COMPARATIVE STUDY OF PROSTACYCLIN ANALOGUE AND THROMBOXANE A2 SYNTHETASE INHIBITOR COMBINED WITH PROTEASE INHIBITOR AS ANTICOAGULANT FOR LEFT VENTRICULAR ASSIST DEVICE:

[Aim] Protease inhibitor (FUT) alone, and the combined administration of FUT and prostacyclin analogue (PG) or thromboxane A2 synthetase inhibitor (OKY) were studied as anticoagulants for left LVAD instead of heparin. [Materials and Methods] On 36 mongrel dogs, LVAD was performed for 24 hours, and blood coagulative study was made before and during LVAD performance. Dogs were divided into the following 4 groups according to the type of anticoagulation. GroupI: no anticoagulation, Group II: FUT alone (15μ g/ kg/min), Group III: FUT (15 μ g/kg/min) + OKY (2 mg/kg/h). Group IV:FUT (15 μ g/kg/min) + PG(1 μ g/kg/min) [Results] In all groups, LVAD could be performed without any thrombogenic trouble. Prothrombin time and activated partial thromboplastin time showed gradual prolongation in all groups. Fibrinogen showed a marked decrease and reached 50 % of preoperative value (below 100 mg/dl) in 24 h in Gr.I (no anticoagulation); whereas, in Gr.II (FUT) and Gr.III (FUT+OKY), it showed a slight decrease till 3 h after the start, but thereafter came gradually back to the previous level. In Gr.IV (FUT + PG), it was almost unchanged all the time. α 2-plasmin inhibitor was almost unchanged in Gr.II (FUT), Gr.III (FUT+OKY) and Gr.IV (FUT + PG); whereas, in Gr.I (no anticoagulation), it showed severe decrease and reached to 55% of preoperative value in 24 h. The decrease of fibrinogen and α 2-PI in Gr.IV was significantly less than that of in Gr.III. Factor XII showed gradual significant decrease in all groups. [Conclusion] PG, combined with FUT, can prevent the activation of intrinsic pathway of blood coagulation system more completely than OKY, through intense inhibition of platelet aggregatin and other multiple stage of blood cagulation by PG.