Kohanna F H, Smith M H, Salzman E W
Blood. 1984 Jul;64(1):205-9.
Reports of circulating platelet aggregates (ie, microemboli) in thromboembolism and other vascular disorders are based on a method (Wu and Hoak , 1974) in which venous blood is collected via scalp vein needle and tubing into either formaldehyde, which fixes aggregates, or EDTA, which disperses them. The ratio of platelet counts in platelet-rich plasma (PRP) from the two blood samples after centrifugation is interpreted as a measure of platelet aggregates in the circulation in vivo. We compared this standard Wu and Hoak technique with a modified one, in which blood was drawn directly into a syringe, and with a third method that avoided centrifugation by counting single platelets in whole blood. Both modified techniques could detect aggregates generated in vitro with adenosine diphosphate (ADP). In 12 normal subjects, the three methods were equivalent, but in 37 patients with thromboembolic disorders, the standard Wu and Hoak method gave a lower ratio than the other methods. Similar results were found in a subset of eight patients with myocardial infarction. Heparin treatment of patients did not influence the results. The data suggest that formation of platelet aggregates occurred during venipuncture. Platelets may be hyperactive in patients with thromboembolic disease and may form aggregates in vitro during collection, but the concept of chronic microembolism in such patients should be reassessed.
关于血栓栓塞及其他血管疾病中循环血小板聚集体（即微栓子）的报告，是基于一种方法（Wu和Hoak，1974年），即通过头皮静脉针和导管将静脉血收集到甲醛（用于固定聚集体）或乙二胺四乙酸（用于分散聚集体）中。将离心后两份血样中富血小板血浆（PRP）的血小板计数之比，解释为体内循环中血小板聚集体的一种度量。我们将这种标准的Wu和Hoak技术与一种改良技术进行了比较，改良技术是将血液直接抽入注射器，还与第三种方法进行了比较，第三种方法通过对全血中的单个血小板计数来避免离心。两种改良技术均能检测出由二磷酸腺苷（ADP）在体外生成的聚集体。在12名正常受试者中，三种方法的结果相当，但在37名血栓栓塞性疾病患者中，标准的Wu和Hoak方法得出的比值低于其他方法。在8名心肌梗死患者的亚组中也发现了类似结果。对患者进行肝素治疗并未影响结果。数据表明，血小板聚集体的形成发生在静脉穿刺过程中。血栓栓塞性疾病患者的血小板可能处于高活性状态，在采集过程中可能在体外形成聚集体，但对此类患者慢性微栓塞的概念应重新评估。
