University Hospital, Sendai, Japan, and four hospitals (Tohoku Medical and Pharmaceutical University Wakabayashi Hospital, Sendai, JAPAN; Wakayama Medical University Hospital, Kimiidera, Japan; Hiraka General Hospital, Yokote, Japan; Iwate Prefectural Isawa Hospital, Oshu, Japan) with pulmonary physicians from March 1, 2013 to November 30, 2014.

RESULTS

The prevalence of patients with FEV₁/FVC <70% was 31.0% of those in their 50s, 40.2% of those in their 60s and 61.9% of those in their 70s or older. The prevalence of those patients with lung diffusion impairment (i.e. the percent predicted values of diffusing capacity of the lung for carbon monoxide (DLco %predicted) <80%) or emphysematous findings in HRCT (i.e. the appearance of low attenuation area (LAA)) was 18.3% of those in their 50s, 13.8% of those in their 60s and 35.7% of those in their 70s or older.

CONCLUSIONS

Nearly half of the patients with FL in elderly asthma show coexisting COPD components when assessed by DLco %predicted and LAA in HRCT.

Left atrial appendage ligation with the next generation LARIAT(+) suture delivery device: Early clinical experience

BACKGROUND

The purpose of the study was to determine the efficacy and safety of left atrial appendage (LAA) closure with a micropuncture pericardial access approach and the new LARIAT(+) suture delivery device.

METHODS

Seventy-two patients with atrial fibrillation were enrolled to undergo telescopic micropuncture pericardial access and percutaneous ligation of the LAA with the LARIAT(+) device. LAA closure was confirmed with transesophageal echocardiography (TEE) and contrast fluoroscopy immediately, then with TEE at 30days and 90days post-LAA ligation. Patients were monitored for 12months by an independent clinical research organization for adverse events, stroke, embolic events and death of any cause.

RESULTS

72 patients were screened for the LARIAT(+) procedure. Fourteen patients were screened failures (7 patients due to unfavorable anatomy and 7 patients with LAA thrombus). Fifty-eight patients underwent successful LAA ligation. All 58 patients had complete acute closure of the LAA. At 1month 52 of 54 patients (96.3%) had LAA closure, while at 3months 48 of 52 patients (92.3%) had LAA closure. There were no leaks greater than 3mm at both 1 and 3months. There were no device or procedural related complications, and only 1 30day adverse event involving late pericardial effusion. There were no strokes, embolic events or deaths after 12months.

CONCLUSIONS

LAA closure with the micropuncture pericardial access approach and the LARIAT(+) device can be performed effectively with acceptably low periprocedural adverse events.

Exposure-response modeling of non-cancer effects in humans exposed to Libby Amphibole Asbestos; update

The United States Environmental Protection Agency (EPA) developed a quantitative exposure-response model for the non-cancer effects of Libby Amphibole Asbestos (LAA) (EPA, 2014). The model is based on the prevalence of localized pleural thickening (LPT) in workers exposed to LAA at a workplace in Marysville, Ohio (Lockey et al., 1984; Rohs et al., 2008). Recently, Lockey et al. (2015a) published a follow-up study of surviving Marysville workers. The data from this study increases the number of cases of LPT and extends the observation period for a number of workers, thereby providing a strengthened data set to define and constrain the optimal exposure-response model for non-cancer effects from inhalation exposure to LAA. The new data were combined with the previous data to update the exposure-response modeling for LPT. The results indicate that a bivariate model using cumulative exposure and time since first exposure is appropriate, and the benchmark concentration is similar to the findings previously reported by EPA (2014). In addition, the data were also used to develop initial exposure-response models for diffuse pleural thickening (DPT) and small interstitial opacities (SIO).

Comparison of end-diastolic versus end-systolic cardiac-computed tomography reconstruction interval in patient's prior to pulmonary vein isolation

Purpose

Aim of the study was to investigate diagnostic accuracy of cardiac computed tomography angiography (CCTA) between left ventricular end-systolic (LVES) and left ventricular end-diastolic (LVED) cardiac phase for thrombus detection in patient’s prior to pulmonary vein isolation (PVI).

