Primary Prevention of Ischaemic Stroke

Primary Prevention of Ischaemic Stroke

Allyson R Zazulia, Andria L Ford
Published: European Neurological Disease 2007
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Stroke is the second most common cause of death worldwide and a leading cause of long-term neurological impairment, with as many as 30% of survivors permanently disabled.1–3 Of all strokes, approximately 70% are first-time events, thus primary-care physicians have a great opportunity to identify patients who may benefit from risk factor modification.2 Furthermore, neurologists frequently evaluate non-stroke patients who carry modifiable stroke risk factors. In these settings, initiation of primary prevention strategies may have the greatest impact on the disease and its enormous toll on the healthcare system.

Risk Factors for Ischaemic Stroke
Numerous factors contribute to the risk of first stroke. The non-modifiable risk factors include increasing age, sex, race/ethnicity, family history, 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 benefit from aggressive treatment of any modifiable risk factors. Regarding age, each decade above 55 years of age leads to a doubling of stroke risk.4 Men carry an overall higher risk of stroke than women at younger ages, but women are at greater risk over the age of 85 years.5 This relatively greater risk in older women may reflect changing hormonal status and/or the use of hormone replacement therapy (HRT), as well as the fact that men with stroke risk factors may die earlier from cardiovascular disease.6–7 Race and ethnic contributions to stroke risk are difficult to separate from other risk factors such as hypertension and diabetes, which are more prevalent in certain populations. Even taking into account these risk factors, however, stroke incidence rates remain higher among some racial–ethnic groups (e.g. African-Americans).8,9 Unidentified genetic risk factors may predispose these groups to stroke and may eventually help to explain the contribution of family history to stroke risk. Stroke is a manifestation of a variety of rare genetic disorders, but the association between most inherited coagulopathies – e.g. protein C and S deficiency – and arterial events is weak.10–12 Finally, stroke incidence and stroke mortality are increased among individuals with low birth weight.13,14

The long list of modifiable stroke risk factors is best separated into two groups:

  • those that clearly contribute to risk and, if modified, reduce the risk of incident stroke; and
  • those that are associated with stroke, but have not been well studied or do not reduce the risk of stroke when treated.

Well-documented risk factors that clearly benefit from specific management include hypertension, cigarette smoking, atrial fibrillation, dyslipidaemia, diabetes mellitus and asymptomatic carotid stenosis (see Table 1).15–17 The discussion and treatment of these risk factors will be the focus of this article. Other well-documented risk factors are cardiovascular and peripheral arterial disease, sickle cell disease and obesity. Less well documented or potentially modifiable risk factors include metabolic syndrome, hyperhomocysteinaemia, hypercoagulability, oral contraceptive use, inflammatory processes, migraine headache and sleep apnoea, among others.18

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