Coagulation factors and fibrinolytic activity in the left atrial appendage and other heart chambers in patients with atrial fibrillation: is there a local intracardiac prothrombotic state? (HEART-CLOT study)

Long-term outcomes of left atrial appendage closure with or without concomitant pulmonary vein isolation:a propensity score matching analysis based on CLACBAC study

BACKGROUND

The combined procedure of left atrial appendage closure (LAAC) with concomitant pulmonary vein isolation (PVI) has demonstrated its efficacy and safety. However, there is still a lack of comparative investigations regarding the long-term benefits of the combined procedure when compared to LAAC alone. Our study aims to assess the long-term outcomes of combined procedure of LAAC with concomitant PVI in comparison with a propensity matched LAAC alone group.

METHODS

Propensity score matching (PSM) was employed to rectify covariate imbalances, resulting in the inclusion of 153 comparable patients from the initial cohort of 333 non-valvular atrial fibrillation (AF) patients. Clinical outcomes, encompassing thrombotic events, major cardiocerebrovascular adverse events (MACCE), re-hospitalization due to cardiovascular disease (CVD), and atrial tachycardia (AT), were juxtaposed between the two groups. Bleeding events and peri-device complications, such as residual flow, device-related thrombus, and device replacement, were also compared. Additionally, a patients group underwent PVI alone was included for comparing AF recurrence rates between the PVI alone group and the combined group.

RESULTS

Following PSM, 153 patients (mean age 70.3 ± 8.9, 62.7% men) were included, with 102 undergoing the combined procedure and 51 undergoing LAAC alone. No significant differences were found in baseline characteristics between the two groups. The mean follow-up time was 37.6 ± 7.9 months, and two patients were lost to follow-up in the combined procedure group. Thrombotic events were observed in 4 (7.8%) patients in the LAAC alone group and 4 (4.0%) in the combined group (Log-rank p = 0.301). The proportion of patients experiencing MACCE, re-hospitalization due to CVD, and AT between the two groups was comparable, as were bleeding events and peri-device complications. Among patients from the combined procedure group without AF recurrence, a significant difference was noted in prior-procedure left ventricular ejection fraction (LVEF) and LVEF at the 12th month after the procedure (57.2% ± 7.1% vs. 60.5% ± 6.5%, p = 0.002).

CONCLUSION

The concomitant PVI and LAAC procedure did not increase procedure-related complications, nor did it confer significant benefits in preventing thrombotic events or reducing other cardiovascular events. However, the combined procedure improved heart function, suggesting potential long-term benefits.

The Association between Coagulation and Atrial Fibrillation

The existing literature highlights the presence of numerous coagulation factors and markers. Elevated levels of coagulation factors are associated with both existing and newly diagnosed cases of atrial fibrillation (AF). However, this article summarizes the role of coagulation in the pathogenesis of AF, which includes fibrinogen and fibrin, prothrombin, thrombomodulin, soluble urokinase plasminogen activator receptor, von Willebrand factor, P-selectin, D-dimer, plasminogen activator inhibitor-1, and platelet activation. Coagulation irregularities play a significant role in the pathogenesis of AF.

Postoperative Coagulation Changes in Patients after Epicardial Left Atrial Appendage Occlusion Varies Based on the Left Atrial Appendage Size

Left atrial appendage occlusion affects systemic coagulation parameters, leading to additional patient-related benefits. The aim of this study was to investigate the differences in coagulation factor changes 6 months after epicardial left atrial appendage occlusion in patients with different LAA morphometries. This is the first study to analyze these relationships in detail. A prospective study of 22 consecutive patients was performed. Plasminogen, fibrinogen, tPA concentration, PAI-1, TAFI and computed tomography angiograms were performed. Patients were divided into subgroups based on left atrial appendage body and orifice diameter enlargement. The results of blood tests at baseline and six-month follow-up were compared. In a population with normal LAA body size and normal orifice diameter size, a significant decrease in analyzed clotting factors was observed between baseline and follow-up for all parameters except plasminogen. A significant decrease between baseline and follow-up was observed with enlarged LAA body size in all parameters except TAFI, in which it was insignificant and plasminogen, in which a significant increase was observed. Occlusion of the left atrial appendage is beneficial for systemic coagulation. Patients with a small LAA may benefit more from LAA closure in terms of stabilizing their coagulation factors associated with potential thromboembolic events in the future.

