ABSTRACT
Cardioplegic arrest during cardiopulmonary bypass [CPB] is essential for the majority of cardiac surgical procedures; Cardioplegia protects the myocardium by providing continuous or intermittent oxygen while simultaneously reducing cardiomyocyte oxygen demand, but it does not inherently increase the ischemic-reperfusion injury tolerance of the cardiomyocytes. Aminophylline and milrinone by their phosphodiesterase inhibitor and anti-inflammatory activity may decrease this type of injury. This study has been designed to compare between the protective effect of aminophylline and milrinone during open heart surgery for valve replacement with CPB. Sixty adult patients undergoing elective single valve replacement were randomized to receive aminophylline 5 mg/kg [n=20], milrinone 50 -microg/kg [n=20], or normal saline as control group [n=20] through intravenous infusion 10 minutes before the aortic cross-clamping. The cardiac troponin I, inotrope score, duration of mechanical ventilation, and length of ICU stay and other hemodynamic variables were measured and recorded. There were no differences between the three groups with regard to clinical variables. Cardiac troponin I raised significantly after declamping in the three groups, however it was significantly lower in aminophylline and milrinone group compared to control group immediately after CBP and after 8 hours with no significant differences between aminophylline and milrinone group, inotrope score duration of mechanical ventilation and length of ICU stay showed no significant differences between the three groups. Administration of aminophylline or milrinone reduces the subclinical myocardial injury with no difference between both agents and with no effect on the hemodynamic parameters or short term clinical outcome in patients undergoing single valve replacement with CPB