Preventing recurrent ischemic stroke: A 3-step plan
To prevent recurrent stroke, address the patient’s risk factors, clear stenosis, and thin the blood
Lifestyle risk factors
Cigarette smoking. Early studies on the association between cigarette smoking and stroke reported variable results. The Framingham Study, in a multivariate analysis, found that when hypertension and age are taken into account, smoking is a significant risk factor.27 In a prospective study of 7735 men, Wannamethee and colleagues found benefit to stopping smoking, with light smokers dropping to the level of nonsmokers and heavy smokers dropping to about a twofold risk of nonsmokers in 5 years.28 The benefit was greatest for hypertensive patients.
With the data now available, it is clear that cigarette smoking is a modifiable risk factor for ischemic infarction. Patients at risk for stroke should be given assistance in smoking cessation.
Alcohol use and abuse. The relationship between alcohol consumption and stroke risk is complex; risk with heavy use differs from that with light use. There may be racial differences in regard to alcohol risk and stroke.
Palomaki and colleagues found a protective effect of light alcohol use, with ≤50 g/wk reducing the risk of ischemic stroke.29 Data from the Framingham Study failed to show an association between alcohol consumption and ischemic stroke although there was a suggestion of reduced risk with wine.30 While the data are not completely clear, it is reasonable to recommend avoiding heavy alcohol consumption as a measure of stroke risk reduction.
Physical activity. Regular exercise has been shown to reduce the risk of cardiovascular disease by decreasing blood pressure, reducing obesity, and improving glucose homeostasis, all of which should help reduce stroke risk.
Studies looking for an association between exercise and reduced stroke risk have produced mixed results. An evidence-based recommendation cannot be made. However, in view of the low cost and low risk of the intervention, instituting a program of progressive physical activity as part of a risk reduction program after stroke is a reasonable recommendation.
The American Heart Association’s Guidelines for Primary Prevention of Cardiovascular Disease and Stroke from 2002 suggest there is a benefit from vigorous activity for 20 to 40 minutes, 3 to 5 days per week, if no medical contraindications exist.31
Diet. There is a paucity of good data regarding the potential protective effects of diet in secondary stroke prevention. Diets high in fruits and vegetables may have a protective effect against ischemic stroke.32
Current recommendations from the American Heart Association include 5 or more servings of fruits and vegetables per day, and 6 servings of grain products.33 They recommend limiting foods with high content of cholesterol raising fatty acids and food high in cholesterol.
Step 2: Clear blocked arteries
Carotid stenosis
Carotid stenosis was recognized as an important risk factor for stroke in the 1950s. Carotid endarterectomy (CEA) was reported as a putative therapy shortly thereafter. The popularity of the surgery increased steadily through the mid-1980s despite an absence of evidence for the operation’s safety or efficacy. Trials were organized in North America and Europe to test the surgery’s potential risks and benefits. More recently, trials comparing CEA to angioplasty with and without stenting were organized.
Clinical trials with carotid endarterectomy/angioplasty, with or without stenting. Several multicenter trials have explored the benefit of CEA for symptomatic patients with varying degrees of ipsilateral carotid artery stenosis. These trials found a high degree of benefit for best medical management plus CEA compared with medical treatment alone for symptomatic patients with high-grade stenosis (70% to 99%), but only moderate stroke risk reduction with moderate carotid stenosis (50% to 69%). With mild stenosis (<50%), no benefit was found for surgical intervention.34
Even for patients with 70% to 99% stenosis, benefit can be eliminated by a high rate of perisurgical complications.35 Surprisingly, CEA was also of little or no benefit for patients with symptomatic carotid near occlusion.35
Other factors influencing the relative benefit of CEA include gender (men benefit more than women), age ≥75 years (older patients do better), and timing of surgery (maximum benefit when done within 2 weeks of the most recent symptoms).36
Devices for performing carotid angioplasty with or without stenting were recently approved by the Food and Drug Administration. However, this is a new technology that has not been proven superior to CEA for most patients with symptomatic stenosis.
Applying the evidence. Be sure all patients with severe or moderate stenosis receive appropriate surgical evaluation for CEA (TABLE 2). For symptomatic patients with very high-grade carotid stenosis and surgical risks so high that the surgeon believes CEA is not an option, carotid angioplasty and stenting can be considered. A recent trial found a trend toward non-inferiority for angioplasty and stenting compared with CEA in a high-risk population. However, widespread application of this technique should await completion of clinical trials testing it in more typical cerebrovascular patients.
