Blood cardioplegic leukocyte filtration and myocardial oxidative stress

OBJECTIVE:The protective role of leukodepletion in on-pump cardiac surgery is controverse. The potential myocardial protective role of blood cardioplegic leukodepletion in unclear. We sought to investigate the effect of leukocyte filtration on myocardial oxidative stress after cardioplegic arrest induced by cold blood cardioplegia, by dosing molecules specific in the oxidative process. METHODS:Twenty consecutive patients undergoing elective coronary artery bypass grafting (CABG) were randomly assigned to two groups, with the use of a systemic and cardioplegic leukocyte filter in the CPB circuit (study group, n=10) or with a standard CPB circuit (control group, n=10). Blood samples from coronary sinus were collected before aortic cross-clamping and at 1, 5 and 10 minutes after aortic unclamping. Concentrations of malondialdehyde (MDA), heart fatty-acids binding protein (HFABP), creatin-kinaseMB (CPK-MB) and troponin I (TnI) were evaluated by dot blotting and specific antibodies determinations. Chemoluminescence detections and densitometric quantifications were performed. RESULTS:Demographic characteristics and preoperative and operative data were similar in the two groups. No major cardiac events occurred in either group and no differences in ICU stay or in hospital stay were observed. At statistical analysis (ANOVA within-between groups), patients in the study group showed higher concentrations of MDA, HFABP and TnI with statistical significance. No differences were demostrated in CPK-MB concentrations. CONCLUSIONS:This prospective, randomised study suggests the potential role of leukocyte depleting filters in the cardioplegic line in raising the degree of myocardial oxidative stress, evaluated by single specific molecules. Further studies are necessary to investigate the metabolic and biophysical mechanisms underlying these findings.