LARIAT or AtriClip: Complications Profile and Comparison in Patients with Atrial Fibrillations Based on Manufacturer and User Facility Device Experience Database

Background and Objectives: Left atrial appendage closure is an alternative treatment to reduce thromboembolism in patients with atrial fibrillation in whom oral anticoagulation (OAC) is contraindicated. The aim of this study was to evaluate the complications profiles of the LARIAT and AtriClip devices and perform a comparison between them based on the MAUDE (Manufacturer and User Facility Device Experience) database. Materials and Methods: The Manufacturer and User Facility Device Experience database was searched on 15 January 2023. For AtriClip, only reports regarding isolated procedures or procedures associated with minimally invasive ablation were included. Adverse effects and causes of death were defined based on the literature on the topic and the causes described in the reports. In total, 63 patients were included in the LARIAT group and 53 patients were included in the AtriClip group. Results: With the LARIAT device, the most common complication without device problems was pericardial effusion (n = 18, 52.9%), whereas this complication was not observed with AtriClip (p < 0.001). Postoperative bleeding was a second complication that occurred significantly more often in the LARIAT group-in 15 (44.1%) cases versus 1 (2.7%) case with AtriClip (p < 0.001). In addition, significant differences were found in the prevalence of stroke (LARIAT n = 0 vs. AtriClip n = 7, 18.9%, p = 0.012) and thrombus (LARIAT n = 2, 5.9% vs. n = 11, 29.7%, p = 0.013). Conclusions: Each type of left atrial appendage closure procedure is associated with device-specific requirements and complications that, if known, can be avoided.

Mechanisms and Prediction of Ischemic Stroke in Atrial Fibrillation Patients

Atrial fibrillation (AF) is the most common arrhythmia in adults worldwide and represents an important burden for patients, physicians, and healthcare systems. AF is associated with substantial mortality and morbidity, due to the disease itself and its specific complications, such as the increased risk of stroke and thromboembolic events associated with AF. The temporal relation between AF episodes and stroke is nonetheless incompletely understood. The factors associated with an increased thromboembolic risk remain unclear, as well as the stroke risk stratification. Therefore, in this review, we intend to expose the mechanisms and physiopathology leading to intracardiac thrombus formation and stroke in AF patients, together with the evidence supporting the causal hypothesis. We also expose the risk factors associated with increased risk of stroke, the current different risk stratification tools as well as future prospects for improving this risk stratification.

Morphology and Anatomical Classification of Pericardial Cavities: Oblique and Transverse Sinuses

The pericardial sinuses are an important anatomical feature of the pericardial cavity, however, their clinical anatomy has not been thoroughly studied. In this study, we aim to provide the first classification of the oblique and transverse sinuses. We analyzed 121 computer tomography scans (46.3% female, age of 66 ± 12 years) of the pericardial cavity. The oblique sinuses were classified into four types: 1 (shallow with narrow entrance), 2 (shallow with wide entrance), 3 (deep with narrow entrance), and 4 (deep with wide entrance). The transverse sinuses were classified into four types: Concave, Wine-type, Straight, and Convex. The most common oblique sinus type was Type 1. The median oblique sinus volume was 8.4 (5.3) mL, the median entrance length was 33.0 (13.2) mm, and the depth was 38.2 (11.8) mm. The most common transverse sinus type was Concave. The median transverse sinus volume was 14.8 (6.5) mL, and the median length was 52.8 (17.7) mm. Our study provides an anatomical classification of the pericardial sinuses. The individual variability of the sinuses' morphology highlights the importance of understanding the clinical topography of the sinuses, particularly for minimally invasive thoracic ablation procedures.

Predicting the Absolute Risk of Ischemic Stroke in Asian Patients with Atrial Fibrillation: Comparing the COOL-AF Risk Score with CARS/mCARS Models for Absolute Risk and the CHA2DS2-VASc Score

BACKGROUND

The aims of this study were (1) to validate the CARS and mCARS methods in an Asian population with atrial fibrillation (AF) and (2) to compare the CARS and mCARS models for absolute risk using the COOL-AF method and CHA₂DS₂VASc scores for the prediction of ischemic stroke or systemic embolism (SSE).

