The Clinical Effects and Mechanisms of Leukocyte Depletion Filters During Cardiac Surgery

ctivated leukocytes play a key role in thegeneralized inflammatory response thatoccurs after cardiac surgery. To minimize or evenprevent postoperative tissue injury, it is thusattractive to target the leukocytes. Various methodshave been tried to attenuate nearly all stages of theinflammatory pathway. Currently, the mostimportant strategies try to prevent leukocyteactivation, such as heparin coated bypass circuits,to modulate the inflammatory response by the useof pharmacological agents, such as aprotinin andcorticosteroids, and to remove factors that triggerthe inflammatory response, such as ultra-filtration.Although leukocyte depletion by means offiltration is common in blood banks, the applicationduring surgery is a relatively new development.The basic idea is to remove activated leukocytes,thereby minimizing organ injury. One of thebenefits of leukocyte depletion is that in contrastto pharmacological interventions, side effects areminimal. In this review we will not only considerclinical studies regarding leukocyte depletionduring cardiac surgery, but also go more in depthabout the filtration mechanisms in the filters, as thismay help to understand the application of thistechnology.