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 exer cise stress test one month after hospital discharge. The in vivo forma tion of thromboxane and prostacyclin formation before and during the e xercise stress test was analyzed with gas chromatography-mass spectrom etry of the in vivo formed metabolites 2,3-dinor-TxB(2) and 2,3-dinor- 6-keto-PGF(1 alpha). Patients with a significant increase in thromboxa ne formation (>30%) during exercise (P < 0.0001) had a worse prognosis , with a 60% incidence of coronary events during the three years follo wing 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 in cluded patients not detected by classical risk factors. Our findings s uggest that exercise-induced thromboxane formation in survivors of an acute myocardial infarction may include prognostic information not def ined by other risk indicators.