Cardiopulmonary and Systemic Effects of Methylprednisolone in Patients Undergoing Cardiac Surgery

Abstract

Cardiopulmonary bypass (CPB)-related inflammatory response can be attenuated by glucocorticoid treatment, but its impact on postoperative cardiopulmonary function remains controversial. It was investigated whether the systemic and myocardial antiinflammatory effects of glucocorticoids are associated with improved cardiopulmonary function in cardiac surgery patients. Eighty patients undergoing elective coronary artery bypass grafting were randomly assigned to receive a single shot of methylprednisolone (15 mg/kg) or placebo before CPB. Variables of myocardial and pulmonary function and systemic hemodynamics were measured before and 1, 4, 10, and 24 hours after CPB. Blood was sampled for measurement of proinflammatory (tumor necrosis factor-alpha, interleukin 6, interleukin 8) and antiinflammatory (interleukin 10) cytokines (by enzyme-linked immunoassay), troponin T, and C-reactive protein. Phosphorylation of inhibitory kappa-B alpha and p38 mitogen-activated protein kinase was determined in right atrial biopsies before and after CPB (phosphoprotein assay). Preoperative and intraoperative characteristics of patients were not different between groups. Methylprednisolone attenuated postoperative tumor necrosis factor-alpha, interleukin 6, interleukin 8, and C-reactive protein levels while increasing interleukin 10 release. Myocardial inhibitory kappa-B alpha was preserved with methylprednisolone (p < 0.05 versus placebo), but p38 mitogen-activated protein kinase activation occurred in both groups after CPB (p < 0.05 versus before CPB). Methylprednisolone improved postoperative cardiac index and was associated with decreased troponin T when compared with placebo (p < 0.05). Postoperative blood glucose, oxygen delivery index, and pulmonary shunt flow were increased in the methylprednisolone group (p < 0.05). There was no difference in postoperative oxygenation index, ventilation time, and clinical outcome between treatment groups. Glucocorticoid treatment before CPB attenuates perioperative release of systemic and myocardial inflammatory mediators and improves myocardial function, suggesting potential cardioprotective effects in patients undergoing cardiac surgery.