Several new drugs for the management of thromboembolic disorders have recently become available. Low-molecular-weight heparins are being evaluated for the prophylaxis of medical and surgical
deep venous thrombosis and
pulmonary embolism; for the treatment of pre-existing
thrombosis; and for cases of coronary syndrome (
unstable angina,
myocardial infarction), thrombotic and
ischemic stroke, interventional cardiology, pregnancy,
cancer, and
transplantation-associated
thrombosis. A chemically synthesized
heparin pentasaccharide, which has purely anti-
factor Xa activity and does not induce
thrombocytopenia, is also in clinical trial.
Thrombin inhibitors, such as
hirudin and
argatroban, are a practical
anticoagulant substitute where
heparin cannot be used. They are also useful for the management of coronary syndrome and as adjunct
therapy. The
antiplatelet agent ticlopidine and its analogue,
clopidogrel, which does not produce blood dyscrasia, are effective for the
secondary prevention of
thrombotic stroke and the management of combined arterial thrombotic syndromes.
Glycoprotein-targeting
antibodies, synthetic derivatives, and
peptides (some of which are orally bioavailable) have added a new dimension to the management of arterial
thrombosis and high-risk patients having angioplasty. Plasma-derived agents, such as
antithrombin III, are available for the management of
thrombophilia and
disseminated intravascular coagulation. Compression devices and the foot pump, alone and in combination with pharmacologic agents, have been used successfully. Combination
therapy using various agents in different proportions have also been found useful. Although there is much enthusiasm in this quickly developing area and clinical trials are demonstrating the antithrombotic efficacy of the new drugs, safety considerations require additional clinical validation. Long-term outcomes and costs also need to be addressed objectively.