AHA/ASA Guideline Guidelines for the Prevention of Stroke in ...

Furie et al Prevention of Stroke in Patients With Stroke and TIA 235F. ObesityObesity, defined as a body mass index of 30 kg/m 2 , hasbeen established as an independent risk factor for CHD andpremature mortality. 106–108 The relationship of obesity andweight to stroke is complex but has been studied mostly inrelation to primary prevention. 109–118Among African-American stroke survivors in the AfricanAmerican Antiplatelet Stroke Prevention Study, cardiovascularrisk factor profiles increased with increasing weight, 119although a relationship with risk of recurrent stroke was notestablished.No study has demonstrated that weight reduction reducesrisk of stroke recurrence.G. Physical ActivityPhysical activity exerts a beneficial effect on multiple strokerisk factors. 108,120–125 In a recent review of existing studies onphysical activity and stroke, moderately or highly activepersons had a lower risk of stroke incidence or mortality thandid persons with a low level of activity. 121 Moderately activemen and women had a 20% lower risk, and those who werehighly active had a 27% lower risk. Physical activity tends tolower BP and weight, 125,126 enhance vasodilation, 127 improveglucose tolerance, 128,129 and promote cardiovascular health. 108Despite the established benefits of an active lifestyle,sedentary behaviors continue to be the national trends. 130,131Disability after stroke is substantial, 132 and neurologicaldeficits can predispose an individual to activity intoleranceand physical deconditioning. 133 Therefore, the challenge forclinicians is to establish a safe therapeutic exercise regimenthat allows the patient to regain prestroke levels of activityand then to attain a level of sufficient physical activity andexercise to optimize secondary prevention. Several studiessupport the implementation of aerobic exercise and strengthtraining to improve cardiovascular fitness after stroke. 133–136Structured programs of therapeutic exercise have been shownto improve mobility, balance, and endurance. 134 Beneficialeffects have been demonstrated in different ethnic groups andin both older and younger groups. 137 Although these studieshave shown that structured exercise programs are not harmfulafter stroke, no controlled studies have determined whethertherapeutic exercise reduces the incidence of subsequent stroke.Physical activity was not measured in any of the recent internationalstudies of recurrent stroke and risk factors. 138–140A few studies have investigated stroke survivors’ awarenessof exercise as a potential preventive measure. A surveyusing the 1999 Behavioral Risk Factor Surveillance System(BRFSS) showed that overall, 62.9% of those who reportedhaving been told they had had a stroke were exercising toreduce their risk of heart attack or another stroke. Mostimportantly, a much larger percentage of stroke survivorswho had received advice to exercise reported actually doingso (75.6%) than stroke survivors who did not receive suchadvice (38.5%). Stroke survivors who reported engaging inmore exercise had fewer days when their activity was limited,fewer days when their physical health was not good, andhealthier days than survivors who did not report exercising afterstroke. 141 This study highlights the importance of provideradvice about exercise, diet, and other lifestyle risk factors. It didnot investigate the incidence of recurrent stroke.Studies have shown that encouragement of physical activityand exercise can optimize physical performance, functionalcapacity, and quality of life after stroke. Recommendations onthe benefits of physical activity for stroke survivors are reviewedmore extensively in other publications. 108,125,127Recommendations1. For patients with ischemic stroke or TIA who arecapable of engaging in physical activity, at least 30minutes of moderate-intensity physical exercise, typicallydefined as vigorous activity sufficient to breaka sweat or noticeably raise heart rate, 1 to 3 times aweek (eg, walking briskly, using an exercise bicycle)may be considered to reduce the risk factors andcomorbid conditions that increase the likelihood ofrecurrent stroke (Class IIb; Level of Evidence C).2. For those individuals with a disability after ischemicstroke, supervision by a healthcare professional,such as a physical therapist or cardiac rehabilitationprofessional, at least on initiation of an exerciseregimen, may be considered (Class IIb; Level of EvidenceC) (Table 4).H. Metabolic SyndromeThe metabolic syndrome refers to the confluence of severalphysiological abnormalities that increase risk for vasculardisease. 142 Those abnormalities are variably counted in differentdefinitions of the metabolic syndrome and includehypertriglyceridemia, low HDL-C, high BP, and hyperglycemia.143–145 Research over the past decade has expanded thesyndrome to include subclinical inflammation and disordersof thrombosis, fibrinolysis, and endothelial function, and hasdemonstrated that it may be transmitted genetically. 142,146,147The metabolic syndrome is commonly diagnosed with criteriaproposed by the NCEP Adult Treatment Panel, the WorldHealth Organization, or the AHA (adopted from the NCEP).According to the AHA criteria, the metabolic syndrome isrecognized when 3 of the following 5 features are present:increased waist circumference (102 cm in men; 88 cm inwomen); elevated triglycerides (150 mg/dL); reducedHDL-C (40 mg/dL in women; 50 mg/dL in men); elevatedBP (systolic 130 mm Hg or diastolic 85 mm Hg); and elevatedfasting glucose (100 mg/dL). 148 Insulin resistance is usuallydescribed as a pathophysiologic state in which a normalamount of insulin produces a subnormal physiological response.Selected consequences include reduced peripheralglucose uptake (into muscle and fat), increased hepaticglucose production, and increased pancreatic insulin secretion(compensatory). 149 Diet, exercise, and use of drugs that enhanceinsulin sensitivity have also been shown to produce many ofthese improvements in persons with the metabolic syndrome. 150–155 The metabolic syndrome affects approximately 22% of USadults 20 years of age. 156 Among patients with ischemicstroke, the prevalence is 40% to 50%. 157–159Considerable controversy surrounds the metabolic syndrome,largely because of uncertainty regarding its etiologyand clinical usefulness. The metabolic syndrome is related toan increased risk for diabetes, cardiovascular disease, andall-cause mortality. 160 It remains uncertain, however, whetherDownloaded from stroke.ahajournals.org by on March 8, 2011