Reduction of the Cardiac Proapoptotic Stress Response by Dexamethasone in Patients Undergoing Coronary Artery Bypass Grafting Surgery

The stress response as induced by myocardial cellular damage during cardiac surgery may lead to myocardial stunning and apoptosis, and could therefore impair postoperative patient recovery. Surgical trauma typically induces the liberation of cytokines. Some of these cytokines are strongly associated with the initiation of intracellular proapoptotic pathways through activation of tyrosine kinases and integrins. The latter are known for their deteriorating effects on cardiac function and are strongly involved in cardiac remodeling. Dexamethasone is typically administered prior to cardiac surgery in order to especially reduce the release of proinflammatory cytokines. It has however never been investigated whether this additionally reduces proapoptotic signaling in the human heart, thereby eliminating risk factors for the induction of cardiac dysfunction. In the present study, the investigators therefore aim to investigate whether dexamethasone inhibits proapoptotic pathways in patients undergoing cardiac surgery. Furthermore, the investigators would like to elucidate whether this proposed effect of dexamethasone is related to the reduction of the stress response in the heart or indirectly by suppression of cytokine release. For this purpose the investigators will obtain cardiac biopsies and plasma from patients, who are randomly assigned to placebo or dexamethasone treatment and undergo on and off-pump coronary artery bypass grafting (CABG) surgery.