Use of Cytokine Filters During Cardiopulmonary Bypass: Systematic Review and Meta-Analysis

Cardiac surgery involving cardiopulmonary bypass (CPB) activates an inflammatory response releasing cytokines that are associated with less favourable outcomes. This study aims to compare i) CPB during cardiac surgery (control) versus ii) CPB with haemoadsorption therapy; and assess the effect of adding this therapy in reducing the inflammatory cytokines burden.A systematic literature review with meta-analysis was conducted regarding the main outcomes (operative mortality, ventilation duration, intensive care unit [ICU] and hospital stays) and day-1 inflammatory markers levels post-surgery. Fifteen (15) studies were included for final analysis (eight randomised controlled trials, seven observational studies) with no evidence of publication bias.Subgroup analysis of non-elective surgeries across observational studies (emergency and infective endocarditis) significantly favoured cytokine filters in terms of 30-day mortality (OR 0.40, 95% CI 0.20, 0.83; p=0.01) and shorter ICU stay (MD -42.36, 95% CI -68.07, -16.65; p=0.001). At day-1 post-surgery, there was a significant difference favouring the cytokine filter group in c-reactive protein (CRP) (MD -0.71, 95% CI -0.84, -0.59; p<0.001) with no differences in white blood count (WBC), procalcitonin (PCT), tumour necrosis factor-alpha (TNF-α), IL-6, IL-8 and lactate. When comparing cytokine filters and control across all studies there was no significant difference in operative mortality, ventilation duration, hospital stay and ICU length of stay. Also, there were no statistical differences in randomised controlled trials (RCTs) using haemadsorption filters.A significant reduction in 30-day mortality and ICU stay could be obtained by using haemadsorption therapy during non-elective cardiac surgery, especially emergency surgery and in patients with higher inflammatory burden such as infective endocarditis.