ASSA14-03-38 Comparison of Urinary11-DehydrothromboxaneB2 detection and Plasma LTA Assay for evaluating aspirin response in the Aged Patients with Coronary Artery Disease

Aims

Aspirin is widely used in the primary and secondary prevention of cardiovascular diseases. Nevertheless, the responses to aspirin administration vary from one patient to another, and there is a lack of efficient and platelet-specific method correlated well with clinical outcomes. The aim of our study was to make comparisons between 2 established methods of aspirin response evaluation)—measurement of urinary 11-dehydrothromboxane B2 (11dhTxB2) and plasma Light Transmission Aggregometry (LTA) assay—in aged patients with coronary artery disease (CAD), and examinethe relationship between AR and clinical outcomes.

Methods

A total of 145 aged patients with CAD on low-dose aspirin (100 mg/d) therapy were enrolled in this study. All patients were measuredby urinary11dhTxB2 and platelet aggregation. Aspirin response was assessed via urinary 11dhTxB2 measurement and plasma LTAassay. AspirinResistance (AR) was defined as urinary11dhTxB2 >1500 pg/mg or 0.5 mg/ml AA-induced platelet aggregation ≥ 15.07%. The Spearman correlation coefficients andkappa statistics were calculated to assess correlation and agreement between the2 tests. The measured clinical outcome was defined as the occurrence of cardiovascular events and death.

Results

Prevalence of aspirin non-responders was 32.1% and 13.2%, according to urinary 11dhTxB2 measurement and LTA assay, respectively. Poor correlation in the results between the 2 tests was observed (r = 0.135, p = 0.151). Besides, the correlation between the 2 methods and AR was weak (kappa = 0.113, p = 0.113). With a mean follow-up time of 12 months, the clinical outcomes occurred more frequently in AR patients based on urinary 11dhTxB2 measurement as compared with normal aspirin response patients (18% vs 2%, OR: 8.8, 95% CI: 1.18~65.4, p = 0.037).

Conclusions

Our research observed poor correlation and lack of agreement between the 2 tests. Urinary 11dhTxB2 measurement might be a better predictor in the risk of cardiovascular events and death as compared to LTA assay. Nevertheless, development of efficient and inexpensive platelet function tests, which should also have a good correlation with clinical outcomes was necessary.