Case Report of an Ischemic Stroke after Electrical Shock of Atrial Fibrillation Under Apixaban

Corresponding Author: Meryem BENNANI This article discusses the case of a patient with ischemic stroke following a cardioversion of Atrial Fibrillation under treatment with Apixaban 5 mg twice daily. Adherence to anticoagulant therapy and normal trans-thoracic ultrasound do not eliminate the possibility of an atrial thrombus, which may contraindicate or delay the cardioversion procedure. The use of transesophageal echocardiography in this case is discussed, to avoid the occurrence of thromboembolic events. This study indicates the need for further studies whether for flutter ablations or cardioversions under oral anticoagulants.


INTRODUCTION
Atrial fibrillation (AF) is the most common chronic cardiac rhythm disorder and is said to be non-valvularwhen not associated with under lying heart valve disease.
New molecules have been developed in nonvalvular atrial fibrillation for the prevention of arterial thromboembolic events in subjects at risk : Direct oral anticoagulants, also known as direct anti-thrombotics drugs (dabigatran, rivaroxaban, apixaban, edoxaban).
Theycompete with Vitamin K antagonists, used for more than fifty years, showing a favorable risk-benefit profile, with a reduction in stroke, intracranial haemorrhage, mortality and a similar major bleeding rate, a part from more frequent gastrointestinal bleeding [1].
This article is about the case of a patient who presented an ischemic stroke as a result of electrical cardioversion of atrial fibrillation under apixaban treatment.

CLINICAL CASE
We report the case of a 72-year-old hypertensive patient with a history of flutter ablation. She was on Vitamin K antagonists, and then on apixaban 5 mg twice a day for one year and a half. The patient was admitted for electrical cardioversion of atrial fibrillation.
Transthoracic Echocardiography performed on admission found no abnormalities outside a dilated left atrium free echoes. Moreover, the patient reported good compliance. Apixaban treatment was continued after cardioversion.
Seventy-two hours after the procedure, the patient presented massive left hemiplegia, with facial involvement. The rhythm was still sinusal with a lot of supraventricular extrasystole.
An urgent computed to mography (CT) scan of the brain was performed, showing early signs of right Sylvian stroke (Figure 1-2).
Thrombolysis is against-indicated in it, given the current anticoagulant therapy, hence the decision to stop antiagregeant platelet and anticoagulant therapy because of the high risk of bleeding.
Magnetic resonance imaging (MRI) control twentyfour hours later, showed acute extended right Sylvian stroke, and electrocardiogram objectified atrial fibrillation.
A reassessment of the risk of haemorrhagic transformation is planned 12 days later, for the reintroduction of oral anticoagulants.

Direct oral anticoagulants and atrial fibrillation
Direct oral anticoagulants, namely direct antithrombin (dabigatran) and factor Xainhibitors (rivaroxaban, apixaban, edoxaban) share several common features: they have a short half-life (compared withVitamin K antagonists), their effectis not subject to large interindividual variations (unlike Vitamin K antagonists), and therefore does not require monitoring of their anticoagulant activity (Table 1).
In addition, a significant part of their eliminationis renal and only Dabigatran has an antidote: Idarucizumab (PRAXBIND * for PRADAXA *).   They are indicated in the European Society of Cardiology's recommendations for the management of atrial fibrillation by 2010, with a clearer place in the update of these recommendations in 2016 [7]. These are anticoagulants, either direct oral anticoagulants, or Vitamin K antagonists, recommended treatments in class I (level of evidence A) in patients with CHA2DS2-VASc≥2 and indicated in recommendation class. IIa (level of evidence A) in patients with CHA2DS2-VASc score = 1.
The ARISTOTLE study of non-inferiority of apixaban vs warfarin [8] was performed in 18,201 patients with AF or atrial flutter, or withat least two episodes of electrocardiogram-documented AF or flutter more than two weeks and less than one year before inclusion. Patients received either 5 mg twicedaily apixaban or warfarin (INR between 2 and 3).

Oral Anticoagulants and Cardio version
Electrical cardioversion is associated with an increase in thromboembolic events in patients with atrial fibrillation. This risk is reduced by anticoagulation. The indication for anticoagulation in the period surrounding cardio version (3 weeks before and 4 weeks after) is based on observational studies of low enrollment and retrospective studies [9][10][11].
In the ARISTOTLE study, including 18,201 patients, 540 under went cardioversion. During the 30-day follow-up period, no thrombo embolic event was observed and the death rate did not differ between patients receiving apixaban and those receiving warfarin [12].

Place of Trans-esophageal Echography (TOE)
According to the recommendations of the European Heart Rhythm Association (EHRA) published in April 2013 updated in 2015 [8]: It's explained that in the absence of monitoring of the level of coagulation in the previous weeks, it is necessary to evaluate the compliance by asking the patient. It is clear that, if compliance is good, cardioversion can be safely performed ( Figure 3). However, a transesophageal echography could be performed if a doubt about compliance exists.

Dose of apixaban
In the prevention of stroke and system icembolism in patients with non-valvular atrial fibrillation, the recommended dose of apixaban is two oral doses of 5 mg daily. A dosage adjustment of 5 mg × 2 / day to 2.5 mg twice daily is proposed when at least two of the following three risk factors are present: serum creatinine ≥ 15 mg / L, or age ≥ 80 years or weight body weight ≤ 60 kg [14].

CONCLUSION
Even if this case shows a hierarchy of complementary examinations according to the recommendations of the EHRA, the occurrence of thromboembolic events after cardioversion of a AF under well managed anti thrombotic treatment (apixaban in this case) can not beavoided. A systematic transesophage alultrasound should be discussed in this case and further studies are needed for either flutter ablations or cardioversions under direct oral anticoagulants.