Resolution Of Left Atrial Appendage Thrombus Research Articles

Comparative effectiveness of different management strategies for left atrial appendage thrombus in patients on optimal NOAC therapy

Abstract Background Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Novel oral anticoagulants (NOACs) effectively reduce the prevalence of LAA thrombosis and stroke risk. Nonetheless, there is no clear advice for patients with a NOAC-resistant thrombus, necessitating individualized decision-making without strong support of the current guidelines. Aims To analyze patients diagnosed with an LAA thrombus despite adequate NOAC therapy and to compare the efficacy of various therapeutic strategies in achieving thrombus resolution. Methods We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 who were diagnosed with LAA thrombus despite being on optimal NOAC therapy. These patients underwent follow-up transesophageal echocardiography (TEE) or cardiac CT angiography. Changes in treatment modalities were divided into four groups: transition to an alternative NOAC, switch to a vitamin K antagonist (VKA), the addition of an antiplatelet agent, or the deliberate maintenance of the current treatment. Results We analyzed the data of 90 patients comprising 103 cycles of treatment. The patients were either on rivaroxaban (41%), apixaban (32%), dabigatran (15%) or on edoxaban (12%) at the time of the initial TEE. A change to a different NOAC was observed in 37% of cases, transition to a VKA in 22%, supplementation with antiplatelet therapy in 16%, while deliberate absence of treatment modification in 25% of cases. Subsequent follow-up TEE (or CT angiography in a minority of cases) was performed at a median of 68 [43 – 94] days from the baseline evaluation. Successful thrombus resolution was achieved in 72% of cases. Evaluation of therapeutic strategies revealed that any modification of treatment was three times more effective than deliberate no change in treatment; thrombus resolution was observed in 60 (81%) vs. 17 (59%) cases (OR 3.03 [1.18 - 7.75], p = 0.021). Nevertheless, no particular strategy demonstrated superior efficacy over others. Conclusions Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the prior anticoagulation strategy; however, none of the commonly employed strategies appears to exhibit distinct superiority over the rest.

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

Introduction and objectiveMitral 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. MethodsThis 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. ResultsA 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. ConclusionThe 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.

Electric cardioversion in patients treated with oral anticoagulants: embolic material in the left atrial appendage.

Atrial fibrillation (AF) remains the most common arrhythmia. The sinus rhythm restoration procedure without adequate anticoagulant preparation may lead to a thromboembolic event in approximately 5-7% of patients. The initiation of oral anticoagulation significantly reduces this risk by inhibiting formation of embolic material in the heart cavities, especially in the left atrial appendage (LAA). However, there is a group of patients who develop embolic material in the LAA despite oral anticoagulation treatment. The best treatment method to dissolve thrombus in the LAA is not clear, due to the lack of studies with adequate power and endpoints that can determine the best management strategy. We present clinical trials comparing the efficacy and safety of oral anticoagulants in patients undergoing AF cardioversion. We evaluate the frequency of LAA thrombus formation in patients with AF on treatment with oral anticoagulants. Furthermore, we discuss the effectiveness of various treatment strategies on LAA thrombus resolution.

P209 HUGE AND OCCLUDING LAA THROMBUS DISSOLUTION IN A CASE OF SEVERE TACHI–CARDIOMYOPATHY

Abstract A 62–year–old man was admitted to our emergency department for worsening nocturnal dyspnea and orthopnea for 15 days. Finding of Acute Pulmonary Edema in a setting of non datable high ventricular response atrial fibrillation (AF) associated with severe LV dysfunction. NT–proBNP 8.252 pg/ml. ECG: atrial fibrillation with high ventricular response (120/bpm). TTE: Severe left ventricular systolic disfunction (EF 20%). TOE/3D TOE: evidence of voluminous oval–shaped thrombotic formation (10 x 17 mm) protruding in LA and completely occluding the left atrial appendage (LAA). LA thrombosis in patients with AF is relatively rare and represents a contraindication to rhythm control strategies. Once an LAA thrombus is identified, effective anticoagulation is recommended for at least three weeks or until LAA thrombus resolution is detected. Available evidence on left atrial thrombus dissolution largely refers to the use of vitamin K antagonist oral anticoagulant (VKAs), but their effectiveness may be influenced by variability in the level of anticoagulant activity obtained, wich may be suboptimal. In a recent prospective observational study has been evaluated the effectiveness of Edoxaban for the resolution of LA thrombosis in 25 patients with AF: it has been demonstrated a complete thrombus resolution in 56% of patients at 4 weeks, similar to studies using VKAs and the other NOACs. Use of NOACs in this setting represents a great field of interest for the near future. In our experience, indeed, after confirmed diagnosis of LAA thrombus, we started anticoagulant therapy with warfarin (currently the first choice), however due to poor INR control, we switched to continuous infusion of unfractionated heparin (UFH), wich represents, in a hospital setting, a safe and effective method for thrombus dissolution, allowing continuous monitoring of efficacy and a rapid cessation of effect in case of major bleeding. In this way we obtained complete thrombus dissolution in about 3 weeks. At the meantime we initiate a rate control therapy, an optimized treatment for HFrEF and intravenous diuretics. Our experience highlights the need of great ductility in the choice of anticoagulant therapy in patients with evidence of voluminous LAA thrombus, monitoring treatment’s efficacy parameters and being ready to change strategy if necessary and it reminds that auricular thrombosis is often inserted in a wider picture of heart disease wich requires multiple other specifics treatments.

