Effect of different aspirin regimens on urinary excretion of 11-dehydro-TXB₂. Shown are individual data on urinary 11-dehydro-TXB₂ excretion rates measured in the different phases of the study, including baseline, washout, and randomized aspirin regimens. During washout, patients took enteric-coated aspirin 100 mg once daily. Horizontal lines indicate medians. Each symbol indicates 1 patient across different treatments. #P < .05 versus baseline and washout. WO indicates washout; od, once daily; bid, twice daily; and EC, enteric-coated.