Assessment of left ventricular systolic function during acute myocardial ischemia: A comparison of transpulmonary thermodilution and transesophageal echocardiography

Background. The PiCCO system provides different variables of cardiac function: the cardiac function index (CFI), the global ejection fraction (GEF) and the maximal pressure developed by the left ventricle (dP/dtMax). The purpose of this study was to investigate the ability of these variables to predict impaired left ventricular ejection fraction (LVEF) derived by transesophageal echocardiography, during acute myocardial ischemia. Methods. In this prospective experimental study, fifteen pigs (28-34 kg) were anesthetized, mechanically ventilated and subjected to left anterior descending (LAD) coronary artery occlusion. PiCCO-derived variables and LVEF were obtained 5, 10, 15, and 20 minutes after LAD occlusion. Receiver operating characteristics analysis was performed to assess the ability of PiCCO-derived parameters to estimate LVEF <= 40% and <= 50%. Results. LAD occlusion induced a decrease in PiCCO-derived variables and LVEF (P < 0.001 for each). Significant correlations were found between LVEF and CFI (r=0.59, P < 0.001), GEF (r=0.64, P < 0.001), dP/dtMax (r=0.36, P < 0.001), and cardiac output (r=0.25, P=0.028). The area under the receiver operating characteristics curve for the estimation of LVEF <= 40% and <= 50% was 0.80 and 0.79 for CFI (P=0.009, P < 0.001), 0.86 and 0.78 for GEF (P=0.002, P < 0.001), 0.76 and 0.68 for dP/dtMax (P=0.033, P=0.012), and 0.57 and 0.58 for cardiac output (P=0.554, P=0.259). Conclusion. Cardiac function indices permit the bedside quantification of left ventricular systolic function during acute myocardial ischemia in pigs. Therefore, the PiCCO system may represent a valuable technique for cardiovascular monitoring, particularly for detecting acute left ventricular systolic dysfunction due to myocardial ischemia. (Minerva Anestsiol 2011;77:132-141)