Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

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

AIMS

Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear.

METHODS AND RESULTS

The LAT study was a multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal echocardiography (TEE). Among 17 436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (P < 0.001). During 1 year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], P = 0.003). Despite limited predictive power (area under the curve, 0.659; P = 0.001), LAAFV ≤ 20.0 cm/s (best cut-off) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; P = 0.015). The incidence of adverse outcomes including ischaemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank P = 0.005).

CONCLUSION

Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Left atrial appendage thrombus with severe mitral stenosis: Responders and non-responders to anticoagulation

INTRODUCTION AND OBJECTIVE

Mitral stenosis (MS) is one of the most frequently observed valvular heart lesions in developing countries and is due to different etiologies. The effects of anticoagulation in different types of left atrial appendage (LAA) are unknown. The current study aimed to determine the resolution of LAA thrombus on transesophageal echocardiography (TEE) after three months of optimal anticoagulation in patients with different types of LAA at baseline cardiac computed tomography of patients with severe MS.

METHODS

This prospective cohort study observed the frequency of LAA thrombus resolution after three months of anticoagulation therapy in patients with severe MS. The response rate in different morphologies of LAA and locations was also assessed. Thrombus resolution after three months of warfarin therapy was assessed on repeat TEE.

RESULTS

A total of 88 patients were included, mean age 37.95±11.87 years. Repeat TEE showed thrombus resolution in only 27.3% of patients. The rate of thrombus resolution was 8/12 (66.7%), 4/28 (14.3%), 8/36 (22.2%), and 4/12 (33.3%) for patients with cactus, cauliflower, chicken wing, and windsock LAA type, respectively. The resolution rate was 0/12 (0%), 4/44 (9.1%), and 20/32 (62.5%) for patients with thrombus in the base, body, and tip of the LAA, respectively.

CONCLUSION

The cactus type of LAA morphology and thrombus at the LAA tip responded well to three months of anticoagulation, however, patients with thrombus in the LAA base and body and cauliflower and chicken wing morphology were non-responders and could benefit from early referral for surgical management.

Frequency and Clinical Significance of Atrial Cavities in situ Thrombosis: A Large-Scale Study and Literature Review

Background

Atrial tachyarrhythmias are the main cause of atrial thrombosis, and are usually in the left appendage. The prevalence and causes of endocavitarian thrombosis have not been investigated in recent large-scale studies. Aim of our work was to describe the epidemiology, the clinical characteristics and predisposing factors of "extra-appendicular" atrial thrombosis and to report a systematic review of recent literature.

Methods and Results

5,862 consecutive adult patients referred to a transesophageal echocardiographic exam, were enrolled. A total of 175 subjects with Atrial Thrombosis were found with a prevalence of 2.98%; among those 22 was found in left (0.38%) and 2 in the right (0.03%) atrium. Among the 22 patients with left atrial thrombosis, 8 were associated with prosthetic valves, 4 with mitral stenosis and the remaining with hypercoagulative conditions (cancer, septic shock, eosinophilic pneumonia, cardiogenic shock and warfarin under-dosage in permanent atrial fibrillation and decompensated heart failure). Cancer was associated in one of the two patients with a right atrial clot. The review of the literature from 2000 to December 2019 revealed conflicting results of 48 case reports of atrial cavity thrombosis; pooling this data proved the rarity of extra-appendage thrombosis and confirmed its association with a valvular heart disease or a systemic hypercoagulable state.

Conclusions

Atrial "extra-appendage" thrombosis is a rare condition usually associated to "valvular" atrial fibrillation (such as prosthetic valves and mitral stenosis). A minority, but significant, cases are secondary to a thrombophilic conditions. In absence of valvular heart disease an underlying condition should be sought.

The risk factors of thrombus formation and the effect of catheter ablation on repetitive thrombus formation in patients with atrial fibrillation: a single center retrospective study in China

BACKGROUND

Atrial fibrillation (AF) predisposes patients to the formation of atrial thrombi. The CHA₂DS₂-VASc score does not include all risk factors for atrial thrombosis. The present study is designed to explore the influencing factors of thrombus formation in patients with AF and to investigate the effect of catheter ablation (CA) on recurrent thrombosis in patients with a history of intracardiac thrombus.

METHODS

(1) This study consisted of 1726 patients that underwent CA, among which 58 patients had a history of intracardiac thrombus prior to CA. The risk factors for thrombus formation were explored by comparing the baseline clinical characteristics of patients with and without atrial thrombus. (2) The left atrial appendage flow velocity (LAAFV) in patients with a history of intracardiac thrombus who were willing to undergo transesophageal echocardiography (TEE) at the latest follow-up were examined, and comparisons of the LAAFV was made before and after CA.

RESULTS

The median follow-up period is 13 months. Persistent AF was found to be the only independent risk factor affecting the formation of atrial thrombus among the investigated factors (OR 3.152; 95%CI 1.806-5.500; p < 0.001). Twenty-seven patients agreed to undergo TEE during follow-up, no clinical ischemic stroke events were recorded, no recurrent intracardiac thrombus formation was detected in patients, 15 patients maintained sinus rhythm (55.6%) during follow-up; successful CA significantly increased LAAFV (difference between latest evaluation prior to CA 17.46 ± 14.81 cm/s, p < 0.001).

CONCLUSIONS

Persistent AF is the only independent risk factor for thrombus formation. Successful CA may improve the LAAFV and thereby decrease the risk of intracardiac thrombus formation.

