Efficacy of the CHADS₂ scoring system to assess left atrial thrombogenic milieu risk before cardioversion of non-valvular atrial fibrillation

Prevalence, predictors and management of left atrial appendage thrombogenic milieu in atrial fibrillation with low thromboembolic risk

BACKGROUND

The present study aimed to investigate the prevalence, predictors, and management of left atrial appendage (LAA) thrombogenic milieu (TM) identified with transesophageal echocardiography (TEE) in non-valvular atrial fibrillation (NVAF) patients with low to moderate thromboembolic (TE) risk.

METHODS

We retrospectively analyzed the baseline clinical data and TEE findings in 391 NVAF patients (54.7 ± 8.9 years, 69.1% male) with low to moderate TE risk according to the CHA₂DS₂-VASc score. LAA TM was defined as LAA thrombus (LAAT), sludge or spontaneous echo contrast (SEC). Management of LAA TM was at the discretion of the treating physician.

RESULTS

A total of 43 patients (11.0%) were detected with LAA TM, including 5 with LAAT (11.6%), 4 with LAAT + Sect. (9.3%), 3 with sludge (7.0%), and 31 with Sect. (72.1%). In multivariate model, non-paroxysmal AF (OR 3.121; 95% CI 1.205-8.083, p = 0.019), and a larger left atrial diameter (LAD) (OR 1.134; 95% CI 1.060-1.213, p < 0.001) were significantly associated with the presence of LAA TM. All LAATs or sludges effectively resolved after mean duration of 117.5 ± 20.0 days for oral anticoagulant (OAC) medication. TE events occurred in 3 patients (18.8%) among those discontinuing OAC over a mean follow-up of 26.2 ± 8.8 months, while no TE events occurred in patients with continuous OAC.

CONCLUSIONS

LAA TM could be identified in 11.0% in NVAF patients with low to moderate TE risk, especially in those with non-paroxysmal AF and enlarged LAD. Short-term OAC medication could effectively resolve the LAAT or sludge.

Heart failure and the risk of left atrial thrombus formation in patients with atrial fibrillation or atrial flutter

AIMS

The aim of the study was to evaluate the prevalence of left atrial thrombus (LAT) on transoesophageal echocardiography (TOE) in patients with atrial fibrillation or atrial flutter (AF/AFl) with reference to the presence of heart failure (HF) and its subtypes.

METHODS AND RESULTS

The research is a sub-study of the multicentre, prospective, observational Left Atrial Thrombus on Transoesophageal Echocardiography (LATTEE) registry, which comprised 3109 consecutive patients with AF/AFl undergoing TOE prior to direct current cardioversion or catheter ablation. TOE parameters, including presence of LAT, were compared between patients with and without HF and across different subtypes of HF, including HF with preserved (HFpEF), mid-range (HFmrEF), and reduced ejection fraction (HFrEF). HF was diagnosed in 1336 patients (43%). HF patients had higher prevalence of LAT than non-HF patients (12.8% vs. 4.4%; P < 0.001). LAT presence increased with more advanced type of systolic dysfunction (HFpEF vs. HFmrEF vs. HFrEF: 7.4% vs. 10.5% vs. 20.3%; P < 0.001). Univariate analysis revealed that HFrEF (odds ratio [OR] 4.13; 95% confidence interval [95% CI]: 3.13-5.46), but not HFmrEF or HFpEF, was associated with the presence of LAT. Multivariable logistic regression indicated that lower left ventricular ejection fraction (OR per 1%: 0.94; 95% CI 0.93-0.95) was an independent predictor of LAT formation. Receiver operator characteristic analysis showed LVEF ≤48% adequately predicted increased risk of LAT presence (area under the curve [AUC] 0.74; P < 0.0001).

CONCLUSION

The diagnosis of HFrEF, but neither HFmrEF nor HFpEF, confers a considerable risk of LAT presence despite widespread utilization of adequate anticoagulation.

Serum heparanase levels and left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation

INTRODUCTION

Data regarding the possible role of heparanase (HPA) in the occurrence of left atrial/left atrial appendage (LA/LAA) thrombus in patients with atrial fibrillation (AF) is lacking. The goal of the present study was to assess the association between plasma levels of HPA and LA/LAA thrombus in AF.

METHODS

A total of 687 patients with nonvalvular AF (NVAF) without anticoagulation therapy were included from January 2016 to June 2019. Serum HPA analysis was performed with a commercially available human ELISA kit. Logistic regression models were used to test for association.

RESULTS

Serum HPA levels were significantly higher in patients with LA/LAA thrombus than in those without LA/LAA thrombus (270.8 [193.4 ± 353.2] pg/mL vs 150.3 [125.2 ± 208.4] pg/mL; P < 0.001). In multivariate analysis, serum HPA remained a significantly independent predictor of LA/LAA thrombus (odds ratio 1.674, 95% confidence interval [CI] 1.339-2.289, P < 0.001). In the receiver operating characteristic (ROC) curve analysis, HPA showed a predictive value with an area under the curve (AUC) of 0.757 (95% CI 0.652-0.810, P < 0.001). The optimal cutoff level for HPA predicting LA/LAA thrombus was 210.7 pg/mL, with a sensitivity of 74.3% and a specificity of 64.8%.