Left Atrial Appendage Thrombus Resolution with Clopidogrel after Apixaban Failure: A Case Series

This hypothesis-generating, case series reviews the evidence available for managing left atrial appendage thrombus in patients already on therapeutic anticoagulation with apixaban. Our six patient cases highlight the first documented evidence of complete, accelerated clot resolution upon the addition of P2Y12 inhibitor, clopidogrel, to current therapeutic doses of apixaban.

Electric cardioversion in patients treated with oral anticoagulants: embolic material in the left atrial appendage.

Atrial fibrillation (AF) remains the most common arrhythmia. The sinus rhythm restoration procedure without adequate anticoagulant preparation may lead to a thromboembolic event in approximately 5-7% of patients. The initiation of oral anticoagulation significantly reduces this risk by inhibiting formation of embolic material in the heart cavities, especially in the left atrial appendage (LAA). However, there is a group of patients who develop embolic material in the LAA despite oral anticoagulation treatment. The best treatment method to dissolve thrombus in the LAA is not clear, due to the lack of studies with adequate power and endpoints that can determine the best management strategy. We present clinical trials comparing the efficacy and safety of oral anticoagulants in patients undergoing AF cardioversion. We evaluate the frequency of LAA thrombus formation in patients with AF on treatment with oral anticoagulants. Furthermore, we discuss the effectiveness of various treatment strategies on LAA thrombus resolution.

Assessment of LAA Strain and Thrombus Mobility and Its Impact on Thrombus Resolution—Added-Value of a Novel Echocardiographic Thrombus Tracking Method

PurposeThe mobility of left atrial appendage (LAA) thrombi and changes hereof under anticoagulation may serve as a marker of both risk of embolism and efficacy of treatment. In this study, we sought to evaluate thrombus mobility and hypothesized that LAA dynamics and thrombus mobility could serve as a baseline marker of thrombus dissolvability.MethodsPatients with two-dimensional transesophageal echocardiographic images of the LAA, and with evidence of LAA thrombus were included in this study. Using a speckle tracking algorithm, functional information from the LAA and thrombi of different patients was computed. While the LAA motion was quantified through the longitudinal strain, thrombus mobility was evaluated using a novel method by directly tracking the thrombus, isolated from the global cardiac motion. Baseline characteristics and echocardiographic parameters were compared between responders (thrombus resolution) and non-responders (thrombus persistence) to anticoagulation.ResultsWe included 35 patients with atrial fibrillation with evidence of LAA thrombi. Patients had a mean age of 72.9 ± 14.1 years, exhibited a high risk for thromboembolism (CHA2DS2-VASc-Score 4.1 ± 1.5) and had moderately reduced LVEF (41.7 ± 14.4%) and signs of diastolic dysfunction (E/E′ = 19.7 ± 8.5). While anticoagulation was initiated in all patients, resolution was achieved in 51.4% of patients. Significantly higher LAA peak strain (− 3.0 ± 1.3 vs. − 1.6 ± 1.5%, p < 0.01) and thrombus mobility (0.33 ± 0.13 mm vs. 0.18 ± 0.08 mm, p < 0.01) were observed in patients in whom thrombi resolved (i.e. responders against non-responders). Receiver operating characteristic (ROC) analysis revealed a high discriminatory ability for thrombus mobility with regards to thrombus resolution (AUC 0.89).ConclusionIsolated tracking of thrombus mobility from echocardiographic images is feasible. In patients with LAA thrombus, higher thrombus mobility appeared to be associated with thrombus resolution. Future studies should be conducted to evaluate the role of the described technique to predict LAA thrombus resolution or persistence.

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.

Short-Term Apixaban for Documented Left Atrial Appendage Thrombus in High-Risk Atrial Fibrillation Patients Undergoing Left Atrial Appendage Occlusion.