Percutaneous balloon mitral valvuloplasty using veno-arterial loop and neuro-embolic protection for mitral stenosis with thrombus

Percutaneous balloon mitral valvuloplasty (PBMV) is not traditionally suitable for patients with mitral stenosis (MS) and left atrium (LA) thrombus. Moreover, PBMV cannot be performed in patients with LA thrombus not resolving after anti-coagulation treatment. Here we present a case of PBMV using a novel technique employing both a veno-arterial loop and neuro-embolic protection, in a patient with MS and LA thrombus resistant to warfarin therapy. The patient successfully underwent PBMV without any complications.

Resolution of left atrial appendage thrombi: No difference between phenprocoumon and non-vitamin K-dependent oral antagonists

Background

Atrial fibrillation is the most important risk factor for left atrial appendage (LAA) thrombi, a potentially life‐threatening condition. Thrombus resolution may prevent embolic events and allow rhythm‐control strategies, which have been shown to reduce cardiovascular complications.

Hypothesis

There is no significant difference between phenprocoumon and non‐Vitamin K‐dependent oral anticoagulants (NOACs) in the resolution of LAA‐thrombi in a real‐world setting.

Methods

Consecutive patients with LAA‐thrombi from June 2013 to June 2017 were included in an observational single‐center analysis. The primary endpoint was defined as the resolution of the thrombus. The observational period was 1 year. Resolutions rates in patients on phenprocoumon or NOACs were compared and the time to resolution was analyzed.

Results

We identified 114 patients with LAA‐thrombi. There was no significant difference in the efficacy of resolution between phenprocoumon and NOACs (p = .499) at the time of first control which took place after a mean of 58 ± 42.2 (median 48) days. At first control most thrombi were dissolved (74.6%). The analysis after set‐time intervals revealed a resolution rate of 2/3 of LAA‐thrombi after 8–10 weeks in the phenprocoumon and NOAC groups. After 12 weeks a higher number of thrombi had resolved in the presence of NOAC (89.3%) whereas in the presence of phenprocoumon 68.3% had resolved (p = .046).

Conclusion

In this large observational study NOACs were found to be potent drugs for the resolution of LAA‐thrombi. In addition, the resolution of LAA‐thrombi was found to be faster in the presence of NOAC as compared to phenprocoumon.

Prevalence and Rate of Resolution of Left Atrial Thrombus in Patients with Non-Valvular Atrial Fibrillation: A Two-Center Retrospective Real-World Study

Background and aim. Thromboembolic events due to left atrial appendage (LAA) thrombosis are the main complication of non-valvular atrial fibrillation (NVAF). Although anticoagulants are effective in patients with NVAF, a minimal residual thromboembolic risk persists. Little is known about the prevalence of LAA thrombus and the rate of resolution after the recommended period of anticoagulation therapy, including vitamin K antagonists (VKA), heparin, and non-vitamin K antagonist oral anticoagulants (NOACs). Methods and results. We aimed to study the prevalence of LAA thrombus in an unselected cohort of patients undergoing transesophageal echocardiogram (TEE), and the determinants of LAA thrombus resolution. We retrospectively analyzed 8888 consecutive TEEs performed over five years in two high-volume centers and included all patients with LAA thrombus. A total of 265 patients (3%) had an LAA thrombus. Among these, 97% presented with AF. Fifty-eight percent of patients were on anticoagulants at least three weeks before the diagnosis. After the LAA thrombus diagnosis, VKAs were prescribed in 52%, heparin in 18.5%, and NOAC in 27% of patients. Among the 183 patients with repeat TEE, performed at (25–75th) 39 days (21–84), 67% showed resolution of the LAA thrombus. Although the rate of thrombus resolution was higher in patients treated with NOACs (NOACs 71%, VKA 66%, Heparin 60%) the difference between anticoagulants was statistically non-significant (VKA, OR 0.9, p = 0.83; NOAC, OR 1.23, p = 0.42; heparin, OR 0.69, p = 0.35). Thus, NOACs were demonstrated to be at least as effective as other anticoagulants in the rate of LAA thrombus resolution. Upon multivariate-adjusted analysis, higher LAA emptying velocities were the only predictor of thrombus resolution. In conclusion, the majority of patients were already on anticoagulants. NOACs could be at least as effective as other anticoagulants, yielding an LAA thrombus resolution in two-thirds of patients. This may have clinical relevance, especially in patients undergoing cardioversion or catheter ablation.

Imaging of left heart intracardiac thrombus: clinical needs, current imaging, and emerging cardiac magnetic resonance techniques

Intracardiac thrombus in the left atrium and atrial appendage (LA/LAA) and left ventricle (LV) increases the risk of systemic thromboembolism and causes potentially devastating diseases such as ischemic stroke and acute ischemia in abdominal organs and lower extremities. Detecting the presence and monitoring the resolution of left heart intracardiac thrombus are of vital importance for stratifying patients and guiding treatment decisions. Currently, echocardiography is the most frequently used method for the above clinical needs, followed by computed tomography. An increasing number of studies have been performed to investigate the value of cardiac magnetic resonance (CMR) as an alternative imaging modality given its several unique strengths. This article provides an overview of the clinical relevance of the LA/LAA and LV thrombus as well as the diagnostic performance of the current imaging modalities and emerging CMR techniques.

