Introduction

Cerebrovascular disease or stroke is a major cause of death and disability. Stroke is the third leading cause of death and ranks eleventh in disabling conditions that restrict activity. The major types of stroke are cerebral thrombosis, cerebral embolism, intracerebral hemorrhage and subarachnoid hemorrhage.

Thromboembolic, ischemic stroke accounts for nearly 80% of all strokes. Hemorrhagic stroke has a different epidemiology and prognosis than ischemic stroke. Distinguishing among subtypes requires neurologic examination and use of neuroimaging of computerized tomography and magnetic resonance imaging.

Mortality from stroke varies by country, with the highest rates reported for Japan and the lowest rates for Switzerland and Canada.[77] Change has occurred in stroke occurrence in most countries with the exception of eastern Europe. There are also marked differences in stroke mortality between whites and blacks in the United States. [78] Overall death rates are approximately twice as high in blacks as in whites.

As has been observed for diseases of the heart, there has been a striking decline in mortality rates for stroke in the past several decades. Reductions in mortality rates have been ob-served for both sexes and all race groups. The decline has been attributed primarily to a decreasing incidence of stroke due to efforts to control hypertension and, to a lesser extent, to a reduc-tion in case fatality.[79,80]

Data from the Rochester Epidemiology Project has shown that the incidence rates of stroke in 1985 to 1989 is lower than of the 1950's and 1960's but has stabililized over the last two decades. [80] The incidence rate for 1985 to 1989 was 145 per 100,000. A higher incidence was observed for men (174 vs 122) but the number of persons with a stroke is higher in women. Prevalence of stroke was 759 per 100,000 for women and 917 per 100,000 for men. Stroke subtype specific incidence rates were 120 per 100,000 for cerebral infarction, 15.5 per 100,000 for intracerebral hemorrhage and 7.5 per 100,000 for subarachnoid hemorrhage.

The primary prevention of stroke is through control of hypertension. Hypertension is the major risk factor for ischemic stroke and intracerebral hemorrhage. Studies have shown a consistent reduction in stroke occurrence with blood pressure control and most recently for the elderly. [81,82,83] Other risk factors for ischemic stroke include diabetes mellitus, tran-sient ischemic attacks, and cardiac disease. [84] In contrast diabetes mellitus and cholesterol level is not associated with increased risk of hemorrhagic stroke. Migraine headaches may be associated with stroke. A case-control study indicated that women under the age of 45 had 4.3-fold increased risk with migraine. [85,86] In the Physicians Health Study the relative risk for migraine and ischemic stroke in all participants was 2.0. [87] Cigarette smoking has been associated in some studies with risk of both ischemic and hemorrhagic stroke. It may be the leading risk factor for cerebral aneurysms and subarchnoid hemorrhage. Data from the Nurses Health Study suggest that smoking cessation can reduce the risk of stroke. [88] The role of alcohol consumption in increasing risk of stroke is less certain and may vary by type of stroke.[89] One study in women found that moderate consumption of alcohol was associated with a lower risk of ischemic strokes but with an increased risk of subarachnoid hemorrhage.[90,91] The role of binge drinking and stroke has also been demonstrated. Drugs of abuse particularly stimulants and diet pills have been associated with stroke occurrence.

Secondary prevention of stroke through antiplatelets (aspirin and ticlopidine) in patients with transient ischemic attacks and minor strokes has been shown to be effective in prevention of recurrent events and severe strokes. [92,93] Treatment of patients with nonvalvular atrial fibrillation with aspirin or warfarin has been shown also to prevent ischemic stroke occurrence.[94] In patients who have major stenosis or occlusion of the carotid arteries also there is benefit from surgical carotid endarterectomy in prevention of future stroke events. [95,96,97] For tertiary prevention the use of thrombolytic therapy has been shown to be effective in decreasing the disability from stroke if administered within 3 hours of onset.[98,99] Several clinical trials of neuroprotective agents are underway.

References

77. Bonita R and Beaglehole R: Stroke mortality. In Stroke:Populations,Cohorts, and Clinical Trials, JP Whisnant (ed), Butterworth-Heinemann Ltd,Oxford, 1993, pp. 59-79.

