University of NSW, Sydney, Australia.
Heart Lung Circ. 2011 Aug;20(8):525-31. doi: 10.1016/j.hlc.2011.04.004. Epub 2011 May 17.
Stent thrombosis (ST) remains a major adverse outcome of percutaneous coronary intervention (PCI). We examined potential associations between high on treatment platelet reactivity and the risk of ST and assessed the effects of increased antiplatelet dosage on platelet inhibition.
Differences in clinical characteristics and the effect of aspirin and clopidogrel on platelet reactivity were determined after angiographically proven ST in 16 patients and in 40 patients without ST. Platelet reactivity was determined using the VerifyNow assays (Accumetrics Inc., San Diego, CA). Patients found with high on treatment platelet reactivity (P2Y12 Reaction Units ≥ 235 and/or Aspirin Reaction Units ≥ 550) returned following two weeks of double dose antiplatelet therapy for further analyses.
High post aspirin and/or clopidogrel platelet reactivity was significantly more common in patients with ST versus controls (75% vs. 2.5%, p = < 0.001). Overall, ST patients were younger (52.8 ± 10.5 vs. 59 ± 9.6 years; p = 0.039), had more pre-existing coronary artery disease (75% vs. 42%; p = 0.028) and smaller reference vessel diameters (2.9 ± 0.36 vs. 3.2 ± 0.54 mm; p = 0.047) when compared to controls. After double dose therapy, antiplatelet reactivity improved significantly in ten out of 12 subjects on clopidogrel (83.3%) and the two patients on aspirin who initially had high on treatment platelet reactivity.
This study demonstrates that high on treatment platelet reactivity with aspirin and/or clopidogrel is common amongst patients who develop stent thrombosis. Additionally this resistance can be improved with doubling the prior dose of antiplatelet therapy.
支架血栓形成（ST）仍然是经皮冠状动脉介入治疗（PCI）的主要不良后果。我们研究了治疗中血小板高反应性与 ST 风险之间的潜在关联，并评估了增加抗血小板剂量对血小板抑制的影响。
在经血管造影证实的 16 例 ST 患者和 40 例无 ST 患者中，确定了临床特征的差异以及阿司匹林和氯吡格雷对血小板反应性的影响。使用 VerifyNow 检测试剂盒（Accumetrics Inc.，圣地亚哥，CA）测定血小板反应性。发现高治疗中血小板反应性（P2Y12 反应单位≥235 和/或阿司匹林反应单位≥550）的患者在接受两周双剂量抗血小板治疗后返回进行进一步分析。
与对照组相比，ST 患者的高阿司匹林后和/或氯吡格雷后血小板反应性明显更为常见（75%比 2.5%，p<0.001）。总体而言，ST 患者更年轻（52.8±10.5 岁比 59±9.6 岁；p=0.039），有更多的预先存在的冠状动脉疾病（75%比 42%；p=0.028）和更小的参考血管直径（2.9±0.36 毫米比 3.2±0.54 毫米；p=0.047）。与对照组相比。在接受双倍剂量治疗后，12 例氯吡格雷患者中的 10 例（83.3%）和最初血小板高反应性的 2 例阿司匹林患者的抗血小板反应性显著改善。
本研究表明，在发生支架血栓形成的患者中，阿司匹林和/或氯吡格雷的治疗中血小板高反应性很常见。此外，这种抵抗可以通过将抗血小板治疗的剂量加倍来改善。
