Clinical Laboratory, Keio University Hospital, Tokyo, Japan.
Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan.
Int J Lab Hematol. 2020 Jun;42(3):292-298. doi: 10.1111/ijlh.13168. Epub 2020 Feb 20.
Acceleration of fibrinolysis by direct oral anticoagulants (DOACs) has been reported by several groups, suggesting contribution of not only anticoagulant but also fibrinolytic effects to the therapeutic efficacy. The present study aims to evaluate the usability of clot-fibrinolysis waveform analysis (CFWA) for assessment of in vitro effects of DOACs on fibrinolysis.
The experimental conditions were optimized according to how t-PA concentrations and a time length after t-PA adjustment affect parameters of CFWA. Addition of the activated partial thromboplastin time (APTT) reagent followed by that of calcium and t-PA was done to obtain clotting and fibrinolytic reaction curves which were mathematically differentiated for CFWA (APTT-CFWA). The positive and negative modes of waveforms were defined as the direction toward fibrin generation and that toward fibrin degradation, respectively. The maximum positive and negative values (Max 1 and Max 1) correspond to the maximum coagulation velocity and the maximum fibrinolysis velocity, respectively. Plasma spiked with each of DOACs (rivaroxaban, apixaban, edoxaban, and dabigatran) was subjected to APTT-CFWA.
Optimization of t-PA use was based on Max 1. Roughly biphasic effects of rivaroxaban and dabigatran but not apixaban or edoxaban on fibrinolysis were observed through Max 1 and the fibrinolysis peak time, which was defined as a time length from the time when Max 1 (Max 1 time) to the time when Max 1 appears (Max 1 time).
The results suggest the usability of CFWA for assessment of DOAC effects and provide insights into relevance of anticoagulation to therapeutic efficacy and bleeding risk from the perspective of fibrinolysis.
一些研究小组报道，直接口服抗凝剂（DOAC）可加速纤维蛋白溶解，这表明其治疗效果不仅与抗凝作用有关，还与纤维蛋白溶解作用有关。本研究旨在评估血栓纤维蛋白溶解波形分析（CFWA）在评估 DOAC 对纤维蛋白溶解体外作用的可用性。
根据 t-PA 浓度和调整 t-PA 后的时间长度如何影响 CFWA 参数，优化实验条件。加入活化部分凝血活酶时间（APTT）试剂，然后加入钙和 t-PA，以获得凝血和纤维蛋白溶解反应曲线，对其进行数学分化以获得 CFWA（APTT-CFWA）。波形的正负模式分别定义为朝向纤维生成的方向和朝向纤维降解的方向。最大正和最大负值（Max 1 和 Max 1）分别对应最大凝血速度和最大纤维蛋白溶解速度。向含有 DOAC（利伐沙班、阿哌沙班、依度沙班和达比加群）的血浆中加入 APTT-CFWA。
根据 Max 1 优化 t-PA 的使用。通过 Max 1 和纤维蛋白溶解峰值时间观察到利伐沙班和达比加群对纤维蛋白溶解的大致两相作用，但阿哌沙班和依度沙班则没有，这两个参数分别定义为从出现 Max 1（Max 1 时间）到出现 Max 1（Max 1 时间）的时间长度。
结果表明 CFWA 可用于评估 DOAC 作用，并从纤维蛋白溶解的角度提供关于抗凝与治疗效果和出血风险相关性的见解。
