The efficacy of preemptive Milrinone or Amrinone therapy in patients undergoing coronary artery bypass grafting

Acute deterioration in ventriculax function and oxygen transport is common after cardiac surgery. We hypothesized that milrinone or amrinone may reduce their occurrence and catecholamine requirements and increase cellular enzyme levels in patients undergoing coronary artery bypass. In 45 patients, we randomly administered milrinone 50 mug/kg plus 0.5 mug.kg(-1).min(-1) infusion for 10 h, amrinone 1.5 mg/kg plus 10 mug.kg(-1).min(-1) infusion for 10 h, or placebo at release of aortic cross-clamp. Hemodynamic variables, dopamine requirement, and laboratory values were recorded, At the postoperative nadir, stroke volume index was higher in the Milrinone and Amrinone groups (mean+/-SD, 27.8+/-4.0 and 26.1+/-3.2 vs 20.4+/-5.1 mL.min(-1).m(-2) per beat, P<0.0001), and oxygen transport index was higher (354.7 +/- 57.8 and 353.7 +/- 91.2 vs 283.0 +/- 83.9 mL.min(-1).m(-2), P=0.009). The postoperative dopamine requirement was less (6.6 +/- 2.7 and 6.8 +/- 2.6 vs 10.4 +/- 2.0 mg/kg, P<0.008), and postoperative serum lactate, alanine and aspartate aminotransferase, lactate dehydrogenase, creatinine kinase, C-reactive protein, and glucose levels were less (P<0.01). The mean postoperative heart rate was faster in the Milrinone group than in the Amrinone and Placebo groups (96.8 +/- 10.3 vs 86.9 +/- 9.5 and 87.8 +/- 10.8 bpm, P<0.01). Milrinone and amrinone administered pre-emptively reduce postoperative deterioration in cardiac function and oxygen transport, dopamine, requirement, and increases in serum lactate, glucose, and enzyme levels, although milrinone may increase heart rate.