Transient monocular blindness, also called amaurosis fugax, is usually caused by retinal ischemia. In patients younger than 45 years it may be vasospasm or symptom of a migraine but in older patients or patients with atherosclerosis it is usually emboli, thrombus or plaque, giant cell arteritis or cerebrovascular ischemia that temporarily obstructs the ophthalmic artery causing symptomatic ischemia in the optic nerve and the retina. It is generally monocular and lasts for 2–30 min. Patients describe it as darkness or a gray curtain over one eye.

Patients with carotid artery disease typically suffer from other systemic diseases like hypertension, diabetes mellitus, obesity, arteriosclerosis, and pulmonary disease from smoking. It is important to note that patients with hypertension and diabetes are also at high risk for renal disease. Morbidity and possibly mortality are increased in patients with renal disease who undergo carotid endarterectomy (CEA). There is increased risk of stroke, death, and cardiac complications in this population [1, 2].

Previous stroke or transient ischemic attack (TIA), cardiovascular disease and sickle cell disease significantly increase risk of serious complications [3]. The most consistent risk factor is age; increasing age is also associated with increasing probability of stroke. This may be related to anatomical changes in the vessel wall that occur with aging [4]. Carotid artery (CA) disease is one manifestation of atherosclerosis.

The preoperative evaluation must assess the patient for recognized associated comorbid conditions. Of particular importance would be the history of neurological impairment. As high as 25% of patients with CAD also have CA disease [5–7]. Stress makes these patients at risk for myocardial ischemia [8]. When planning for an elective procedure, optimizing comorbid conditions can reduce perioperative complication. When significant symptoms of cardiac ischemia are present, consultation with a cardiologist to optimize the patient’s health is important.

When CA therapy is elective, use of standard assessment and management protocols for each comorbid condition are recommended. For example, patients with sleep disordered breathing (obstructive sleep apnea or OSA) receive medical optimization prior to surgery followed by postoperative management.

When CA treatment is emergently required, best judgment regarding the evaluation is necessary. The 1-hour goal of event to therapy for a stroke or TIA patient requires an efficient standard protocol to prevent unnecessary delays.

The clinician must decide anesthetic management goals based on both the CA procedure and the patient’s active medical problems [9].

Preoperative evaluation of the CA disease focuses on defining the diseased vessel. To determine the extent of the cerebrovascular disease, these diagnostic modalities are suggested

Preexisting medical therapy for these often include administration of antiplatelet/anticoagulant/antifibrinolytic agents. Aspirin [10, 11], and clopidogrel therapy [12] may be initiated prior to CA stenting or carotid endarterectomy. Statins and beta-blockers should be continued in these patients. Statins may induce vascular remodeling and regression for carotid atherosclerotic lesions [13, 14]. Statin administration use may reduce neurologic morbidity among patients undergoing carotid angioplasty and stent procedures. Long-term therapy may reduce carotid plaques in high-risk patients.

Rapid evaluation and therapy, “Stroke Alert” requires endovascular treatment within 1 h of onset of symptoms in the adult [15]. This is an opportunity to treat a CA lesion when appropriate or establish the extent of CA disease for a surgical intervention.

Patients with carotid stenosis greater than 70% may cause cerebral hypoperfusion and patients will benefit from a CEA or endovascular intervention. Patients with stenosis between 50 and 69% will only have marginal increase in blood flow. This patient has symptoms due acute hypoperfusion and requires therapy.

Accepted indications for a therapy include the following:

The benefits of CEA are seen primarily in men, patients older than 75 years of age and patients who after the onset of symptoms with “undergo surgery within <2 weeks after initial [16].”

Therapy includes reducing hypercoagulability (e.g., antiplatelet drugs, systemic anticoagulation drugs, aspirin), and increase vessel diameter with surgical or endovascular management (e.g., carotid stenting and angioplasty, CEA) [17].

Procedural intervention, carotid stent placement or carotid endarterectomy is safe and effective options in patients with occlusive disease. Patients with multiple comorbid conditions may benefit more from carotid stenting and include patients with

These factors are implicated in poor outcomes regardless of the technique chosen [18, 19].

Surgical treatment is more often recommended in patients

Premedication reduces anxiety but may increase the risk of hypoventilation and delayed awakening. Use of premedication is a judgment best made by the anesthesiologist.

Standard ASA monitors and an intra-arterial blood pressure monitor are routinely recommended. A patient with poor ventricular function may benefit from a transesophageal echocardiogram (TEE). It may complicate surgical and endovascular procedures. If a carotid artery shunt is placed emboli occur. Some organizations use transcranial Doppler to detect emboli and allow the surgeon to modify their technique. Cerebral oximetry is used to estimate adequacy of cerebral perfusion. Its efficacy is not determined [20, 21].

Electroencephalogram (EEG), processed EEG, somatosensory evoked potentials (SSEP) are often used as a functional indicator of perfusion since they record neuronal and synaptic activity. EEG slowing indicates decreased perfusion. Administration of volatile anesthesia and TIVA increases EEG slowing in a dose dependent fashion. Slowing due to hypoperfusion may be ipsilateral only and can be treated with placement of a shunt and increasing blood pressure. Treatment may prevent neurologic injury since persistent slowing is associated with postoperative neurologic complications [22–24].

EEG measurement is limited to the electrical activity in the superficial cerebral cortex near the electrodes. EEG limitations allow false positive and false negatives interpretations. Even more limited is processed EEG; it is used by anesthesia personnel to monitor the frontal cortex; its value has not been established.

Somatosensory evoked potentials (SSEP) can detect hypoperfusion in the sensory cortex while transcranial motor evoked potentials (MEP) detect hypoperfusion in the motor cortex. MEP require modifications in anesthetic technique to obtain. SSEP and MEP indicate laterality and if adequate perfusion is present. They do not provide information about focal ischemic events [25].

Carotid stump pressure is the pressure obtained by transducing the CA above the cross-clamp. It has been used as a surrogate for perfusion. Perfusion pressure presumably reflects the collateral blood flow. Stump pressure does not reliably correlate with EEG, SSEP, or changes in an awake patient’s neurological exam. Stump pressure when used in conjunction with transcranial Doppler is predictive of cerebral ischemia [26].

Ideally, the anesthesia must maintain oxygenation, cardiovascular stability and best surgical or endovascular conditions. Both regional and general anesthesia are successfully used.

General anesthesia is the most frequently used technique in the United States. Its use is based on the clinician, surgeon, and patient preference. The major advantages of general anesthesia include

The disadvantages include