Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation

Fighting Cardiac Thromboembolism during Transcatheter Procedures: An Update on the Use of Cerebral Protection Devices in Cath Labs and EP Labs

Intraprocedural stroke is a well-documented and feared potential risk of cardiovascular transcatheter procedures (TPs). Moreover, subclinical neurological events or covert central nervous system infarctions are concerns related to the development of dementia, future stroke, cognitive decline, and increased risk of mortality. Cerebral protection devices (CPDs) were developed to mitigate the risk of cardioembolic embolism during TPs. They are mechanical barriers designed to cover the ostium of the supra-aortic branches in the aortic arch, but newer devices are able to protect the descending aorta. CPDs have been mainly designed and tested to provide cerebral protection during transcatheter aortic valve replacement (TAVR), but their use in both Catheterization and Electrophysiology laboratories is rapidly increasing. CPDs have allowed us to perform procedures that were previously contraindicated due to high thromboembolic risk, such as in cases of intracardiac thrombosis identified at preprocedural assessment. However, several concerns related to their employment have to be defined. The selection of patients at high risk of thromboembolism is still a subjective choice of each center. The aim of this review is to update the evidence on the use of CPDs in either Cath labs or EP labs, providing an overview of their structural characteristics. Future perspectives focusing on their possible future employment are also discussed.

Role of Cardiac Magnetic Resonance in Diagnosis and Treatment of Ball Thrombus in Left Atrium - Trust But Verify! - Case Report

Male patient with left atrial cardiac mass was in need of a quick diagnosis for individualized and effective treatment. Transthoracic echocardiography showed presence of а giant left atrial cardiac mass with atypical location for thrombus. Cardiac Magnetic Resonance (CMR) Imaging was performed for histological discrimination, and showed a large cardiac mass wall attached in the left atrium, homogeneous, with diameter of 3.4cm x 3.2cm. Late Gadolinium Enhancement sequences revealed black avascular tissue without signal, confirming the characterization of a thrombus. The patient refused hospital initiation of low molecular weight heparin treatment and started treatment with Rivaroxaban. Six weeks later he presented with NYHA class II, almost complete dissolving of the thrombus on CMR scan. Seven months from the initial CMR scan, echocardiography screen was done showing complete absence of the left atrial mass. With this case report we have demonstrated the significance of the CMR as one step further in the precise diagnostics of cardiac masses, solving critical clinical dilemma.

Trombo Atrial Esquerdo e Contraste Espontâneo Denso no Uso de Anticoagulante Oral de Ação Direta em Fibrilação Atrial: Visão de Centro Referenciado

Fundamento

Objetivo

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Conclusão

Bailout left atrial appendage occluder for pulmonary vein isolation and electrical cardioversion in patients with atrial fibrillation and left atrial appendage thrombus: a pilot study

BACKGROUND

Cardioversion and catheter-based circumferential pulmonary vein isolation (CPVI) are established rhythm control treatment strategies for patients with atrial fibrillation (AF). However, these treatments are contraindicated for AF patients with a left atrial appendage (LAA) thrombus.

METHODS

We conducted the first-in-man case series study to evaluate the feasibility and safety of performing cardioversion or CPVI in AF patients with LAA thrombus immediately after implantation of LAA Occluder (LAAO) in a combined procedure. In our multi-center LAAO registry of 310 patients, 27 symptomatic and drug-refractory AF patients underwent a combined procedure of LAAO and CPVI, among whom 10 (mean age 68 ± 16 years, 6 men) having anticoagulant-resistant LAA thrombus received a bailout procedure of LAAO implantation first then CPVI, and the other 17 patients without LAA thrombus received CPVI first then LAAO for comparison.

RESULTS

The mean CHA₂DS₂-VASc score and HAS-BLED score were comparable between these two groups. In patients with LAA thrombus, we put carotid filters and did a no-touch technique, neither advancing the wire and sheath into the LAA nor performing LAA angiography. After LAAO implantation, the connecting cable was still connected to the occluder when cardioversion was performed. During CPVI, the occluder location was registered in the LA geometry by three-dimensional mapping to guide the catheter not to touch the LAAO. The procedure was successful in all the patients without intra-procedural complications. After a mean follow-up of 1.7 ± 0.7 years, there was no device embolization, peri-device leak ≧ 5 mm or stroke event in both groups. The AF recurrence rate was also similar between the two groups (P = 0.697).