Diagnosis and Treatment of Intracardiac Thrombus

ABSTRACT

Intracardiac thrombi can occur in a variety of locations and are frequently encountered in clinical practice. Yet evidence-based guidance for clinicians managing patients with intracardiac thrombi is often limited. This review summarizes what is known regarding the prevalence of intracardiac thrombus, diagnostic strategies, clinical relevance, and treatment options, focusing on four specific types of thrombus for which recent research has shifted clinical understanding and treatment decisions: (1) left atrial appendage thrombus, (2) cardiac implantable electronic device lead thrombus, (3) bioprosthetic aortic valve thrombus, and (4) left ventricular thrombus. Additional studies, ideally prospective, randomized, and head-to-head in design, are needed to better inform best practices in patients with intracardiac thrombi.

Cardioversion of atrial fibrillation and atrial flutter revisited: current evidence and practical guidance for a common procedure

Cardioversion is widely used in patients with atrial fibrillation (AF) and atrial flutter when a rhythm control strategy is pursued. We sought to summarize the current evidence on this important area of clinical management of patients with AF including electrical and pharmacological cardioversion, peri-procedural anticoagulation and thromboembolic complications, success rate, and risk factors for recurrence to give practical guidance.

Papillary Fibroelastoma in Differential Diagnosis of Left Atrial Appendage Masses

Papillary fibroelastomas are benign tumors that usually originate from cardiac valves but may have other endocardial origins. We report the cases of 2 patients in whom left atrial appendage masses were initially diagnosed as thrombus. They were treated for embolic stroke and their symptoms resolved; however, their left atrial appendage masses did not regress. After surgery, histologic analysis of the resected masses revealed papillary fibroelastoma in both cases. We discuss the diagnostic and therapeutic dilemmas encountered in patients with papillary fibroelastomas and cardiac masses other than thrombus.

A new risk model of assessing left atrial appendage thrombus in patients with atrial fibrillation - Using multiple clinical and transesophageal echocardiography parameters

BACKGROUNDS

Predicting left atrial appendage thrombus (LAAT) in non-valvular atrial fibrillation (NVAF) patients need more precisely quantified risk models. In this study, we attempted to review the risk markers for LAAT and develop a simple and reliable model for LAAT prediction.

METHODS

The study included 307 patients with NVAF who were scheduled for transesophageal echocardiography (TEE) to exclude LAA thrombus before synchronized electrical cardioversion or radiofrequency ablation for atrial fibrillation (AF). We analyzed the relationship between echo, clinical parameters and the presence or absence of LAAT.

RESULTS

A total of 33 patients were found having LAAT (10.7%, 33/307). The age, left atrial appendage emptying velocity (LAAEV), left atrial or left atrial appendage spontaneous echocardiographic contrast (SEC), less than moderate to severe mitral regurgitation (≤mild MR), and left atrial enlargement showed association with LAAT. The multivariate logistic regression analysis revealed that LAAEV, SEC and ≤mild MR were independent risk factors of the LAAT. We used LAAEV ≤ 21.5 cm/s, SEC and ≤mild MR to construct a combined predictive model for LAAT in NVAF patients (the area under receiver operator characteristic curve: 0.88; 95% confidence interval: 0.82-0.95, P < 0.0001).

CONCLUSION

Comprehensive evaluation of LAAEV, SEC, and MR with associated LAAT may help risk stratifying the NVAF patients, especially if the LAA imaging quality was suboptimal for identifying thrombus. These parameters may facilitate the decision-making process at the time of TEE.

Comparison of Long-Term Outcomes Between Combination Antiplatelet and Anticoagulant Therapy and Anticoagulant Monotherapy in Patients With Atrial Fibrillation and Left Atrial Thrombi

Background: Anticoagulation for patients with atrial fibrillation (AF) complicated by left atrial thrombi (LAT) is a frequent cause of bleeding complications, but risk factors remain unknown.

Methods and Results: Of 3,139 AF patients who underwent transesophageal echocardiography, 82 with LAT under anticoagulation were included in this study. Patients treated with combination antiplatelet and anticoagulant therapy (n=31) were compared with those receiving anticoagulant monotherapy (n=51) to investigate the effects of antiplatelet agents during anticoagulation on bleeding complications. Over a mean (±SD) follow-up of 878±486 days, bleeding events occurred more frequently in the combination therapy than monotherapy group (58% vs. 20%; P<0.001), but there was no significant difference in embolic events (6.5% vs. 3.9%; P=0.606). Kaplan-Meier analysis also showed a significantly higher rate of bleeding events in the combination therapy group, but no significant difference in the rate of embolic events. Inverse probability of treatment weighting revealed that combination therapy was independently associated with an increased risk of bleeding (hazard ratio [HR] 2.98, 95% confidence interval [CI] 1.14–7.89, P=0.026), but not with the risk of embolic events (HR 0.30, 95% CI 0.04–2.59, P=0.275). Net clinical benefit analysis was almost negative for combination therapy vs. monotherapy.

Conclusions: In patients with AF and LAT, combination therapy was significantly associated with an increased risk of bleeding events, but not with a reduced risk of embolic events.

Clinical outcomes and thrombus resolution in patients with solid left atrial appendage thrombi: results of a single-center real-world registry

BACKGROUND

Data on thrombus resolution and clinical outcome data after a therapy of LAA thrombus with novel oral anticoagulants (NOACs) are scarce.

METHODS

In this single-center study, we retrospectively analyzed 78 patients diagnosed with a solid LAA thrombus by transesophageal echocardiography (TEE). We assessed baseline clinical and echocardiographic characteristics, the anticoagulatory regimens and outcomes of patients with (responders) and without (non-responders) thrombus resolution.

