Wong Shen, Ward Christopher M, Appleberg Michael, Lewis David R
Department of Vascular Surgery, University of Sydney, The Royal North Shore Hospital, St Leonards, NSW, Australia.
ANZ J Surg. 2006 Oct;76(10):873-7. doi: 10.1111/j.1445-2197.2006.03693.x.
The reported range in rates of aspirin resistance (5.5-60%) may reflect difficulties in studying platelet function and the variety of tests used. This study used a platelet function analyzer (PFA-100) to prospectively document aspirin resistance in a cohort of patients with arterial disease.
Patients with internal carotid artery (ICA) stenosis or intermittent claudication (IC) were recruited. Exclusion criteria were contraindications to aspirin, prescription of other medication with known antiplatelet effects or known platelet abnormalities. After prescription of 100 mg aspirin/day for 2 weeks an uncuffed venous blood sample was taken and analysed with the PFA-100. Aspirin resistance was defined as closure time (CT) less than the upper limit of normal (158 s collagen/epinephrine agonist; 118 s collagen/adenosine diphosphate (ADP) agonist).
Thirty-three patients with IC and 12 patients with ICA stenosis were recruited (n = 45). Median (range) age was 74 years (49-85) and the male to female ratio was 1.5:1. The median (range) CT was >300 (85 to >300) s with collagen/epinephrine and 100 (52 to >300) s with collagen/ADP agonist. Twelve patients (27%) in the collagen/epinephrine group had normal CT despite treatment with 100 mg aspirin, indicating resistance. Of the 33 patients with collagen/epinephrine CT prolonged by aspirin, 10 patients also had prolonged collagen/ADP CT, suggesting excessive platelet inhibition.
A significant proportion of patients taking aspirin do not show laboratory evidence of platelet inhibition and may not be protected from atherothrombotic events. The PFA-100 appears to be a useful tool to screen for both aspirin resistance and excessive aspirin mediated platelet inhibition.
报道的阿司匹林抵抗发生率范围（5.5 - 60%）可能反映了研究血小板功能的困难以及所使用检测方法的多样性。本研究使用血小板功能分析仪（PFA - 100）对一组动脉疾病患者的阿司匹林抵抗情况进行前瞻性记录。
招募患有颈内动脉（ICA）狭窄或间歇性跛行（IC）的患者。排除标准为阿司匹林禁忌证、使用已知具有抗血小板作用的其他药物或已知的血小板异常。在每天服用100mg阿司匹林2周后，采集无袖带静脉血样本并用PFA - 100进行分析。阿司匹林抵抗定义为封闭时间（CT）小于正常上限（胶原/肾上腺素激动剂为158秒；胶原/二磷酸腺苷（ADP）激动剂为118秒）。
招募了33例IC患者和12例ICA狭窄患者（n = 45）。年龄中位数（范围）为74岁（49 - 85岁），男女比例为1.5:1。胶原/肾上腺素组的CT中位数（范围）>300（85至>300）秒，胶原/ADP激动剂组为100（52至>300）秒。胶原/肾上腺素组中有12例患者（27%）尽管服用了100mg阿司匹林，但CT正常，表明存在抵抗。在33例胶原/肾上腺素CT因阿司匹林而延长的患者中，有10例患者的胶原/ADP CT也延长，提示血小板抑制过度。
相当一部分服用阿司匹林的患者未表现出实验室证据表明血小板受到抑制，可能无法预防动脉粥样硬化血栓形成事件。PFA - 100似乎是筛查阿司匹林抵抗和阿司匹林介导的血小板抑制过度的有用工具。