CONCLUSION

We demonstrated that cardioversion or CPVI is doable in symptomatic AF patients with LAA thrombus if LAA was occluded ahead as a bailout procedure.

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.

Are Three Weeks of Oral Anticoagulation Sufficient for Safe Cardioversion in Atrial Fibrillation?

Background and Objectives: Patients with atrial fibrillation (AF), lasting >48 h, considered for cardioversion, are recommended ≥3 weeks of oral anticoagulation before sinus rhythm restoration because of high risk of development of left atrial thrombosis (LAT) and stroke. However, the optimal duration of anticoagulation in the presence of overt LAT is unknown. Materials and Methods: An open-label study aimed to investigate the prevalence of spontaneous echo contrast (SEC) and LAT before and after 3 weeks of direct oral anticoagulant (DOAC) treatment. We included 51 consecutive patients (50.9% males), mean age 69.3 ± 7.4 years with paroxysmal/unknown duration of AF, considered for cardioversion, who agreed to have transesophageal echocardiography at enrollment and 3 weeks later. Results: At baseline SEC was present in 26 (50.9%) and LAT in 10 (19.6%) of 51 patients. After 3 weeks on DOAC, SEC persisted in 12 (25.0%) and LAT in 7 (14.5%) of 48 patients, p < 0.05 vs. baseline. Factors, associated most strongly with persistence of SEC/LAT, were left atrial appendage (LAA) emptying velocity <20 cm/s (OR = 2.82), LAA lobes >2 (OR = 1.84), and indexed left atrial volume ≥34 mL/m² (OR = 1.37). Conclusions: In our study the incidence of SEC/LAT, particularly in AF with unknown duration, was not as low as we expected. The prevalence of SEC/LAT seemed to be dependent on factors not routinely evaluated in AF patients planned for cardioversion (indexed LA volume, LAA morphology and number of lobules, LAA emptying velocity, etc.). Our data suggested an individualized approach for DOAC duration in AF patients before an attempt for restoration of sinus rhythm is made, taking into consideration the LAA morphology and function.

Three-Dimensional Echocardiographic Left Atrial Appendage Volumetric Analysis

BACKGROUND

Left atrial appendage (LAA) echocardiographic assessment is difficult because of the complex shape and relatively small size of the LAA. Three-dimensional (3D) echocardiographic imaging can overcome the limitations of two-dimensional imaging. Pulsed-wave Doppler is the only currently standard LAA functional parameter. The aim of this study was to test a new approach for 3D echocardiographic volumetric analysis to obtain LAA ejection fraction (EF), its size and shape.

METHODS

Transesophageal two-dimensional and 3D LAA images were prospectively obtained in 159 consecutive patients. LAA volumes were measured from 3D echocardiographic images using available software. Pulsed-wave Doppler was considered the reference value for LAA function and was used for comparison with LAA EF. Comparison with cardiac computed tomography was performed in a subgroup of 32 patients. Comparisons included linear regression and Bland-Altman analyses. Repeated measurements were performed to assess measurement variability.

RESULTS

Nine patients were excluded because of suboptimal image quality (94% feasibility). Three-dimensional LAA calculated EF was in good agreement with LAA pulsed-wave measurements. Three-dimensional morphologic evaluation showed that 43% of the patients had "chicken wing," 33% "cactus," 19% "windsock," and 5% cauliflower shapes. At the time of data acquisition, patients with atrial fibrillation had nonsignificantly larger LAA end-systolic and end-diastolic volumes, leading to lower calculated EFs. Three-dimensional echocardiographic LAA end-systolic volumes were in good agreement with cardiac computed tomography (r = 0.75), with small biases (mean, -2.5 ± 3.9 ml). Reproducibility was better for larger LAA volumes.

CONCLUSIONS

A novel 3D echocardiographic approach can determine the geometry, size, and function of the LAA. A new parameter, LAA EF, provides functional quantitation.

Prevalence of left atrial thrombus by real time three-dimensional echocardiography in patients undergoing electrical cardioversion of atrial fibrillation: A contemporary cohort study

BACKGROUND

The prevalence of left atrial thrombi in patients scheduled for electrical cardioversion (ECV) of atrial fibrillation (AF) remains unknown in contemporary real-life practice.

