Acute failure of artificial heart valves.

mg). A recent trial of short term use in patients who have had acute myocardial infarctions has shown that 160 mg aspirin daily reduces mortality after five weeks by a fifth.9 Despite the lack of evidence from clinical trials many patients with transient ischaemic attack and stroke are treated with 75 mg daily (a dose enshrined in the current British National Formulary), with the risk that they may be receiving an inadequate dose, albeit a safe one. On the basis of properly conducted clinical trials patients with transient ischaemic attacks and minor ischaemic strokes and no previous problems of peptic ulceration should be treated with 300 mg aspirin daily. The dose may be reduced to 150 mg and then 75 mg if I Antiplatelet Trialists' Collaboration. Secondary prevention of vascular disease by prolonged antiplatelet treatment.