Transient Ischemic Attacks
TRANSIENT ISCHEMIC ATTACKS
Transient Ischemic Attacks (TIAs) are transient neurological deficits, such as temporary blindness of one eye (amaurosis fugax), hemiparesis, or aphasia. Most typically, these symptoms last for periods of minutes or even hours, and they may persist for up to twenty-four hours. TIAs frequently result from platelet aggregates forming and then dislodging to embolize peripherally, or from significant atherosclerotic disease of extracranial carotid arteries, especially at the carotid bifurcation.
Because TIAs due to extracranial carotid stenosis (constriction) were recognized to be harbingers of larger and even devastatingly severe strokes, efforts to eliminate these offending lesions resulted in widespread carotid endarterectomies (CEA) being performed in the expectation of averting strokes. To scientifically assess the value of CEAs, three large-scale prospective randomized studies were undertaken, and the results were published in 1991. In patients with TIAs in the carotid distribution, and showing significant extracranial disease (greater than 70% diameter stenosis at the carotid bifurcation), carotid endarterectomy in competent surgical hands was shown to reduce stroke recurrence significantly. In these patients, control of risk factors for atherosclerosis should also be instituted, such as those for hypertension, smoking, diabetes mellitus, elevated cholesterol, stress, and, perhaps, sedentary lifestyle. In nonsurgical candidates, in addition to risk factor reduction, aspirin and other antiplatelet drugs can prevent subsequent strokes.