METHODS AND RESULTS

Patients scheduled for ECV underwent transesophageal echocardiography (TEE) regardless of AF duration and type of anticoagulant. Of 277 consecutive patients (65% men, mean age 71 ± 10 years, CHA₂ DS₂ -VASc 3.1 ± 1.4), 92 were on direct oral anticoagulants (DOACs) and 99 on antivitamin K (AVK) oral agents for at least 3 weeks before and 4 after ECV. Eighty-five patients with paroxysmal AF on low-molecular-weight heparin were also considered. Real time three-dimensional TEE detected left atrial appendage (LAA) thrombus in 7% of patients, without significant difference among three groups (P = .334). Anticoagulation was ineffective in eight patients on AVK oral agents, two of them had thrombus. Eight patients assumed incorrectly DOACs, four of them had thrombus. Among the 175 patients on effective anticoagulation, five showed thrombus, three on AVK oral agents, and two on DOACs (P = .716). Effective anticoagulation was associated with reduced risk of thrombosis (OR: 0.16, 95%CI: 0.06-0.45, P = .001). In patients with correct anticoagulation, predictors of thrombus were CHA₂ DS₂ VASc (for each point of increment OR: 1.97, 95%CI: 1.08-3.61, P = .029), low left ventricular ejection fraction (OR: 0.92, 95%CI: 0.86-0.99, P = .026), and degree of spontaneous echo-contrast (for each point increase OR: 10, 95%CI: 2-39, P < .0001).

CONCLUSION

Patients with AF, on effective anticoagulation, had a prevalence of thrombus not negligible regardless of type of anticoagulant. TEE is prudent before ECV and mandatory if unsuccessful anticoagulation is proved or suspected.

Atrial thrombi in elective patients considered for atrial fibrillation rhythm control: Risk factors and prognostic value

The prognostic value of atrial thrombi (AT) among elective patients with atrial fibrillation (AF) referred for a rhythm control strategy is unclear. In this study, clinical variables were correlated with the presence of AT and long term survival among 205 patients submitted to transesophageal echocardiography before elective AF cardioversion or ablation. Atrial thrombi were present in 7.8% of cases and were significantly associated with reduced survival. Obesity was the only independent clinical predictor of AT [OR 4.27 (1.15-15.79), p = 0.03]. In patients with AF, AT appear to be associated with adverse outcomes, possibly indicating more advanced atrial cardiomyopathy.

Management of periprocedural anticoagulant therapy: a novel individualized approach-a transeusophageal echocardiographic study

Patients with non-valvular atrial fibrillation who are under chronic oral anticoagulant therapy (OAC) treatment frequently require interruption of OAC treatment. By examining the presence of left atrial/left atrial appendage (LA/LAA) thrombus or dense spontaneous echo contrast (SEC) with transesophageal echocardiography (TEE) we aimed to develop an individualized strategy. To test the validity of CHA₂DS₂VASc score based recommendations was our secondary purpose. In this prospective study patients with non-valvular atrial fibrillation on OAC therapy were included. Patients' baseline characteristics, CHA₂DS₂VASc and HASBLED scores, medications, type of invasive procedures and clinical events were recorded. Each patient underwent to TEE examination prior to the invasive procedure. Bridging anticoagulation was recommended only to patients with LA/LAA thrombus. We included 155 patients and mean CHA₂DS₂VASc score of the study population was 3.4 ± 1.4. Seventy-one of them had LA/LAA thrombi or SEC on TEE examination and bridging anticoagulation was applied. OAC treatment was not bridged in 8 of 11 patients with prior cerebrovascular accident and 17 of 31 patients with CHA₂DS₂VASc score of > 4. 57 of 124 patients with CHA₂DS₂VASc score of ≤ 4 required bridging anticoagulation. There were 14 major bleedings decided according to ISTH bleeding classification. Major bleeding was observed only in patients underwent to high-risk bleeding procedure. In conclusion CHA₂DS₂VASc score by itself is not enough for decision-making regarding ischemic risk. Furthermore, since major bleedings occurred only in patients underwent to high-risk bleeding surgery, TEE-based individualisation may be a feasible approach particularly for those with high thromboembolic risk undergoing high-bleeding risk procedure.

Does mitral regurgitation reduce the risks of thrombosis in atrial fibrillation and flutter?