CONCLUSION

An elevated HPA level was associated with the presence of LA/LAA thrombus in patients with AF. HPA might portend the risk for the prothrombotic state in AF patients.

Determinants of left atrium thrombi in scheduled cardioversion: an ENSURE-AF study analysis

Aims

ENSURE-AF (NCT 02072434) was the largest prospective randomized clinical trial of anticoagulation for cardioversion in atrial fibrillation (AF), which also provides the largest prospective dataset for transoesophageal echocardiography (TOE) prior to cardioversion. This ancillary analysis investigated determinants of TOE-detected left atrium thrombi (LAT) in patients scheduled for electrical cardioversion (ECV).

Methods and results

The ENSURE-AF multicentre PROBE evaluation trial compared edoxaban 60 mg once daily (QD) with enoxaparin/warfarin in 2199 subjects undergoing ECV of non-valvular AF. Patients were stratified by the use of TOE, anticoagulant experience, and selected edoxaban dose. Electrical cardioversion was cancelled or deferred when TOEdetected LAT. In total, 1183 subjects were stratified to the TOE arm and LAT was reported in 91 (8.2%). In univariate analysis, age ≥75 years (26.4% vs. 16.9%, P = 0.0308), lower weight (86.5 ± 15.0 vs. 90.7 ± 18.0 kg, P = 0.0309), lower creatinine clearance (80.1 ± 30.6 vs. 93.2 ± 33.9 mL/min, P = 0.0007), heart failure (59.3% vs. 43.0%, P = 0.0029), and diuretic treatment (53.9% vs. 40.1%, P = 0.0141) were more prevalent in the LAT group. Non-significant trends were seen for higher mean CHA₂DS₂-VASc score (3.0 ± 1.41 vs. 2.7 ± 1.48, P = 0.0571) and more prevalent anticoagulation use prior to enrolment (60.4% vs. 50.3%, P = 0.0795) in the LAT group. In logistic regression analysis, age (P = 0.0202) and heart failure (P = 0.0064) were independently associated with LAT.

Conclusion

Elective ECV is commonly cancelled or deferred due to TOE-detected LAT in patients with non-valvular AF. Age ≥75 years and heart failure were associated with the presence of LAT.

A novel risk score for predicting left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation

BACKGROUND

Although the CHADS2 and CHA2DS2-VASc scoring systems are commonly used as measures of thromboembolic risk in patients with nonvalvular atrial fibrillation (NVAF), data are inconsistent as to their value in predicting the presence of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM). The present study aimed to establish a novel risk score to assess the risk of LA and/or LAATM in NVAF patients.

METHODS

This is a retrospective case-control study that included 125 consecutive patients with NVAF plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 1 February 2017. The controls were 1098 NVAF patients without TM during the same period. Risk factors for LA and/or LAATM were identified using univariable analysis and multivariable logistic regression. The risk score model was developed based on 10-fold validation and multiple regression. Risk model performance was evaluated using receiver operating characteristic (ROC) curves. Net reclassification improvement (NRI) was used for the comparison of C-statistics. The AUCs were compared using the Z test.

RESULTS

Among all 1223 NVAF patients, 125 (10.22%) patients had LA and/or LAATM. A score system (0-12) was developed based on the following 6 independent variables identified by 10-fold validation with sequential methods. Different points were assigned for each variable, according to multivariable regression using relative coefficients (coefficient of the index risk factor divided by the lowest coefficient among the 6 risk factors; rounded to closest integer): 1 for blood type A and N-terminal B-type natriuretic peptide (NT-proBNP) ≥864.85 pg/mL; 2 for LAD ≥43.5 mm and age ≥ 73.5 years old; 3 for previous heart failure and previous stroke or TIA. The present risk score system had a sensitivity of 58.3%, specificity of 91.4 and accuracy of 81.6%. The area under the ROC curve (AUC) was 0.832, (95% CI: 0.784-0.881; P < 0.001). The negative predictive value (NPV) was 92% when we set the cut-off point at 4; when the cut-off point was set at 8, the positive predictive value (PPV) was 85.7%. Compared with CHADS2 and CHA2DS2-VASc score, the present novel risk score has better predictive power [net reclassification improvement (NRI) +96.3% and +66.2%, respectively; all P < 0.001].

CONCLUSION

This study developed a novel risk score to help predicting LA and/or LAATM in NVAF patients, which had higher accuracy than CHADS2 and CHA2DS2-VASc score system.

