A left atrial appendage thrombus that developed during prophylactic low-dose dabigatran treatment resolved after switching to apixaban

Switching from warfarin to direct-acting oral anticoagulants: it is time to move forward!

Oral vitamin K antagonists (VKAs), warfarin, have been in routine clinical use for almost 70 years for various cardiovascular conditions. Direct-Acting Oral Anticoagulants (DOACs) have emerged as competitive alternatives for VKAs to prevent stroke in patients with non-valvular atrial fibrillation (AF) and have become the preferred choice in several clinical indications for anticoagulation. Recent guidelines have limited the use of DOACs to patients with non-valvular AF to reduce the risk of cardioembolic complications and to treat venous thromboembolism (VTE). Although emerging evidence is suggestive of its high efficacy, there was a lack of data to support DOACs safety profile in patients with mechanical valve prosthesis, intracardiac thrombi, or other conditions such as cardiac device implantation or catheter ablation. Therefore, several clinical trials have been conducted to assess the beneficial effects of using DOACs, instead of VKAs, for various non-guideline-approved indications. This review aimed to discuss the current guideline-approved indications for DOACs, advantages, and limitations of DOACs use in various clinical indications highlighting the potential emerging indications and remaining challenges for DOACs use. Several considerations are in favour of switching from warfarin to DOACs including superior efficacy, better adverse effect profile, fewer drug-drug interactions, and they do not require frequent international normalized ratio (INR) monitoring. Large randomized controlled trials are required to determine the safety and efficacy of their use in various clinical indications.

Clinical Discussions in Antithrombotic Therapy Management in Patients With Atrial Fibrillation: A Delphi Consensus Panel

Background

In recent years, direct-acting oral anticoagulants (DOACs) have entered clinical practice for stroke prevention in non-valvular atrial fibrillation or prevention and treatment of venous thromboembolism. However, remaining uncertainty regarding DOAC use in some clinical scenarios commonly encountered in the real world has not been fully explored in clinical trials.

Methods

We report on use of a Delphi consensus process on DOAC use in non-valvular atrial fibrillation patients. The consensus process dealt with 9 main topics: (i) DOACs vs vitamin K antagonists in atrial fibrillation (AF) patients; (ii) therapeutic options for patients with stable total time in range treated with vitamin K antagonists; (iii) therapeutic options for patients aged > 85 years; (iv) therapeutic management of hyperfiltering patients; (v) pharmacologic interactions; (vi) therapeutic options in the long-term treatment (prevention) of patients with AF and acute coronary syndrome after the triple therapy; (vii) low doses of DOACs in AF patients; (viii) ischemic stroke in patients inappropriately treated with low doses of DOACs; (ix) management of patients taking DOACs with left atrial appendage thrombosis.

Results

A total of 101 physicians (cardiologists, internists, geriatricians, and hematologists) from Italy expressed their level of agreement on each statement by using a 5-point Likert scale (1 = strongly disagree; 2 = disagree; 3 = somewhat agree; 4 = agree; 5 = strongly agree). Votes 1-2 were considered to be disagreement; votes 3-5 were considered to be agreement. Agreement among the respondents of ≥ 66% for each statement was considered consensus. A brief discussion of the results for each topic is also reported.

Conclusions

In clinical practice, there is still uncertainty on DOAC use, especially in elderly, fragile, comorbid, and hyperfiltering patients.

Non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation and atrial thrombosis: An appraisal of current evidence

Major thromboembolic complications in patients with atrial fibrillation, secondary to thromboembolism from the left atrium or the left atrial appendage, are a major concern because of their burden of disabling stroke and mortality. To date, non-vitamin K antagonist oral anticoagulants (NOACs) are considered the first-line strategy in most patients with atrial fibrillation receiving chronic anticoagulation, as they have major advantages compared with vitamin K antagonists, including minimization of intracranial bleeding risk. Although several studies and post-hoc analyses have provided initial data on the use of NOACs in patients with documented atrial and/or left atrial appendage thrombosis, the benefit of NOACs in these patients has not been fully elucidated. In this review, we reappraise current evidence supporting the use of NOACs in patients with established atrial and/or left atrial appendage thrombosis, discussing potential mechanisms favouring the use of a NOAC-based strategy in this special setting.

Left atrial appendage thrombus on full-dose dabigatran treatment: a case report

Background

Dabigatran is a direct competitive thrombin inhibitor approved for stroke prevention in non-valvular atrial fibrillation. At full-dose, dabigatran showed similar rates of bleedings and higher efficacy compared to warfarin.