AIMS

Blood stasis is the main cause of left atrial thrombosis (LAT) in atrial tachyarrhythmias. The high-velocity flow inside the left atrium, due to mitral valve regurgitation, may prevent clot formation but the topic has never been investigated in large-scale studies. The aim of our study was to evaluate whether the presence and degree of mitral regurgitation have a protective role against LAT risk.

METHODS

A total of 1302 consecutive adult patients with paroxysmal or persistent atrial fibrillation or flutter undergoing cardioversion, submitted to transesophageal echocardiography, were retrospectively enrolled in the study. The study population was divided into three groups according to the mitral regurgitation degree: absent, mild-to-moderate and severe.

RESULTS

Among 1302 patients enrolled in the study, patients without mitral regurgitation were 248 (19%), those with mild-to-moderate 970 (75%), whereas 84 had severe mitral regurgitation (6%). LAT incidence was significantly lower in patients with severe mitral regurgitation compared with those with mild-to-moderate (mitral regurgitation) (2.4 vs. 8.9%, P < 0.05), and similar to subjects without mitral regurgitation (2.4%).

CONCLUSION

Despite patients with severe regurgitation having clinical and echo characteristics predisposing to LAT (higher age, heart failure, higher atrial size, lower ventricular function) thrombosis prevalence was significantly lower than for those with mild-to-moderate mitral regurgitation. The percentage of LAT in severe mitral regurgitation cases was very low and similar to that of cases without regurgitation which were characterized by lower age, normal left ventricular function or other risk factors, reinforcing the hypothesis of a protecting role against atrial thrombosis of mitral regurgitation.

Incidence and Predictors of Intracardiac Thrombus on Pre-electrophysiological Procedure Transesophageal Echocardiography

Background

Cerebral thromboembolism is a potentially devastating complication of atrial fibrillation (AF) and atrial flutter (AFl). The use of transesophageal echocardiogram (TEE) before electrophysiological procedures in anticoagulated patients is variable. Our objective was to determine the incidence and identify predictors of intracardiac left atrial appendage (LAA) thrombus on TEE in patients with AF/AFl before electrical cardioversion or ablation.

Methods

We reviewed TEEs of 401 patients undergoing an electrical cardioversion, AF, or AFl ablation from April 2013 to September 2015 at the McGill University Health Center. Clinical and echocardiographic variables were collected at the time of the TEE and follow-up visits. Multivariate logistic regression was used to determine predictors of LAA thrombus.

Results

Of 401 patients, 11.2% had LAA thrombus on TEE. The majority (87%) of patients were anticoagulated for at least 3 weeks before the TEE. The incidence of LAA thrombus was 21% (23/110) in patients taking warfarin vs 6.4% (15/236) in patients taking direct oral anticoagulants. Multivariate analysis identified prior stroke (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.1-6.9) and heart failure (OR, 2.2; 95% CI, 1.0-4.7) as predictors of thrombus, whereas direct oral anticoagulant use (OR, 0.4; 95% CI, 0.2-0.8) was associated with reduced odds of thrombus.

Conclusions

LAA thrombus was identified in a significant proportion of patients undergoing TEE before cardioversion or ablation of AF/AFl despite preprocedural anticoagulation. Patients at increased risk of LAA thrombus (heart failure and prior stroke) may benefit from TEE before cardioversion, AF, or AFl ablation.

Animal model of left atrial thrombus in congestive heart failure in rats

The aim of the present study was to develop and study a new model of left atrial thrombus (LAT) in rat with congestive heart failure (CHF). CHF was induced by aortic banding for 2 mo, followed by ischemia-reperfusion (I/R) and subsequent aortic debanding for 1 mo. Cardiac function and the presence of LAT were assessed by echocardiography. Masson's staining was performed for histological analysis. All CHF rats presented with significantly decreased cardiac function, fibrosis in remote myocardium, and pulmonary edema. The incidence rate of LAT was 18.8% in the rats. LAT was associated with severity of aortic constriction, aortic pressure gradient, aortic blood flow velocity, and pulmonary edema but not myocardial infarction or a degree of left ventricular depression. The progressive process of thrombogenesis was characterized by myocyte hypertrophy, fibrosis, and inflammation in the left atrial wall. Fibrin adhesion and clot formation were observed, whereas most LAT presented as a relatively hard "mass," likely attributable to significant fibrosis in the middle and outer layers. Some LAT mass showed focal necrosis as well as fibrin bulging. Most LAT occurred at the upper anterior wall of the left atrial appendage. Aortic debanding had no significant impact on large LATs (>5 mm2) that had formed, whereas small LATs (<5 mm2) regressed 1 mo after aortic release. LAT is found in a rat model of aortic banding plus I/R followed by aortic debanding. The model provides a platform to study molecular mechanisms and potential new pathways for LAT treatment. NEW & NOTEWORTHY It is critically important to have a rodent model to study the molecular mechanism of thrombogenesis in the left atrium. Left atrial thrombus (LAT) is not a simple fibrin clot like those seen in peripheral veins or arteries. Rather, LAT is a cellular mass that likely develops in conjunction with blood clotting. Studying this phenomenon will help us understand congestive heart failure and promote new therapies for LAT.