Materials and methods

182 consecutive Patients with drug refractory AF scheduled for PVI (62.6% male, mean age 64.1 ± 10.2 years) underwent routine pre-procedural evaluation including transesophageal echocardiography (TEE) and CCTA for evaluation of left atrial (LA)/left atrial appendage (LAA) anatomy and thrombus formation. Qualitative and quantitative analysis (using aorta ascendens (AA)/LAA ratio) was performed. Measurements of the LA/LAA in LVES and LVED cardiac phase were obtained.

Results

End-systolic volumes (LA/LAA) measured in 30 patients without filling defects as control group and all 14 with filling defects of 182 patients were significantly larger (p < 0.01) than in end-diastolic phase. Qualitative analysis was inferior to quantitative analysis using LA/LAA ratio (<0.5; accuracy: 100%, 88%,100%, 99% vs 100%). 5 out of 182 patients (2.7%) showed thrombus formation of the LAA in CCTA confirmed by TEE and quantitative analysis. Intra/-interobserver variability was lower in end-systolic vs end-diastolic reconstruction interval.

Conclusion

For evaluating CCTA datasets in patients prior PVI, the LVES reconstruction interval is recommended due to significantly larger LA/LAA volumes and lower intra/- interobserver variability’s.

The CELSR1 polymorphisms rs6007897 and rs4044210 are associated with ischaemic stroke in Chinese Han population

BACKGROUND

Recently, CELSR1 was identified by genome-wide association studies (GWAS) as a susceptibility gene for ischaemic stroke (IS) in Japanese individuals.

AIM

The goal was to examine whether CELSR1 variants are associated with IS in the Chinese Han population.

SUBJECTS AND METHODS

This study genotyped two single nucleotide polymorphisms (SNPs) of CELSR1, rs6007897 and rs4044210, in a Chinese sample of 569 IS cases and 581 controls and assessed their genotype and allele associations with IS.

RESULTS

The results showed that rs6007897 and rs4044210 variants of CELSR1 were significantly (p < 0.01) associated with IS. These associations remained after adjustment for age, gender, smoking status, hypertension, diabetes mellitus and hypercholesterolemia. In addition, a significant association was observed of rs6007897 and rs4044210 of CELSR1 with large artery atherosclerosis (LAA), a sub-type of IS (p < 0.01).

CONCLUSION

Taken together, the present study has proven for the first time that CELSR1 is a susceptibility gene for IS in the Chinese Han population, especially for LAA.

Left atrial appendage closure devices

Atrial fibrillation (AF) increases the risk for thromboembolic stroke five-fold. The left atrial appendage (LAA) has been shown to be the main source of thrombus formation in the majority of strokes associated with AF. Oral anticoagulation with warfarin and novel anticoagulants remains the standard of care; however, it has several limitations, including bleeding and poor compliance. Occlusion of the LAA has been shown to be an alternative therapeutic approach to drug therapy. The purpose of this article is to review the different techniques and devices that have emerged for the purpose of occluding this structure, with a particular emphasis on the efficacy and safety studies published to date in the medical literature.

The CURE-AF trial: a prospective, multicenter trial of irrigated radiofrequency ablation for the treatment of persistent atrial fibrillation during concomitant cardiac surgery

BACKGROUND

Ablation technology has been introduced to replace the surgical incisions of the Cox-Maze procedure in order to simplify the operation. However, the efficacy of these ablation devices has not been prospectively evaluated.

OBJECTIVE

The purpose of this study was to examine the efficacy and safety of irrigated unipolar and bipolar radiofrequency ablation for the treatment of persistent and long-standing persistent atrial fibrillation (AF) during concomitant cardiac surgical procedures.