RESULTS

Mean age was 76.1 ± 8.3 years, patients were male in 57.7% and presented with a high risk for thromboembolism (CHA₂DS₂-VASc: 4.3 ± 1.1). At thrombus diagnosis, 44.9% patients were treated with a NOAC, while 41.0% were under therapy with a VKA. Complete thrombus resolution was achieved after a mean of 116 ± 79 days in a total of 51.3% of patients, 35.9% showed a reduction of thrombus size, whereas 12.8% showed no changes in thrombus dimensions. There was no statistically significant difference in the rate of LAA thrombus resolution between VKA and NOACs (41.2 vs. 57.1%, p = 0.18). However, in cases in which only the therapy with a NOAC led to complete thrombus resolution, the time needed was significantly shorter than with VKA (81 ± 38 vs. 129 ± 46 days, p = 0.03). Regarding safety outcomes, no differences in bleeding or thromboembolism were observed between patients with and without thrombus resolution.

CONCLUSIONS

In this registry, approximately 85% of LAA thrombi were diagnosed in patients with ongoing OAC. Thrombus resolution was observed in nearly 50% of cases. Although there was no difference in the rate of LAA thrombus resolution between VKA and NOACs, the resolution time was shorter in patients prescribed a NOAC.

Poor enhancement pattern of left atrial appendage in cardiac computed tomography is associated with stroke in persistent atrial fibrillation patients

Background

In atrial fibrillation (AF) patients, the left atrial appendage (LAA) is the major source of thrombi. We assessed the hypothesis that poor contrast enhancement in the LAA during the early phase of cardiac computed tomography (CT) predicts a high risk of thrombus formation, leading to cardiogenic stroke.

Methods

We studied 147 consecutive patients with chronic AF who underwent cardiac CT. Three different patterns of medium contrast enhancement in the LAA were used to categorize the stroke risk: poor, intermediate, and good enhancement pattern.

Results

The CT scans of 147 patients were analyzed (age, 69±9 years; 82% men; 43% with a CHA₂DS₂-VASc score ≥2). Seventy-two patients (49%) had a poor enhancement LAA enhancement pattern, 33 (22%) had an intermediate enhancement pattern, and 42 (29%) had a good enhancement pattern. Of the 147 patients, 58 (39%) had a history of ischemic stroke or transient ischemic attack (TIA). The prevalence of a stroke history associated with each pattern was 58%, 27%, and 17%, respectively (P<0.001). After controlling for the CHADS₂ or CHA₂DS₂-VASc score and the ejection fraction using a multivariable logistic model, the poor enhancement pattern was found to be significantly more likely to be associated with a stroke history than other patterns [odds ratio (OR): 5.3; 95% confidence interval (CI): 2.5-11.1; P<0.0001].

Conclusions

The LAA enhancement pattern observed using cardiac CT is associated with the risk of stroke. Poor enhancement in the LAA suggests a potential high risk of stroke.

Baseline D-Dimer Levels as a Risk Assessment Biomarker for Recurrent Stroke in Patients with Combined Atrial Fibrillation and Atherosclerosis

Background: We investigated the effect of D-dimer levels and efficacy of different antithrombotic therapies according to the baseline D-dimer levels on recurrent stroke in patients with atrial fibrillation (AF)-related stroke and atherosclerosis. Methods: We enrolled 1441 patients with AF-related stroke and atherosclerosis in this nationwide multicenter study. The primary outcome measure was the occurrence of recurrent ischemic stroke over a 3-year period. Results: High D-dimer levels (≥2 μg/mL) were significantly associated with higher risk of recurrent ischemic stroke (adjusted hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.13–2.84; p = 0.012). The risk of recurrent stroke was similar between the anticoagulant and the antiplatelet groups in all subjects (adjusted HR, 0.78; 95% CI, 0.46–1.32; p = 0.369). However, in patients with high D-dimer levels (≥2 μg/mL), risk of recurrent stroke was significantly lower in the anticoagulant group than in the antiplatelet group (adjusted HR, 0.40; 95% CI, 0.18–0.87; p = 0.022). Conclusion: Our findings suggested that baseline D-dimer levels could be used as a risk assessment biomarker of recurrent stroke in patients with AF-related stroke and atherosclerosis. High D-dimer levels would facilitate the identification of patients who are more likely to benefit from anticoagulants to ensure secondary prevention of stroke.

New-Onset Atrial Fibrillation in Adult Patients After Cardiac Surgery

Purpose of Review

An overview of recent literature regarding pathophysiology, risk factors, prophylaxis, and treatment of new-onset atrial fibrillation (AF) in post-cardiac surgical patients.

Recent Findings

AF is the most frequent adverse event after cardiac surgery with significant associated morbidity, mortality, and financial cost. Its causes are multifactorial, and models to stratify patients into risk categories are progressing but a consistent, evidence-based system has not yet been developed. Pharmacologic and surgical interventions to prevent and treat this complication have been an area of ongoing research and recent societal guidelines reflect this.

Summary

Inconsistencies remain surrounding how to best identify higher-risk AF patients, which interventions should be used to prevent and treat AF, and which patient groups should receive these interventions. The evidence for these available strategies and their place in contemporary guidelines are summarized.

Prevalence and clinical characteristics associated with left atrial thrombus detection: Apixaban

BACKGROUND

The prevalence of left atrial appendage (LAA) thrombus detection by transesophageal echocardiogram (TEE) in patients with non-valvular atrial fibrillation (AF) anticoagulated with apixaban is not well defined and identification of additional risk factors may help guide the selection process for pre-procedural TEE. The purpose of our study was to retrospectively analyze the prevalence of LAA thrombus detection by TEE in patients continuously anticoagulated with apixaban for ≥ 4 wk and evaluate for any cardiac risk factors or echocardiographic characteristics which may serve as predictors of thrombus formation.

