Active or passive bio-coating: does it matters in extracorporeal circulation?

Area of Science:

• Biomaterials Science
• Cardiovascular Surgery
• Immunology

Background:

• Surface coatings for cardiopulmonary bypass (CPB) include bioactive (heparin, nitric oxide) and biopassive (albumin, polyethyleneoxide, phosphorylcholine) types.
• Combining haemocompatible coatings with aspiration techniques can attenuate coagulation and complement cascades, improving platelet preservation.
• This study investigates if combining a bioactive (unfractionated heparin) with a biopassive (phosphorylcholine) coating offers synergistic benefits.

Purpose of the Study:

• To evaluate the efficacy of a combined unfractionated heparin and phosphorylcholine coating on CPB circuits.
• To determine if this combined coating offers additional benefits over phosphorylcholine alone in elective CABG patients.
• To assess the impact on coagulation, complement activation, and platelet preservation.

Main Methods:

• Prospective randomized study of 30 elective coronary artery bypass grafting (CABG) patients.
• Control group (PC): CPB circuit coated with phosphorylcholine (PC).
• Study group (XPC): CPB circuit with unfractionated heparin embedded in a PC matrix.

Main Results:

• No significant differences in haemolytic index, thrombin-anti-thrombin complex, IL-6, IL-10, or blood loss between groups.
• Platelet factor 4 (PF4) concentrations increased similarly in both groups.
• Terminal complement complex (TCC) generation was significantly higher in the XPC group compared to the PC group, particularly after aortic cross-clamp release and at CPB completion.

Conclusions:

• Combining phosphorylcholine with unfractionated heparin provides no additional benefit for elective CABG patients.
• The combined coating resulted in significantly higher complement activation.
• Massive hemodilution may contribute to enhanced complement activation during CPB.