Nafamstat mesilate attenuates pulmonary hypertension in heparin-protamine reactions.
Rapid protamine reversal of heparin anticoagulation in awake sheep caused, after 1 min, a approximately 15-fold increase of arterial plasma thromboxane B2 (TxB2) levels, a 4-fold rise of pulmonary vascular resistance (PVR), a 2-fold rise of pulmonary arterial pressure, and after 3 min, a 2-fold rise of ovine arterial plasma complement C3a levels (P less than 0.05). Infusion of nafamstat mesilate (FUT-175), a protease and complement pathway inhibitor, before protamine reduced these increases by approximately 60-90% (P less than 0.05). FUT-175 did not modify heparin + protamine-induced leukopenia, suggesting that FUT-175 incompletely blocked C5a production. We also learned that infusing protamine first and heparin 5 min later did not increase either plasma C3a or TxB2 levels or PVR while the activated clotting time increased only minimally. Thus, in awake sheep, the sequence of heparin and protamine infusion influences complement activation and pulmonary vasoconstriction. FUT-175 pretreatment reduces thromboxane release and pulmonary vasoconstriction probably by limiting complement activation.
Kreil
E
E
Department of Anesthesia, Massachusetts General Hospital, Boston 02114.
Montalescot
G
G
Greene
E
E
Fitzgibbon
C
C
Robinson
D
D
Chenoweth
D
D
Zapol
W M
WM
D000818:Animals; D001550:Benzamidines; D001794:Blood Pressure; D015926:Complement C3a / Q000378:metabolism; D003169:Complement Inactivator Proteins / Q000627:therapeutic use*; D004347:Drug Interactions; D006146:Guanidines / Q000627:therapeutic use*; D006439:Hemodynamics / Q000502:physiology; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000517:prevention & control*; D008168:Lung / Q000098:blood supply; D011479:Protamines / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D011480:Protease Inhibitors / Q000627:therapeutic use*; D011651:Pulmonary Artery / Q000503:physiopathology; D012756:Sheep; D013929:Thromboxane B2 / Q000097:blood; D014655:Vascular Resistance
D001550:Benzamidines; D003169:Complement Inactivator Proteins; D006146:Guanidines; D011479:Protamines; D011480:Protease Inhibitors; D013929:Thromboxane B2; D015926:Complement C3a; D006493:Heparin; C032855:nafamostat