PROPHYLAXIS AND TREATMENT OF STROKE - THE STATE-OF-THE-ART IN 1993

The most significant impact on cerebral infarction comes from the primary prevention of the processes that lead to stroke in at-risk individuals prior to the development of symptoms. Antithrombotic therapy with warfarin or aspirin significantly reduces thromboembolic risk in nonvalvular atrial fibrillation. The failure of primary preventive measures and the progression of disease is heralded by the development of cerebral or retinal ischaemic events; the majority of clinical trials investigating stroke prevention have targeted the secondary prevention of stroke in patients with ischaemic symptoms. A 25% risk reduction has been demonstrated with antiplatelet therapy. This was typically aspirin 1000 to 1300 mg/day, but more recently even lower doses have been beneficial, with lower rates of minor and major bleeding. Ticlopidine has demonstrated efficacy in the secondary prevention of stroke after transient ischaemic attacks and completed stroke, with a 2% risk of significant neutropenia. The benefits of carotid endarterectomy have been demonstrated in patients with symptomatic internal carotid artery stenosis involving 70 to 99% of the arterial diameter. Surgery is not indicated in patients with less than 30% internal carotid artery stenosis; 30 to 69% continues to be studied. When primary and secondary preventive measures have failed, strategies directed at managing acute focal cerebral ischaemia include re-establishing cerebral blood flow and limiting ischaemic neuronal injury. Advances in basic research that have identified components of the ischaemic cascade have been translated clinically into numerous clinical trials, each targeted to one or sometimes two steps in the hope of improving neuronal salvage. Because of the complex intracellular and extracellular processes evolving during ischaemia, it is naive to expect that a single drug directed toward one component of this cascade will provide dramatic results and thus far many trials have had minimal or negative results.