Anticoagulation may be considered for asymptom- atic patients with severe mitral stenosis and left atrial dimension 55 mm by echocardiography (Class IIb; Level of Evidence B). 11. Anticoagulation may be considered for patients with severe mitral stenosis, an enlarged left atrium, and spontaneous contrast on echocardiography (Class IIb; Level of Evidence C). 12. Anticoagulant therapy may be considered for patients with STEMI and anterior apical akinesis or dyskinesis (Class IIb; Level of Evidence C). 13. Antithrombotic treatment and catheter-based closure are not recommended in patients with PFO for primary prevention of stroke (Class III; Level of Evidence C). *Risk factors include AF, previous thromboembolism, left ventricular dys- function, and hypercoagulable condition. Meschia et al Guidelines for the Primary Prevention of Stroke 3781 Asymptomatic Carotid Artery Stenosis Atherosclerotic stenosis in the extracranial internal carotid artery or carotid bulb has been associated with an increased risk of stroke. What follows is a summary of recommendations for managing asymptomatic patients with carotid atheroscle- rotic stenosis. Further details are available in an earlier guide- line endorsed by the AHA that is dedicated to this topic.512 Previous randomized trials have shown that prophylac- tic carotid endarterectomy (CEA) in appropriately selected patients with carotid stenosis results in a relative risk reduc- tion of stroke of 53% and an absolute 5-year risk reduction of 6% compared with patients treated by medical management However, since these trials were performed, medi- cal management has improved. The question has been raised if invasive treatment of carotid bifurcation disease remains an effective way to reduce stroke risk compared to contemporary medical management alone. Assessment of Carotid Stenosis A hemodynamically significant carotid stenosis produces a pressure drop across the lesion, a flow reduction distal to the lesion, or both. 