Diagnosis and Management of Left Atrium Appendage Thrombosis in Atrial Fibrillation Patients Undergoing Cardioversion

Atrial fibrillation is the most common cardiac arrhythmia and is associated with an increased risk of stroke and thromboembolic complications. A rhythm control strategy with both electrical and pharmacological cardioversion is recommended for patients with symptomatic atrial fibrillation. Anticoagulant therapy for 3–4 weeks prior to cardioversion is recommended in order to avoid thromboembolic events deriving from restoring sinus rhythm. Transesophageal echocardiography has a pivotal role in this setting, excluding the presence of left atrial appendage thrombus before cardioversion. The aim of this review is to discuss the epidemiology and risk factors for left atrial appendage thrombosis, the role of echocardiography in the decision making before cardioversion, and the efficacy of different anticoagulant regimens on the detection and treatment of left atrial appendage thrombosis.

Clinical outcomes after AF cardioversion in patients presenting left atrial sludge in trans-esophageal echocardiography

BACKGROUND

Direct-current cardioversion (DCC) for atrial fibrillation carries a risk of stroke, probably associated with the temporary atrial stunning following cardioversion. The presence of a cardiac thrombus, usually localized in the left atrial appendage (LAA), is recognized as a clear contra-indication to the cardioversion. However, the presence of atrial sludge without LAA thrombus in trans-esophageal echocardiography (TEE) remains, for many cardiologists, a relative contra-indication to the cardioversion. The aim of this study was to evaluate the safety of DCC in patients presenting atrial sludge without LAA thrombus.

METHODS

We prospectively included all consecutive patients demonstrating atrial sludge without LAA thrombus in TEE and undergoing DCC for persistent atrial fibrillation (AF). Safety of DCC was evaluated by the occurrence of clinical events at 1 month following cardioversion, i.e., up to the end of the atrial stunning period, as assessed by clinical examination and the standardized and validated Questionnaire for Verifying Stroke-Free Status (QVSFS).

RESULTS

Over a period of 2 years, 21 patients presenting atrial sludge without LAA thrombus underwent DCC for AF. During the follow-up period of 1 month after DCC, no clinical embolic event, cardiac event, or unscheduled consultations/hospitalizations occurred. At 1 month, 67% of the patients remained in sinus rhythm.

CONCLUSION

No clinical event occurred in patients demonstrating atrial sludge without thrombus and undergoing DCC for AF. These findings support current guidelines that only keep atrial thrombus as a contraindication to cardioversion, but warrant further investigation in large studies.

Chronic Kidney Disease as a Possible Predictor of Left Atrial Thrombogenic Milieu Among Patients with Nonvalvular Atrial Fibrillation

Patients with chronic kidney disease (CKD) experiencing atrial arrhythmia are hypothesized to have elevated CHADS₂ and CHA₂DS₂-VASc scores, thereby predisposed to left atrial (LA) thrombus formation and subsequent thromboembolism. We examined possible association of LA thrombogenic milieu (TM) with CKD in patients with nonvalvular atrial fibrillation. A total of 581 patients (181 women; mean age, 67 years) who underwent transesophageal echocardiography were examined. Patients were divided into 4 groups based on the estimated glomerular filtration rate (eGFR) (ml/min/1.73 m²): eGFR ≥90 (n = 29), 60≤ eGFR <90 (n = 329), 30≤ eGFR <60 (n = 209), and eGFR <30 (n = 14). TM was defined as the presence of LA thrombus, dense spontaneous echo contrast, or LA appendage velocity ≤25 cm/s. Of 581 patients, 147 (25%) had TM. The prevalence of TM increased with decreasing eGFR (4%, 18%, 36%, and 86% for each group, p <0.001). Similar trends were observed for some of the clinical and echocardiographic variables including CHA₂DS₂-VASc score and LA size. Multivariate logistic regression analysis revealed that every 10 ml/min/1.73 m² decrement in eGFR was a significant independent correlate of TM (odds ratio 0.80, p = 0.005), along with nonparoxysmal atrial fibrillation (AF) (odds ratio 0.45, p = 0.004), higher CHA₂DS₂-VASc score (odds ratio 1.24, p = 0.012), every 5 ml/m² increment in LA volume index (odds ratio 1.57, p <0.001), and every 10% decrement in left ventricular ejection fraction (odds ratio 0.51, p <0.001). In conclusion, CKD may be a significant risk factor for LA thrombus formation in patients with nonvalvular atrial fibrillation.

Predicting Thromboembolic and Bleeding Event Risk in Patients with Non-Valvular Atrial Fibrillation: A Systematic Review

BACKGROUND

 Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of stroke. Medical therapy for decreasing stroke risk involves anticoagulation, which may increase bleeding risk for certain patients. In determining the optimal therapy for stroke prevention for patients with AF, clinicians use tools with various clinical, imaging and patient characteristics to weigh stroke risk against therapy-associated bleeding risk.

AIM

 This article reviews published literature and summarizes available risk stratification tools for stroke and bleeding prediction in patients with AF.

METHODS

 We searched for English-language studies in PubMed, Embase and the Cochrane Database of Systematic Reviews published between 1 January 2000 and 14 February 2018. Two reviewers screened citations for studies that examined tools for predicting thromboembolic and bleeding risks in patients with AF. Data regarding study design, patient characteristics, interventions, outcomes, quality, and applicability were extracted.

