This patient should be restarted on statin therapy for primary prevention of stroke and myocardial infarction. The patient has type 2 diabetes mellitus and coronary artery disease, and patients with these disorders benefit from high-intensity statin therapy to reduce the risk of atherosclerotic cardiovascular disease, including myocardial infarction and stroke. High-intensity statins also are recommended for patients with stroke or transient ischemic attack of a presumed atherosclerotic subtype (although this patient is not symptomatic). With improvements in medical therapy, particularly statins, the risk of stroke has been declining in patients with asymptomatic internal carotid artery (ICA) stenosis. In a recent study, the use of a statin in patients with this diagnosis was associated with a stroke risk of less than 2% per year. Although this patient developed apparent statin myopathy from rosuvastatin, switching to another statin less associated with statin myopathy is appropriate.

Although carotid endarterectomy may benefit some patients with greater than 60% asymptomatic ICA stenosis, its effectiveness is highly dependent on the patient's underlying risks and those associated with the procedure itself. The benefit of carotid surgery is modest in patients without symptoms, and this patient's multiple medical comorbidities make him a relatively poor surgical candidate. Some studies have suggested that additional clinical factors increase the risk of stroke further in patients with asymptomatic carotid stenosis, including rapidly progressive or greater than 80% stenosis, asymptomatic infarcts on brain imaging, or abnormal results of transcranial Doppler ultrasonography. However, the role that these factors should play in clinical decisions about treatment of asymptomatic carotid stenosis has not been established. Carotid revascularization with either endarterectomy or stenting can be considered in patients at low risk for perioperative cardiovascular morbidity.

Magnetic resonance angiography (MRA) of the neck is inappropriate in this patient because an additional diagnostic test is unlikely to change the medical management of his condition. The accuracy of MRA without contrast is likely similar to that of carotid ultrasonography.

No clear evidence supports the superiority of clopidogrel over aspirin for the primary prevention of stroke in the setting of asymptomatic ICA stenosis.