Hirudin: Its Biology and Clinical Use

Over a century has passed since the anticoagulant properties of hirudin were identified. Our understanding of this unique and promising 65 amino acid polypeptide has grown steadily, allowing clinical experience to be gained. In acute myocardial infarction, hirudin has been associated with a higher incidence of early and sustained TIMI grade 3 flow, a higher rate of infarct-related artery patency at 18-36 hours with a decreased rate of reocclusion, and a lower incidence of in-hospital death and reinfarction as compared with heparin. hirudin has also been associated with a stable level of articoagulation and an acceptable hemorrhagic complication rate when given in carefully chosen doses. In acute coronary syndromes, the initial results indicate that hirudin can improve the resolution of coronary thrombus and reduce the incidence of recurrent ischemic events. Similarly impressive reductions in thrombotic complications and ischemia have been observed in the early balloon angioplasty experience. Promising results have also been seen with hirudin in preventing deep venous thrombosis following orthopedic surgery. The favorable effects of hirudin as compared with heparin in phase II clinical trials have prompted further investigation in two large phase III trials, TIMI 9 and GUSTO 2. It is hoped that these initial results can be confirmed and that hirudin can be proved to be a safe and effective treatment for thrombotic syndromes of the venous and arterial circulatory systems.