Esmolol before cardioplegia and as cardioplegia adjuvant reduces cardiac troponin release after cardiac surgery. A randomized trial

Abstract

Background: Cardioplegic solutions are the standard in myocardial protection during cardiac surgery, since they interrupt the electro-mechanical activity of the heart and protect it from ischemia during aortic cross-clamping. Nevertheless, myocardial damage has a strong clinical impact. We tested the hypothesis that the short-acting beta-blocker esmolol, given immediately before cardiopulmonary bypass and as a cardioplegia additive, would provide an extra protection to myocardial tissue during cardiopulmonary bypass by virtually reducing myocardial activity and, therefore, oxygen consumption to zero. Materials and methods: This was a single-centre, double-blind, placebo-controlled, parallel-group phase IV trial. Adult patients undergoing elective valvular and non-valvular cardiac surgery with end diastolic diameter >60 mm and ejection fraction <50% were enrolled. Patients were randomly assigned to receive either esmolol, 1 mg/kg before aortic cross-clamping and 2 mg/kg with Custodiol® crystalloid cardioplegia or equivolume placebo. The primary end-point was peak postoperative troponin T concentration. Troponin was measured at Intensive Care Unit arrival and at 4, 24 and 48 hours. Secondary endpoints included ventricular fibrillation after cardioplegic arrest, need for inotropic support and intensive care unit and hospital stay. Results: We found a reduction in peak postoperative troponin T, from 1195 ng/l (690–2730) in the placebo group to 640 ng/l (544–1174) in the esmolol group (p=0.029) with no differences in Intensive Care Unit stay [3 days (1-6) in the placebo group and 3 days (2-5) in the esmolol group] and hospital stay [7 days (6–10) in the placebo group and 7 days (6–12) in the esmolol group]. Troponin peak occurred at 24 hours for 12 patients (26%) and at 4 hours for the others (74%). There were no differences in other secondary end-points. Conclusions: Adding esmolol to the cardioplegia in high-risk patients undergoing elective cardiac surgery reduces peak postoperative troponin levels. Further investigation is necessary to assess esmolol effects on major clinical outcomes.