Effect of pre-operative angiotensin-converting enzyme inhibitors on haemodynamic parameters and vasoconstrictor requirements in patients undergoing off-pump coronary artery bypass surgery

The effects of pre-operative angiotensin-converting enzyme inhibitor (ACEI) treatment on haemodynamic status and vasoconstrictor requirements during off-pump coronary artery bypass surgery (OPCAB) were studied. Eighty patients selected for OPCAB were divided into those who had been treated with ACEIs for 4 weeks or more pre-operatively (ACEI group) (n = 43) and those who had not been treated with ACEIs (control group) (n = 37). Noradrenaline was infused during the operation when the mean systemic arterial pressure (SAP) fell below 60 mmHg. No significant differences in the haemodynamic parameters measured were detected between the two groups, except for cardiac output, which was found to be significantly greater in the control group. During anastomosis of the obtuse marginal branch of the left circumflex artery (OM), a significantly larger amount of noradrenaline was required by the ACEI group compared with the control group. In conclusion, pre-operative treatment with ACEIs significantly increased the amount of vasoconstrictor necessary to maintain the target SAP during OM anastomosis during OPCAB.