Stroke is the third leading cause of death in the United States behind cardiovascular disease and cancer. Approximately 2.7% of men and 2.5% of women > 18 years of age have a history of stroke and there are nearly 800,000 stroke occurrences each year with a mortality rate approaching 150,000.1 Of all strokes, 87% are ischemic in origin with the remainder hemorrhagic.2 This chapter will focus on ischemic strokes.
Most cranial occlusions result from an embolus formed in either the carotid arteries or the ventricles of the heart. Atherosclerosis of the carotid arteries commonly leads to plaque formation. If plaque rupture occurs, collagen is exposed which results in platelet aggregation and thrombus formation. When a clot forms, it can break off and travel distally to the cranial vasculature. This causes cranial vessel occlusion which decreases blood flow to the brain region it supplies, ultimately resulting in ischemia. Strokes originating from a cardioembolic source are presumed to originate from thrombus formation in the left ventricle.
Ischemic stroke commonly presents as an acute onset of focal neurological deficit lasting greater than 24 hours.3 Most patients present with weakness on one side of the body, visual impairment, and inability to speak. Diagnosis is confirmed with computed tomography (CT) scanning and magnetic resonance imaging (MRI). Patients at highest risk of developing an ischemic stroke are those with hypertension, diabetes, dyslipidemia, atrial fibrillation, cigarette smoking, and obesity (Table 5-1).3,4
TABLE 5-1 Risk Factors for Ischemic Stroke3,4 |Favorite Table|Download (.pdf)
TABLE 5-1 Risk Factors for Ischemic Stroke3,4
|Age||Risk doubles every 10 y after 55 y of age|
|Race||African Americans have a greater risk than Hispanics who have a greater risk than Caucasians|
|Gender||Men have a greater risk than women|
|Hypertension||Risk is decreased by 50% if blood pressure is lowered to <120/80 mm Hg compared to patients with HTN|
|Dyslipidemia||25% reduction in risk with concomitant use of statin therapy|
|Diabetes||There is no correlation with glycemic control; however, risk is reduced when blood pressure is lowered to <130/80 mm Hg|
|Cigarette smoking||Risk is decreased by 50% within 1 y of quitting|
|Atrial fibrillation||Risk is decreased with concomitant use of warfarin therapy|
The immediate goal of therapy in acute stroke is to reduce neurologic injury and long-term disability. Once the patient is through the hyperacute period, the goal of therapy is to prevent reoccurrence and ultimately decrease mortality.3,4
Primary prevention against ischemic stroke focuses on the reduction of modifiable risk factors (see Table 5-1).
The treatment for acute ischemic stroke has a narrow therapeutic window making a timely evaluation and diagnosis essential.5 Currently, only two pharmacologic agents have received a Class I, Level of Evidence A recommendation from the American Heart Association Stroke Council for use in treatment of acute stroke. These agents are intravenous (IV) recombinant ...