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.