RESULTS

 Sixty-one studies were relevant to predicting thromboembolic risk and 38 to predicting bleeding risk. Data suggest that CHADS₂, CHA₂DS₂-VASc and the age, biomarkers, and clinical history (ABC) risk scores have the best evidence for predicting thromboembolic risk (moderate strength of evidence for limited prediction ability of each score) and that HAS-BLED has the best evidence for predicting bleeding risk (moderate strength of evidence).

LIMITATIONS

 Studies were heterogeneous in methodology and populations of interest, setting, interventions and outcomes analysed.

CONCLUSION

 CHADS₂, CHA₂DS₂-VASc and ABC scores have the best prediction for stroke events, and HAS-BLED provides the best prediction for bleeding risk. Future studies should define the role of imaging tools and biomarkers in enhancing the accuracy of risk prediction tools.

PRIMARY FUNDING SOURCE

 Patient-Centered Outcomes Research Institute (PROSPERO #CRD42017069999).

Non-cardioembolic risk factors in atrial fibrillation-associated ischemic stroke

Introduction

Cardioembolic (CE) risks is usually considered as the main mechanism of ischemic stroke in non-valvular atrial fibrillation (NVAF) patients. However, a substantial number of ischemic strokes in NVAF patients are related to non-CE mechanisms. The aim of this study was to investigate the non-CE risk factors in ischemic stroke patients had NVAF.

Methods

We included 401 patients (65.6% male, 68.6 ± 9.6 years old) who had been hospitalized due to ischemic stroke and had a known or newly diagnosed NVAF. The CE (intracardiac thrombus, dense spontaneous echo contrast, or low left atrial appendage flow velocity) and non-CE (complex aortic plaque, significant carotid stenosis, or intracranial arterial stenosis) risk factors were investigated at the time of the index stroke.

Results

The number of CE and non-CE risk factors increased with increasing CHA₂DS₂-VASc scores (p for trends < 0.001). The presence of CE risk factors was independently associated with persistent atrial fibrillation (p < 0.001), body mass index (p = 0.003), heart failure (p = 0.003), and left atrial volume index (p < 0.001). In contrast, the presence of non-CE risk factors was independently associated with age (p < 0.001), hypertension (p = 0.049), diabetes (p = 0.030), and coronary artery calcium score (CACS; p < 0.001). CACS had the added value in predicting non-CE risk factors of ischemic stroke regardless of the CHA₂DS₂-VASc risk category (p < 0.001).

Conclusion

Non-CE risk factors in ischemic stroke patients with NVAF are associated with high CHA₂DS₂-VASc score and CACS. Atherosclerotic non-CE risk factors should be considered as potential mechanisms of stroke even in patients with AF-associated ischemic stroke.

The impact of the latest echocardiographic chamber quantification recommendations on the prediction of left atrial appendage thrombus presence by transthoracic echocardiography

INTRODUCTION

The latest recommendations for echocardiographic chamber quantification have implemented updated normal values for all cardiac chambers.

PURPOSE

To evaluate the incidence of normal and abnormal values of routine echocardiographic parameters such as left ventricular ejection fraction (LVEF) and left atrial volume indexed to body surface area (LAVi) in patients with non-valvular atrial fibrillation (AF) and to determine the influence of LVEF and LAVi reclassification on the prediction of LAAT by transthoracic echocardiography.

METHODS

We retrospectively analysed the database of 1674 transesophageal echocardiograms performed between 2012 and 2015 in our echo lab. The study involved patients (mean age 70 ± 7 years, 80% men) with paroxysmal or persistent AF (35 patients with left atrial appendage thrombus [LAAT] and 35 sex- and age-matched controls without LAAT). LVEF and LAVi were categorised in two ways: semi-quantitative using four-degree scale (normal or abnormal graded from mild and moderate to severe) and qualitative (normal vs. abnormal).

RESULTS

We reclassified 6 (9%) and 4 (6%) patients with regard to LVEF as well as 38 (54%) and 16 (23%) with regard to LAVi on semi-quantitative and qualitative scale, respectively. After adjustment for effective anticoagulation and approved risk factors in the multivariate models, we identified LVEF categorised in semi-quantitative manner according to both documents, LAVi categorised in a binary manner by new guidelines and semi-quantitative scale by both recommendations as independently associated with LAAT.

CONCLUSIONS

Differentiation between normal and abnormal value enhanced the diagnostic meaning of LAVi in the aspect of higher LAAT risk. LVEF reclassification had no significant influence.

Growth differentiation factor 15 is associated with left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation

BACKGROUND

There is evidence suggesting that growth differentiation factor 15 (GDF-15) appears to be associated with stroke in patients with atrial fibrillation (AF). AF-related thromboembolic stroke is predominantly attributed to the thrombus from the left atrium (LA) or left atrial appendage (LAA).