AIM

To retrospectively analyze the prevalence of LAA thrombus detection by TEE in patients continuously anticoagulated with apixaban.

METHODS

Clinical and echocardiographic data for 820 consecutive patients with AF undergoing TEE at Augusta University Medical Center over a four-year period were retrospectively analyzed. All patients (apixaban: 226) with non-valvular AF and documented compliance with apixaban for ≥ 4 wk prior to index TEE were included.

RESULTS

Following ≥ 4 wk of continuous anticoagulation with apixaban, the prevalence of LAA thrombus and LAA thrombus/dense spontaneous echocardiographic contrast was 3.1% and 6.6%, respectively. Persistent AF, left ventricular ejection fraction < 30%, severe LA dilation, and reduced LAA velocity were associated with thrombus formation. Following multivariate logistic regression, persistent AF (OR: 7.427; 95%CI: 1.02 to 53.92; P = 0.0474), and reduced LAA velocity (OR: 1.086; 95%CI: 1.010 to 1.187; P = 0.0489) were identified as independent predictors of LAA thrombus. No Thrombi were detected in patients with a CHA₂DS₂-VASc score ≤ 1.

CONCLUSION

Among patients with non-valvular AF and ≥ 4 wk of anticoagulation with apixaban, the prevalence of LAA thrombus detected by TEE was 3.1%. This suggests that continuous therapy with apixaban does not completely eliminate the risk of LAA thrombus and that TEE prior to cardioversion or catheter ablation may be of benefit in patients with multiple risk factors.

Prevalence and Resolution of Left Atrial Thrombus in Patients With Nonvalvular Atrial Fibrillation and Flutter With Oral Anticoagulation

Left atrial appendage (LAA) thrombus in nonvalvular atrial fibrillation or flutter (AF) is a major cause of stroke and presents a therapeutic dilemma in a rhythm-control strategy. The prevalence and resolution of LAA thrombus has not been studied well in the era of non-vitamin K antagonist oral anticoagulant use. This study sought to establish (1) the prevalence of LAA thrombus (2) the prevalence of LAA thrombus despite antithrombotic therapy, (3) the rate of persistence of LAA thrombus despite appropriate anticoagulant prescriptions, and (4) determinants of LAA thrombus persistence. Consecutive transesophageal echocardiograms (TEE) performed in patients with AF were reviewed to estimate the overall prevalence of LAA thrombus and the resolution rate in those with repeat studies. Multivariable logistic regression was used to identify clinical and echocardiographic predictors of thrombus resolution. Of 1,485 patients with AF, 117 (8%) had LAA thrombus. Of those, 62 had repeat TEE within 1 year and 58 (94%) were prescribed adequate anticoagulation in TEE studies (mean interval 96 ± 72 days). Thirty-seven patients (60%) had LAA thrombus resolution. Thrombus resolution rate was only 79% in patients considered on appropriate anticoagulation. Patients with persistent LAA thrombus were more likely to have diabetes; no other clinical or echocardiographic variable was independently associated with thrombus resolution. There was no significant difference in LAA thrombus resolution between non-vitamin K antagonist oral anticoagulants and warfarin. LAA thrombus persistence despite adequate anticoagulation is relatively common and difficult to predict clinically; TEE before electrical cardioversion should be considered regardless of anticoagulation status.

Left atrial thrombus resolution in non-valvular atrial fibrillation or flutter: biomarker substudy results from a prospective study with rivaroxaban (X-TRA)

BACKGROUND

Non-vitamin K antagonist oral anticoagulants including rivaroxaban are widely used for stroke prevention in patients with atrial fibrillation (AF). We investigated the relationship between plasma biomarkers (indicative of thrombogenesis, fibrinolysis and inflammation) and left atrial thrombus resolution after rivaroxaban treatment.

METHODS

This was an ancillary analysis of the X-TRA study, which was a prospective interventional study evaluating the use of rivaroxaban for left atrial/left atrial appendage (LA/LAA) thrombus resolution in AF patients. We assessed various biomarkers of thrombogenesis/fibrinolysis [D-dimer, plasminogen activator inhibitor-1 (PAI-1), prothrombin fragment 1 + 2 (F1,2), thrombin-antithrombin (TAT) complexes, von Willebrand factor (vWF)] and inflammation [high-sensitivity interleukin-6 (hsIL-6), and high-sensitivity C-reactive protein (hsCRP)], measured at baseline and after 6 weeks' of rivaroxaban treatment.

RESULTS

There was a significant decrease in the mean levels of hsCRP, D-dimer, vWF, and TAT from baseline to end of treatment with rivaroxaban. Although none of the thrombogenesis/fibrinolysis biomarkers showed a significant relationship with thrombus resolution, high inflammatory biomarkers at baseline were significantly associated with an increased chance of the thrombus being completely resolved (hsIL-6) or reduced/resolved (hsCRP).

CONCLUSIONS

Biomarkers of inflammation are significantly associated with LA/LAA thrombus outcomes in AF patients prospectively treated with rivaroxaban.