Stroke prevention with left atrial appendage (LAA) occlusion is an important alternative treatment for high-risk atrial fibrillation (AF) patients with contraindications to oral anticoagulation (OAC).[1] [2] The presence of LAA thrombus detected on preprocedural imaging usually precludes implantation of the endocardial device because of a prohibitively high periprocedural embolic risk.[3] Although successful resolution of LAA thrombus with OAC has been described, all previous reports are in patients without contraindications to OAC.[4] [5] [6] Furthermore, long-term data in these patients are lacking. We hypothesized that short-term OAC with apixaban could safely facilitate resolution of LAA thrombi even in a high-risk population, thereby allowing safe LAA occluder device implantation, with good outcomes over the long term.

Management of thrombus formation after electrical isolation of the left atrial appendage in patients with atrial fibrillation.

Left atrial appendage (LAA) electrical isolation (LAAEI) in addition to pulmonary vein isolation is an emerging catheter-based therapy to treat symptomatic atrial fibrillation. Previous studies found high incidences of LAA thrombus formation after LAAEI. This study sought to analyse therapeutic strategies aiming at the resolution of LAA thrombi and prevention of thromboembolism. Left atrial appendage electrical isolation was conducted via creation of left atrial linear lesions or cryoballoon ablation. Follow-up including transoesophageal echocardiography was conducted. In patients with LAA thrombus, oral anticoagulation (OAC) was adjusted until thrombus resolution was documented. Percutaneous LAA closure (LAAC) under use of a cerebral protection device was conducted in case of medically refractory LAA thrombi. Left atrial appendage thrombus was documented in 54 of 239 analysed patients who had undergone LAAEI. Thrombus resolution was documented in 39/51 patients (72.2%) with available follow-up after adjustment of OAC. Twenty-nine patients underwent LAAC and 10 patients were kept on OAC after LAAEI. No thromboembolic events or further LAA thrombi were documented after 553 ± 443 days of follow-up in these patients. Persistent LAA thrombi despite adaption of OAC was documented in 12/51 patients. One patient remained on OAC until the end of follow-up, while LAAC with a cerebral protection device was performed in 11 patients in the presence of LAA thrombus without complications. Left atrial appendage thrombus formation is common after LAAEI. Adjustment of OAC leads to LAA thrombus resolution in most patients. Left atrial appendage closure in the presence of LAA thrombi might be a feasible option in case of failed medical treatment.

Left Atrial or Left Atrial Appendage Thrombus Resolution After Adjustment of Oral Anticoagulant Treatment

Background: There are few reports about non-vitamin K antagonist oral anticoagulant (NOAC) treatment for resolution of left atrium (LA) or left atrial appendage (LAA) thrombus. LAA thrombus is an important cause of cardiogenic cerebral thromboembolism, and the detection rate increases due to more and more patients receiving catheter ablation. However, the results from NOAC use for LA or LAA thrombus are still unknown in real-world practice. The aim of this study was to discover the resolution of LA or LAA thrombus after anticoagulant treatment in real-world practice. Method: From January 2013 to December 2016, a total 864 patients underwent transesophageal echocardiography (TEE), and 41 cases of LA or LAA thrombus were detected in our hospital. Among them, a total of 22 patients underwent follow-up TEE to detect the resolution of LA or LAA thrombus. Result: The average age of the study patients was 72.0 ± 11 years old, and 61% were male. The average CHA2DS2-VASc scores were 3.76 ± 2.01 points. A total of 22 patients underwent follow-up TEE, and 19 (86.4%) patients presented LA or LAA thrombus resolution. The average resolution duration was 258.47 ± 218.17 days. One-year all-cause mortality was 4.9%, and the incidence of ischemic stroke was 4.9%. Most physicians favored titration of the dosage of NOAC or warfarin in real-world practice. Conclusion: In real-world practice, most physicians favored titration of the dosage of NOAC or warfarin for LA or LAA thrombus. LA or LAA thrombus could exist if the patient received a reduced dose of NOAC. High frequency of LAA or LA thrombi could resolve, and a low incidence of ischemic stroke occurred after adjustment of oral anticoagulant treatment.

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.

Efficacy of Direct Acting Oral Anticoagulant Drugs in Treatment of Left Atrial Appendage Thrombus in Patients With Atrial Fibrillation

Direct acting oral anticoagulants (DOACs) are increasingly used for thromboembolic prophylaxis in patients with atrial fibrillation (AF). However, there is limited data to evaluate the use of DOACs for the treatment of pre-existing left atrial appendage thrombus. We aimed to determine the efficacy of DOACs in treatment of left atrial appendage (LAA) thrombus utilizing transesophageal echocardiographic (TEE) and clinical outcomes. In this single-center study, we identified 33 patients that were treated for LAA thrombus with DOAC. Eighteen were treated with apixaban, 10 with dabigatran, and 5 with rivaroxaban. The primary endpoint was defined as resolution of LAA thrombus (in patients undergoing TEE), or death, major bleeding requiring transfusion, intracranial hemorrhage, ischemic stroke, or peripheral embolization. In this study, 15 of the 16 patients treated with DOACs who underwent follow-up TEE had resolution of LAA thrombus, with a mean duration of 112 days. Of the 15 patients who achieved resolution of the LAA thrombus, 14 had resolution by their first follow-up TEE. In the 17 patients without a follow-up TEE, 1 died of a retroperitoneal bleed (28 days after DOAC initiation), and 1 suffered an ischemic stroke (484 days after DOAC initiation). In general, patients without a follow-up TEE were older and had more co-morbidities. Although these results are descriptive and limited in number of patients, we believe this is ample evidence that DOACs are relatively safe and efficacious in treatment of patients with AF and concomitant LAA thrombus.

