Isert Mecki, Miesbach Wolfgang, Schüttfort Gundolf, Weil Yvonne, Tirneci Vanessa, Kasper Alexander, Weber Adele, Lindhoff-Last Edelgard, Herrmann Eva, Linnemann Birgit
Division of Vascular Medicine, Department of Internal Medicine, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt/Main, Germany.
Ann Hematol. 2015 Aug;94(8):1291-9. doi: 10.1007/s00277-015-2374-3. Epub 2015 Apr 10.
Because of the possible interference of antiphospholipid antibodies (APL) with the phospholipid component of thromboplastin reagents, concerns have been raised about the validity of international normalized ratio (INR) testing to monitor anticoagulant therapy with vitamin K antagonists in patients with antiphospholipid syndrome (APS). To investigate the reliability of the INR, we determined the INR using various prothrombin time (PT) assays and compared the results with those of a chromogenic factor X (CFX) assay. The study cohort consisted of 40 APS patients and 100 APL-negative patients who were on anticoagulant therapy for reasons other than APS. The agreement (i.e. the percentage of patients with a difference ≤0.5 INR units) between the PT-derived INR and CFX-derived INR equivalents was only moderate in both patient groups. The best agreement with CFX-derived INR equivalents was observed for the Thromborel S reagent in APS patients (69.1 %) and for Neoplastin Plus in APL-negative patients (72.0 %). Regarding the results for the point-of-care system CoaguChek XS, an agreement between the INR and the CFX-derived INR equivalent was less frequently observed in the APS patients (55.6 vs. 67.8 %; p = 0.050). When considering all 3058 pairs of INR tests within the international sensitivity index (ISI)-calibrated range of 1.5 to 4.5 s, we did not observe a higher variability of INR values in either the APS patient group or the subgroup of APS patients positive for lupus coagulants compared with the APL-negative controls. In conclusion, monitoring vitamin K antagonists (VKA) therapy with laboratory INR measurements seems to be suitable for the majority of APS patients.
由于抗磷脂抗体（APL）可能干扰凝血活酶试剂中的磷脂成分，因此人们对抗磷脂综合征（APS）患者使用国际标准化比值（INR）检测来监测维生素K拮抗剂抗凝治疗的有效性提出了担忧。为了研究INR的可靠性，我们使用各种凝血酶原时间（PT）检测方法测定了INR，并将结果与发色底物法X因子（CFX）检测结果进行了比较。研究队列包括40例APS患者和100例因非APS原因接受抗凝治疗的APL阴性患者。在两组患者中，PT衍生的INR与CFX衍生的INR等效值之间的一致性（即差异≤0.5 INR单位的患者百分比）仅为中等程度。在APS患者中，Thromborel S试剂与CFX衍生的INR等效值一致性最佳（69.1%）；在APL阴性患者中，Neoplastin Plus试剂一致性最佳（72.0%）。关于即时检测系统CoaguChek XS的结果，APS患者中INR与CFX衍生的INR等效值之间的一致性观察频率较低（55.6%对67.8%；p = 0.050）。当考虑国际敏感指数（ISI）校准范围在1.5至4.5秒内的所有3058对INR检测时，与APL阴性对照组相比，我们未观察到APS患者组或狼疮抗凝物阳性的APS患者亚组中INR值有更高的变异性。总之，通过实验室INR测量监测维生素K拮抗剂（VKA）治疗似乎适用于大多数APS患者。