METHODS

We analyzed the results from a prospective nationwide multicenter AF registry. Follow-up data were collected for 3 years. The main outcomes were SSE. Predictive models of the 3-year SSE of the COOL-AF model, the CHA₂DS₂VASc score, the CARS for the no-OAC group, and the mCARS for the OAC group were developed and evaluated by C-statistics, and calibration plots were created for the whole group, as well as for oral anticoagulant (OAC) users and no-OAC patients.

RESULTS

We studied 3405 patients (mean age: 67.8 years; 58.2% male, 75.4% OAC). The incidence rates of SSE were 1.51 (1.26-1.78), 1.93 (1.39-2.60), and 1.37 (1.10-1.68) for all patients, no-OAC patients, and OAC patients, respectively. For the whole population, the COOL-AF score had a C-statistic of 0.697 (0.682-0.713), which was superior to the CHA₂DS₂-VASc [0.655 (0.639-0.671)]. For the no-OAC group, the CARS predicted SSE with a C-statistic of 0.685 (0.652-0.716), which was similar to the CHA₂DS₂-VASc [0.684 (0.651-0.7150] and COOL-AF models [0.692 (0.659-0.723)]. For the OAC group, the mCARS had a C-statistic of 0.687 (0.669-0.705) that was similar to the COOL-AF [0.704 (0.686-0.721)] and better than the CHA₂DS₂-VASc score [0.655 (0.637-0.674)].

CONCLUSIONS

The calculation of the individual absolute risks using the CARS and mCARS models can predict SSE in an Asian population. Small differences were evident between the COOL-AF and CHA₂DS₂-VASc scores.

Enhanced neutrophil extracellular traps formation in AF patients with dilated left atrium

BACKGROUND

Atrial fibrillation (AF) is associated with cardiac remodelling and prothrombotic state. Enhanced neutrophil extracellular traps (NETs) formation has been reported in AF, contributing to thromboembolism.

PURPOSE

We investigated whether increased left atrium (LA) diameter and reduced left ventricular ejection fraction (LVEF) affect NETs formation and prothrombotic state in AF patients.

METHODS

In 243 AF patients (median CHA₂ DS₂ -VASc = 4) we measured LA diameter and LVEF, 123 of them with LVEF<50%. Moreover, we determined 3 markers of NETosis: circulating citrullinated histone H3 (H3cit), myeloperoxidase (MPO) and peptidylarginine deiminase 4 (PAD4), along with prothrombotic markers, including endogenous thrombin potential, plasma fibrin clot permeability (K_s ) and clot lysis time (CLT). Ischaemic cerebrovascular events, major bleeding and death were recorded during a median follow-up of 53 months, on anticoagulation.

RESULTS

LA diameter correlated positively with H3cit, MPO and PAD4, while LVEF was inversely associated with the same NETosis markers. After adjustment for age and body mass index, concentrations of MPO (per 10 units; β = -1.9, 95%CI -3.40;-0.42) and H3cit (per 10 units; β = 2.02, 95%CI 0.61-3.42) were independently associated with LVEF and LA diameter. LA diameter, but not LVEF, correlated inversely with Ks and positively with CLT. The Cox regression analysis revealed that H3cit >6.16 ng/mL (HR = 21.76, 95%CI 2.85-166.28, p = .003) and LA diameter > 46 mm (HR = 2.89, 95%CI 1.04-8.03, p = .043) independently predicted cerebrovascular ischaemic events (1.9%/year).

CONCLUSIONS

This hypothesis-generating study suggests that in AF enlarged LA diameter and reduced LVEF are associated with enhanced NETs formation, which might have clinical importance and contribute to thromboembolic events despite anticoagulation.

Changes in fibrinolytic activity and coagulation factors after epicardial left atrial appendage closure in patients with atrial fibrillation

BACKGROUND

The left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). We investigate whether epicardial LAA occlusion (LAAO) from the cardiovascular system has an effect on coagulation and prothrombotic status in AF.

METHODS

Twenty-two patients with nonvalvular AF, who were not currently receiving oral anticoagulation (OAC) therapy, participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with plasma fibrin clot permeability, clot lysis time (CLT) and endogenous thrombin potential (ETP) before the LAAO procedure, at discharge and 1 month afterward.

