Platelet Function Testing for Aspirin Resistance Is Reasonable to Do

When discussing the issue of aspirin resistance and platelet function testing, there are a number of data-based conclusions that I believe we can agree on:(1) Aspirin resistance is a real phenomenon. There are dozens of studies and a number of meta-analyses that show on average 15% to 25% of individuals will be aspirin-resistant (ie, lack of the anticipated antiplatelet response when taking aspirin).1,2 The largest meta-analysis included 42 studies and reported a 27% rate of aspirin resistance.3 Rates may be slightly higher in patients with stroke.4,5 The rate of aspirin resistance tends to increase with lower doses of aspirin and may be higher when using enteric-coated aspirin.3,4 The rate of aspirin resistance appears to increase with age above the mid-60s.1 Perhaps this relates to gastrointestinal issues such as stomach pH, which increases with age due to lower acid production.(2) Aspirin resistance has clinical consequences. Various studies, most in cardiac patients, have shown that individuals with aspirin resistance have an increased risk of having a …