METHODS

Between May 2007 and July 2011, 150 consecutive patients were enrolled at 15 U.S. centers. Patients were followed for 6 to 9 months, at which time a 24-hour Holter recording and echocardiogram were obtained. Recurrent AF was defined as any atrial tachyarrhythmia (ATA) lasting over 30 seconds on the Holter monitor. The safety end-point was the percent of patients who suffered a major adverse event within 30 days of surgery. All patients underwent a biatrial Cox-Maze lesion set.

RESULTS

Operative mortality was 4%, and there were 4 (3%) 30-day major adverse events. Overall freedom from ATAs was 66%, with 53% of patients free from ATAs and also off antiarrhythmic drugs at 6 to 9 months. Increased left atrial diameter, shorter total ablation time, and an increasing number of concomitant procedures were associated with recurrent AF (P <.05).

CONCLUSION

Irrigated radiofrequency ablation for treatment of AF during cardiac surgery was associated with a low complication rate. No device-related complications occurred. The Cox-Maze lesion set was effective at restoring sinus rhythm and had higher success rates in patients with smaller left atrial diameters and longer ablation times.

The arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene SG13S114 polymorphism and ischemic stroke in Chinese population: a meta-analysis

Previous studies have indicated that the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene SG13S114 polymorphism is associated with risk of ischemic stroke (IS), but the results remain inconclusive even in Chinese population. A meta-analysis of 10 case-control studies was conducted on the relationship between ALOX5AP SG13S114 polymorphism and susceptibility to IS in Chinese population published domestically and abroad from September 2007 to December 2012. Data were extracted by two authors and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Meta-analysis results showed that the significant association between SG13S114 variant and IS was found under the allelic (OR=0.87, 95% CI: 0.80-0.96, P=0.004), dominant (OR=0.75, 95% CI: 0.62-0.92, P=0.005), and recessive (OR=0.89, 95% CI: 0.82-0.97, P=0.005) genetic models in Chinese population. In subgroup meta-analysis, SG13S114 variant and atherothrombotic stroke, rather than lacunar stroke, showed the significant association under the allelic (OR=0.86, 95% CI: 0.80-0.92, P<0.0001), dominant (OR=0.72, 95% CI: 0.57-0.91, P=0.006), and recessive (OR=0.86, 95% CI: 0.78-0.95, P=0.002) models. ALOX5AP SG13S114 polymorphism is associated with susceptibility to IS in Chinese population.

Management of focal atrial tachycardias originating from the atrial appendage with the combination of radiofrequency catheter ablation and minimally invasive atrial appendectomy

BACKGROUND

Focal atrial tachycardias (ATs) originating from the left and the right atrial appendage (AA) were the most difficult to eliminate.

OBJECTIVE

To evaluate the safety and long-term efficacy of minimally invasive surgical atrial appendectomy in combination with radiofrequency catheter ablation (RFCA) in the management of focal atrial appendage tachycardias (AATs).

METHODS

We included 42 consecutive patients with 42 AATs confirmed by activation mapping and contrast venography. Thirty of them were successfully managed with RFCA (RFCA-successful group), while the remaining 12 (28.6%) finally resorted to video-assisted thoracoscopic atrial appendectomy owing to RFCA failure (resort-to-surgery group). We searched for predictors of RFCA failure, and the need for surgery by using a binomial logistic regression model.

RESULTS

In the RFCA-successful group, 6 (20.0%) patients experienced recurrence and re-do ablation and 11 (36.7%) AATs originated from distal AAs. In the resort-to-surgery group, the tachycardias involved exclusively distal AAs and required more RFCA attempts compared with those of the RFCA-successful group (1.58 ± 0.51 vs 1.20 ± 0.41; P = .0165). During atrial appendectomy, incessant ATs were terminated immediately after resection of the AA at the base. Long-term success was achieved in all 42 patients with a follow-up of 29.1 ± 17.5 months. No complications occurred. Fourteen patients with tachycardia-induced cardiomyopathy recovered fully. We identified origin at distal AATs and longer time to tachycardia termination by ablation as predictors of RFCA failure and the need for surgical intervention.

