Background
Cardiopulmonary bypass (CPB) during cardiac surgery triggers a systemic inflammatory response, driven by cytokines like IL-6, IL-8, and TNF-alpha, which may lead to postoperative complications. The CytoSorb® haemoadsorption (HA) device was tested for its potential to mitigate this inflammatory response by filtering cytokines from the bloodstream during CPB.
Methods
The study recruited patients over 65 undergoing elective on-pump cardiac surgery. Participants were randomly assigned to receive HA with CytoSorb® or standard care without HA. Blood samples were collected at multiple time points to measure cytokine levels, particularly IL-6. The primary outcome was the difference in IL-6 concentrations upon ICU admission. Secondary outcomes included organ dysfunction markers, fluid requirements, length of ICU stay, and mortality.
Results
- Primary Outcome: No significant difference was found in IL-6 levels between the treatment and control groups upon ICU admission (214.4 ± 328.8 vs. 155.8 ± 159.6 pg/mL, p = 0.511). Similarly, IL-6 levels on ICU days 1 and 2 did not differ significantly.
- Cytokine Clearance: Intraoperative blood samples showed significant reductions in IL-2, IL-6, IL-8, and IL-10 levels post-HA within the CPB circuit. However, this clearance was not sustained in postoperative systemic measurements.
- Haemodynamic Stability: Patients in the HA group demonstrated better cardiac index recovery by ICU day 2 and required less dobutamine and crystalloid fluids. A shorter duration of renal replacement therapy was also noted in the HA group.
- Clinical Outcomes: No significant differences were observed in ICU length of stay, ventilator time, postoperative complications, or mortality rates between the groups.
Discussion
Although HA effectively removed cytokines during surgery, this did not translate into improved postoperative outcomes. The modest haemodynamic benefits suggest potential for HA in high-risk subgroups or extended use beyond the intraoperative period. Variability in cytokine release dynamics and individual responses might have influenced the outcomes.
Limitations
The study’s small sample size and single-center design limit the generalizability of its findings. Additionally, the short duration of HA application may not have been sufficient to impact cytokine levels post-surgery.
Conclusion
While intraoperative HA reduced cytokine concentrations in the CPB circuit, it did not lead to significant reductions in systemic cytokine levels or improved clinical outcomes. Future research should focus on optimizing HA timing, patient selection, and its integration with postoperative care.
