Historically, because of the difficulty of using
warfarin safely and effectively, many patients with
cardioembolic stroke who should have been anticoagulated were instead given ineffective antiplatelet
therapy (or no antithrombotic
therapy). With the arrival of new oral
anticoagulants that are not significantly more likely than
aspirin to cause severe haemorrhage, everything has changed. Because
antiplatelet agents are much less effective in preventing
cardioembolic stroke, it is now more prudent to anticoagulate patients in whom
cardioembolic stroke is strongly suspected. Recent advances include the recognition that intermittent
atrial fibrillation is better detected with more prolonged monitoring of the cardiac rhythm, and that percutaneous closure of
patent foramen ovale (PFO) may reduce the risk of
stroke. However, because in most patients with
stroke and PFO the PFO is incidental, this should be reserved for patients in whom
paradoxical embolism is likely. A high shunt grade on transcranial Doppler saline studies, and clinical clues to
paradoxical embolism, can help in appropriate selection of patients for percutaneous closure. For patients with
atrial fibrillation who cannot be anticoagulated, ablation of the left atrial appendage is an emerging option. It is also increasingly recognised that high levels of
homocysteine, often due to undiagnosed metabolic deficiency of
vitamin B12, markedly increase the risk of
stroke in
atrial fibrillation, and that
B vitamins (
folic acid and B12) do prevent
stroke by lowering
homocysteine. However, with regard to B12,
methylcobalamin should probably be used instead of
cyanocobalamin. Many important considerations for judicious application of
therapies to prevent
cardioembolic stroke are discussed.