Alterations in plasma-, monocyte-, and lymphocyte-associated fibronectin during cardiopulmonary bypass surgery

The changes in plasma fibronectin and IgG, and monocyte- and lymphocyte-associated fibronectin were studied in patients undergoing elective cardiopulmonary bypass surgery. A significant fall (P = less than 0.0005) in plasma fibronectin occurred during bypass, resulting largely from hemodilution as assessed by IgG concentrations, but also related to consumption of fibronectin. Plasma levels were still reduced 48 hours following the operative procedure, despite variable amounts of blood components infused in the immediate post-bypass period. Monocyte-associated fibronectin increased significantly (P = less than 0.05) during bypass, and lymphocyte-associated fibronectin levels decreased. Our studies confirm a reduction in circulating fibronectin in cardiac surgery, with accompanying fall in lymphocyte-associated levels presumed to reflect nonspecific adsorption. In contrast, the increased binding to monocytes may be an important functional aspect requiring further investigation, together with assessment of monocyte-macrophage function, before empiric use of cryoprecipitate therapy in these patients is recommended.