When to start anticoagulation in patients with an acute ischaemic stroke and atrial fibrillation (AF) is a relevant unanswered question in clinical practice. Direct oral anticoagulants (DOACs) are highly effective for secondary stroke prevention in these patients, but DOACs were never initiated <7 days after stroke onset in recent trials. The ELAN trial will determine the net benefit of early versus late initiation of DOACs in patients with acute ischaemic stroke related to AF.

The main objective is to estimate the net benefit of early versus late initiation of DOACs in patients with acute ischaemic stroke related to AF.

The secondary objectives are to assess all vascular events and all-cause mortality after early initiation of DOACs in patients with acute ischaemic stroke related to AF compared to late initiation.

Background Atrial fibrillation (AF) is the most common cardiac arrhythmia increasing the risk of stroke and systemic thromboembolism and thus mortality and morbidity. Anticoagulation therapy, such as with vitamin K antagonists effectively prevents strokes in patients with AF, however, increases bleeding complications leading to symptomatic intracerebral haemorrhage. Direct oral anticoagulants (DOACs) are at least as effective as vitamin K antagonists in preventing recurrent strokes, but with lower rates of symptomatic intracerebral haemorrhage. Therefore, these new agents are potentially ideal drugs to treat patients with ischaemic stroke related to AF. However, in previous trials comparing DOACs with vitamin K antagonists, therapy was initiated later than 7-14 days after onset of ischaemic stroke. Whether, earlier initiation of DOACs may prevent recurrent stroke without increasing the risk of symptomatic intracerebral haemorrhage remains to be determined.

Objectives The main objective is to estimate the net benefit of early versus late initiation of DOACs in patients with acute ischaemic stroke related to AF.

The secondary objectives are to assess all vascular events and all-cause mortality after early initiation of DOACs in patients with acute ischaemic stroke related to AF compared to late initiation.

Methods All patients of 18 years or older with an acute ischaemic stroke related to AF should be screened for this trial.

Patients in the experimental arm (early treatment) and the control arm (late treatment) will receive direct oral anticoagulants for prevention of stroke and systemic embolism in patients with AF. Depending on the size of the infarction, early treatment will be started within 48 hours after symptom onset (minor and moderate ischaemic stroke) or at day 6 + 1 day after symptom onset (major ischaemic stroke). Patients in the control arm will receive late treatment as per current recommendations (i.e. minor ischaemic stroke after day 3 + 1 day, moderate ischaemic stroke after day 6 + 1 day and major ischaemic stroke after day 12 + 2 day).

The primary outcome is a composite of major bleeding, recurrent ischaemic stroke, systemic embolism and/or vascular death at 30 ± 3 days after randomisation.

Inclusion Criteria:

• Written informed consent according to country specific details
• Age: ≥18 years
• Acute ischemic stroke, either confirmed by MRI or CT scan (tissue based definition) or by sudden focal neurological deficit of presumed ischaemic origin that persisted beyond 24 hours and otherwise normal non-contrast CT scan. Please note: prior intravenous or endovascular treatment is allowed.
• Permanent, persistent, or paroxysmal spontaneous AF previously known or diagnosed during the index hospitalization
• Agreement of treating physician to prescribe DOACs

Exclusion Criteria:

• Atrial fibrillation due to reversible causes (e.g. thyrotoxicosis, pericarditis, recent surgery, myocardial infarct)

• Valvular disease requiring surgery

• Mechanical heart valve(s)

• Moderate or severe mitral stenosis. Please note that other valvular diseases and biological valves are eligible

• AF and conditions other than AF that require anticoagulation, including therapeutical dose of low-molecular-weight heparin or heparin. Please note: infratherapeutic anticoagulation at ischaemic stroke onset defined as follows is not an exclusion criteria:

  • Vitamine K antagonist: International Normalized Ratio (INR) <1.7
  • Anti-IIa: thrombin time <80 seconds and/or anti-IIa <50 ng/ml
  • Anti-Xa: anti-Xa <50 ng/ml

• Subject who is contraindicated to DOACs

• Female who is pregnant or lactating or has a positive pregnancy test at time of admission

• Patients with serious bleeding in the last 6 months or is at high risk of bleeding (e.g. active peptic ulcer disease, platelet count < 100'000/mm3 or haemoglobin < 10 g/dl or INR ≥ 1.7, documented haemorrhagic tendencies or blood dyscrasias)

• Subject currently uses or has a recent history of illicit drug(s) or abuses alcohol (defined as regular or daily consumption of more than four alcoholic drinks per day)

• Severe comorbid condition with life expectancy < 6 months

• Severe or moderate renal insufficiency as defined by creatinine clearance < 50 ml/min

• Subject who requires haemodialysis or peritoneal dialysis

• Subject with aortic dissection

• Current participation in another investigational trial

• Dual antiplatelet therapy at baseline or strong likelihood to be treated with dual antiplatelet therapy during the course of the trial

• CT or MRI evidence of haemorrhage classified as PH1 (defined as parenchymal haemorrhage = blood clots in <30% of the infarcted area without or with slight space-occupying effect) and PH2 (defined as blood clots in >30% of the infarcted area with a substantial space-occupying effect) independently of clinical deterioration. Please note that HI1 (defined as haemorrhagic infarct = small petechiae along the margins of the infarct) and HI2 (defined as confluent petechiae within the infarcted area but no space occupying effect) are acceptable if not associated with clinical deterioration and if the treating physician feels comfortable to treat patients with DOACs.

• CT or MRI evidence of mass effect or intra-cranial tumour (except small meningioma)

• CT or MRI evidence of cerebral vasculitis

• Endocarditis

• Evidence of severe cerebral amyloid angiopathy if MRI scan performed