Resolution of Left Ventricular Thrombus by Vitamin K Antagonist after Failed Treatment with Apixaban in Hemodialysis Patient: Case Report

Background

Left ventricular (LV) thrombus is a serious complication of numerous cardiovascular conditions, such as myocardial infarction, dilated cardiomyopathy, and severe cardiac wall dysfunction [1]. Dilated cardiomyopathy is the most common etiology of LV thrombus [2]. LV thrombus is responsible for significant morbidity and mortality [2]. Anticoagulation with oral vitamin K antagonists such as warfarin is the standard treatment for LV thrombus and is recommended to reduce the risk of embolization [3]. Direct oral anticoagulants (DOACs) have been introduced as a replacement to oral vitamin K antagonists in a variety of indications for anticoagulation, such as preventing strokes and other thromboembolic events in non-valvular atrial fibrillation, as well as for the treatment of venous thromboembolism (pulmonary embolism and deep vein thrombosis) [4].

Patients with cardiac conditions share comorbidities with patients with end-stage renal disease (ESRD), and patients with advanced kidney disease are predisposed to atherothrombotic and thromboembolic complications [4,5]. The efficacy of DOACs in patients with LV thrombus has not been well studied. Furthermore, the evidence of DOACs is conflicting as to whether they are safe and effective in the ESRD population. We report a case of LV thrombus that was successfully dissolved by warfarin after treatment with apixaban failed.

Case Report

A 50-year-old man with diabetes, hypertension, paroxysmal atrial fibrillation, chronic kidney disease, coronary artery disease, heart failure with reduced ejection fraction, and treated hepatitis B infection was admitted to a tertiary hospital as a case of acute myocardial infarction and underwent successful revascularization with drug-eluting stent implantation. After the myocardial infarction, the patient was placed on dual antiplatelet therapy (aspirin 100 mg orally once daily and clopidogrel 75 mg orally once daily) for 24 months to prevent stent occlusion, followed by single antiplatelet therapy (aspirin 100 orally once daily). Three years after that admission, the chronic kidney disease progressed to ESRD and hemodialysis sessions were started. On regular outpatient follow-up with the cardiology clinic, the patient was free of symptoms, and a routine transthoracic echocardiogram was requested. His weight during that follow-up visit was 73 kg (body mass index of 26). Laboratory assessment revealed a hemoglobin level of 13.2 g/dL. His electrocardiographic result revealed normal sinus rhythm. The transthoracic echocardiogram showed akinesia of the mid to apical anterior wall, mid to apical septum, and LV apex, and large apical thrombus measuring (20×15 mm; Figure 1), and ejection fraction was 30%. Apixaban 5 mg orally twice daily was started.

The transthoracic echocardiogram was done after 3 months and after 6 months, and there was insignificant reduction in the size of the LV thrombus despite the patient compliance with apixaban (Figure 2). The apixaban was shifted to warfarin. The international normalized range was maintained at the therapeutic range (INR 2.0–3.0). After 4 months of receiving warfarin, the patient showed a complete resolution of LV thrombus (Figure 3).

Discussion

LV thrombus is one of the well-known complications of myocardial infarction and cardiomyopathy [1]. The risk of atherothrombotic and thromboembolic complications is even higher in the ESRD population [5]. Warfarin remains the safe and effective criterion standard of treatment for LV thrombus in the ESRD population and in the non-ESRD population, despite a lack of clear evidence in the ESRD population [6]. Apixaban is one of the DOACs. It is a direct inhibitor of factor Xa, which prevents the formation of thrombin, and has been approved for the prevention of stroke and other thromboembolic events in patients with atrial fibrillation and for the treatment of venous thromboembolism [4]. The introduction of DOACs, including apixaban, overcame many disadvantages associated with the use of warfarin [4]. Compared with warfarin, DOACs exert a superior pharmacokinetic profile due to the quick onset of action and therefore do not require bridge therapy with parenteral anticoagulants [4]. DOACs have fewer drug-drug interactions and food interactions. DOACs also have a predictable therapeutic effect requiring no monitoring [7]. Because patients with advanced kidney disease were underrepresented in the landmark clinical trials of DOACs, there are limited data about their efficacy and safety in these populations [8]. The 2019 Focused Update of the US Atrial Fibrillation Management Guidelines added the use of apixaban as an alternative to warfarin, with a class IIB recommendation, for anticoagulation for stroke prevention in atrial fibrillation patients with ESRD on hemodialysis [4]. In a multicenter cohort study of anticoagulation strategies for LV thrombus, DOAC treatment was associated with a higher risk of stroke or systemic embolism, compared with warfarin [9].

The presented case is the first report to demonstrate a failure of apixaban in resolution of LV thrombus and demonstrate complete resolution of LV thrombus after administration of warfarin in a patient with ESRD on dialysis.

Conclusions

We reported a case of LV thrombus that was successfully dissolved by warfarin after treatment with apixaban failed. This case challenges the general assumption of apixaban’s effectiveness in patients with ESRD on dialysis.