Primary prevention of coronary heart disease with aspirin

According to meta-analysis and the results of the two studies with the highest power, aspirin is effective in primary prevention of coronary heart disease. These beneficial effects, however, are at least partially out-weight by unwanted effects-such as intense gastrointestinal bleeding and hemorrhagic stroke. These side effects remain constant with increasing risk of coronary heart disease, whereas the protective effects increase. If an annual risk of coronary heart disease of < or =0.6% exists, aspirin is normally not indicated; for a risk of 0.7-1.4% the facts should be discussed with the patient. If a risk of > or =1.5% exists, aspirin should be given. Problems of aspirin therapy--such as "aspirin paradox" and "aspirin resistance"--have been documented for secondary prevention; they might, however, have likewise clinical implications in primary prevention.