Stroke is a disease of the elderly and, as a result of the expected demographic changes in many industrialised countries, its incidence is likely to increase in the future. A first-ever
stroke significantly increases the likelihood of further events; thus,
secondary prevention is of major importance. Only a minority of recurrent
strokes can be prevented by surgical or other invasive methods, meaning that most secondary preventive measures involve
drug treatment, which has become increasingly sophisticated in recent years.
Ischaemic stroke constitutes the vast majority of all
strokes; effective
secondary prevention depends on a variety of factors, of which the correct classification in terms of subtypes and aetiological mechanisms is a pivotal prerequisite, as is the assessment of the patient's cardiovascular risk profile. In addition to the evaluation of pathomechanisms, stratification of subtypes of
brain infarction is mainly based on morphology seen with brain imaging techniques, which provides additional evidence for the presumed cause of the
stroke. Inhibitors of platelet function and
anticoagulants are the two major groups of antithrombotic drugs used for the
secondary prevention of
stroke.
Antiplatelet agents are still indicated in the majority of patients after
ischaemic stroke, especially if an arterial origin is presumed. In addition to
aspirin (
acetylsalicylic acid), the position of which as the first-line
antiplatelet drug is increasingly being questioned, other compounds with antiplatelet activity have been developed and have proven effective in secondary
stroke prevention, including
ticlopidine,
clopidogrel and
dipyridamole.
Anticoagulants are principally indicated after cardioembolic
ischaemic stroke; however, their inherent
bleeding risks render their use in many cases rather difficult, in particular for elderly patients. Patient compliance with the recommended treatment is of major importance, given the somewhat limited efficacy of
antithrombotic agents in
stroke prevention. Since 'real world' experience does not match the circumstances under which clinical trials are conducted, this article will also deal with problems not covered by specific studies, such as risk stratification for
anticoagulant treatment and how to proceed in cases of unknown
stroke aetiology. The management of major cardiovascular risk factors is the other mainstay of secondary
stroke prevention. Recent evidence indicates that
antihypertensive treatment may be as effective as antithrombotic drugs for
secondary prevention of
stroke. This still needs to be proven for the treatment of other cardiovascular risk factors, such as
diabetes mellitus and
hypercholesterolemia. Nevertheless, the results of recent studies investigating the effect of
HMG-CoA reductase inhibitors ('
statins') on cardiovascular events strongly suggest a
stroke-preventive effect.