Case summary

We report a case of acute ischaemic stroke in a patient treated with dabigatran 150 mg b.i.d. for atrial fibrillation. After an off-label treatment with idarucizumab, a humanized monoclonal antibody approved for dabigatran reversal, we performed a successful intravenous thrombolysis (IVT). Transoesophageal echocardiography showed a left atrial appendage (LAA) thrombus, despite full-dose dabigatran and an adequate therapy adherence.

Discussion

There are few cases of LAA thrombus during dabigatran treatment reported in literature till date. We analyse the possible pathogenetic mechanisms involved in dabigatran failure, including drug interactions and unexpected genetic variations interfering with dabigatran serum levels suggesting periodical assessment of direct Oral Anticoagulant levels. Furthermore, we confirm initial reports of safety and efficacy of intravenous thrombolysis after idarucizumab, in case of dabigatran failure.

Effect of Switching from the Initial Direct Oral Anticoagulant to Another One on Exacerbation of Venous Thromboembolism in Patients with Cancer: A Retrospective Study

Objective: To determine the effect of switching from the initial direct oral anticoagulant (DOAC) to another DOAC on exacerbation of deep vein thrombosis (DVT).

Materials and Methods: We retrospectively reviewed the data of patients with advanced cancer who experienced exacerbated DVT during initial treatment with DOAC due to new venous thromboembolism (VTE). After switching to another DOAC for VTE recurrence, changes in the thrombus and bleeding were evaluated for 3 months. Eighteen patients met these criteria. We compared the effect of anticoagulant switching on the switched-drug group in those 18 patients with the effect of no anticoagulant switching on the single-drug group of patients (n=78) with a similar background.

Results: The recurrence rate of VTE in the switched-drug group was 6%. Non-major bleeding occurred in 11% of patients. Recurrent VTE occurred in 6% of patients in both the switched-drug and single-drug groups, respectively [risk ratio (RR): 0.9, 95% confidence interval (CI): 0.11–7.6]. Non-major bleeding occurred in 11% and 14% of patients in the switched-drug and single-drug groups, respectively (RR: 0.79, 95%CI: 0.19–3.2).

Conclusion: Switching DOAC may be a treatment option for exacerbation of DVT in patients with advanced cancer.

Newly developed left ventricular apical thrombus under dabigatran treatment

: Left ventricular (LV) thrombi are mostly formed in the aneurysmal or akinetic segment of the LV apex. Thromboembolism to the brain is usually fatal. There is not enough information available regarding the use of these new oral anticoagulant agents in LV thrombi. In this case, we present a 56-year-old male patient who was given dabigatran (150 mg, twice a day) for paroxysmal atrial fibrillation after experiencing anterior myocardial infarction. During the use of dabigatran, thrombus formation, which was not present earlier, was observed in the LV apical aneurysm. The dabigatran treatment discontinued and warfarin was initiated and, in the follow-ups, the thrombus was observed to shrink, and complete resolution was seen 6 weeks after treatment with warfarin. The patient did not experience any thromboembolic event. Our case is the first report showing that the treatment of dabigatran 150 mg may not prevent LV thrombus development.

THROMBOSIS OF LEFT ATRIAL APPENDAGE DURING THERAPY WITH DIRECT ORAL ANTICOAGULANT. CLINICAL CASE

The article presents a clinical observation of the left atrial appendage thrombosis in a 51-year-old female patient with a paroxysmal form of nonvalvular atrial fibrillation which occurred despite long-term anticoagulant therapy with apixaban in a full dose (5 mg b.i.d.), and the patient’s management. The patient was admitted with recurrent symptomatic paroxysm for more than 48 hours, because of which, in accordance with the recommendations, transesophageal echocardiography was performed before an emergency rhythm restoration. Thrombus in the left atrial appendage 0.5×1.03 cm in size was detected. It was decided to refrain from the immediate restoration of the rhythm due to the very high risk of thromboembolic complications. In connection with the categorical refusal of the patient from warfarin, it was decided to replace apixaban with another direct oral anticoagulant – dabigatran 150 mg bid for a period of 4 weeks followed by performing a control transesophageal echocardiographic study. As a result, no thrombus was found on control echocardiography. The particularity of this observation is concomitant hypertrophic cardiomyopathy and diabetes mellitus type 1 in this patient.