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Stroke
Primary Prevention of Ischaemic Stroke
a report by
Andria L Ford
1
and Allyson R Zazulia
2
1. Vascular Neurology Fellow, Washington University School of Medicine; 2. Assistant Professor of Neurology and Radiology and
Director of Pre-clinical Neurological Education, Washington University School of Medicine
Stroke is the second most common cause of death worldwide and a of family history to stroke risk. Stroke is a manifestation of a variety of rare
leading cause of long-term neurological impairment, with as many as genetic disorders, but the association between most inherited
30% of survivors permanently disabled.
1–3
Of all strokes, approximately coagulopathies – e.g. protein C and S deficiency – and arterial events is
70% are first-time events, thus primary-care physicians have a great weak.
10–12
Finally, stroke incidence and stroke mortality are increased
opportunity to identify patients who may benefit from risk factor among individuals with low birth weight.
13,14
modification.
2
Furthermore, neurologists frequently evaluate non-stroke
patients who carry modifiable stroke risk factors. In these settings, The long list of modifiable stroke risk factors is best separated into
initiation of primary prevention strategies may have the greatest impact two groups:
on the disease and its enormous toll on the healthcare system.
• those that clearly contribute to risk and, if modified, reduce the risk of
Risk Factors for Ischaemic Stroke incident stroke; and
Numerous factors contribute to the risk of first stroke. The non-modifiable • those that are associated with stroke, but have not been well studied
risk factors include increasing age, sex, race/ethnicity, family history, or do not reduce the risk of stroke when treated.
genetic factors and low birth weight. While not modifiable, these risk
factors may identify those who are at highest risk of stroke and who may Well-documented risk factors that clearly benefit from specific management
benefit from aggressive treatment of any modifiable risk factors. Regarding include hypertension, cigarette smoking, atrial fibrillation, dyslipidaemia,
age, each decade above 55 years of age leads to a doubling of stroke risk.
4
diabetes mellitus and asymptomatic carotid stenosis (see Table 1).
15–17
The
Men carry an overall higher risk of stroke than women at younger ages, but discussion and treatment of these risk factors will be the focus of this article.
women are at greater risk over the age of 85 years.
5
This relatively greater Other well-documented risk factors are cardiovascular and peripheral arterial
risk in older women may reflect changing hormonal status and/or the use disease, sickle cell disease and obesity. Less well documented or potentially
of hormone replacement therapy (HRT), as well as the fact that men with modifiable risk factors include metabolic syndrome, hyperhomo-
stroke risk factors may die earlier from cardiovascular disease.
6–7
Race and cysteinaemia, hypercoagulability, oral contraceptive use, inflammatory
ethnic contributions to stroke risk are difficult to separate from other risk processes, migraine headache and sleep apnoea, among others.
18
factors such as hypertension and diabetes, which are more prevalent in
certain populations. Even taking into account these risk factors, however, Hypertension
stroke incidence rates remain higher among some racial–ethnic groups Blood pressure is a powerful determinant of stroke risk and, because
(e.g. African-Americans).
8,9
Unidentified genetic risk factors may predispose hypertension is the most prevalent of the modifiable stroke risk factors
these groups to stroke and may eventually help to explain the contribution throughout middle and older age, its treatment would produce the greatest
impact on reducing the burden of stroke.
19
Recent evidence-based
guidelines on management of hypertension recommend antihypertensive
Andria L Ford is a Vascular Neurology Fellow at Washington
University School of Medicine in St Louis, Missouri. She is a
agents and lifestyle modification to keep blood pressure <140/90, with even
Member of the American Academy of Neurology. Her tighter control recommended for those with additional vascular risk factors
research interests include the alternative splicing of genes
such as diabetes and chronic kidney disease (see Table 2).
20
Overall, across
involved in apoptotic cell death after ischaemic stroke.
multiple classes of antihypertensive therapy, blood pressure reduction is
associated with approximately 30–40% reduction in the incidence of stroke,
with more intensive lowering superior to less.
21–22
Placebo-controlled studies
have demonstrated the efficacy of thiazide diuretics, beta-blockers,
Allyson R Zazulia is an Assistant Professor of Neurology and
Radiology and Director of Pre-clinical Neurological Education at
angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor
Washington University School of Medicine in St Louis, Missouri. blockers and calcium-channel blockers in reducing stroke and cardiovascular
She is a diplomate of the American Board of Psychiatry and
outcomes.
21–22
In general, the choice of a particular class of agents is less
Neurology with subspeciality certification in vascular neurology,
and is a Member of the American Academy of Neurology and
important than the degree of blood pressure reduction achieved.
the Stroke Council of the American Heart Association. Her
research focuses on cerebral blood flow and metabolism and
neuroimaging of cerebrovascular disease. She has received
Cigarette Smoking
numerous teaching awards and is listed among the Best Multiple studies have demonstrated that cigarette smoking
Doctors in America and Marquis Who's Who in America.
independently increases the risk of ischaemic stroke approximately
E: allyson@npg.wustl.edu
two-fold and places individuals at even greater risk of haemorrhagic
stroke.
23–25
Moreover, smoking may act synergistically with other stroke
24 © TOUCH BRIEFINGS 2007
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