78. Heart and Stroke Facts. 1995 Statistical Supplement. Dallas, AmericanHeart Association, 1995, pp. 11-12.

79. Broderick JP, Phillips SJ, Whisnant JP et al: Incidence rates of strokein the eighties:The decline in stroke. Stroke 20:577-582, 1989.

80. Brown RD, Whisnant JP, Sicks JD et al: Stroke incidence, prevalence,and survival: Secular trends in Rochester, Minnesota, Through 1989. Stroke27:373-380, 1996.

81. Collins R, Peto R, MacMahon S et al: Blood pressure, stroke, andcoronary heart disease. Part 2, Short-term reductions in blood pressure:overview of randomized drug trials in their epidemiological context. Lancet 335:827-838, 1990.

82. Shep Cooperative Research Group: Prevention of stroke byantihypertensive drug treatment in older persons with isolatedhypertension: Final results of the Systolic Hypertension in Elderly Program(SHEP). JAMA 265:3255-3264, 1991.

83. Meissner 1, Whisnant JP, Garraway WM: Hypertension manage-ment andstroke recurrence in a community (Rochester, Minnesota, 1950-79). Stroke 19:459-463, 1988

84. Dyken ML: Stroke risk factors. In Prevention of Stroke, JW Norris andVC Hachinski (eds), Springer-Verlag, New York, 1991, pp 83-102.

85. Tsourio C, Iglesias S, Hubert JB et al: Migraine and risk of ischaemicstroke: a case-control study. BMJ 307:289-292, 1993.

86. Buring JE, Hbert P, Romero J et al: Migraine and subsequent risk ofstroke in the Physicians' Health Study. Archives of Neurology 52:129-134,1995.

87. Shinton R, Beevers G: Meta-analysis of relation between cigarette smoking and stroke. BMJ 25:298:784-794, 1989.

88. Kawachi I, Colditz GA, Stampfer MJ et al: Smoking cessation anddecreased risk of stroke in women. JAMA 269:232-236, 1993

89. Stampfer MJ, Colditz GA, Willett WC, Spaizer FE, Hennekens CH: Aprospective study of moderate alcohol consumption and the risk of coronarydisease and stroke in women. N Engl J Med 319:267-273, 1988

90. Longstreth WT Jr, Koepsell TD, Yerby MS et al: Cigarette smoking,alcohol use, and subarachnoid hemorrhage. Stroke 23:1242-1249, 1992.

91. Torner JC: Epidemiology of subarachnoid hemorrhage. Semin Neurol 4:354-369, 1984.

92. Antiplatelet Trialists; Collaboration. Collaborative overview ofrandomized trials of antiplatelet treatment. Part I: Prevention of death,myocardial infarction, and stroke. By prolonged antiplatelet therapy invarious categories of patients. BMJ 304:81-106, 1994.

93. Hass WK, Easton JD, Adams HP Jr et al. for the Ticlopidine AspirinStroke Study Group: A randomized trial comparing ticlopidine hydrochloridewith aspirin for the prevention of stroke in high-risk patients. N EnglJ Med 321:501-507, 1989.

94. Stroke Prevention in Atrial Fibrillation Investigators: StrokePrevention in Atrial Fibrillation Study- final results. Circulation84:527-539, 1991.

95. North American Symptomatic Carotid Endarterectomy Trial Collaborators:Beneficial effect of carotid endarterectomy in symptomatic patients withhigh-grade stenosis. N Eng J med 325:445-453, 1991.

96. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study:Endarterectomy for asymptomatic carotid artery stenosis. JAMA273:1421-1428, 1995.

97. Moore WS, Barnett HJ, Beebe HG et al: Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the ad hocCommittee, American Heart Association. Stroke 26:188-201, 1995.

98. The National Institute of Neurological Disorders and Stroke rt-PAStroke Study Group: Tissue plasminogen activator for acute ischemic stroke.N eng J Med 333:1581-1587, 1995.

99. Adams HP, Brott TG, Furlan AJ, et al: Guidelines for thrombolytictherapy for acute stroke: A supplement to the guidelines for the management of patients with acute ischemic stroke. Circulation 94:1167-1174, 1996. 

 

Title Page