Effect of low-dose heparin treatment on fibrinolysis in patients with previous myocardial infarction.
The present study was designed to investigate whether medium-term, low-dose heparin treatment is able to affect the fibrinolytic system. In a randomized cross-over study 10 asymptomatic patients with previous (1-6 years) myocardial infarction underwent two sequential 15-day treatments, respectively, on heparin and on placebo (saline solution), preceded and separated by 10-day wash-out periods. Heparin (as calcium heparin, 12,500 IU in 0.5 ml) and saline (0.5 ml) were subcutaneously administered once a day at 8 a.m. Blood samples for fibrinolysis studies were withdrawn on the first and 15th day of each period immediately before and 4 h after heparin or saline administration before and after 10 min venous occlusion (VO) respectively. Four hours after the first heparin administration tissue plasminogen activator antigen (t-PA ag) levels significantly increased with respect to saline administration (p < 0.01 and p < 0.05, respectively). After 15-day heparin treatment a decrease in euglobulin lysis time (p < 0.05) and an increase in t-PA activity (act) (p < 0.05) and in t-PA ag (p < 0.01) in comparison with placebo were observed before VO. No statistically significant changes in plasminogen activator inhibitor-1 (PAI-1) levels were found. The variations of fibrinolytic system activity induced by heparin treatment were more marked when evaluated after VO. These results indicate that medium-term low-dose heparin treatment increases t-PA ag formation and/or release with consequent t-PA act increase.
Prisco
D
D
Clinica Medica I, University of Florence, Italy.
Paniccia
R
R
Gensini
G F
GF
Coppo
M
M
Colella
A
A
Filippini
M
M
Brunelli
T
T
Abbate
R
R
Neri Serneri
G G
GG
D000328:Adult; D000368:Aged; D005260:Female; D005342:Fibrinolysis / Q000187:drug effects*; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D010959:Tissue Plasminogen Activator / Q000097:blood
D017395:Plasminogen Activator Inhibitor 1; D006493:Heparin; D010959:Tissue Plasminogen Activator