Left atrial thrombus despite continuous direct oral anticoagulant or warfarin therapy in patients with atrial fibrillation: insights into rates and timing of thrombus resolution

PURPOSE

Left atrial thrombus (LAT) may be detected by transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF) or flutter (AFL) despite continuous anticoagulation therapy. We sought to examine the rates and timing of LAT resolution in response to changes in anticoagulation regimen.

METHODS

A retrospective study of 1517 consecutive patients on ≥ 4 weeks continuous oral anticoagulation (OAC) undergoing TEE prior to either direct current cardioversion or catheter ablation for AF or AFL was performed. Patients who had LAT on index TEE imaging and had follow-up TEEs were analyzed.

RESULTS

Despite ≥ 4 weeks of continuous anticoagulation therapy, 63 (4.2%) patients had LAT. Forty-four patients (median age 67 [IQR 58, 74]; 33 [75%] male; 25 [57%] on direct oral anticoagulant [DOAC]) had follow-up TEEs performed. Upon detection of LAT on index TEE, 8 patients switched from warfarin to a DOAC, 21 patients switched from a DOAC to warfarin or another DOAC, and 15 patients remained on the same OAC. Over median 4.2 months (IQR 2.9, 6.6), LAT resolution was seen in 25 (57%) patients. Of the 25 patients who had LAT resolution, 7 (28%) required TEE imaging > 6 months after index TEE to show clearance of thrombus. Rates of LAT resolution were similar between patients who had alterations in OAC and those who did not (52 vs. 60%; P = 0.601).

CONCLUSIONS

After initial detection of left atrial thrombus despite uninterrupted anticoagulation for atrial fibrillation or flutter, > 40% patients have persistent clot despite additional extended anticoagulation.

Submassive Pulmonary Embolism and Left Atrial Thrombus

•LA thrombus was seen in the setting of acute PE. •Surgical and medical management strategies are discussed. •Factors that predict thrombus resolution and systemic embolism are discussed.

Comparison of prevalence and management of left atrial appendage thrombi under old and new anticoagulants prior to left atrial catheter ablation

BACKGROUND

The prevalence and management of left atrial appendage (LAA) thrombi associated with new anticoagulants remain to be elucidated, especially prior to atrial fibrillation (AFib) ablation. This study sought to (1) compare the prevalence of LAA thrombi and/or severe LAA contrast under vitamin K antagonist (VKA) agents and novel oral anticoagulants (NOACs), (2) evaluate the rate of LAA thrombus resolution after anticoagulation modification, and (3) determine the predictive factors of LAA thrombi and severe LAA contrast in patients prior to LA AFib ablation.

METHODS

Between January 2013 and March 2016, 576 consecutive patients referred for AFib ablation were included, and the prevalence of transesophageal echocardiography-detected thrombi was similar under NOACs (2.1%) and VKA agents (2.6%).

RESULTS

Thrombus resolution was obtained in 50% of cases following anticoagulation modification. Through multivariate exact logistic regression analysis with relevant clinical and echocardiographic features, age (P<.001), LAA hypocontractility (P<.001), and left ventricular ejection fraction (P=.007) were found to be independently associated with the occurrence of LAA thrombus. The relevant factors independently associated with LAA thrombus or severe contrast were LAA hypocontractility (P<.001) and age (P<.001).

CONCLUSIONS

The prevalence of transesophageal echocardiography-detected thrombi in patients referred for AFib ablation is similar under NOACs (2.1%) and VKA agents (2.6%). Under VKA therapy with 3-4 international normalized ratio, 50% of thrombi dissolved. Independent predictive factors of procedure contraindication included age, LAA hypocontractility, and left ventricular ejection fraction.

2017 consensus of the Asia Pacific Heart Rhythm Society on stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia, causing a 2-fold increase in mortality and a 5-fold increase in stroke. The Asian population is rapidly aging, and in 2050, the estimated population with AF will reach 72 million, of whom 2.9 million may suffer from AF-associated stroke. Therefore, stroke prevention in AF is an urgent issue in Asia. Many innovative advances in the management of AF-associated stroke have emerged recently, including new scoring systems for predicting stroke and bleeding risks, the development of non-vitamin K antagonist oral anticoagulants (NOACs), knowledge of their special benefits in Asians, and new techniques. The Asia Pacific Heart Rhythm Society (APHRS) aimed to update the available information, and appointed the Practice Guideline sub-committee to write a consensus statement regarding stroke prevention in AF. The Practice Guidelines sub-committee members comprehensively reviewed updated information on stroke prevention in AF, emphasizing data on NOACs from the Asia Pacific region, and summarized them in this 2017 Consensus of the Asia Pacific Heart Rhythm Society on Stroke Prevention in AF. This consensus includes details of the updated recommendations, along with their background and rationale, focusing on data from the Asia Pacific region. We hope this consensus can be a practical tool for cardiologists, neurologists, geriatricians, and general practitioners in this region. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician׳s decision remains the most important factor in the management of AF.

Watchman in ascending aorta for systemic protection (WAASP): Novel use of Watchman in ascending aorta for embolic protection-first in man

We report two cases where left atrial appendage closure (LAA) with Watchman was successfully performed despite presence of definite LAA thrombus. Because there was the risk of thrombus dislodgement, we transiently placed an additional Watchman device in the ascending aorta for embolic protection. © 2017 Wiley Periodicals, Inc.