HYPOTHESIS

GDF-15 is related to LA/LAA thrombus in nonvalvular AF (NVAF) patients.

METHODS

A total of 894 patients with NVAF without anticoagulation therapy were included in this study. All patients routinely underwent transesophageal echocardiography for detection of LA/LAA thrombus. GDF-15 was measured by enzyme-linked immunosorbent assay. Logistic regression models were used to test for association.

RESULTS

LA/LAA thrombus was detected by transesophageal echocardiography in 69 (7.72%) patients with AF. The GDF-15 levels in the patients with LA/LAA thrombus were significantly higher than those without LA/LAA thrombus (log₁₀ GDF-15: 2.989 ± 0.023 ng/L vs 2.831 ± 0.007 ng/L; P < 0.001). Logistic regression analysis showed that GDF-15 was an independent risk factor for LA/LAA thrombus (odds ratio [per quarter]: 1.799, 95% confidence interval: 1.381-2.344, P < 0.001) after adjusting for potential clinical risk factors. The optimal cutoff point for GDF-15 predicting LA/LAA thrombus was 809.9 ng/L (sensitivity, 75.3%; specificity, 61.5%), determined by ROC curve. The area under the curve was 0.709 (95% confidence interval: 0.644-0.770, P < 0.001).

CONCLUSIONS

Elevated GDF-15 indicated a significantly increased risk for LA/LAA thrombus in NVAF patients. Thus, GDF-15 might be a potentially useful adjunct in discriminating LA/LAA thrombus in NVAF patients.

The Refinement of Risk Stratification for Atrial Thrombus or Spontaneous Echo Contrast in Nonvalvular Atrial Fibrillation

As for nonvalvular atrial fibrillation (NVAF) patients with left atrial thrombus or spontaneous echo contrast (LAT/SEC), we evaluated the additional predictive value of serum uric acid (SUA) and Left atrial diameter (LAD) for CHADS₂ and CHA₂DS₂-VASc, and explored the influence from the level of SUA and LAD to LAT/SEC in moderate risk group. Thus, we put forward the concept of a borderline high risk group to guide clinical anticoagulant therapy in patients with NVAF.A total of 284 NVAF patients without the history of anticoagulant prior to hospitalization were enrolled. They were divided into LAT/SEC group or No LAT/SEC group according to transesophageal echocardiography (TEE). Then, we explored and compared the additional predictive value of serological and ultrasonic indexes after combining them to CHADS₂/CHA₂DS₂-VASc.61 patients (21.48%) had LAT/SEC. SUA and LAD were the independent risk factors of LAT/SEC. After being added with LAD and SUA, the predictive value of CHADS₂ and CHA₂DS₂-VASc were increased much more than others. In the moderate risk group, the incidence of LAT/SEC rose significantly when SUA or LAD was higher than cut-off values.SUA and LAD enhanced the predictive ability of CHADS₂ and CHA₂DS₂-VASc for LAT/SEC as additional factors. For patients in moderate risk group, if SUA or LAD was higher than cut-off values, the risk of thromboembolism events would rise accompanied by the elevated risk of LAT/SEC.

Use of the CHA2DS2VASc score to reduce utilisation of transoesophageal echocardiography prior to ablation for atrial fibrillation

Transoesophageal echocardiography (TOE) is frequently performed prior to atrial fibrillation (AF) ablation to exclude left atrial appendage (LAA) thrombus. However, patients undergoing AF ablation are usually anticoagulated, thus making the presence of thrombus unlikely in most cases. This study aimed to determine whether the CHA₂DS₂VASc scoring system can be used to identify patients that do not require TOE prior to AF ablation. In this single-centre retrospective study, local institutional and primary care databases and electronic patient records were searched to identify patients that had undergone TOE prior to AF ablation. Patient demographics, CHA₂DS₂VASc score, TOE findings and anticoagulation status were collected for analysis. Over a 7-year period (2008–2014), 332 patients (age 57 ± 10 years; 74% male) underwent TOE prior to proposed AF ablation. CHA₂DS₂VASc scores of 0, 1, 2 and >2 were found in 39, 34, 15 and 12% of patients, respectively. The prevalence of LAA thrombus was 0.6% (2 patients) and these 2 patients had risk scores of 2 and 4. No patients with a score of 0 or 1 had LAA thrombus. Patients that are classed as low risk by the CHA₂DS₂VASc score do not require a pre-ablation TOE to screen for LAA thrombus provided they are adequately anticoagulated. This would lead to a significant reduction in health care expenditures by reducing unnecessary TOE requests and thereby improve patient experience.

ABO blood groups: A risk factor for left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation

BACKGROUND

Previous studies have identified ABO blood groups as predictors of thromboembolic diseases. In patients with atrial fibrillation (AF), however, potential association between ABO blood groups and the risk of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM) has not been established.

METHODS

This is a retrospective case-control study that included 125 consecutive patients with non-valvular atrial fibrillation (NVAF) plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 31 December 2016. The controls were selected randomly from 1072 NVAF without TM at a 1:2 ratio. Potential association between ABO blood groups and TM was analyzed using multivariate logistic regression analysis.

