Laboratory studies of the effect of Pall extracorporeal leucocyte filters LG6 and AV6 on patients undergoing coronary bypass grafts.

A total of 14 patients with ischaemic heart disease undergoing coronary artery bypass grafts were studied for the effect of AV6 control filter and LG6 neutrophil filter, used in the extracorporeal circulation, on different laboratory parameters. There was no statistical difference between the effects of AV6 and LG6 filters on total white cells, neutrophils, monocytes, lymphocytes, platelets or haemoglobin. The expression of neutrophil activation antigens identified with a panel of monoclonal antibodies demonstrated that for the LG6 filter the leucocyte tyrosine phosphate CD45Ro fell during the procedure, whilst there were no significant changes in any of the other neutrophil antigens. The AV6 filter did not significantly diminish the expression of any of the neutrophil antigens. An indirect measure of superoxide production using Dihydrorhodamine 123 identified that the more activated cells appeared to be depleted across the LG6 filter which was not evident with the AV6 filter. These studies indicate that the LG6 is not capable of significantly depleting the neutrophil load generated during extracorporeal circulation but may be capable of selectively removing the more activated forms.