Correlation of the myocardial performance index with conventional echocardiographic indices of systolic and diastolic function: A study in cardiac surgical patients

Background: The aim of this investigation was to compare the myocardial performance index (MPI), a Doppler-derived parameter of global ventricular function, with standard echocardiographic measures of systolic and diastolic function in patients undergoing coronary artery bypass graft (CABG) surgery. Methods: Complete two-dimensional and Doppler examinations were performed on 46 CABG patients after induction of anesthesia (baseline), 15 minutes postcardiopulmonary bypass (CPB), and at the end of the surgical procedure. Results: A strong inverse correlation between MPI and both fractional area change (adjusted r² = 0.588-0.802) and ejection fraction (adjusted r² = 0.576-0.656, both P < 0.001) of the left ventricle was observed throughout the intraoperative period. Following CPB, a weaker correlation was observed between MPI and overall diastolic heart function classification (adjusted r² = 0.224-0.268, P <0.001). Weak, though statistically significant, correlations were observed between MPI and deceleration time (P < 0.05), peak atrial reversal (AR) wave velocity (P ≤0.002), and duration of the AR wave (P < 0.05). Conclusion: Our data suggest that the MPI correlates well with standard echocardiographic measures of systolic function and modestly well with overall diastolic heart function classification. The MPI may be a useful, complementary marker of global left ventricular function in patients undergoing CABG surgery.