RESULTS

The risk of TM was higher in patients with blood group A (33.6% vs. 20.2% in non-A blood groups, P=0.005). After adjusting for age, sex, oral anticoagulant use, AF type and duration, and relevant functional measures (e.g., NT-pro BNP level, left atrium diameter, and left ventricular ejection fraction), blood group A remained associated with an increased risk of TM (OR=2.99, 95% CI 1.4-6.388, P=0.005).

CONCLUSION

Blood group A is an independent risk factor for TM in NVAF patients.

Association of CHADS2 and CHA2DS2-VASc Scores with Left Atrial Thrombus with Nonvalvular Atrial Fibrillation: A Single Center Based Retrospective Study in a Cohort of 2695 Chinese Subjects

The main mechanism of the CHADS₂ and CHA₂DS₂-VASc scores to predict stroke in nonvalvular atrial fibrillation (NVAF) is still controversial. We evaluated the association of the CHADS₂ and CHA₂DS₂-VASc scores with left atrial thrombus (LAT) as detected by transesophageal echocardiographic (TEE) and compared the predictive ability of these risk stratification schemes with nonvalvular atrial fibrillation (NVAF). Data from 2,695 consecutive NVAF patients in whom TEE was performed for screening LAT from July 2007 to February 2014 were analyzed. Only 3% of the subjects had LAT. Presence of LAT was not significantly associated with either CHADS₂  (P = 0.07) or CHA₂DS₂-VASc score (P = 0.12). The area under the curve (AUC) concerning LAT prediction using CHADS₂ and CHA₂DS₂-VASc was 0.574 and 0.569, respectively. A composition model includes previous stroke or transient ischemic attack, nonparoxysmal AF, moderate to severe left ventricular systolic dysfunction, left atrial enlargement, and cardiomyopathy which improved the discrimination significantly (AUC = 0.743). In our cohort, both CHADS₂ and CHA₂DS₂-VASc scores were of limited value for predicting LAT in patients with NVAF. This questions the CHADS₂/CHA₂DS₂-VASc score predicting stroke mainly through the mechanism of cardiogenic embolism. A scoring scheme combining clinical and echocardiographic parameters may better predict LAT as a surrogate for cardioembolic risk in NVAF patients.

Impact of Diastolic Function Parameters on the Risk for Left Atrial Appendage Thrombus in Patients with Nonvalvular Atrial Fibrillation: A Prospective Study

BACKGROUND

In patients with nonvalvular atrial fibrillation (NVAF), the impact of left ventricular diastolic function on the risk for left atrial appendage (LAA) thrombus has not been prospectively studied.

METHODS

At two academic medical centers, patients with NVAF were prospectively enrolled to undergo investigational transthoracic echocardiography immediately before clinically indicated transesophageal echocardiography. Mitral inflow E velocity and tissue Doppler septal and lateral mitral annulus velocities (e') were measured, and E/e' ratios were calculated.

RESULTS

Among 266 subjects (mean age, 65 years; 32% women), 17 (6.4%) had LAA thrombus. Patients with LAA thrombus had a higher mean CHA2DS2-VASc score (4.6 ± 1.7 vs 3.0 ± 1.8, P < .001), a higher mean lateral E/e' ratio (19.4 ± 10.1 vs 10.2 ± 5.6, P < .001), and a lower mean lateral e' velocity (7.0 ± 3.2 vs 10.4 ± 3.7 cm/sec, P = .001). There was a good discriminative capacity for E/e' (area under the curve, 0.83; P < .001) and e' velocity (area under the curve, 0.76; P = .001). None of the patients with normal E/e' ratios or normal e' velocities had LAA thrombus. Both E/e' (odds ratio, 1.13 per point; 95% CI, 1.06-1.20; P < .001) and e' velocity (odds ratio, 0.76 per 1 cm/sec; 95% CI, 0.63-0.92; P = .005) provided independent and incremental predictive value beyond the CHA2DS2-VASc score; however, E/e' provided greater incremental value than e' velocity (P = .036). Analyses using septal and averaged E/e' and septal e' velocity yielded similar results. Diastolic function parameters were also associated with the presence and intensity of left atrial spontaneous echo contrast, a precursor of LAA thrombus.

CONCLUSIONS

This prospective and concomitant evaluation of diastolic function and LAA thrombus in patients with NVAF demonstrates that E/e' ratio and e' velocity are associated with LAA thrombus, independent of CHA2DS2-VASc score, and may play a role in identifying patients at low risk for LAA thrombus. These data suggest that diastolic function assessment may improve stroke prediction in patients with NVAF.