Dual-Energy Computed Tomography-Enabled Material Separation in Diagnosing Left Atrial Appendage Thrombus

We explored the potential clinical value of material separation enabled by dual-energy spectral computed tomography in detecting left atrial appendage thrombi. The study enrolled 24 patients who were scheduled to undergo atrial fibrillation ablation (12 with and 12 without left atrial appendage thrombi). Computed tomograms were acquired in gemstone spectral imaging mode; the densities in the regions of the left atrial appendage cavities, pectinate muscles, and left atrial appendage thrombi were analyzed on monochromatic 70-keV images. Iodine and blood were chosen as the material basis pair; the iodine and blood densities were observed and quantitatively determined from the iodine- and blood-specific material decomposition images. On the 70-keV monochromatic and iodine-specific images, the left atrial appendage pectinate muscles and thrombi appeared as areas of hypodense attenuation. On the blood-specific images, similar areas of high attenuation were observed in the thrombi and cavities, whereas lower attenuation was noticed in the pectinate muscles. The quantitative iodine and blood densities in the pectinate muscles were lower than those in the cavities (P <0.001). The iodine densities in the thrombi were lower than those in the cavities (P <0.001); however, blood densities did not differ significantly between the thrombi and cavities (P=0.192). Compared with the pectinate muscles, the thrombi showed lower blood-density differences (P=0.003) and higher iodine-density differences (P=0.006) in relation to the cavities. Spectral computed tomography-enabled material separation is a novel method for differentiating left atrial appendage thrombi from pectinate muscles. The potential applications of this technology warrant further studies.

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.

Outcomes for Atrial Fibrillation Patients with Silent Left Atrial Thrombi Detected by Transesophageal Echocardiography

Although we have occasionally experienced silent thrombi in the left atrium (LA), defined as thrombi free from embolic events, by screening transesophageal echocardiography (TEE) for atrial fibrillation (AF), few data are available on predictors and outcomes of silent LA thrombi in patients with AF. We retrospectively reviewed clinical records and identified 83 patients (2.6%) with silent LA thrombi, out of 4,214 TEE procedures in 3,139 patients with AF at 6 hospitals from January 2010 to December 2012. The median [interquartile range] CHA₂DS₂-VASc score was 3 [2, 5]. Most patients (n = 71, 86%) were taking oral anticoagulants before the TEE, and 59 patients (71%) had heart failure (HF). During follow-up periods of 905 [620, 1301] days, ischemic stroke and systemic embolism, and hemorrhagic stroke occurred only in 3 (3.6%) and 2 patients (2.4%), respectively. All-cause death developed in 14 patients (17%), and cardiac death was the primary cause of death (n = 9, 11%). Multivariate Cox regression analysis showed the composite end point of death, stroke, systemic embolism, and major bleeding was significantly associated with age (hazard ratio; 1.06, 95% confidence interval; 1.01 to 1.11, p = 0.019) and HF (3.18, 1.27 to 7.99, p = 0.014). In conclusion, the incidence of ischemic stroke after detecting silent LA thrombi was relatively low in patients with AF under oral anticoagulation. Advanced age and HF were predictors for worse outcomes in AF patients with silent LA thrombi.

Elective Cardioversion in the Era of Novel Oral Anticoagulants - Does a Nurse Administered Verbal Questionnaire for Compliance Negate the Need for Routine Transoesophageal Echocardiography?

BACKGROUND

Anticoagulation prior to elective external direct current cardioversion (EDCCV) is mandatory. The inability to monitor compliance with novel oral anticoagulants (NOACs) raises a potential safety issue. We aimed to evaluate whether a structured, nurse-led assessment of compliance prior to EDCCV ensures safety without the need for routine transoesophageal echocardiography (TOE).

