Pilot study: A comparison of the extent of haemolysis induced by conventional versus miniaturised extracorporeal circulation during coronary artery bypass grafting surgery, and the influence on the release of damage associated molecular patterns (DAMPs), leukocyte activation and neutrophil extracellular trap (NET) formation.

Each year approximately eight thousand patients in the Netherlands undergo
coronary artery bypass grafting (CABG) surgery. . In the majority of cases a
heart-lung machine (HLM) is used for extracorporeal circulation (ECC). Two
different types of heart-lung machine set-ups are currently in use for CABG
surgery in the Amphia hospital; the conventional HLM and a miniaturised HLM. It
is known that contact of blood with the components of the HLM induces
haemolysis. We aim to collect data on the extent of haemolysis induced by each
type of HLM, as such information may be used for a more evidence based decision
in the use of a specific HLM and will potentially improve patient outcome.
Secondly, this study will focus on the release of damage associated molecular
patterns (DAMPs), leukocyte activation and neutrophil extracellular trap (NET)
formation induced by ECC. Leukocytes, including neutrophils, may be directly
activated after contact with the HLM, or as a consequence of the released
haemolytic breakdown products and the associated tissue damage. Since the HLM
is known to cause significant haemolysis during ECC, we will look for possible
correlations between haemolysis and the release of DAMPs, leukocyte activation
markers and markers of NET formation in patients undergoing CABG surgery.

Primary Objective: To compare the extent of haemolysis associated with the use
of the conventional versus the miniaturised heart lung machine in the Amphia
hospital, with the aim to set up evidence-based guidelines for the use of a
specific type of heart-lung machine in CABG surgery.
Secondary Objectives: (1) To explore the extent of DAMPs release, leukocyte
activation and neutrophil extracellular trap release in patients undergoing
CABG surgery with extracorporeal circulation. (2) To determine whether direct
correlations exist between the extents of haemolysis on the one hand, and DAMPs
release, leukocyte activation and neutrophil extracellular trap release on the
other hand, in the context of the use of two types of heart-lung machines in
patients undergoing CABG surgery.

Prospective randomized cohort study.

A total of 72ml blood will be collected at six time point from patients
undergoing coronary artery bypass grafting procedures. There is at present no
evidence to suggest that participation in the study holds additional risk.
Patients are not positively or negatively affected when participating in this
study. No additional venepuncture is needed for blood collections.