RESULTS

One month after the LAAO procedure, plasma fibrin clot permeability improved by 39.3% as measured by clots prepared from peripheral blood (P=0.019) and also after adjustment for fibrinogen (P=0.027). Higher plasma fibrin clot permeability was associated with improved clot susceptibility to lysis (r=-0.67, P=0.013). CLT was reduced by 10.3% (P=0.0020), plasminogen activator inhibitor-1 antigen levels were reduced by 52% (P=0.023) and plasminogen activity was increased by 8.9% (P=0.0077). A trend toward decreased thrombin generation, reflected by a decreased ETP and peak thrombin generated was also observed 1 month after LAAO procedure (P=0.072 and P=0.087, respectively). No differences were observed in tissue-type plasminogen activator and thrombin-activatable fibrinolysis inhibitor plasma levels (both P>0.05).

CONCLUSIONS

Obtained results seem to confirm that LAA plays a key role in thrombogenesis. Elimination of LAA from the circulatory system may improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.

Left Atrial Appendage Morphology and Course of the Circumflex Artery: Anatomical Implications for Left Atrial Appendage Occlusion Procedures

OBJECTIVE

The aim of this study was to evaluate the anatomic topography of the circumflex artery (Cx) and left atrial appendage (LAA) and to determine the safety zones for epicardial LAA closure and LAA occlusion procedures.

METHODS

The left coronary artery was segmented and visualized from 116 computed tomography angiography scans. Four points were located on the Cx portion periappendicularly, starting from the entry point. The landing zone plane was defined as parallel to the LAA orifice at the level of the beginning of the periappendicular course of the Cx, and the plane of the neck bend was located at the end of the LAA neck. A distance smaller than 2 mm was considered a dangerous distance.

RESULTS

The distance between the Cx and the LAA landing zone was 4.3 ± 2 mm. The distance between the Cx and the LAA neck bend was 5.1 ± 2.2 mm. The distance between the Cx and the LAA bottom surface was 5.8 ± 2.9 mm. In 38.8% of patients, at least 1 distance between Cx and LAA was smaller than 2 mm in at least 1 dimension. These distances occurred in 30.2% of the LAA landing zone dimensions, 19.8% of LAA neck bend dimensions, and 11.2% of the LAA bottom surface distances.

CONCLUSIONS

The study showed that most dangerous distances (30.2%) occurred in the LAA landing zone dimension. The data showed that landing zones more distal from the orifice of the LAA are safer in terms of Cx damage. Therefore, LAA closure should always be performed with caution, to avoid iatrogenic complications.

The Complex Relation between Atrial Cardiomyopathy and Thrombogenesis

Heart disease, as well as systemic metabolic alterations, can leave a ‘fingerprint’ of structural and functional changes in the atrial myocardium, leading to the onset of atrial cardiomyopathy. As demonstrated in various animal models, some of these changes, such as fibrosis, cardiomyocyte hypertrophy and fatty infiltration, can increase vulnerability to atrial fibrillation (AF), the most relevant manifestation of atrial cardiomyopathy in clinical practice. Atrial cardiomyopathy accompanying AF is associated with thromboembolic events, such as stroke. The interaction between AF and stroke appears to be far more complicated than initially believed. AF and stroke share many risk factors whose underlying pathological processes can reinforce the development and progression of both cardiovascular conditions. In this review, we summarize the main mechanisms by which atrial cardiomyopathy, preceding AF, supports thrombogenic events within the atrial cavity and myocardial interstitial space. Moreover, we report the pleiotropic effects of activated coagulation factors on atrial remodeling, which may aggravate atrial cardiomyopathy. Finally, we address the complex association between AF and stroke, which can be explained by a multidirectional causal relation between atrial cardiomyopathy and hypercoagulability.

Metabolic Effects of the Left Atrial Appendage Exclusion (THE HEART HORMONE STUDY)

OBJECTIVE

The effect of epicardial LAA occlusion therapy on lipid and glucose metabolism in AF patients over the long term follow up is 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 hours, 7 days, 1 month, 3 months, 6 months, 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 month, 3 months, 6 months, 12 months, and 24 months follow-up. The leptin levels showed a significant increase in 6 months, 12 months, and 24 months when compared to baseline. Whereas the adiponectin levels showed a significant decrease at 3 months, 6 months, 12 months, 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. This article is protected by copyright. All rights reserved.

