Cardiopulmonary Bypass Circuit Coatings: Recent Advances and Future Perspectives

ABSTRACT Introduction: Cardiopulmonary bypass (CPB) circuits expose blood to non-physiological surfaces, leading to platelet activation, coagulation disturbances, complement activation, hemolysis, and systemic inflammation. Early-generation heparin-coated circuits reduced thrombin formation, decreased heparin requirements, and mitigated inflammatory responses, laying the foundation for modern hemocompatible devices. Objective: This review aims to summarize recent advances in CPB circuit coatings, critically evaluate their hemocompatibility, and highlight emerging strategies that enhance blood compatibility and reduce complications during extracorporeal circulation. Method: Literature from the past decade was analyzed, focusing on polymer-based, zwitterionic, endothelial-mimetic, and nitric oxide–releasing coatings. Studies evaluating in vitro, preclinical, and clinical outcomes were considered, with emphasis on platelet activation, coagulation, complement activation, hemolysis, and inflammatory markers. Results: Hydrophilic polymers such as PEG- and PMEA-based coatings reduced protein adsorption and platelet adhesion. Zwitterionic polymers demonstrated non-fouling properties under prolonged blood contact. Endothelial-mimetic coatings replicated vascular surface functions, enhancing hemocompatibility in preclinical models. Nitric oxide–releasing surfaces inhibited platelet activation and fibrin deposition. Improved hemocompatibility assessment using biomarkers including PF4, β-thromboglobulin, P-selectin, complement factors, and hemolysis indices enabled comparative evaluation of coating performance. Miniaturized extracorporeal circuits further decreased systemic inflammation and improved clinical outcomes. Conclusion: Contemporary CPB circuit coatings substantially improve blood compatibility compared with uncoated circuits. While heparin-coated systems remain widely used, emerging polymeric, zwitterionic, endothelial-mimetic, and nitric oxide–releasing surfaces offer additional benefits. Ongoing research into hybrid multifunctional coatings, long-term durability, and clinical translation is essential to optimize CPB safety and physiological performance. Keyswords: Cardiopulmonary Bypass, Circuit Coatings, Hemocompatibility, Heparin Coating, Zwitterionic Polymers.