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

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. 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%). 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). 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.

Resolution of Left Atrial Appendage Thrombus with Apixaban in a Patient with Heart Failure

The effect of non-vitamin K antagonist oral anticoagulants on left atrial appendage (LAA) thrombus has not been fully elucidated. There are a few reports showing resolution of LAA thrombus with apixaban. An 84-year-old woman was admitted to our hospital due to acute exacerbation of chronic heart failure and marked tachycardia with atrial fibrillation. She had permanent atrial fibrillation and was treated with warfarin; however, transthoracic echocardiography revealed a non-mobile thrombus in the LAA. Therefore, we switched warfarin to apixaban at a dose of 5 mg/day. After two weeks on that therapy, the thrombus in the LAA was successfully resolved.

Resolution of left atrial appendage thrombus with apixaban

Left atrial appendage (LAA) thrombosis is an important cause of cardiogenic cerebral thromboembolism. Apixaban is a member of the class of novel oral anticoagulants (NOAC) and is superior to warfarin in preventing stroke or systemic embolism, causes less bleeding, and results in lower mortality in patients with atrial fibrillation. There are few reports of resolution of LAA thrombus with other NOAC. We present a 72-year-old male patient with persistent atrial fibrillation associated with left atrial thrombus. Sixteen days of apixaban treatment showed complete thrombus resolution. In this study, soluble fibrin and D-dimer levels decreased without prolongation of international normalized ratio (INR) and activated partial thromboplastin time (APTT).

Resolution of giant left atrial appendage thrombus with rivaroxaban

doi:10.1160/TH12-11-0821 Thromb Haemost 2013; 109: 583–584 A 64-year-old man was transferred to our hospital for external cardioversion (ECV) of symptomatic persistent atrial fibrillation (AF). At the time of hospital admission the patient presented with functional NYHA class III; he had a clinical history of symptomatic coronary artery disease, ischaemic cardiomyopathy with severely impaired left ventricular function, and chronic kidney disease stage 3B to 4 (creatinine clearance [CrCL] 29 ml/minute). Pretreatment with the vitamin-K antagonist (VKA) phenprocoumon was instituted in 2006 due to a high AF related thromboembolic risk with an actual CHA2DS2VASc score of 6. Since the international normalised ratio (INR) was not well controlled before elective ECV we performed a transesophageal echocardiography (TEE), which revealed a small thrombus formation (11 x 12 mm) in the apex of the left atrial appendage (LAA) (▶ Figure 1 A). Therefore, ECV was deferred for six weeks under closely controlled VKA therapy with levels of INR ranging between 2.5 – 3.5 (mean 3.2 ± 0.7, range 2.4 to 4.2). Interestingly, repeated TEE (▶ Figure 1 B) showed a markedly increased giant thrombus mass (12 x 45mm) now protruding into the left atrium. In general VKAs have a slow onset of action and their indirect anticoagulant activity depends on clearance of the vitamin K–dependent clotting proteins and replacement with functionally impaired factors (1). In contrast to current guidelines, there is increasing evidence that VKAs have a poor capability to resolve large intracardiac thrombi. Therefore, we decided to switch oral anticoagulation (OAC) to the direct factor Xa (FXa) inhibitor rivaroxaban dosed with 15 mg once daily. After four weeks of rivaroxaban treatment TEE showed a relevantly decreased thrombus size (▶ Figure 1 C) and a complete thrombus resolution was achieved after six weeks of anticoagulant therapy with the FXa inhibitor (▶ Figure 1 D). Finally, ECV was performed successfully without clinical signs of cardiac embolism and the patient was discharged in good medical conditions under continued anticoagulant treatment with rivaroxaban. To the best of our knowledge this is the first documented case of LAA thrombus resolution under rivaroxaban therapy and illustrates some clinically important characteristics of the new direct acting FXa inhibitor. First, in contrast to indirect acting VKAs, FXa inhibitors have the potential to (a) prevent de novo thrombus formation and more importantly (b) to resolve established thrombi by direct inhibition of free and thrombusassociated FXa. Thereby they reduce clot-induced fibrinopeptide A generation to a similar extent as hirudin, a potent inhibitor of thrombin (2).