The effects of apixaban on clot characteristics in atrial fibrillation: A novel pharmacodynamic biomarker

Atrial fibrillation (AF) is a major risk factor for stroke. We aim to characterize AF patients and the effects of apixaban therapy in terms of clot microstructure using gel point analysis, a novel biomarker. Seventy-eight patients were included in the study, 50 Stroke with AF (AF-S), and 28 AF without stroke (AF). Pre- and post-anticoagulation samples were collected: gel point (GP) analysis was performed to obtain (i) TGP (the time taken to reach the GP or the clot formation time) and (ii) d_{f ,} the fractal dimension of the clot, a quantification of clot fibrin microstructure at the GP. At baseline, the AF-S group had a d_f  = 1.70 (±0.05) and TGP = 306 (±73 s). The AF group had a df = 1.70 ± 0.05 and TGP = 346 ± 78 s, showing a significantly shortened TGP in the stroke group (p = .008). For both groups, apixaban significantly prolonged TGP, p = .005, but resulted in no change in df. Apixaban prolonged clotting time while having no significant impact on the blood's ability to form stable clots (no change in d_f ). This indicates that apixaban provides protection from the formation of thrombi by reducing clotting kinetics.

Thermally responsive hydrogel for atrial fibrillation related stroke prevention

Atrial fibrillation induced stroke accounts for up to 15% of all strokes. These strokes are caused approximately 90% of the time by clot formation in the left atrial appendage (LAA). To prevent these clots, the most common approach is to administer blood thinners. However, contraindications prevent some people from being able to have blood thinners. Devices have been developed to seal the LAA to prevent clot formation in these patients. Current devices, such as the LARIAT® tie off the LAA theoretically preventing blood from entering the LAA. These have had limited clinical success mainly due to failure to completely close the LAA leaving holes and orifices for thrombi to form. To overcome this lack of complete closure, many surgeons use off-label approaches, classically filling the LAA filamentous coils, to cover these holes. Although this usually helps largely cover the holes, placement is challenging, the coils can migrate, the holes are not fully closed as there is space within and around the coils that don't fully mold to the LAA geometry. Furthermore, the coils can develop device related thrombi defeating their purpose. Therefore, these are not fully sufficient to complement the closure techniques in closing the LAA. To address limitation of the closure devices and coil sealing of remaining holes, we developed a thermally responsive hydrogel (Thermogel) that solidifies once injected into the LAA to uniformly and fully close off the LAA thus preventing clot formation and device related thrombi. This Thermogel consists of three portions: 1) a structural component composed of thiolated Pluronic F127 for gel to solid transition following injection, 2) Heparin for anticoagulation, and 3) Dopamine for adhesion to the surrounding endothelium in the turbulent flow encountered in cardiovascular applications. Here we have demonstrated that Thermogel, in conjunction with the LARIAT®, is capable of filling the defects in small and large animals through catheter injection. Thermogel was biocompatible and led to atrophy of the LAA at 5 weeks in a large animal model. Given the advantages of this Thermogel for sealing this defect and ability to be delivered through an endovascular approach, Thermogel presents a viable adjuvant to current occlusion-based treatments for sealing cardiovascular defects.

Risk factors for left atrial thrombus or spontaneous echo contrast in non-valvular atrial fibrillation patients with low CHA2DS2-VASc score

OBJECTIVE

Risk factors of left atrial thrombus (LAT) or spontaneous echo contrast (LASEC) in non-valvular atrial fibrillation (NVAF) had been reported. However, information in the subgroup of NVAF patients with low CHA₂DS₂-VASc scores was limited. Here, we evaluated the risk factors of LAT/LASEC in NVAF patients with low CHA₂DS₂-VASc scores.

METHODS

Transesophageal echocardiography (TEE) file of NVAF patients with low CHA₂DS₂-VASc scores was reviewed (between June 2009 and Feb 2019) in this retrospective observational study. Binary logistic regression analysis was performed to identify risk factors other than the CHA₂DS₂-VASc score. Propensity score matching (PSM) was used to further evaluate independent risk markers for LAT/LASEC. The newly discovered factors were added to the CHA₂DS₂-VASc score, and receiver operating characteristic analysis was used to evaluate the ability of the model to predict LAT/LASEC.

