Specific complement inhibition with heparin-coated extracorporeal circuits.
BACKGROUND
Although it is well established that heparin-coated extracorporeal circuits reduce complement activation during cardiac operations, little in vivo information is available on the reduction in alternative and classic pathway activation.


METHODS
In a prospective, randomized study involving patients undergoing coronary artery bypass grafting with standard full heparinization, we compared heparin-coated circuits (Duraflo II) (10 patients) with uncoated circuits (10 patients) and assessed the extent of initiation of complement activation by detecting iC3 (C3b-like C3) concentrations, classic pathway activation by C4b/c (C4b, iC4b, C4c) concentrations, terminal pathway activation by soluble C5b-9 concentrations, and C3 activation by C3a (C3a desArg) and C3b/c (C3b, iC3b, C3c) concentrations.


RESULTS
Heparin-coated extracorporeal circuits significantly reduced circulating complement activation product C3b/c and soluble C5b-9 concentrations at the end of cardiopulmonary bypass and after protamine sulfate administration compared with the uncoated circuits, but not iC3, C4b/c, or C3a concentrations.


CONCLUSIONS
Heparin-coated extracorporeal circuits reduce complement activation through the alternative complement pathway, probably at the C3 convertase level, and, consequently, the terminal pathway. C3b/c seems to be a more sensitive marker than C3a to assess complement activation during cardiac operations.
te Velthuis
H
H
Centre for Cardiopulmonary Surgery Amsterdam, The Netherlands.
Jansen
P G
PG
Hack
C E
CE
Eijsman
L
L
Wildevuur
C R
CR
D000368:Aged; D000771:Anesthesia, Intravenous / Q000379:methods; D002315:Cardiopulmonary Bypass / Q000379:methods / Q000706:statistics & numerical data; D003167:Complement Activation / Q000187:drug effects*; D003170:Complement Pathway, Alternative / Q000187:drug effects; D003171:Complement Pathway, Classical / Q000187:drug effects; D003165:Complement System Proteins / Q000032:analysis; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D005112:Extracorporeal Circulation / Q000295:instrumentation* / Q000706:statistics & numerical data; D005260:Female; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018709:Statistics, Nonparametric
D006493:Heparin; D003165:Complement System Proteins