METHODS

Data was prospectively collected on consecutive patients undergoing EDCCV during 2014-2015. All procedures were supervised by an electrophysiology clinical nurse consultant (EPCNC). Drug compliance was verbally assessed using a standardised questionnaire by the EPCNC. Novel oral anticoagulants compliance was required for a continuous period of 3 weeks prior to EDCCV; otherwise a TOE-guided EDDCV was performed. All patients had follow-up 30 days post-procedure.

RESULTS

Three hundred and eleven cardioversions were performed on 256 patients in whom 154 (49.5%) were prescribed a NOAC (rivaroxaban (n=105; 68.2%), dabigatran (n=38; 24.7%), apixaban (n=11; 7.1%)). Median age was 63 years (24-94 yrs), mean CHADS₂-Vasc score was 2.0±1.5 and 138 (89.6%) were outpatients. One hundred and twenty-nine (83.8%) EDCCV were for atrial fibrillation and 25 (16.2%) for atrial flutter. Sinus rhythm was achieved in 90.3% of cases. Fourteen patients (9%) assessed as non-compliant underwent TOE. 129 (83.8%) EDCCV were performed without prior TOE. No stroke or systemic embolism was identified in any patient treated with either warfarin or a NOAC.

CONCLUSIONS

A standardised, verbal questionnaire can be administered to detect NOAC non-compliance in patients undergoing EDCCV. With appropriate compliance assessment a nurse-led EDCCV without routine TOE did not significantly compromise safety in this study group.

Findings of transoesophageal echocardiogram in appropriately anticoagulated patients with persistent atrial fibrillation prior to planned cardioversion

Background

To evaluate a diagnostic value of transoesophageal echocardiogram (TEE) in appropriately anticoagulated patients with a non-valvular atrial fibrillation (AF) and to establish possible additional indications for TEE; to evaluate the incidence of left atrial (LA) thrombi in appropriately anticoagulated patients in daily clinical practice.

Methods

This retrospective study analyses data of 432 patients who had been anticoagulated by means of oral anticoagulants (OACs) prior to planned cardioversion during the period from 2012 to 2015. Thromboembolic (TE) and bleeding risks were assessed using CHA2DS2-VASc and HAS-BLED scores. Transthoracic and transoesophageal echocardiograms were evaluated. TE complications during 30 days after discharge were assessed.

Results

432 patients were selected, aged from 22 to 89 years (mean 65.0 ±11.5), 277 (64.1%) males and 155 (35.9%) females, 306 (70.8%) on warfarin and 126 (29.2%) on non-vitamin K antagonist oral anticoagulants (NOAC). Mean CHA2DS2-VASc score was 3.5 ±1.5. TEE was performed for 120 (27.8%) patients, more frequently for patients on NOACs and for ones with III° LA enlargement.

TEE revealed LA thrombi in seven (5.8%) of the patients. In warfarin and NOACs groups thrombi were revealed in five (7.0%) and two (4.1%) patients, respectively. TEE did not reveal any thrombi in patients with normal left ventricular (LV) function; however, thrombi were found in two (6.1%) patients with slightly decreased LV function, and in five (17.9%) patients with markedly decreased LV function.

In patients with decreased left ventricular ejection fraction (LVEF) thrombi in LA were found more frequently than in patients with normal and slightly decreased LVEF (17.9% vs 2.2%, p=0.008). CHA2DS2-VASc score of all 7 patients was ≥5. None of the patients after cardioversion had TE complications 30 days after discharge.

Conclusions

The risk of LA thrombi in patients prepared for scheduled cardioversion in line with the guidelines is low. Higher risk of thrombi was present in patients with decreased LVEF (≤40%), CHA2DS2-VASc ≥5. In order to assess more accurately indications to perform TEE for appropriately anticoagulated patients prior to scheduled cardioversion a study with larger number of patients is required.

Plasma fibrin D-dimer and the risk of left atrial thrombus: A systematic review and meta-analysis

Background

Plasma fibrin d-dimer has been taken as a marker for thrombus. The aim of this study was to evaluate the relationship between d-dimer (DD) levels and left atrial spontaneous echo contrast (SEC)/left atrial thrombus (LAT).

