Biphasic pro-thrombotic and inflammatory responses after coronary artery bypass surgery

Early graft failure after coronary artery bypass grafting (CABG) is related to thrombosis and inflammation in the grafted vessel(s). The time courses of, and relationships between, pro-thrombotic and inflammatory responses to CABG surgery have, however, not been well defined. Fifteen patients undergoing CABG were examined before, and 1 h, 1 day, 7 days, and 3 months after surgery. Cellular markers of platelet and leukocyte activation were monitored by whole blood flow cytometry, and plasma markers of pro-thrombotic and inflammatory responses were analyzed by immunoassays. CABG immediately increased circulating P-selectin-positive platelets, leukocyte CD11b expression, and platelet-leukocyte aggregates (PLAs). Thrombin generation (F1 + 2 levels) and cytokine release [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-8, and IL-10], soluble P-selectin, and soluble E-selectin also increased immediately. These alterations persisted during the first week after surgery, with re-bound increases of circulating activated platelets and PLAs, TNF-alpha, and F1 + 2 on day 7. Platelet and PLA responsiveness to in vitro stimulation was suppressed immediately after CABG, but markedly enhanced 1 week after surgery. After 3 months, plasma soluble P-selectin, F1 + 2, and IL-10, and monocyte CD11b expression were still slightly elevated compared with baseline. In conclusion, CABG induces marked pro-thrombotic and inflammatory responses, which persist for at least 1 week. Platelet activation, platelet reactivity, PLA formation, thrombin generation, and TNF-alpha release show a second peak 1 week after surgery. These findings suggest that intensified and prolonged antithrombotic/inflammatory treatment should be considered after CABG surgery.