Leucocyte depletion in cardiopulmonary bypass: a comparison of four strategies

Abstract

Leucocytes have been shown to play a fundamental role in the pathophysiology of inflammation. This prospective, randomized, controlled study was designed to identify the most advantageous leucocyte depletion technique in terms of reduction in systemic inflammatory response syndrome and myocardial ischaemia reperfusion injury associated with cardiopulmonary bypass (CPB). Forty consecutive patients undergoing elective coronary artery bypass graft (CABG) surgery were randomly allocated to one of four groups. The four groups consisted of a control group, a systemic leucocyte depletion (SLD) group, a cardioplegic leucocyte depletion (CLD) group and a total leucocyte depletion (TLD) group. There were 10 patients in each group. Lactoferrin (marker of neutrophil activation) and troponin-I (marker of myocardial ischaemia reperfusion injury) were measured at six time points: post induction, 5 min on CPB, 5 min before releasing the aortic crossclamp, 15 min after releasing the clamp and 1 and 24 hours after the discontinuation of CPB. Plasma lactoferrin levels increased rapidly in every group after the commencement of CPB, subsequently reached a peak after releasing the aortic crossclamp and gradually declined after the discontinuation of CPB. The lowest lactoferrin concentration was observed in the TLD (range 2.15-141.9 ng/mL) and CLD groups (7.469-114.6 ng/mL). Regarding myocardial injury, plasma cardiac troponin-I levels did not differ significantly between groups; but troponin-I concentrations rose dramatically after releasing the aortic crossclamp in all groups. Nevertheless, the CLD group had the lowest troponin-I level (1.37-5.55 ng/mL). In conclusion, it is believed that myocardial ischaemia is probably a major contributor to the inflammatory response. Although there is no clear statistical significance shown in this pilot study, the data tend to support the cardioplegic leucocyte depletion strategy as the optimal method for attenuating neutrophil activation and myocardial ischaemia reperfusion injury.

The effects of various leukocyte filtration strategies in cardiac surgery

“…There were no statistically significant findings, although the cardioplegic depletion group had the lowest Troponin I levels [90]. de Vries et al contrasted arterial line systemic depletion, with venous line systemic depletion during the re-warming phase of CPB and finally leucofiltration of the residual heart-lung machine blood during autologous transfusion.…”

“…Although it is indisputable that leukocyte-depleting filters do remove leukocytes from a stream of blood, they do not appear to consistently lower leukocyte concentrations within the circulation, or they do it only transiently [55,57,90]. Recognizing this, it has been claimed that any possible clinical effect of leukocyte-depleting filters may arise from their alleged propensity to preferentially remove activated leukocytes from the circulation.…”

“…Recognizing this, it has been claimed that any possible clinical effect of leukocyte-depleting filters may arise from their alleged propensity to preferentially remove activated leukocytes from the circulation. Given the presence of a large body of evidence in favour [51,52,59,90] and against such claims [9,10,27,46], the issue of preferential removal of activated forms of leukocytes by these filters remains controversial.…”

Systemic Leukofiltration Does Not Attenuate Pulmonary Injury after Cardiopulmonary Bypass

“…29,36,37 Another reason postulated is that although leukodepleting filters certainly remove leukocytes from a stream of blood in vitro, they do not seem to consistently lower leukocyte concentrations in vivo, or they do it only transiently. 67 This has led some to suggest that leukodepleting filters may preferentially remove activated leukocytes from the circulation, but given the significant body of evidence both for 63,67 and against 35,58 this, the issue remains controversial. Regardless of the reasons, we believe this article supports the conclusions made elsewhere that leukocyte filtration has not been as effective as first hoped, and that alternative solutions to attenuate the inflammatory response should be sought.…”

Clinical efficacy of leukofiltration on cardiopulmonary bypass related inflammatory response: Fact or Foe?

“…Filters incorporated in series in the CPB circuit have become popular in early 2000 s in clinical application and also been used to deplete the blood cardioplegic solution or even in retransfused residual blood after CPB (4,5).…”