Prevalence and Clinical Determinants of Left Atrial Appendage Thrombus in Patients With Atrial Fibrillation Before Pulmonary Vein Isolation

The CHADS2 score is considered a reliable predictor of stroke/thromboembolism risk in patients with atrial fibrillation (AF). However, thromboembolism can occasionally occur even in patients with AF with low CHADS2 score (CHADS2 score = 0 or 1). To investigate the incidence and predictors of left atrial appendage (LAA) thrombus (LAAT) formation in patients with AF, we studied consecutive 543 Japanese patients with AF who underwent transesophageal echocardiography before pulmonary vein isolation from 2008 to 2012. All patients were treated with anticoagulation therapy with warfarin, and their clinical and echocardiographic characteristics were evaluated. LAATs were observed in 35 (6.4%) of 543 patients, and the prevalence was clearly correlated with the patient's CHADS2 scores. Of 338 patients with low CHADS2 score, LAATs were observed in 7 patients (2.1%). By multivariate analysis, increased left atrial volume (≥50 ml), decreased ejection fraction (<56%), and increased brain natriuretic peptide level (>75 pg/ml) were significantly associated with increased prevalence of LAATs, even in patients with low CHADS2 score. Accordingly, we proposed a new scoring system to predict LAAT (left atrial volume ≥50 ml: score 2; ejection fraction <56%: score 1; brain natriuretic peptide >75 pg/ml: score 1). Patients with a score ≥2 have a greater risk of LAAT, whereas all patients with score ≤1 have no LAATs. Our scoring system is useful for evaluation of the risk of LAAT in patients with AF even with low CHADS2 score.

Improvement of Predictive Value for Thromboembolic Risk by Incorporating Left Atrial Functional Parameters in the CHADS2 and CHA2DS2-VASc Scores

The discriminative ability of the widely used CHADS2 and CHA2DS2-VASc scores for risk stratification of thromboembolism in atrial fibrillation (AF) is known as modest. Some echocardiographic parameters are known risk factors for thromboembolism. This study aimed to evaluate whether combining echocardiographic parameters with CHADS2 and CHA2DS2-VASc scores can improve the predictive power for embolic risk in AF.A total of 526 (F/M = 83/433, mean age = 57.6 ± 10.7 years) patients with non-valvular AF were enrolled. The predictability for left atrial (LA) thrombus or dense spontaneous echo contrast (SEC) using clinical scores or echocardiographic parameters or combining clinical scores and echocardiographic parameters was calculated and compared.Dense SEC or thrombus was present in 51 patients. The predicting powers of the CHADS2 and CHADS2-VASc scores for the presence of dense SEC or thrombus were modest (c-statistics 0.65 and 0.68, respectively, 95% confidence interval [CI] 0.61-0.69 and 0.64-0.74, respectively, both P < 0.001). Impaired LA function was the most descriptive predictor for the presence of thrombus or dense SEC among echocardiographic parameters. Combining impaired LA function (LA emptying fraction < 30%) with the CHADS2 and CHA2DS2-VASc scores showed the improvement of predictive power in detecting dense SEC or thrombus (c-statistics 0.78 and 95% CI 0.74-0.81 and c-statistics 0.77 and 95% CI 0.73-0.81, respectively, both P < 0.001).Adding LA functional markers to the CHADS2 or CHA2DS2-VASc score improved the predictive value of the presence of thrombus or dense SEC. In clinical situations, anticoagulation should be considered to prevent embolism in patients with low-risk scores when they have LA dysfunction.

Novel Oral Anticoagulants for DC Cardioversion Procedures: Utilization and Clinical Outcomes Compared with Warfarin

BACKGROUND

Novel oral anticoagulant (NOAC) agents dabigatran, rivaroxaban, and apixaban are increasingly utilized as thromboembolic prevention for patients with atrial fibrillation undergoing direct current cardioversion (DCCV) with post hoc analyses of clinical trials suggesting satisfactory safety and efficacy. This study characterizes utilization, effectiveness, and complications of NOAC agents for stroke prophylaxis in the setting of DCCV.

METHODS

Comparison of warfarin and NOAC agents as periprocedural anticoagulation for DCCV procedures performed at Cleveland Clinic from January 2009 through December 2013. Variables of interest include utilization rates for each NOAC agent stratified by clinical parameters including CHADS2 score, and associated clinical outcomes including cerebrovascular accident (CVA), transient ischemic attack (TIA), peripheral arterial embolism (PAE), and bleeding events during 8 weeks of postprocedure follow-up.

RESULTS

Among 5,320 DCCV procedures, 673 (12.6%) cases were excluded due to inadequate follow-up. Warfarin was utilized in 3,721 (80.1%), dabigatran in 719 (15.5%), rivaroxaban in 159 (3.4%), and apixaban in 48 (1.0%) with a steady increase in NOAC utilization from 2011 to 2013. There were low rates of CVA/TIA (warfarin: 0.97% vs NOAC 1.62%, P = 0.162) and bleeding (warfarin: 1.02% vs NOAC: 0.5%, P = 0.247) and no significant differences detected between agents. Higher CHADS2 /CHA2 DS2 -VASC scores were associated with thromboembolic and bleeding risk. Increasing age, chronic kidney disease, diabetes, coronary disease, and deep vein thrombosis/pulmonary embolism were associated with increased bleeding risk.

