FIBRINOLYTIC-ACTIVITY IS SIMILAR IN PHYSICALLY ACTIVE MEN WITH AND WITHOUT A HISTORY OF MYOCARDIAL-INFARCTION

The purpose of this study was to evaluate fibrinolytic potential at re st and after a fibrinolytic stressor in men with a history of myocardi al infarction (MI) compared with an age- and activity-matched group of men without coronary artery disease (CAD). All men were currently enr olled in exercise programs. Tissue-type plasminogen activator (TPA) an d plasminogen activator inhibitor 1 (PAI-1) activity and antigen level s were measured at rest and after a maximal exercise test. A 2x2 (grou p x time) ANOVA with repeated measures was used to evaluate fibrinolyt ic potential. Bivariate regressions were conducted to evaluate relatio ns between fibrinolytic potential and maximal oxygen uptake ((V) over dotO(2max)). Age was similar between groups (CAD, 57.5 +/- 6.6; non-CA D, 58.1 +/- 7.3 years); however, V(over dot)O-2max was higher in non-C AD subjects (36.2 +/- 6.2 vs 27.5 +/- 5.9 mL.kg(-1).min(-1)). Mean +/- SEM resting TPA and PAI-1 activities were similar between CAD and non -CAD subjects (TPA, 2.8 +/- 0.2 vs 2.8 +/- 0.2 IU/mL: PAI-1, 15.9 +/- 3.1 vs 13.1 +/- 4.1 AU/mL). Both groups showed similar significant inc reases in TPA activity with exercise (P<.05), and postexercise TPA act ivity, was also similar (CAD, 9.1 +/- 2.0 IU/mL, non-CAD, 11.7 +/- 2.6 IU/mL). Both groups also showed similar significant decreases in PAI- 1 activity with exercise (P<.05) and no differences in postexercise PA I-1 activity (CAD, 13.2 +/- 2.5 AU/mL; non-CAD, 10.4 +/- 3.6 AU/mL). S ignificantly higher resting TPA antigen levels were seen in CAD (14.8 ng/mL) than non-CAD (10.2 ng/mL) subjects (P<.05), but neither group s howed significant changes with exercise (CAD, 12.9 ng/mL; non-CAD, 11. 8 ng/mL). Resting PAI-1 antigen was similar in the two groups (CAD, 71 .4 ng/mL; non-CAD, 74.2 ng/mL) and did not significantly change with e xercise (CAD, 77.9 ng/mL; non-CAD, 72.3 ng/mL). ((V) over dotO(2max)) was positively correlated with postexercise TPA activity (r=.52, P<.05 ) and negatively correlated with resting TPA antigen (r=-.43, P<.05). Resting TPA antigen was also directly correlated with body mass index (r=.63, P<.05). The finding that functional fibrinolytic activity was not different in physically active men with and without CAD contrasts with previous reports. This suggests that matching subjects on the bas es of age and habitual physical activity status and controlling exerci se intensity are important factors to consider when evaluating fibrino lytic potential.