Avendaño A, Ferguson J J
St. Luke's Episcopal Hospital, Texas Heart Institute, Baylor College of Medicine, Houston 77225.
J Am Coll Cardiol. 1994 Mar 15;23(4):907-10. doi: 10.1016/0735-1097(94)90636-x.
The aim of this study was to determine whether activated coagulation time measurements from Hemochron and HemoTec machines can be used interchangeably and whether similar activated coagulation time target ranges for adequate anticoagulation can be applied to both machines.
Adequate anticoagulation is necessary for the safe performance of intravascular interventions such as percutaneous transluminal coronary angioplasty. In current practice, anticoagulation status is frequently assessed by way of the activated coagulation time with one of two commercially available systems, HemoTec and Hemochron. Each one employs a different technique to determine the time of clot formation; however, the same target activated coagulation time values for adequate anticoagulation have been used interchangeably in published studies.
A total of 311 paired samples were compared in 113 high risk patients undergoing angioplasty enrolled in a randomized trial of a platelet glycoprotein IIb/IIIa receptor antibody. Simultaneous activated coagulation time measurements were obtained before and after administration of heparin, and the difference between the values of both machines was calculated. The relation between the Hemochron and HemoTec values was determined by using linear regression analysis. All activated coagulation time measurements were classified as either therapeutic or subtherapeutic using an arbitrary activated coagulation time target of 300 s.
There was a correlation between values from the two machines (r = 0.86), but the Hemochron values were consistently higher than the HemoTec values by a mean value +/- SD of 28 +/- 29%, with wide individual variation. After heparin administration, there was a significant (p < 0.0001) difference between the number of measurements classified as therapeutic by HemoTec (53%) and by Hemochron (94%).
HemoTec and Hemochron activated coagulation time measurements cannot be used interchangeably. Appropriate target activated coagulation time ranges to determine adequate anticoagulation during coronary angioplasty need to be established for both machines; the target range for one machine should not be extrapolated to the other.
本研究旨在确定Hemochron和HemoTec机器所测活化凝血时间是否可互换使用，以及相似的用于充分抗凝的活化凝血时间目标范围是否可应用于这两种机器。
充分抗凝对于诸如经皮腔内冠状动脉成形术等血管内介入操作的安全进行是必要的。在当前实践中，抗凝状态常通过使用两种商用系统（HemoTec和Hemochron）之一的活化凝血时间来评估。每种系统采用不同技术来确定凝血形成时间；然而，在已发表的研究中，用于充分抗凝的相同目标活化凝血时间值却被互换使用。
在一项血小板糖蛋白IIb/IIIa受体抗体的随机试验中，对113例接受血管成形术的高危患者的311对样本进行了比较。在给予肝素之前和之后同时进行活化凝血时间测量，并计算两种机器测量值之间的差异。通过线性回归分析确定Hemochron和HemoTec测量值之间的关系。使用300秒这一任意活化凝血时间目标将所有活化凝血时间测量值分类为治疗性或亚治疗性。
两种机器的测量值之间存在相关性（r = 0.86），但Hemochron测量值始终比HemoTec测量值高，平均值±标准差为28±29%，个体差异较大。给予肝素后，HemoTec分类为治疗性的测量次数（53%）与Hemochron分类为治疗性的测量次数（94%）之间存在显著差异（p < 0.0001）。
HemoTec和Hemochron活化凝血时间测量不能互换使用。需要为这两种机器分别确定用于冠状动脉成形术期间充分抗凝的合适目标活化凝血时间范围；一台机器的目标范围不应外推至另一台机器。