CONCLUSION

ATs originating from the distal portion of AA were more refractory to RFCA. The combination of catheter ablation and video-assisted thoracoscopic atrial appendectomy was an effective strategy to manage AATs.

Left atrial appendage occlusion: opportunities and challenges

Stroke prevention in patients with atrial fibrillation is a growing clinical dilemma as the incidence of the arrhythmia increases and risk profiles worsen. Strategies in patients with nonvalvular atrial fibrillation have included anticoagulation with a variety of drugs. Knowledge that stroke in this setting typically results from thrombus in the left atrial appendage has led to the development of mechanical approaches, both catheter-based and surgical, to occlude that structure. Such a device, if it were safe and effective, might avoid the need for anticoagulation and prevent stroke in the large number of patients who are currently not treated with anticoagulants. Regulatory approval has been difficult due to trial design challenges, balance of the risk-benefit ratio, specific patient populations studied, selection of treatment in the control group, and specific endpoints and statistical analyses selected. Accumulating data from randomized trials and registries with longer-term follow-up continues to support a role for left atrial appendage exclusion from the central circulation as an alternative to anticoagulation in carefully-selected patient populations.

Regional annular geometry in patients with mitral regurgitation: implications for annuloplasty ring selection

BACKGROUND

The saddle shape of the normal mitral annulus has been quantitatively described by several groups. There is strong evidence that this shape is important to valve function. A more complete understanding of regional annular geometry in diseased valves may provide a more educated approach to annuloplasty ring selection and design. We hypothesized that mitral annular shape is markedly distorted in patients with diseased valves.

METHODS

Real-time 3-dimensional echocardiography was performed in 20 patients with normal mitral valves, 10 with ischemic mitral regurgitation, and 20 with myxomatous mitral regurgitation (MMR). Thirty-six annular points were defined to generate a 3-dimensional model of the annulus. Regional annular parameters were measured from these renderings. Left ventricular inner diameter was obtained from 2-dimensional echocardiographic images.

RESULTS

Annular geometry was significantly different among the three groups. The annuli were larger in the MMR and in the ischemic mitral regurgitation groups. The annular enlargement was greater and more pervasive in the MMR group. Both diseases were associated with annular flattening, although though the regional distribution of that flattening was different between groups. Left ventricular inner diameter was increased in both groups. However, relative to the Left ventricular inner diameter, the annulus was disproportionately dilated in the MMR group.

CONCLUSIONS

Patients with MMR and ischemic mitral regurgitation have enlarged and flattened annuli. In the case of MMR, annular distortions may be the driving factor leading to valve incompetence. These data suggest that the goal of annuloplasty should be the restoration of normal annular saddle shape and that the use of flexible, partial, and flat rings may be ill advised.

Left atrial appendage closure followed by 6 weeks of antithrombotic therapy: a prospective single-center experience

BACKGROUND

Currently, 2 different left atrial appendage (LAA) closure systems are available for stroke prevention in nonvalvular atrial fibrillation but comparative data are lacking.

OBJECTIVES

To prospectively compare procedural data and patient outcome for 2 contemporary LAA closure systems and to investigate an alternative antithrombotic treatment regimen in high-risk patients.

METHODS

Patients with nonvalvular atrial fibrillation, with high risk for stroke, and who either had contraindication or were not willing to accept oral anticoagulation were prospectively enrolled. Watchman (Boston Scientific, Natick, MA; group A) or Amplatzer Cardiac Plug (St Jude Medical, Minneapolis, MN; group B) devices were implanted. All patients received antithrombotic therapy for 6 weeks. After repeat transesophageal echocardiography, patients were switched to aspirin.

