FACTORS AFFECTING FIBRINOLYTIC POTENTIAL - CARDIOVASCULAR FITNESS, BODY-COMPOSITION, AND LIPOPROTEIN(A)

The purpose of the study was to determine the factors that affect basa l (resting) and poststressor fibrinolytic activity or potential. Varia bles of interest included cardiovascular fitness (maximal oxygen consu mption [VO(2)max]), body fat, body mass index (BMI), and lipids/lipopr oteins, including lipoprotein(a) [Lp(a)]. Blood was collected from 46 middle aged men before and after a maximal exercise test. Pearson and Spearman correlation coefficients were calculated to determine associa tions between the variables of interest and tissue plasminogen activat or (t-PA) and plasminogen activator inhibitor-1 (PAI-1) activities in the basal state Ind after stimulation with maximal exercise. Multiple regression analyses were also conducted to determine independent predi ctors of the fibrinolytic variables. Maximal exercise produced signifi cant increases in t-PA activity and decreases in PAI-I activity. Poste xercise t-PA activity was inversely related to basal PAI-1 activity (r =-.34). Vo(2)max was positively correlated with t-PA activity (basal, r=.39; postexercise, r=.67) and inversely related to PAI-1 activity (b asal, r=-.41; postexercise, r=-.42). Body fat was correlated with post exercise t-PA activity (r=-.60) and both basal and postexercise PAI-1 activity (r=.42), but the correlation with basal t-PA activity was not significant (P=.058): Postexercise t-PA activity was positively corre lated (r=.37) with high-density lipoprotein cholesterol (HDL-C) and ne gatively correlated (r=-.42) with low-density lipoprotein cholesterol (LDL-C). Basal PAI-1 activity was negatively correlated with HDL-C (r= -.37). Lp(a) was not correlated with any fibrinolytic variable or fitn ess. Multiple regression analyses showed that Vo(2)max was an independ ent predictor of both basal and postexercise t-PA activity (R(2)=.16 a nd .34, respectively). Triglyceride (TG) levels and Vo(2)max were sign ificant independent predictors of PAI-1 activity (R(2)=.31). In conclu sion, cardiovascular fitness was a strong independent predictor of fib rinolytic potential. In addition, poststressor measures of fibrinolyti c potential may provide more information about the fibrinolytic system than basal values. Copyright (C) 1996 by W.B. Saunders Company