Shore-Lesserson L, Manspeizer H E, Bolastig M, Harrington D, Vela-Cantos F, DePerio M
Department of Anesthesiology, Mount Sinai Medical Center. Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York 10029, USA.
Anesth Analg. 2000 Apr;90(4):813-8. doi: 10.1097/00000539-200004000-00008.
Patients receiving heparin infusions have an attenuated activated clotting time (ACT) response to heparin given for cardiopulmonary bypass (CPB). We compared patients receiving preoperative heparin (Group H) to those not receiving heparin (REF group) with respect to ACT, high-dose thrombin time (HiTT), and markers of thrombin generation during CPB. Sixty-five consecutive patients (33 Group H, 32 REF group) undergoing elective CPB were evaluated. ACT and HiTT were measured at multiple time points. Plasma levels of thrombin-antithrombin III complex and fibrin monomer were determined at baseline, during CPB, and after protamine administration. Transfusion requirements and postoperative blood loss were measured and compared. ACT values after heparinization increased less in Group H and were significantly lower than those in the REF group (P < 0.01). HiTT values did not differ significantly between the two groups. Blood loss and transfusion requirements were not significantly different between the two groups. Plasma levels of thrombin-antithrombin III complexes and fibrin monomer also did not differ between groups at any time, despite a lower ACT in Group H after heparinization and during CPB. Our data suggest that thrombin formation and activity are not enhanced in patients receiving heparin therapy, despite a diminished ACT response to heparin. The utility of ACT and the threshold values indicative of adequate anticoagulation for CPB are relatively undefined in patients receiving preoperative heparin. HiTT should be investigated as a safe and accurate monitor of anticoagulation for CPB in patients receiving preoperative heparin therapy.
The diminished activated clotting time response to heparin, in patients receiving preoperative heparin therapy, poses difficulties when attempting to provide adequate anticoagulation for cardiopulmonary bypass. Current data suggest that heparin resistance is not observed when high-dose thrombin time is used to monitor anticoagulation and that a lower activated clotting time value in these patients may be safe.
接受肝素输注的患者在接受体外循环（CPB）时给予肝素后，活化凝血时间（ACT）反应减弱。我们比较了术前接受肝素治疗的患者（H组）和未接受肝素治疗的患者（REF组）在CPB期间的ACT、高剂量凝血酶时间（HiTT）以及凝血酶生成标志物。对连续65例接受择期CPB的患者（33例H组，32例REF组）进行了评估。在多个时间点测量ACT和HiTT。在基线、CPB期间和给予鱼精蛋白后测定血浆凝血酶 - 抗凝血酶III复合物和纤维蛋白单体水平。测量并比较输血需求和术后失血量。H组肝素化后的ACT值升高较少，且显著低于REF组（P < 0.01）。两组之间的HiTT值无显著差异。两组之间的失血量和输血需求无显著差异。尽管H组在肝素化后和CPB期间ACT较低，但两组在任何时候血浆凝血酶 - 抗凝血酶III复合物和纤维蛋白单体水平也无差异。我们的数据表明，尽管对肝素的ACT反应减弱，但接受肝素治疗的患者凝血酶形成和活性并未增强。在接受术前肝素治疗的患者中，ACT的效用以及指示CPB充分抗凝的阈值相对不明确。应研究HiTT作为接受术前肝素治疗患者CPB抗凝的安全准确监测指标。
接受术前肝素治疗的患者对肝素的活化凝血时间反应减弱，在试图为体外循环提供充分抗凝时会带来困难。目前的数据表明，当使用高剂量凝血酶时间监测抗凝时未观察到肝素抵抗，并且这些患者中较低的活化凝血时间值可能是安全的。
