Prognostic value of urinary 11-dehydro-thromboxane B2 for mortality: A cohort study of stable coronary artery disease patients treated with aspirin. 
There is a variable cardiovascular risk reduction attributable to aspirin because of individual differences in the suppression of thromboxane A2 and its downstream metabolite 11-dehydro-thromboxane B2 (11dhTxB2 ).  The aim of this study is to evaluate the optimal cut point of urinary 11dhTxB2 for the risk of mortality in aspirin-treated coronary artery disease (CAD) patients.  This was a prospective cohort study including stable CAD patients who visited the Baylor Heart and Vascular Hospital in Dallas or the Texas Heart Hospital Baylor Plano, TX between 2010 and 2013.  The outcome of all-cause mortality was ascertained from chart review and automated sources.  The 449 patients included in this analysis had a mean age of 66.1 ± 10.1 years.  67 (14.9%) patients died within 5 years; 56 (87.5%) of the 64 patients with known cause of death suffered a cardiovascular related mortality.  Baseline ln(urinary 11dhTxB2 /creatinine) ranged between 5.8 and 11.1 (median = 7.2) with the higher concentrations among those who died (median: 7.6) than those who survived (median = 7.2, P < 0.001).  Using baseline ln(11dhTxB2 ) to predict all-cause mortality, the area under the curve was 0.70 (95% CI: 0.64-0.76).  The optimal cut point was found to be ln(7.38) = 1597.8 pg/mg, which had the following decision statistics: sensitivity = 0.67, specificity = 0.62, positive predictive value = 0.24, negative predictive value = 0.92, and accuracy = 0.63.  Our data indicate the optimal cut point for urine 11dhTxB2 is 1597.8 (pg/mg) for the risk prediction of mortality over five years in stable patients with CAD patients treated with aspirin.