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Increased prothrombotic state lasting as long as one month after on-pump and off-pump coronary surgery.Parolari A, Mussoni L, Frigerio M, et al. J Thorac Cardiovasc Surg 130:303-308, 2005Reviewer: Mark A. Chaney, MD
Abstract Excerpt: This study investigated whether the activation of coagulation, fibrinolysis, and endothelium occurring during the first postoperative month after on-pump coronary artery bypass surgery differs from that after off-pump coronary artery bypass grafting. Thirty-five patients undergoing coronary surgery were randomized to undergo on-pump (n = 18) or off-pump (n = 17) coronary artery bypass grafting. Blood samples were collected prior to surgery and up to one month after surgery. Prothrombin fragment F1.2, thrombin-antithrombin complex, and D-dimer increased after surgery and were persistently higher than preoperative values as late as 30 postoperative days in both on-pump and off-pump groups. Higher levels of these variables were detected after on-pump surgery relative to off-pump surgery only at the time point after termination of cardiopulmonary bypass (fragment F1.2 and thrombin-antithrombin complex) or from bypass end to eight postoperative days (D-dimer). Fibrinogen levels decreased after surgery and then increased in parallel in both groups to eight days after surgery. The von Willebrand factor level increased postoperatively in both groups and returned to baseline 30 days after surgery; it was higher after on-pump surgery from bypass end to eight postoperative days. Soluble vascular cell adhesion molecule one was increased significantly from baseline in both groups 30 days after surgery, with no difference between groups. The investigators conclude that patients undergoing off-pump cardiac surgery showed protection against activation of coagulation and fibrinolysis and against endothelial injury only during the intraoperative period, which was followed by the development of a prothrombotic pattern comparable to that of patients undergoing on-pump cardiac surgery, lasting at least as late as 30 days after surgery. Comments: Use of cardiopulmonary bypass is associated with activation of several metabolic pathways and cellular components leading to a systemic inflammatory response. While this extensive physiologic response has mainly been documented in the early postoperative period, some studies have revealed a marked activation of the hemostatic, thrombotic, and inflammatory systems that persists for several weeks following surgery. Previous studies in patients undergoing cardiac surgery have revealed a markedactivationofthecoagulation-fibrinolytic system lasting several weeks, perhaps accounting for the increased thrombotic complications that frequently occur during the postoperative period. The early period after cardiac surgery is characterized by the highest rates of myocardial infarction, cerebrovascular accident, and bypass graft occlusion, all occurring within the first few postoperative months. Over the past decade, the use of off-pump cardiac surgery has increased dramatically, in hopes of avoiding the known detrimental physiologic effects of cardiopulmonary bypass (neurologic dysfunction, pulmonary dysfunction, renal dysfunction, hematologic abnormalities, activation of systemic inflammatory response, etc.). The clinical advantages of off-pump versus standard on-pump cardiac surgery, however, are still controversial. It is also unclear whether cardiopulmonary bypass is the main cause of the postoperative inflammatory and procoagulant responses that occur following cardiac surgery. Recent studies have shown that surgical trauma alone may cause activation of the systemic inflammatory response. Thus, these investigators attempted to determine whether activation of coagulation and fibrinolysis differed between patients undergoing off-pump cardiac surgery and on-pump cardiac surgery. Because graft occlusion mainly occurs during the first postoperative month, thrombotic variables were assessed up to one month after surgery. These investigators found that patients undergoing off-pump cardiac surgery demonstrate a persistent activation of coagulation and of fibrinolytic pathways that lasts up to 30 days following surgery. However, these potentially detrimental physiologic effects are somewhat delayed (in contrast to immediate detrimental findings in patients undergoing on-pump cardiac surgery). These findings suggest that avoidance of cardiopulmonary bypass may protect from the early postoperative appearance of a prothrombotic state yet does not prevent the increases in prothrombotic and endothelial injury markers that occur during the later postoperative period. These findings also indicate that the early phase prothrombotic state may be initiated by cardiopulmonary bypass and the later phase prothrombotic state may be ascribable to the inflammatory reaction induced by general surgical trauma. Evidence indicating definitive clinical advantages of either technique of myocardial revascularization is currently lacking, and the differences between on-pump and off-pump techniques in terms of clinical outcomes are controversial. However, these findings indicate that the off-pump technique may protect against pro-oxidant, proinflammatory, and pro-thrombotic activation during the immediate postoperative period. However, during midterm follow-up, whatever surgical strategy is adopted, a significant prothrombotic activation (with endothelial dysfunction) occurs and persists for weeks following surgery. These findings (in addition to other investigations) indicate the need to reevaluate antithrombic treatment in patients undergoing both on-pump and off-pump cardiac surgery. Table of Contents:
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