In particular, should MRI of the brain be obtained in all IE patients because cerebral emboli are so com- monplace? As previously mentioned in an earlier section (3D Echocardiography and Other Imaging Modalities), some have advocated this strategy in all patients who are to undergo valve surgery to identify those who may harbor embolic lesions that could pose a higher risk of intracranial bleeding with cardio- pulmonary bypass and heparin administration used for cardiac surgery. Anticoagulation Anticoagulation in IE patients is controversial, particularly in mechanical valve IE.286 Some authorities recommend con- tinuation of anticoagulant therapy in patients with mechani- cal valve IE. However, the general advice is to discontinue all forms of anticoagulation in patients with mechanical valve IE who have experienced a CNS embolic event for at least 2 This time should allow for thrombus organization and prevent the acute hemorrhagic transformation of embolic lesions. Reintroduction of anticoagulation in these patients should be done with great caution, beginning with intravenous unfractionated heparin titrated to an activated partial thrombo- plastin time range of 50 to 70 seconds and transitioning care- fully to adjusted dose warfarin. The novel oral anticoagulants are not approved for use with either mechanical valves or bio- prosthetic valves when risk factors for thromboembolism exist (eg, atrial fibrillation). The benefit of therapeutic anticoagulation has never been demonstrated convincingly in patients with NVE. In part related to findings that demonstrated a salutary effect of intra- venous aspirin therapy in established experimental S aureus a randomized trial compared oral aspirin 325 mg/d with placebo in 115 IE patients.288 No significant benefit was observed in aspirin-treated patients in terms of vegetation resolution and embolic events. Moreover, there was a trend toward more bleeding episodes in the aspirin-treated patients. 