RESULTS

TEE files of 3056 NVAF patients with low CHA₂DS₂-VASc scores were reviewed. Regression analysis revealed elevated fibrinogen and enlarged left atrium (LA) were risk factors for LAT/LASEC. Further PSM analysis confirmed that elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC. After including fibrinogen and left atrial diameter (LAD), the CHA₂DS₂-VASc score was more accurate for LAT/LASEC prediction in NVAF patients with low CHA₂DS₂-VASc scores (area under the curve difference is 0.241, 95% confidence interval (CI) 0.188-0.294, Z = 8.890, P < 0.0001).

CONCLUSIONS

Elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC in NVAF patients with low CHA₂DS₂-VASc scores. Taking fibrinogen and LAD into consideration may help improve LAT/LASEC risk evaluation, which warrants further validation studies.

[Independent risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation and low CHA2DS2-VASc scores]

OBJECTIVE

To explore the risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation(NVAF)with low CHA₂DS₂-VASc scores at admission (≤1 for male and ≤2 for female patients).

METHODS

We retrospectively analyzed the clinical data of 10 382 patients with NVAF undergoing transesophageal echocardiography in our hospital from 2009 to 2019, and enrolled 48 NVAF patients with thrombosis as the observation group and another 240 NVAF patients without thrombosis as the control group.The baseline characteristics, biochemical indicators, and echocardiographic findings of the patients were analyzed using univariate analysis, multivariate logistic regression analysis and Pearson correlation analysis.

RESULTS

The baseline data did not differ significantly between the two groups (P > 0.05).Compared with those in the control group, the patients with atrial thrombosis had an increased left atrial diameter (LAD; P < 0.001), a greater likelihood of hypertrophic cardiomyopathy (HCM; P < 0.001), significantly higher levels of C-reactive protein (CRP; P < 0.05) and uric acid (P < 0.001), and greater standard deviation of red blood cell distribution width(RDW-SD; P < 0.001).LAD(P < 0.001), HCM(P < 0.05)and CRP(P < 0.05) were identified as the independent factors affecting the occurrence of atrial thrombosis in patients with low CHA₂DS₂-VASc scores.

CONCLUSIONS

LAD enlargement, HCM, and an elevated CRP level are independent risk factors for atrial thrombosis in NVAF patients with low CHA₂DS₂-VASc scores.Active anticoagulation therapy should be administered for these patients once these risk factors are detected to prevent the occurrence of stroke.

Coronary Embolism despite CHA₂DS₂-VASc Score of Zero: Should We Reconsider Anticoagulation?

Coronary embolism (CE) is a rare but important cause of acute coronary syndrome. The most common source of emboli is considered to be infective endocarditis and atrial fibrillation. Various studies have estimated the prevalence of coronary embolism; however, diagnosis is challenging. Often, it is difficult to differentiate. Nonetheless, this is an important step as treating the underlying cause of an embolism is essential to limit recurrence. However, while this condition may have fatal consequences, due to its uncommon occurrence, there is no consensus on diagnosis and management. We present a case of a 53-year-old obese male, with a history of paroxysmal atrial fibrillation not on anticoagulation due to a low CHA₂DS₂-VASc score, who presented with chest pain associated with lightheadedness. ECG on admission revealed coarse atrial fibrillation, and troponin was gradually elevating on serial lab workup. Coronary angiography revealed a distal left anterior descending artery occlusion with apical wall akinesis without any evidence of atherosclerotic coronary artery disease. A presumptive diagnosis of coronary embolism secondary to paroxysmal atrial fibrillation was made, and the patient was started on anticoagulation despite a low CHA₂DS₂-VASc score. This case not only highlights coronary embolism but also illustrates that a low CHA₂DS₂-VASc score does not mean there is no risk of emboli. For such patients, it is important to take clinical reasoning into account along with the CHA₂DS₂-VASc score to determine the benefit of anticoagulation.

