"Biomarker testing for efficacy of therapy is an accepted way for clinicians to individualize dosing to genetic and/or environmental factors that may be influencing a treatment regimen.  Aspirin is used by nearly 43 million Americans on a regular basis to reduce risks associated with various artherothrombotic diseases.  Despite its widespread use, many clinicians are unaware of the link between suboptimal response to aspirin therapy and increased risk for inferior clinical outcomes in several disease states, and biomarker testing for efficacy of aspirin therapy is not performed as routinely as efficacy testing in other therapeutic areas.  This article reviews the clinical and laboratory aspects of determining whole-body thromboxane production, particularly as it pertains to efficacy assessment of aspirin responsiveness."

"Aspirin use has been shown to cause a dose-dependent reduction in urinary levels of 11-dehydroTxB₂."

"Elevated 11-DHTXB₂ was associated with a prothrombotic state indicated by high TIP-FCS. Our data suggest that measurement of urinary 11-DHTXB₂ may be a useful method to optimize statin dosing in order to reduce thrombotic risk."

"Our baseline results are in line with earlier studies, which have shown an association between glycemic control and urinary 11-DHTXB₂ excretion. In addition, improving glycemic control has been shown to lead to a decreased 11-DHTXB₂ excretion."

"In the present study, the difference in urinary 11-DHTXB₂ excretion was also influenced by C-reactive protein levels, which were different between the study groups and may reflect the influence of the inflammatory state found in diabetes on thromboxane formation."

"Both environmental and genetic factors, including aspirin pharmacokinetics, inflammation, platelet COX-2, use of non-steroid anti-ainflammatory drugs and dyslipidaemia may determine variable platelet response to acetylsalicylic acid.”’ 

"However, CRP level was significantly associated with the extent of platelet refractoriness to acetylsalicylic acid in these patients, which points out that even subclinical inflammatory states may be considered possible candidates for suboptimal acetylsalicylic acid response."

"Among aspirin-treated patients at high risk of cardiovascular events, persistent thromboxane generation predicts the risk of the composite outcome of myocardial infarction, stroke, or cardiovascular death, independent of other cardiovascular risk factors."