REVIEWS  CARDIAC PAPERS 

The Journal of Cardiovascular Surgery 2000 December;41(6):849-62

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Leukocyte activation during cardiopulmonary bypass: limitations of the inhibitory mechanisms and strategies

Kaul T. K., Fields B. L.

From the Department of Cardiac Surgery Baptist Medical Center, Birmingham, Alabama, USA

Car­di­o­pul­mo­nary ­bypass, ­initiates a gen­er­al­ised ­response, ­which is pri­marily defen­sive in ­nature. ­This ­response is ­self reg­u­lated and ter­mi­nated spon­ta­ne­ously. ­Obvious prob­lems are com­ple­ment and leu­co­cyte acti­va­tion, but sev­eral ­other cas­cades are ­also stim­u­lated, ­which ­interact, accen­tuate or mod­ulate ­this ­response. ­These sup­porting ­casc­ades ­include, ­release of inflam­ma­tory cyto­kines, an acti­va­tion of kal­lik­rein ­system, clot­ting and fibrin­o­lytic mech­a­nisms, and arach­i­donic ­acid metab­olism. ­Because of an effec­tive auto­reg­u­la­tory mech­a­nism, ­only a ­small pro­por­tion of ­patients (<3%), under­going car­di­o­pul­mo­nary ­bypass are ­adversely ­effected by ­this pro­cess. Prog­nosis of ­these ­patients is ­often unpre­dict­able, but in gen­eral, ­high ­risk ­patients are ­likely to ­suffer ­most. A ­number of spe­cific and non spe­cific arti­fi­cial meas­ures ­have ­been intro­duced to con­trol post­per­fu­sion prob­lems, ­resulting ­from ­this pro­cess. ­These con­trol meas­ures are usu­ally effec­tive ­against a spe­cific com­po­nent of ­this gen­er­al­ised ­problem, and ­often ­fail to ­achieve ­desired ­effects. Effi­cacy of con­trol meas­ures is fur­ther lim­ited by a con­tinued acti­va­tion of com­ple­ment and leu­coc­ytes, via inter­ac­tions ­between the men­tioned inflam­ma­tory cas­cades. In ­view of ­these lim­i­ta­tions, we ­have intro­duced cer­tain mod­ifi­ca­tions in our pre­vi­ously ­reported con­trol ­strategy. ­These ­include an ­early iden­tifi­ca­tion of ­high ­risk and sus­cep­tible indi­vid­uals and ­using spe­cific inhib­i­tors of com­ple­ment acti­va­tion for ­both ­initial and ter­minal ­stages.