Compartmentalization of the Inflammatory Response in the Pericardial Cavity in Patients Undergoing Cardiac Surgery

The systemic inflammatory response after cardiopulmonary bypass has been widely studied. However, there is a paucity of studies that focus on the local inflammatory changes that occur in the pericardial cavity. The purpose of this study is to assess the inflammatory mediators in the pericardial fluid of patients undergoing cardiac surgery. We conducted a prospective cohort study on patients undergoing aortic valve replacement. Pericardial fluid and peripheral venous blood samples were collected after the opening of the pericardium. Additional samples were obtained from peripheral blood and the pericardial fluid shed through mediastinal drains 24 and 48 h after surgery. Levels of interleukin 1α (IL-1α), interleukin 1β (IL-1β), interleukin 2 (IL-2), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1), epidermal growth factor (EGF), soluble E-selectin, L-selectin, P-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were determined in all pericardial fluid and serum samples. A total of 45 patients with a mean age of 74 years were included, of which 66% were males. Serum levels of IL-6, IL-8, and MCP-1 were significantly increased at 24 and 48 h after surgery. No significant changes were observed in the serum levels of the remaining mediators. A significant increase of postoperative pericardial fluid levels of IL-1α, IL-1β, IL-6, IL-8, IL-10, IFN-γ, VEGF, MCP-1, VCAM-1, and P-selectin was observed at 24 and 48 h after surgery. There is a robust systemic and pericardial inflammatory response after cardiac surgery on cardiopulmonary bypass. However, postoperative pericardial inflammatory activity shows a distinct pattern and is more marked than at the systemic level. These findings suggest that there is a compartmentalization of the inflammatory response within the pericardial cavity after cardiac surgery.