Aspirin resistance: fact or fiction?

A meta-analysis of clinical studies of patients with cardiovascular disease demonstrated that the use of aspirin was associated with a 22% decrease in death rates and relevant ischemic vascular events. However, clinical studies demonstrated that patients that regularly took aspirin presented recurrence of cardiovascular events. Such observation led to the question whether, in some patients, the aspirin was not effective in blocking platelet aggregation and these patients were called unresponsive to aspirin or aspirin-resistant.