White Harvey D, Braunwald Eugene, Murphy Sabina A, Jacob Ashok J, Gotcheva Nina, Polonetsky Leonid, Antman Elliott M
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland 1030, New Zealand.
Eur Heart J. 2007 May;28(9):1066-71. doi: 10.1093/eurheartj/ehm081. Epub 2007 Apr 24.
To determine the effects of age on outcomes in patients with STEMI treated with a strategy of enoxaparin (ENOX) vs. unfractionated heparin (UFH).
In the ExTRACT-TIMI 25 trial, 20,479 patients with STEMI were randomized in a double-blind fashion to UFH or ENOX. A novel reduced dose of ENOX was administered to patients >or=75 years, and a reduced dose in those with an estimated creatinine clearance of < 30 mL/min. Anti-Xa levels were measured in a subset of patients (n = 73). The exposure to anti-Xa over time was lower in the elderly (AUC(0-12 h) P < 0.0001; AUC(steady-state) P = 0.0046). The relative risk reduction (RR) with ENOX on the primary endpoint, i.e. death or non-fatal recurrent myocardial infarction, was greater in patients < 75 years (20%) than > 75 years (6%), but the absolute benefits were similar. When compared with UFH, ENOX was associated with an RR of 1.67 for major bleeding, but the magnitude of the excess risk tended to be lower (RR = 1.15) in patients >or= 75 years assigned to ENOX.
A dose reduction of ENOX in the elderly appears to be helpful in ameliorating bleeding risk. A strategy of ENOX was superior to UFH in both young and elderly patients with STEMI treated with fibrinolysis.
确定年龄对采用依诺肝素（ENOX）与普通肝素（UFH）治疗策略的ST段抬高型心肌梗死（STEMI）患者预后的影响。
在ExTRACT-TIMI 25试验中，20479例STEMI患者以双盲方式随机分为接受UFH或ENOX治疗。对年龄≥75岁的患者给予新型低剂量ENOX，对估计肌酐清除率<30 mL/min的患者也给予低剂量ENOX。在一部分患者（n = 73）中测量抗Xa水平。随着时间推移，老年患者的抗Xa暴露量较低（AUC(0 - 12小时) P < 0.0001；AUC(稳态) P = 0.0046）。ENOX治疗主要终点事件（即死亡或非致死性再发心肌梗死）的相对风险降低（RR）在<75岁患者中（20%）大于>75岁患者（6%），但绝对获益相似。与UFH相比，ENOX导致大出血的RR为1.67，但在接受ENOX治疗的≥75岁患者中，额外风险的幅度往往较低（RR = 1.15）。
老年患者减少ENOX剂量似乎有助于降低出血风险。在接受纤溶治疗的年轻和老年STEMI患者中，ENOX治疗策略均优于UFH。
