Feasibility of Myocardial Performance Index for Evaluation of Left Ventricular Function during Dobutamine Stress Echocardiography before and after Coronary Artery Bypass Grafting

Aims Myocardial performance index ( MPI ) is a measure of combined systolic and diastolic myocardial function. In patients with coronary artery disease ( CAD ) an increase in MPI is consistent with myocardial dysfunction. The objectives of this study were to characterize the changes in MPI after coronary artery bypass graft ( CABG ) at rest and at peak dobutamine stress echocardiography ( DSE ). Methods and Results Thirty‐six patients diagnosed with CAD and accepted for CABG were studied by standard echocardiography and DSE 1 month prior and 3 month after CABG . The MPI was calculated using pulsed‐wave tissue Doppler imaging ( PW ‐ TDI ) of the left ventricular ( LV ) wall‐motion velocity. At baseline, ejection fraction ( EF ; 42.7 ± 8%) and wall‐motion score index ( WMSI ; 1.1 ± 0.2) were impaired at rest as well as at peak DSE ( EF ; 49.2 ± 9 and WMSI 1.4 ± 0.2). MPI was prolonged both at rest (0.61 ± 0.13) and at peak DSE (0.78 ± 0.16). After CABG , EF and WMSI did not improve at rest (43.7 ± 8% and 1.1 ± 0.2, respectively). On the other hand, MPI improved substantially both at rest (0.45 ± 0.08; P < 0.001) and at peak DSE (0.56 ± 0.1; P < 0.001). At peak DSE an improvement of EF (54.2 ± 9; P < 0.05) and WMSI (1.1 ± 0.16; P < 0.001) was seen as well. Conclusion Myocardial performance index shows significant improvement after CABG in patients with CAD both at rest and peak DSE and appears to be a sensitive measure of myocardial function.