The Comparative Myocardial Protection by Propofol and Isoflurane in an In Vivo Model of Ischemia Reperfusion

Abstract

Background. Anesthetic Agents protect the heart from ischemic injury during perioperative period. We evaluated the protective effects of 2 anesagents on myocardial ischemia -reperfusion injury in rabbit models. Methods. 58 anesthetized and mechaniventilated rabbits randomly received isoflurane (ISO) 2%, propofol (PRP), or were observed as the control group for 15 minutes. We applied vascular tourniquet around the left anterior descending artery (LAD). Myocardium was reperfused for 4 hours. Derivative of pressure over time (dP/dTmax), left ventricular pressure (dLVP), isovolumetric relaxation time (Tau), and segment shortening (SS) were measured over the ischemic and non-ischemic regions of left ventricle (LV). Cardiac troponin I (cTnI), tissue concentrations of tumor necrosis factor á (TNFá), myeloperoxidase activity assay (MPO), and tissue malonyl dialdehyde (MDA) concentrations were measured as indices of cellular injury and inflammatory response. Results. dP/dTmax values significantly decreased during ischemia. Following reperfusion, dP/dTmax, dLVP, and Tau remained depressed in the control animals. Both PRP and ISO restored the function of the myocardium globally. Conclusion. Only ISO improved the recovery of the ischemic myocardium during reperfusion. The effects of PRP were global in nature and involved compensatory hypercontractile state in nonischemic regions of the myocardium. Implication. PRP and ISO protect the heart against an ischemic injury, but only ISO preserves the function of the myocardium at the ischemic region. The survival rate of the PRP-treated group versus the ISO-treated group supports the claim that PRP has smaller contribution to recovery from myocardial ischemia.