RESUMO
INTRODUCTION: There is a longstanding clinical uncertainty regarding the optimal timing of initiating oral anticoagulants (OAC) for non-valvular atrial fibrillation following acute ischemic stroke. Current international recommendations are based on expert opinions, while significant diversity among clinicians is noted in everyday practice. METHODS: We conducted an updated systematic review and meta-analysis including all available randomized-controlled clinical trials (RCTs) and observational cohort studies that investigated early versus later OAC-initiation for atrial fibrillation after acute ischemic stroke. The primary outcome was defined as the composite of ischemic and hemorrhagic events and mortality at follow-up. Secondary outcomes included the components of the composite outcome (ischemic stroke recurrence, intracranial hemorrhage, major bleeding, and all-cause mortality). Pooled estimates were calculated with random-effects model. RESULTS: Nine studies (two RCTs and seven observational) were included comprising a total of 4946 patients with early OAC-initiation versus 4573 patients with later OAC-initiation following acute ischemic stroke. Early OAC-initiation was associated with reduced risk of the composite outcome (RR = 0.74; 95% CI:0.56-0.98; I2 = 46%) and ischemic stroke recurrence (RR = 0.64; 95% CI:0.43-0.95; I2 = 60%) compared to late OAC-initiation. Regarding safety outcomes, similar rates of intracranial hemorrhage (RR = 0.98; 95% CI:0.57-1.69; I2 = 21%), major bleeding (RR = 0.78; 95% CI:0.40-1.51; I2 = 0%), and mortality (RR = 0.94; 95% CI:0.61-1.45; I2 = 0%) were observed. There were no subgroup differences, when RCTs and observational studies were separately evaluated. CONCLUSIONS: Early OAC-initiation in acute ischemic stroke patients with non-valvular atrial fibrillation appears to have better efficacy and a similar safety profile compared to later OAC-initiation.
RESUMO
Cardioembolic stroke is a major cause of morbidity, with a high risk of recurrence, and anticoagulation represents the mainstay of secondary stroke prevention in most patients. The implementation of endovascular treatment in routine clinical practice complicates the decision to initiate anticoagulation, especially in patients with early hemorrhagic transformation who are considered at higher risk of hematoma expansion. Late hemorrhagic transformation in the days and weeks following stroke remains a potentially serious complication for which we still do not have any established clinical or radiological prediction tools. The optimal time to initiate therapy is challenging to define since delaying effective secondary prevention treatment exposes patients to the risk of recurrent embolism. Consequently, there is clinical equipoise to define and individualize the optimal timepoint to initiate anticoagulation combining the lowest risk of hemorrhagic transformation and ischemic recurrence in cardioembolic stroke patients. In this narrative review, we will highlight and critically outline recent observational and randomized relevant evidence in different subtypes of cardioembolic stroke with a special focus on anticoagulation initiation following endovascular treatment. We will refer mainly to the commonest cause of cardioembolism, non-valvular atrial fibrillation, and examine the possible risk and benefit of anticoagulation before, during, and shortly after the acute phase of stroke. Other indications of anticoagulation after ischemic stroke will be briefly discussed. We provide a synthesis of available data to help clinicians individualize the timing of initiation of oral anticoagulation based on the presence and extent of hemorrhagic transformation as well as stroke severity.