Cardioembolic strokes as a result of nonvalvular atrial fibrillation [AF]: All patients with an ischemic stroke secondary to nonvalvular atrial fibrillation would have a CHA2DS2-VASc score of >2, and therefore anticoagulation is recommended. Two first-line drug therapies can be recommended: direct oral anticoagulants [DOACs] such as apixaban, dabigatran, edoxaban, and rivaroxaban; and warfarin with an international normalized ratio [INR] between 2.0 and 3.0. DOACs have been shown to result in a lower rate of intracerebral hemorrhage. Although more expensive than warfarin, DOACs do not require monitoring, do not have the dietary issues associated with warfarin, and have fewer drug-drug interactions. However, patients on enzyme-inducing medications such as phenytoin or HIV patients on protease inhibitors cannot use DOACs. Warfarin is still preferred in patients with marked renal impairment [see specific information available from the FDA about renal impairment and dosing for each DOAC] and in patients with mechanical heart valves or valvular causes of atrial fibrillation. Reversible therapies for some of the DOACs have recently been made available. A patient on a DOAC experiencing a recurrent stroke should only receive tissue plasminogen activator [t-PA] if the patient has been off the medication for at least 48 hr. For patients on warfarin, an INR of less than 1.7 allows for administration of t-PA. There is no evidence that aspirin monotherapy is helpful in reducing cardioembolic events. The Active-A trial suggested that a combination of aspirin and clopidogrel is slightly better than aspirin alone for those unable to tolerate warfarin, but patients on dual therapy experienced an increased risk of hemorrhagic complications. Because dual-antiplatelet therapy and DOACs have similar rates of bleeding complications but different levels of efficacy for prevention of cardioembolic stroke, the use of aspirin/clopidogrel dual therapy instead of a DOAC is almost never indicated. Furthermore, apixaban and aspirin monotherapies have beenshown to have similar rates of bleeding. Thus patients at risk of bleeding who previously were put on aspirin rather than warfarin could now be prescribed apixaban and experience the same bleeding risk but with actual benefit in terms of stroke risk reduction.
Cardioembolic strokes as a result of a prosthetic metallic valve: Anticoagulant therapy with warfarin is recommended with a goal INR between 2.5 and 3.5.
Strokes as a result of large-vessel extracranial atherosclerosis [i.e., symptomatic carotid stenosis]: For patients with recent TIA or ischemic stroke and ipsilateral severe [70% to 99%] carotid artery stenosis, carotid endarterectomy [CEA] or carotid stenting is recommended, preferably within 14 days of the event if no contraindication. For patients with recent TIA or ischemic stroke and ipsilateral moderate [50% to 69%] carotid stenosis, intervention is recommended on a case-by-case basis only if the surgeon’s perioperative morbidity and mortality rate is