Changes in peripheral vascular and cardiac sympathetic activity before and after coronary artery bypass surgery: interrelationships with hemodynamic alterations.

The plasma catecholamine levels obtained simultaneously from radial artery (A), pulmonary artery (MV), brachial vein (PV), and coronary sinus (CS) were measured concurrent with hemodynamic determinations during coronary artery bypass graft (CABG) operations. Arterial catecholamine levels decreased after induction of anesthesia and increased after sternotomy; changes in veno-arterial norepinephrine (NE) differences ([PV-A]ne, [MV-A]ne, and [CS-A]ne) were of the same magnitude and direction, suggesting that NE release from various organs was of the same extent. After operation, arterial NE increased further, but the veno-arterial NE differences were in striking contrast; [PV-A]ne became markedly positive, whereas [CS-A]ne became markedly negative, indicating that NE release from extremity peripheral vasculature increased markedly while cardiac NE release decreased. These differential changes in regional sympathetic activity appear to be related to postoperative hypertension (HT) and low cardiac output (CO). There were close relationships of changes in [MV-A]ne to mean arterial pressure (r = 0.78, p less than 0.001) and systemic vascular resistance (r = 0.62, p less than 0.010, suggesting that the sympathetic nervous system plays an important role in CABG perioperative hemodynamic alterations.