Although the activated partial thromboplastin time (aPTT) has historically been the method of choice for anticoagulation monitoring in patients undergoing mechanical circulatory support with intravenous unfractionated heparin, it is being progressively superseded by the anti-factor Xa (anti-Xa) method. A retrospective single-arm, single-centre analysis of 20 patients who underwent total artificial heart implantation entailed simultaneous determinations of aPTT and anti-Xa. Agreement between these parameters was assessed using the Bland-Altman method. Despite a positive correlation between aPTT and anti-Xa, normal target ranges were poorly aligned: from 5th to 30th postoperative day, for anti-Xa values of 0.2 and 0.4 U/ml corresponding aPTT values were 52.1 and 65.2 s, 7.9 and 14.8 lower than predicted values, respectively. This was not associated with thromboembolic sequalae. It was not possible to demonstrate a significant relationship between the predictor variables (postoperative day; white blood cell count; C-reactive protein concentration; alanine transaminase and alkaline phosphatase level; bilirubin; haemoglobin; albumin and total protein concentration) and the agreement between aPTT and anti-Xa levels. In summary, when anti-Xa levels were used to guide anticoagulation therapy, corresponding aPTT levels were low with respect to target range. Methodology applied in this study is generalizable to other forms of mechanical circulatory support.

中文翻译：

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合心病全人工心脏受者的抗凝：抗Xa因子还是活化部分促凝血酶原激酶时间？

尽管活化部分促凝血酶原激酶时间 (aPTT) 历来是使用静脉普通肝素进行机械循环支持的患者进行抗凝监测的首选方法，但它正逐渐被抗 Xa 因子 (anti-Xa) 方法所取代。对 20 名接受全人工心脏植入术的患者进行的回顾性单臂、单中心分析需要同时测定 aPTT 和抗 Xa。使用 Bland-Altman 方法评估这些参数之间的一致性。尽管 aPTT 和抗 Xa 呈正相关，但正常目标范围的一致性很差：从术后第 5 天到第 30 天，对于 0.2 和 0.4 U/ml 的抗 Xa 值，相应的 aPTT 值分别为 52.1 和 65.2 秒、7.9 和 14.8 低分别比预测值。这与血栓栓塞后遗症无关。无法证明预测变量（术后天数；白细胞计数；C 反应蛋白浓度；丙氨酸转氨酶和碱性磷酸酶水平；胆红素；血红蛋白；白蛋白和总蛋白浓度）与 aPTT 之间的一致性之间存在显着关系和抗 Xa 水平。总之，当抗Xa水平用于指导抗凝治疗时，相对于目标范围，相应的aPTT水平较低。本研究中应用的方法可推广到其他形式的机械循环支持。丙氨酸转氨酶和碱性磷酸酶水平；胆红素；血红蛋白；白蛋白和总蛋白浓度）以及 aPTT 和抗 Xa 水平之间的一致性。总之，当抗Xa水平用于指导抗凝治疗时，相对于目标范围，相应的aPTT水平较低。本研究中应用的方法可推广到其他形式的机械循环支持。丙氨酸转氨酶和碱性磷酸酶水平；胆红素；血红蛋白；白蛋白和总蛋白浓度）以及 aPTT 和抗 Xa 水平之间的一致性。总之，当抗Xa水平用于指导抗凝治疗时，相对于目标范围，相应的aPTT水平较低。本研究中应用的方法可推广到其他形式的机械循环支持。