Implications of the prognostic importance of exercise-induced thromboxane formation in survivors of an acute myocardial infarction.

Thirty-two patients with acute myocardial infarction performed an exercise stress test one month after hospital discharge. The in vivo formation of thromboxane and prostacyclin formation before and during the exercise stress test was analyzed with gas chromatography-mass spectrometry of the in vivo formed metabolites 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha. Patients with a significant increase in thromboxane formation (> 30%) during exercise (P < 0.0001) had a worse prognosis, with a 60% incidence of coronary events during the three years following the index infarction as compared to only 8% in the group without such an increase in thromboxane formation during exercise (P = 0.008). The group with coronary events and increased thromboxane formation included patients not detected by classical risk factors. Our findings suggest that exercise-induced thromboxane formation in survivors of an acute myocardial infarction may include prognostic information not defined by other risk indicators.