Left atrial thrombus resolution in atrial fibrillation or flutter: Results of a prospective study with rivaroxaban (X-TRA) and a retrospective observational registry providing baseline data (CLOT-AF)

BACKGROUND

Data on left atrial/left atrial appendage (LA/LAA) thrombus resolution after non-vitamin K antagonist (VKA) oral anticoagulant treatment are scarce. The primary objective of X-TRA was to explore the use of rivaroxaban for the resolution of LA/LAA thrombi in patients with nonvalvular atrial fibrillation (AF) or atrial flutter, with the CLOT-AF registry providing retrospective data after standard-of-care therapy in this setting.

METHODS

X-TRA was a prospective, single-arm, open-label, multicenter study that investigated rivaroxaban treatment for 6 weeks for LA/LAA thrombus resolution in patients with nonvalvular AF or atrial flutter and LA/LAA thrombus confirmed at baseline on a transesophageal echocardiogram (TEE). CLOT-AF retrospectively collected thrombus-related patient outcome data after standard-of-care anticoagulant treatment for 3 to 12 weeks in patients with nonvalvular AF or atrial flutter who had LA/LAA thrombi on TEE recorded in their medical file.

RESULTS

In X-TRA, patients were predominantly (95.0%) from Eastern European countries. The adjudicated thrombus resolution rate was 41.5% (22/53 modified intention-to-treat [mITT] patients, 95% CI 28.1%-55.9%) based on central TEE assessments. Resolved or reduced thrombus was evident in 60.4% (32/53 mITT patients, 95% CI 46.0%-73.6%) of patients. In CLOT-AF, the reported thrombus resolution rate was 62.5% (60/96 mITT patients, 95% CI 52.0%-72.2%) and appeared better in Western European countries (34/50; 68.0%) than in Eastern European countries (26/46; 56.5%).

CONCLUSION

X-TRA is the first prospective, multicenter study examining LA/LAA thrombus resolution with a non-VKA oral anticoagulant in VKA-naïve patients or in patients with suboptimal VKA therapy. Rivaroxaban could be a potential option for the treatment of LA/LAA thrombi.

Dissolution of large intracardiac thrombus, potential role of the emerging oral fibrinolytic agent

Intracardiac thrombus may persist in some cases even after anticoagulant therapy. This opens a possibility to add a potent thrombolytic agent into therapeutic regimen without increasing bleeding risk any further. Increasing evidence showed a promising efficacy and safety of oral fibrin specific lumbrokinase as a thrombolytic agent. To the best of our knowledge, report of the use of lumbrokinase on intracardiac thrombus is limited. We reported two cases of intracardiac thrombi. In first patient, after two-month therapy with lumbrokinase, the previous 8 cm2 left atrial thrombus was completely disappeared. Second patient had left ventricular thrombus due to low left ventricular ejection fraction caused by coronary artery disease. A significant dissolution in thrombus size on repeated follow-up was found. Both patients did not experience any significant adverse effect. This case series aims to present the potential use of lumbrokinase as as oral antithrombotic therapy in intracardiac thrombus.

Filling defects of the left atrial appendage on multidetector computed tomography: their disappearance following catheter ablation of atrial fibrillation and the detection of LAA thrombi by MDCT

Filling defects of the left atrial appendage (LAA) on multidetector computed tomography (MDCT) are known to occur, not only due to LAA thrombi formation, but also due to the disturbance of blood flow in the LAA of patients with atrial fibrillation (AF). The purpose of this study was to evaluate the impact of the maintenance of sinus rhythm via ablation on the incidence of LAA filling defects on MDCT in patients with AF. A total of 459 consecutive patients were included in the present study. Prior to ablation, MDCT and transesophageal echocardiography (TEE) were performed. AF ablation was performed in patients without LAA thrombi confirmed on TEE. The LAA filling defects were evaluated on MDCT at 3 months after ablation. LAA filling defects were detected on MDCT in 51 patients (11.1 %), among whom the absence of LAA thrombi was confirmed in 42 patients using TEE. The LAA Doppler velocity in patients with LAA filling defects was lower than that of patients without filling defects (0.61 ± 0.19 vs. 0.47 ± 0.21 m/s; P < 0.0001). The sensitivity, specificity and negative predictive value of MDCT in the detection of thrombi were 100, 91 and 100 %, respectively. No LAA filling defects were observed on MDCT at 3 months after ablation in any of the patients, including the patients in whom filling defects were noted prior to the procedure. MDCT is useful for evaluating the presence of LAA thrombi and the blood flow of the LAA. The catheter ablation of AF not only suppresses AF, but also eliminates LAA filling defect on MDCT suggesting the improvement of LAA blood flow.

Cardiac implantable electronic device lead-based masses and atrial fibrillation ablation: a case-based illustration of periprocedural anticoagulation management strategies

INTRODUCTION

Cardiac implantable electronic device (CIED) leads frequently develop echogenic masses. However, the nature of these masses is not well understood. In patients in whom atrial fibrillation (AF) catheter ablation is planned, there is concern that transseptal puncture may result in cerebrovascular embolism of these masses. The optimal therapeutic strategy in this setting remains undefined.

METHODS

We describe six patients identified over a 6-year period (2008-2014) with device lead-based masses prior to or at the time of AF ablation. We examined the anticoagulation strategy and periprocedural management based on mass identification.

RESULTS

In all six patients (age 39-73; four males), the device lead mass was found in the right atrium. The average mass size was 11 ± 1.3 mm. The majority of patients were already on anticoagulation (5/6; 83 %), and an intensified anticoagulation regimen was initiated (INR goal 3.0). In all six patients, the size of the device lead mass decreased on repeat imaging. In two sixths (33 %) patients, the lead-based mass completely resolved within 2 months. The remaining four patients had persistent lead-based masses (average follow-up of 10.9 ± 9.6 months).

