Propofol Is Cardioprotective in a Clinically Relevant Model of Normothermic Blood Cardioplegic Arrest and Cardiopulmonary Bypass

Abstract

The general anesthetic propofol has been shown to be cardioprotective. However, its benefits when used in cardioplegia during cardiac surgery have not been demonstrated. In this study, we investigated the effects of propofol on metabolic stress, cardiac function, and injury in a clinically relevant model of normothermic cardioplegic arrest and cardiopulmonary bypass. Twenty anesthetized pigs, randomized to propofol treatment ( n = 8) and control ( n =12) groups, were surgically prepared for cardiopulmonary bypass (CPB) and cardioplegic arrest. Doses of warm blood cardioplegia were delivered at 15-min intervals during a 60-min aortic cross-clamped period. Propofol was continuously infused for the duration of CPB and was therefore present in blood cardioplegia. Myocardial biopsies were collected before, at the end of cardioplegic arrest, and 20 mins after the release of the aortic cross-clamp. Hemodynamic parameters were monitored and blood samples collected for cardiac troponin I measurements. Propofol infusion during CPB and before ischemia did not alter cardiac function or myocardial metabolism. Propofol treatment attenuated the changes in myocardial tissue levels of adenine nucleotides, lactate, and amino acids during ischemia and reduced cardiac troponin I release on reperfusion. Propofol treatment reduced measurable hemodynamic dysfunction after cardioplegic arrest when compared to untreated controls. In conclusion, propofol protects the heart from ischemia-reperfusion injury in a clinically relevant experimental model. Propofol may therefore be a useful adjunct to cardioplegic solutions as well as being an appropriate anesthetic for cardiac surgery.