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 rest and after a fibrinolytic stressor in men with a history of myocardial infarction (MI) compared with an age- and activity matched group of men without coronary artery disease (CAD). All men were currently enrolled in exercise programs. Tissue type plasminogen activator (TPA) and plasminogen activator inhibitor I (PAI-I) activity and antigen levels were measured at rest and after a maximal exercise test. A 2x2 (groupxtime) ANOVA with repeated measures was used to evaluate fibrinolytic potential. Bivariate regressions were conducted to evaluate relations between fibrinolytic potential and maximal oxygen uptake (VO(2max)). Age was similar between groups (CAD, 57.5±6.6: non-CAD, 58.1±7.3 years); however, VO(2max) was higher in non-CAD subjects (36.2±6.2 vs 27.5±5.9 mL · kg^-1 min^-1). Mean±SEM resting TPA and PAI-I activities were similar between CAD and non- CAD subjects (TPA.2.8±0.2 vs 28±0.2 IU/mL; PAI-I, 15.9±3.1 vs 13.1±4.1 AU/mL). Both groups showed similar significant increases in TPA activity with exercise (P<.05) and postexercise TPA activity 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 PAI-1 activity (CAD, 13.2±2.5 AU/mL; non-CAD, 10.4±3.6 AU/mL). Significantly 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 showed 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 exercise (CAD, 77.9 ng/mL; non-CAD, 72.3 ng/mL). VO(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 bases of age and habitual physical activity status and controlling exercise intensity are important factors to consider when evaluating fibrinolytic potential.