CONCLUSION

In a high-volume, single-center experience, NOAC utilization has grown to account for over a third of cardioversion procedures, and these agents appear safe and effective compared to warfarin with low rates of thromboembolic and bleeding complications.

Left atrial thrombus formation and resolution during dabigatran therapy: A Japanese Heart Rhythm Society report

BACKGROUND

Protocols on the use of novel oral anticoagulants for stroke prevention in patients with atrial fibrillation (AF) undergoing electrical cardioversion (ECV) are lacking.

AIM

The study was aimed at evaluating the efficacy of dabigatran (Dabi) treatment in preventing peri-ECV stroke.

METHODS

A retrospective survey of the incidence and fate of left atrial (LA) thrombus during Dabi therapy in patients with AF was conducted between December 2012 and January 2013 by the Japanese Heart Rhythm Society.

RESULTS

A total of 198 patients from 299 institutions underwent transesophageal echocardiography (TEE) to rule out LA thrombus before ECV. Of these, LA thrombus was found in eight patients (4%), who tended to be older (67.3 vs. 61.3 years, p=0.175), had higher CHADS2 scores (1.88 vs. 0.95, p=0.058), and a higher prevalence of prior stroke or transient ischemic attack (22.2% vs. 2.6%, p=0.034) than those without LA thrombus. Of the eight patients with LA thrombus, one had LA thrombus during a Dabi 150 mg b.i.d treatment, whereas the remaining seven were receiving 110 mg b.i.d for 3 weeks or longer. In 6 of the 8 patients with LA thrombus, a second TEE was performed, revealing complete resolution of LA thrombus in five; among these five patients, one received Dabi dosage of 150 mg b.i.d unchanged, two received an increased dosage from 110 mg to 150 mg b.i.d, and two were switched to warfarin. Two patients had a stroke 3 and 15 days after ECV, and one had a major large intestine bleeding episode during Dabi therapy.

CONCLUSIONS

LA thrombus developed in 4% of patients with AF receiving Dabi. Older patients with a higher CHADS2 score receiving a lower Dabi dosage were more likely to develop LA thrombus, which was resolved with a prolonged or increased dosage. A higher Dabi dosage may be more beneficial before ECV but prospective randomized studies would be needed to confirm these results.

Relationship between CHADS2 score and complex aortic plaques by transesophageal echocardiography in patients with nonvalvular atrial fibrillation

The CHADS2 score is widely used for risk stratification of thromboembolism in patients with non-valvular atrial fibrillation (NVAF). Although the correlation of CHADS2 score with left atrial (LA) abnormality as detected by transesophageal echocardiography (TEE) has been reported in previous studies, the relationship between CHADS2 score and complex aortic plaque, which is also a significant risk factor for thromboembolism, has not been fully investigated. We assessed aortic plaques by TEE in 150 patients age ≥ 55 y with NVAF. The prevalence of complex aortic plaques increased along with increases in CHADS2 score (p = 0.001). In a multivariate analysis that included atherosclerotic risk factors and LA abnormality, a CHADS2 score ≥2 was independently associated with the presence of complex aortic plaques (odds ratio [OR] 3.39; 95% confidence interval [CI], 1.29-8.90). A high CHADS2 score is closely associated with the presence of complex aortic plaques, which explains, in part, the increased risk of thromboembolism in NVAF patients with high CHADS2 score.

Transesophageal echocardiography-guided cardioversion after cardiac operations

BACKGROUND

Transesophageal echocardiography (TEE) is often performed during cardiac operations. The need to repeat TEE to exclude left atrial or left atrial appendage thrombus before direct current cardioversion (DCCV) in patients with a recent intraoperative TEE showing no thrombus is unclear. We sought to determine the incidence of and risk factors for new thrombus in patients undergoing TEE-guided DCCV after cardiac operations.

METHODS

We reviewed 817 patients referred for TEE-guided DCCV within 30 days of a cardiac operation and an intraoperative TEE. Patients were excluded if the intraoperative TEE showed thrombus or a surgical left atrial appendage intervention was performed. Univariate logistic regression identified risk factors for thrombus.

RESULTS

The study included 362 patients (71% male) with a mean age of 69 years. Median time from the operation to DCCV was 6 days. Thrombus was present in 13 patients (3.6%) on TEE before cardioversion; DCCV was cancelled in these patients. Heart failure was associated with a significantly higher risk of new thrombus formation (7% vs 2%; odds ratio, 3.26; 95% confidence interval, 1.07 to 9.95). Preoperative atrial arrhythmias, duration of perioperative arrhythmias, level of anticoagulation, and time from operation to DCCV were not significantly associated with thrombus. Thrombus was not associated with 30-day mortality.

CONCLUSIONS

Development of new thrombus in patients with atrial arrhythmias early after cardiac operations is not uncommon, especially in patients with heart failure. Patients at high risk for thromboembolic events should undergo TEE before DCCV, even if a recent intraoperative TEE showed no thrombus.