A MULTICENTER, RANDOMIZED, BLIND COMPARISON OF AMRINONE WITH MILRINONE AFTER ELECTIVE CARDIAC-SURGERY

Amrinone and milrinone are phosphodiesterase inhibitors with positive inotropic effects useful for the treatment of ventricular dysfunction after cardiac surgery. Forty-four patients undergoing elective cardiac surgery al four centers received either amrinone (n = 22) or milrinon e (n = 22) in a randomized, blind fashion. Immediately after separatio n from cardiopulmonary bypass (CPB), two bolus doses of either amrinon e 0.75 mg/kg or milrinone 25 mu g/kg were administered over 30 s, sepa rated by 5 min. Hemodynamic measurements were recorded before each dos e and at the end of the 10-min study. Both amrinone and milrinone incr eased the cardiac index (48% vs 52%, P = not significant [NS] for amri none and milrinone, respectively). There was a small increase in mean arterial pressure (MAP) after amrinone administration (from 68 +/- 3 t o 72 +/- 3 mm Hg at 10 min, P < 0.05) with no significant change in MA P after milrinone administration. Central venous pressure was signific antly higher in the amrinone group at baseline and 5 min (12 vs 10 mm Hg and 11 vs 10 mm Hg, respectively; P < 0.05). Systemic and pulmonary vascular resistances decreased significantly and to a similar extent after either amrinone or milrinone administration. Phenylephrine was r equired in 11 of 22 patients receiving amrinone and in 11 of 22 patien ts receiving milrinone to maintain arterial blood pressure. The propor tion of patients requiring an intra vascular volume infusion (15 of 22 vs 17 of 22, P = NS) and the total fluid volume infused were similar (402 +/- 57 vs 350 +/- 49 mt, P = NS for amrinone and milrinone, respe ctively). Amrinone and milrinone seem to have similar hemodynamic effe cts after CPB, with the exception of blood pressure, although the need for vasopressor support of blood pressure did not differ. Selection b etween these two drugs may include nonhemodynamic considerations such as cost. Implications: Amrinone and milrinone are drugs that improve c ardiac contraction. Their effects have never been directly compared in patients. We found that amrinone and milrinone produced similar hemod ynamic effects in adult patients undergoing cardiac surgery. Choice be tween the two drugs can be based on nonhemodynamic considerations such as cost.