Aspirin resistance, platelet turnover, and diabetic angiopathy: A 2011 update

In 2004 an editorial article on the so-called "aspirin resistance" and diabetic angiopathy as related to platelet turnover was published by one of us. An update of this issue is now presented. The evidence of an incomplete inhibition of platelet function by aspirin, despite doses of the drug proved to be clinically effective are employed, was first reported in the '80s, in studies devoted to platelet turnover. Based on this concept, the possibility of monitoring the entry of newly formed platelets into the circulation after aspirin ingestion was documented by measuring the return of thromboxane biosynthesis by platelets challenged in vitro by pairs of aggregating agents. The data obtained showed that platelets with intact cyclooxygenase activity could be detected into the circulation of control individuals as early as 4-6 hrs after aspirin ingestion, but at shorter time intervals in diabetic angiopathy. In the latter setting, it was concluded that "schedules of aspirin which may suffice in normals are not effective in patients with diabetic angiopathy, presumably because these patients have a high rate of entry of new platelets into the circulation". As many as 25 years after its original publication, the clinical relevance of an accelerated platelet turnover as to "aspirin resistance" has been confirmed and extended to other clinical settings at high risk of ischemic events. Newer aspirin dosing and scheduling, tailored at reducing the individual patient risk related to an incomplete inhibition of platelet function by a standard aspirin dose should now be defined.