DISCUSSION

We describe a series of patients with CIED lead-based masses found at the time of ablation. These cases illustrate that lead-based masses can disappear while patients are on high-intensity anticoagulation, most compatible with a thrombotic origin. These early data will need to be assessed in larger cohorts for further validation and evaluation of safety.

Rationale and design of a study exploring the efficacy of once-daily oral rivaroxaban (X-TRA) on the outcome of left atrial/left atrial appendage thrombus in nonvalvular atrial fibrillation or atrial flutter and a retrospective observational registry providing baseline data (CLOT-AF)

There are still many unresolved issues concerning patient outcomes and prognostic factors in patients with atrial fibrillation (AF) and left atrial/left atrial appendage (LA/LAA) thrombi. Rivaroxaban (Xarelto®), a potent and highly selective oral, direct factor Xa inhibitor, is a new therapeutic option in this setting. The planned study program will consist of a prospective interventional study (X-TRA) and a retrospective observational registry (CLOT-AF). The primary objective of the X-TRA study is to explore the efficacy of rivaroxaban in the treatment of LA/LAA thrombi in patients with nonvalvular AF or atrial flutter, scheduled to undergo cardioversion or AF ablation, in whom an LA/LAA thrombus has been found on transesophageal echocardiography (TEE) before the procedure. The primary end point is the complete LA/LAA thrombus resolution rate at 6 weeks of end of treatment confirmed by TEE. The secondary objectives are to describe categories of thrombus outcome in patients (resolved, reduced, unchanged, larger, or new) confirmed on TEE at the end of treatment (after 6 weeks of treatment), incidence of the composite of stroke and noncentral nervous system systemic embolism at the end of treatment and during follow-up, and incidence of all bleeding at the end of treatment and during follow-up. The objective of the CLOT-AF registry is to provide retrospective thrombus-related patient outcome data after standard-of-care anticoagulant treatment in patients with nonvalvular AF or atrial flutter, who have TEE-documented LA/LAA thrombi. The data will be used as a reference for the prospective X-TRA study. In conclusion, X-TRA and CLOT-AF will provide some answers to the many unresolved issues concerning patient outcomes and prognostic factors in patients with AF and LAA thrombi. Results from this study program would provide the first prospective interventional study (X-TRA) and a large international retrospective observational registry (CLOT-AF) on the prevalence and natural history of LA/LAA thrombi. Unique data on clot resolution with rivaroxaban in a prospective cohort would be obtained in X-TRA.

Management of atrial fibrillation: What is new in the 2014 ACC/AHA/HRS guideline?

Recently, the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society published an updated guideline on the management of atrial fibrillation (AF). This document is a complete revision of the 2006 guideline. Prominent changes in the 2014 guideline include the use of the CHA2DS2-VASc score for risk stratification of stroke, recommendations on when and how to use newer oral anticoagulants for thromboprophylaxis, downgrading of the use of aspirin for thromboprophylaxis of moderate-risk patients, and the use of catheter ablation in selected patients as first-line therapy for paroxysmal AF. In regard to rate control, the 2014 guideline reverts back to a previous recommendation for stricter targets for mean and maximum heart rate on therapy. The current guideline incorporates many recent trials in updating existing recommendations from the 2006 guideline. The 2014 guideline will be a vital tool in guiding physicians in the management of AF.

Value of CMR for the differential diagnosis of cardiac masses

OBJECTIVES

The goal of this study was to evaluate the diagnostic value of CMR features for the differential diagnosis of cardiac masses.

BACKGROUND

Differentiation of cardiac tumors and thrombi and differentiation of benign from malignant cardiac neoplasms is often challenging but important in clinical practice. Studies assessing the value of cardiac magnetic resonance (CMR) in this regard are scarce.

METHODS

We reviewed the CMR scans of patients with a definite cardiac thrombus or tumor. Mass characteristics on cine, T1-weighted turbo spin echo (T1w-TSE) and T2-weighted turbo spin echo (T2w-TSE), contrast first-pass perfusion (FPP), post-contrast inversion time (TI) scout, and late gadolinium enhancement (LGE) sequences were analyzed.

RESULTS

There were 84 thrombi, 17 benign tumors, and 25 malignant tumors in 116 patients. Morphologically, thrombi were smaller (median area 1.6 vs. 8.5 cm(2); p < 0.0001), more homogeneous (99% vs. 46%; p < 0.0001), and less mobile (13% vs. 33%; p = 0.007) than tumors. Hyperintensity compared with normal myocardium on T2w-TSE, FPP, and LGE were more common in tumors than in thrombi (85% vs. 42%, 70% vs. 4%, and 71% vs. 5%, respectively; all p < 0.0001). A pattern of hyperintensity/isointensity (compared with normal myocardium) with short TI and hypointensity with long TI was very frequent in thrombi (94%), rare in tumors (2%), and had the highest accuracy (95%) for the differentiation of both entities. Regarding the characterization of neoplastic masses, malignant tumors were larger (median area 11.9 vs. 6.3 cm(2); p = 0.006) and more frequently exhibited FPP (84% vs. 47%; p = 0.03) and LGE (92% vs. 41%; p = 0.001). The ability of CMR features to distinguish benign from malignant neoplasms was moderate, with LGE showing the highest accuracy (79%).

CONCLUSIONS

CMR features demonstrated excellent accuracy for the differentiation of cardiac thrombi from tumors and can be helpful for the distinction of benign versus malignant neoplasms.