Although low molecular weight heparins (
LMWH) have been extensively investigated for the prophylaxis and treatment of
venous thromboembolism in surgical environments, few data in acute
myocardial infarction are available in the literature. In this study two dosages of a new
LMWH,
Parnaparin, and
unfractionated heparin (UF) were investigated in 50 pts with acute
myocardial infarction. 20 pts received UF (15.000 units, three
subcutaneous injections, Group 1), 20 pts received
Parnaparin (6.400 units, single injection, Group 2) and 10 pts received a higher dose of
Parnaparin (12.800 units, single injection, Group 3). Similar
fibrinopeptide A (FpA) levels were observed in Group 1 and Group 2. In Group 3 the dosage of
Parnaparin resulted in a significant prolongation of the APTT and in lower FpA levels.
Fibrin formation was decreased by
Parnaparin in a concentration-dependent way, according to both the anti-Xa activity and the APTT ratio.
Parnaparin did not result in a significant increase in
free fatty acid concentration, in comparison with UF. Thus,
Parnaparin may offer the advantage of a single
subcutaneous injection in patients with acute
myocardial infarction.