讨 论
针对TRITON-TIMI 38试验中STEMI患者的分析显示,在研究期间,与氯吡格雷组相比,普拉格雷组主要复合终点(心血管性死亡、非致死性心肌梗死或非致死性卒中)的风险明显下降。此外,30 d主要次级终点(心血管性死亡、非致死性心肌梗死或紧急靶血管血运重建)也明显下降。
此分析的结果与对TRITON-TIMI 38试验中不稳定型心绞痛或非STEMI患者的分析结果一致[16, 24]。在结合其他PCI治疗STEMI研究中使用的典型终点事件考虑时,本研究中观察到的普拉格雷组30 d和15个月时心血管性死亡、心肌梗死和紧急靶血管血运重建发生率的明显下降,强调了使用普拉格雷的获益[17, 21]。
尽管在STEMI患者中较多应用了糖蛋白Ⅱb/Ⅲa受体拮抗剂,其出血风险与整体急性冠状动脉综合征人群相同[16]。与氯吡格雷相比,普拉格雷并未导致严重出血、危及生命的出血以及严重或轻微出血的风险显著增加。然而,针对相互作用的检验结果为阴性,对这些数据应该谨慎考虑。4%的患者接受了CABG术,此类患者中应用普拉格雷伴随严重出血事件增加。STEMI患者的平均年龄比非STEMI患者小2岁,女性比例较低,较少患有糖尿病,吸烟者较多;这些差异可能对STEMI人群中出血风险较低有一定影响。
采用直接PCI治疗STEMI时,快速抑制血小板活性和聚集是成功治疗的关键。应用阿司匹林和糖蛋白Ⅱb/ Ⅲa受体拮抗剂有助于达到这些结果,但是应用氯吡格雷时效果较小[17–21]。虽然较高负荷剂量的氯吡格雷能加速起效并增强血小板抑制的程度,但高剂量应用对血小板的效果在直接PCI术中和术后即刻较有限[25–29]。据了解,以往还没有在直接PCI患者中应用负荷剂量氯吡格雷的研究报道。此外,有关在PCI治疗STEMI患者中应用氯吡格雷的临床数据仅限于一些随机试验的亚组分析,这些随机试验显示行补救PCI前给予数天预处理效果良好[13, 30–31]。
与氯吡格雷600 mg相比,负荷剂量60 mg普拉格雷能够更快、更持久、更有效地抑制ADP介导的血小板聚集;普拉格雷用药30 min即可见到明显的效果,而氯吡格雷无此效果[14, 32]。令人感兴趣的是,在不可能进行预处理时,普拉格雷较之氯吡格雷在药动学和药效学方面的优势;同样,在行直接PCI治疗STEMI时,快速抑制血小板聚集是理想状态。
TRITON-TIMI 38研究并未被设计用于仅在STEMI患者中检验所有临床终点。从限定的样本规模考虑,分析中所观察到的普拉格雷在缺血事件中的获益值得关注。如果样本量更大,可能会发现发生率较低的事件(包括严重出血)存在差异。
TRITON-TIMI 38研究被设计用于评估普拉格雷的疗效;在极可能行PCI治疗的患者中,普拉格雷被认为具有较标准剂量的氯吡格雷更高的血小板抑制效果[15]。因此,作者的数据既没有涉及普拉格雷与高剂量氯吡格雷之间的差异,也没有显示PCI术前各阶段的效果。基于来自PRINCIPLE-TIMI 44研究[14]的药动学资料,与高负荷剂量及维持剂量的氯吡格雷相比,TRITON-TIMI 38研究中采用的普拉格雷具有更快、更有效的血小板抑制作用。
据了解,本研究是在PCI治疗STEMI患者中使用噻吩吡啶类药物的最大规模随机试验。而且,作者相信此分析结果是STEMI的机械再灌注方面最有力的证据之一。其结果提示了:对于行PCI治疗的STEMI患者,普拉格雷是具有前景的、可替代氯吡格雷的药物。
Lancet 2009; 373: 723–31
(王海玲、贾宁 译 韩常宝 审校)
Acknowledgments:
The TRITON-TIMI 38 trial is supported by Daiichi Sankyo and Eli Lilly.
Institute of Cardiology, INSERM U856, Université Paris 6, Pitié-Salpêtrière Hospital (AP-HP), Paris, France (Prof G Montalescot MD); and TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA (S D Wiviott MD, E Braunwald MD, S A Murphy MPH, C M Gibson MD, C H McCabe BS, E M Antman MD) Correspondence to: Prof Gilles Montalescot, Bureau 236, Institute of Cardiology, INSERM U856, Pitié-Salpêtrière Hospital (AP-HP), 47 Boul de l'Hôpital, 75013 Paris, France(e-mail: gilles.montalescot@psl.aphp.fr)
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