Turpie A G
McMaster University, Hamilton, Ontario, Canada.
Am J Cardiol. 1997 Sep 4;80(5A):21E-24E. doi: 10.1016/s0002-9149(97)00485-2.
Thrombotic occlusion is responsible for most acute manifestations of coronary artery disease, including unstable angina and non-Q-wave myocardial infarction. Antiplatelet therapy plays a major role in reducing the risk of ischemic events in such patients. Since thrombin generation is vital to the pathogenesis of thrombosis, recent studies have focused on thrombin inhibition in the management of acute ischemia. Heparin is the most widely used anticoagulant for acute management of thrombosis and is the treatment of choice in preventing and treating venous thromboembolism. Given in therapeutic doses intravenously, it is more effective than aspirin in reducing the risk of death or myocardial infarction in patients with unstable angina. Low-molecular-weight (LMW) heparins have improved pharmacologic and pharmacokinetic properties over standard heparin that may result in greater efficacy and safety. LMW heparins may be given in a fixed dose subcutaneously without monitoring, resulting in greater clinical utility and cost-effectiveness compared with standard heparin. Given subcutaneously in fixed, weight-adjusted doses they are more effective and safer than intravenous heparin in treating deep-vein thrombosis. Several studies have evaluated LMW heparins in unstable angina. In a small open trial, LMW heparin (nadroparin) reduced the risk of acute myocardial infarction compared with aspirin alone or a combination of aspirin and standard heparin. In 2 large clinical trials, LMW heparin (dalteparin) has been shown to be effective in the management of unstable angina with a 63% reduction in risk of death or acute myocardial infarction over patients treated with aspirin alone (Fragmin during Instability in Coronary Artery Disease; FRISC) and to be as effective as intravenous heparin (Fragmin in Unstable Coronary Artery Disease; FRIC).
血栓形成性闭塞是冠心病大多数急性表现的原因，包括不稳定型心绞痛和非Q波心肌梗死。抗血小板治疗在降低此类患者缺血事件风险方面发挥着重要作用。由于凝血酶生成对血栓形成的发病机制至关重要，最近的研究集中在急性缺血管理中的凝血酶抑制。肝素是急性血栓形成管理中使用最广泛的抗凝剂，是预防和治疗静脉血栓栓塞的首选治疗方法。静脉给予治疗剂量时，它在降低不稳定型心绞痛患者死亡或心肌梗死风险方面比阿司匹林更有效。低分子量（LMW）肝素比标准肝素具有更好的药理学和药代动力学特性，这可能导致更高的疗效和安全性。LMW肝素可以皮下固定剂量给药而无需监测，与标准肝素相比，具有更高的临床实用性和成本效益。以固定的、根据体重调整的剂量皮下给药时，它们在治疗深静脉血栓形成方面比静脉注射肝素更有效、更安全。几项研究评估了LMW肝素在不稳定型心绞痛中的作用。在一项小型开放试验中，与单独使用阿司匹林或阿司匹林与标准肝素联合使用相比，LMW肝素（那屈肝素）降低了急性心肌梗死的风险。在两项大型临床试验中，LMW肝素（达肝素）已被证明在不稳定型心绞痛的管理中有效，与单独使用阿司匹林治疗的患者相比，死亡或急性心肌梗死风险降低63%（冠心病不稳定期的法安明；FRISC），并且与静脉注射肝素一样有效（不稳定型冠心病的法安明；FRIC）。