RESULTS

Eighty patients were enrolled. There was no statistical difference in patient characteristics in groups A and B: CHA2DS2VASC score: 4.1 ± 1.5 versus 4.5 ± 1.8; HASBLED score: 3.1 ± 1.1 versus 3.1 ± 1.1, respectively. LAA closure was achieved in 78 of 80 patients (98%) (group A: 38 of 40 [95%] vs group B: 40 of 40 [100%]). There was no difference in procedure time (group A: 48 ± 16 minutes vs group B: 47 ± 15 minutes; P = .69) and fluoroscopy time (group A: 6.0 ± 4.7 minutes vs group B: 7.3 ± 4.4 minutes; P = .25). Major complications included 1 air embolism and delayed tamponade in each group. After 6 weeks, 1 device dislodgment and 4 device-related thrombi were detected. Ninety-four percent of the patients (73 of 77) were switched to aspirin after 6 weeks. During a median follow-up of 364 days (Q1-Q3: 283-539 days), no systemic embolism occurred, but 3 patients died (heart failure: n = 2; bleeding: n = 1).

CONCLUSIONS

Implantation of both LAA closure devices can be performed with high success rates in high-risk patients. Postprocedural 6 weeks antithrombotic therapy followed by aspirin therapy needs to be confirmed in a larger study.

Atypical complications encountered with epicardial electrophysiological procedures

BACKGROUND

With the increasing use, complexity, anatomical approaches, and tools related to epicardial procedures, complications previously not seen during endovascular ablation are now well recognized with epicardial ablation. Whether newer approaches and the regional anatomy of the pericardial space contribute to unexpected complications after epicardial access (EpiAcc) is presently unknown.

OBJECTIVE

To characterize underreported, or novel, complications associated with percutaneous EpiAcc as part of an electrophysiology procedure.

METHODS

We retrospectively reviewed percutaneous EpiAcc as part of an ablation procedure from January 1, 2004, to December 31, 2011.

RESULTS

Of 116 attempts in 107 patients, 8 atypical ablation complications (no procedural deaths) were noted; complications included delayed pericarditis (2 weeks), chronic refractory pericarditis, requirement for snaring of broken intrapericardial wire, pleural perforation, phrenic nerve injury despite protective strategies, hemoperitoneum, and abdominal-pericardial fistula.

CONCLUSION

Vigilance both during and after EpiAcc is needed to recognize these complications, some of which may be life-threatening.

Single nucleotide polymorphism of CD40 in the 5'-untranslated region is associated with ischemic stroke

OBJECTIVES

Ischemic stroke is influenced by both environmental and genetic factors. The CD40/CD40L system is related to proinflammatory and prothrombogenic responses, which are involved in the pathophysiology of ischemic stroke. The aim of this study was to evaluate association between the CD40 -1C/T single nucleotide polymorphism (SNP) and ischemic stroke in a Chinese population.

METHODS

We conducted a case-control study including 286 ischemic stroke patients and 336 controls. CD40 -1C/T SNP was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods, and evaluated its relevance to ischemic stroke susceptibility.

RESULTS

Significantly increased ischemic stroke risk was found to be associated with the T allele of CD40 -1C/T (OR=1.273, 95% CI=1.016-1.594). The frequencies of CT and TT/CT genotypes of CD40 -1C/T in ischemic stroke patients were significantly higher than those of controls, respectively (for CT: OR=2.350, 95% CI=1.601-3.449; for TT/CT: OR=2.148, 95% CI=1.479-3.119). And, similar results were obtained after adjusting non-matched variables. We found that the frequency of carried T genotypes (TT and TT/CT) was significantly increased in patients with history of stroke compared with patients without (for TT: OR=6.538, 95%CI=1.655-25.833; for TT/CT: OR=3.469, 95%CI=1.031-11.670), respectively.

CONCLUSIONS

The findings suggested that the CD40 -1C/T polymorphism might contribute to the susceptibility to ischemic stroke in the Chinese population, and might be associated with history of previous stroke.