Summary
The aim of this study was to evaluate the existence of an additive effect between
standard heparin and dDAVP in the enhancement of endogenous fibrinolysis. Eight healthy
volunteers were studied in a randomized double blind placebo controlled cross-over
trial. The volunteers were treated i. v. with dDAVP, 0.4 μg/kg, over 15 minutes followed
by an i. v. bolus dose of either standard heparin, 5,000 I.U., or saline. A 48 hour
wash-out period was adopted. The infusion of dDAVP followed by standard heparin resulted
in a higher increase in plasma t-PA actiyity, t-PA antigen, circulating t-PA specific
activity and FPLA when compared with dDAVP followed by saline. The difference was
already statistically significant at 15 minutes after the infusion of dDAVP and lasted
for up to 60 minutes after the end of the infusion of dDAVP. Plasma PAI 1 showed a
slightly higher decrease after dDAVP plus standard heparin than after dDAVP plus saline
but this difference was not statistically significant. No statistically significant
changes of fibrinogen and α2-antiplasmin levels were observed. As expected, the infusion of standard heparin resulted
in an increase in plasma anti-Xa activity and in a prolongation of aPTT Our results
demonstrated an additive effect of dDAVP and standard heparin on the increase in circulating
t-PA, the effect of dDAVP being potentiated and prolonged by heparin. This observation
could prospect a combined use of dDAVP and standard heparin in the prophylaxis and
treatment of thromboembolic diseases.
Keywords
dDAVP - Standard heparin - Fibrinolysis - Tissue-type plasminogen activator
