Antithrombotic Therapy for Cerebrovascular Disorders: Platelet Antiaggregation Agents

Antithrombotic Therapy for Cerebrovascular Disorders: Platelet Antiaggregation AgentsIn 11 trials that recruited patients with TIAs or minor stroke (n = 5,807), nonfatal stroke was reduced by antiplatelet drugs by 24% (p = 0.02). In 10 trials of patients with MI (n = 13,544) the reduction in nonfatal stroke was 25% (p = 0.0002). In these groups of patients, therefore, it seems clear that antiplatelet drugs should be prescribed. The choice (aspirin, sulfinpyrazone, etc) has been addressed in the same meta-analysis. There were few direct comparisons, but those that looked at aspirin vs sulfinpyrazone favored aspirin, and those that compared aspirin with and without dipyridamole revealed no difference. Most trials employed a dose of aspirin of 1.0-1.3 g/day. The recently completed UK trial compared 0.3 and 1.2 g to placebo. Although there was said to be a trend in favor of the higher dose, the numbers were far too low to avoid a type II error, and we must conclude that there are no satisfactory data comparing low- and high-dose aspirin. read more

The Canadian study showed a major decrease in stroke and death in men (by almost 50%) but no difference in women. When all studies that identify men and women are considered, it is apparent that women have fewer strokes and lower mortality than men regardless of treatment. Data in the Hospital Frequency Study suggest that this is limited to older-age groups. In an Italian study in which patients with TIAs were randomly treated with aspirin or sulfinpyrazone, there was further evidence of a sex difference. Male patients treated with aspirin had a highly significant benefit (p<.001), with a 53% reduction of further events, but in women there was a trend in favor of sulfinpyrazone. In the UK aspirin trial men and women were separately randomized. The reduction in stroke/M I/vascular death was only significant in males, but again the number of end points in females was small. The evidence is that aspirin therapy is effective in symptomatic males. The European Stroke Prevention Study showed a reduction in stroke in both men and women. Thus, the case in females is unproved, but could be illuminated by a metaanalysis of those trials in which the data for the two sexes are adequately distinguished.