Atrial Thrombus and Embolic Stroke in a Patient With Surgical Appendage Ligation and Maze Procedure

This case illustrates the incomplete protection of surgical ligation of left atrial appendage and maze procedure at the time of mitral valve replacement against thromboembolic complications and recurrence of atrial fibrillation. The utility of surgical left atrial appendage ligation as stroke prophylaxis and identification of selected high-risk subjects are reviewed. (Level of Difficulty: Intermediate.)

Impact of left atrial appendage location on risk of thrombus formation in patients with atrial fibrillation

Most strokes in patients with atrial fibrillation (AF) are thought to arise from thrombus formation in the left atrial appendage (LAA). Assessing the hemodynamics in LAA and left atrium (LA) may provide some insights in the evaluation of the risk of thrombus formation. This study aims to find out the impact of different LAA locations with respect of LA on the risk of thrombus formation within LAA in patients with AF. Three different LAA locations at LA were modeled and a fully coupled fluid-structure interaction analysis was performed. A discrete phase method was used for particle residence analysis to evaluate risk of the thrombus formation. The results showed that LAA positions on the LA affected the LAA flow velocity distribution, passive contraction ability, and particle residence. In particular, the left pulmonary veins (PVs) had a greater influence on the LAA hemodynamics than the right PVs. The LAA had the lowest contractibility when it was located between left superior and left inferior PVs, and in this case, a larger number of particles were resided, which indicated a higher risk of thrombus formation. The present work provides a quantitative way to evaluate the risk of thrombus formation within LAA in patients with AF.

Case Report: Acute Thrombotic Angiopathy of Atrial Appendage Epicardial Veins: A Seemingly Innocuous Finding Portending a Fatal Outcome

Thrombotic angiopathy is a pathologic description to describe endothelial injury, and with sufficient and sustained injury can lead to exposure of underlying tissue factor and the deposition of associated fibrin material. We present briefly a case of an 87-year-old woman with mitral valve regurgitation and atrial fibrillation undergoing mitral valve annuloplasty, Cox-maze procedure, and excision of the left atrial appendage. Pathologic examination of the excised atrial appendage revealed commonly encountered cardiomyocyte hypertrophy and endocardial fibroelastosis, however also showed a non-occlusive, acute thrombotic angiopathy involving epicardial veins. The surgical and immediate post-operative course was unremarkable; however, 3 weeks after discharge, the patient would develop a fatal pulmonary embolism. While fibrin thrombosis developing within the atrial appendage chamber is a recognized concern in the setting of atrial fibrillation, the significance of an acute thrombotic angiopathy involving epicardial veins of the atrial appendage is less clear although in the presented case was the sole potential harbinger of a subsequent fatal thrombotic event.

Why should cardiac surgeons occlude the left atrial appendage percutaneously?

OBJECTIVES

Percutaneous left atrial appendage (LAA) occlusion (LAAO) is a procedure dominated by cardiologists. The aim of our study was to present the results of percutaneous LAAO performed solely by cardiac surgeons.

METHODS

Two hundred twenty-three consecutive patients with nonvalvular atrial fibrillation underwent percutaneous LAAO in two cardiac surgery sites. In the first center, all 84 LAAO procedures were performed with the endocardial LAA occluders: 60 cases with the Amulet and 24 cases with the LAmbre. In the second center, all 139 LAAO procedures were performed with the LARIAT epicardial device.

RESULTS

The mean CHA₂ DS₂ -VASc-score was 3.7 ± 1.8 points, and mean HAS-BLED score was 3.6 ± 1.2 points. The procedure was successful in 97.3% of cases. Procedural or device-related adverse events were noted in 4.4% (n = 10) of cases: one periprocedural cardiac arrest, one aortic injury, one gastrointestinal bleeding, three cases of vascular access complications, and four cardiac tamponades. After a follow-up of 40.3 ± 17.3 months, 78.4% of patients were alive, with the annual mortality rate of 5.3%. Compared to the predicted risk, the observed incidence of thromboembolism was lower by 71%, and the bleeding incidence was lower by 69%.

CONCLUSIONS

Percutaneous LAAO procedures can be safely performed by cardiac surgeons, with no cardiological assistance. LAAO done by surgeons is safe and effective, and periprocedural and long-term outcomes are excellent. Cardiac surgeons should be trained in both types of LAAO: endocardial and epicardial.