Systemic stress hormone response in patients undergoing open heart surgery with or without cardiopulmonary bypass

Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamics and organ perfusion. Leptin, an adipocyte-derived factor, has been proposed to play a role in systemic inflammation. We examined perioperative release of leptin and cortisol in patients undergoing open heart surgery with or without cardiopulmonary bypass.

Forty-nine patients were enrolled in this prospective study. Conventional coronary artery bypass grafting was performed in 19 patients (ONCABG; group I), and heart valve surgery in 15 patients (group II). Fifteen patients (group III) received off-pump coronary artery bypass grafting (OPCABG). Blood samples were collected preoperatively and for as long as 72 hours postoperatively. Plasma levels of leptin and cortisol were measured by enzyme-linked immunosorbent assay.

Leptin serum levels decreased during the operation, reaching 73.2% of the baseline in group I, 85.3% in group II, and 38.9% in group III (p < 0.05), 2 hours postoperatively. Thereafter, leptin levels increased gradually to 218.6% of the baseline in group I and 313.7% in group II 24 hours after the operation (p < 0.01). However, patients in the OPCABG group showed only a moderate increase in serum leptin levels. Plasma cortisol levels rose to a maximum of 532.9% of baseline in group I, 526.4% in group II, and 280% in group III 12 hours postoperatively (p < 0.01).

Open heart surgery is associated with acute perioperative changes in plasma levels of neurohormonal stress factors leptin and cortisol. A different pattern of leptin and cortisol release was observed in patients operated on without cardiopulmonary bypass.