Methods

We identified clinical studies by systematic search of MEDLINE and EMBASE databases up to Feb 2016. All observational studies that considered DD as a study factor and trans-esophageal echocardiography (TEE) identified SEC/LAT as an outcome were included. Two reviewers independently selected the studies and extracted the data.

Results

Of the 21 included studies, 16 studies (2652 patients) have compared the mean DD differences between patients with and without an evidence of the presence of SEC/LAT, 9 studies (1667 patients) have estimated the diagnostic value of DD in the presence of LAT, and 11 studies (1856 patients) have available information to calculate a ratio of the presence of LAT among individuals in the top and the bottom third of DD levels. The pooled standardized mean difference (SMD) of DD between patients with and without left atrial SEC and/or LAT was 1.29 [95%CI: 0.51, 2.08], with SMDs of 0.42 [95% CI: 0.08, 0.77] and 2.34 [95% CI: 1.01, 3.68] in SEC/LAT and LAT subgroups, respectively. The combined risk ratio of the presence of LAT among individuals between the top of the distribution of DD levels and that in the bottom third was 3.84 [95% CI: 2.35, 6.28], associating with a mean difference of 0.78 ug/ml (1.10 vs 0.32 ug/ml). The pooled sensitivity, specificity and positive likelihood ratio of DD for LAT were 0.75 [95% CI: 0.65, 0.83], 0.81 [95% CI: 0.59, 0.93] and 4.0 [95% CI: 1.7, 9.9], respectively.

Conclusions

High plasma fibrin DD was associated with left atrial SEC/LAT, particularly among patients with LAT. DD levels have moderate sensitivity and specificity for diagnosing LAT.

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.

Prevalence of left atrial thrombus in patients with non-valvular atrial fibrillation. A systematic review and meta-analysis of the literature

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8 % (95 %CI: 7.6 %-12.5 %). LAT presence was associated with a higher age (mean difference: 2.56, 95 %CI: 1.49-3.62), and higher prevalence of female gender (OR: 1.35, 95 %CI: 1.04-1.75), hypertension (OR: 1.78, 95 %CI: 1.38-2.30), diabetes mellitus (OR: 1.86, 95 %CI: 1.33-2.59) and chronic heart failure (OR: 3.67, 95 %CI: 2.40-5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95 %CI: 0.68-1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95 %CI: 2.24-5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: -7.3, p< 0.001). Indeed, studies in which 100 % of patients received oral anticoagulation reported a 3.4 % WMP of LAT (95 %CI: 1.3 %-8.7 %), whereas studies in which 0 % of patients received anticoagulation showed a LAT WMP of 7.4 % (95 %CI: 2.3 %-21.5 %). Our data suggest that LAT is present in ≍10 % of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

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.

Left atrial appendage exclusion for atrial fibrillation

Percutaneous left atrial appendage (LAA) closure is being increasingly used as a treatment strategy to prevent stroke in patients with atrial fibrillation (AF) who have contraindications to anticoagulants. Several approaches and devices have been developed in the last few years, each with their own unique set of advantages and disadvantages. In this article, the published studies on surgical and percutaneous approaches to LAA closure are reviewed, focusing on stroke mechanisms in AF, LAA structure and function relevant to stroke prevention, practical differences in procedural approach, and clinical considerations surrounding management.

Two-week administration of rivaroxaban resolved left atrial thrombus

An 89-year-old man visited our hospital complaining of palpitation. Electrocardiography showed atrial fibrillation, and transthoracic echocardiography demonstrated a mobile thrombus of 28.6 mm × 20.8 mm in the left atrium. Administration of a direct factor Xa inhibitor rivaroxaban (10 mg/day) was started. The thrombus reduced its size and disappeared completely 2 weeks after the commencement of rivaroxaban treatment. To our knowledge, this is the first case report that rivaroxaban successfully dissolved left atrial thrombus during a short period. Rivaroxaban might have a potential, not only to prevent de novo thrombus formation, but also to dissolve established thrombi by direct inhibition of free and thrombus-associated factor Xa. <Learning objective: The incidence of nonvalvular atrial fibrillation is increasing, and left atrial thrombus is the major cause of cardiogenic thrombo-embolism that we need to prevent. Recently, novel oral anticoagulants have been developed. The effects of these agents on intracardiac thrombus resolution have not been fully elucidated. Data from a large cohort study would be required to assess efficacy of novel oral anticoagulants for thrombus resolution.>.