Monitoring the Variation in Myocardial Function With the Doppler-Derived Myocardial Performance Index During Aortic Cross-Clamping

ObjectivesTo investigate the effects of acute elevation in afterload on global (systolic and diastolic) myocardial function by performing serial intraoperative transesophageal echocardiograms during and after cross-clamp application on patients undergoing elective abdominal aortic aneurysm (AAA) surgery.DesignA prospective observational study.SettingA tertiary care university hospital.ParticipantsPatients undergoing elective AAA repair under general anesthesia (GA).InterventionThe use of perioperative transesophageal echocardiography to calculate a tissue Doppler–derived myocardial performance index (MPI) during different stages of the surgery.Measurement and ResultsTwenty consecutive patients scheduled for suprarenal AAA repair under GA were included in the study. Perioperative transesophageal echocardiography was performed after the induction of GA. MPI was calculated with Doppler tissue imaging as the sum of isovolumetric contraction and relaxation times divided by the ejection time before cross-clamping of the aorta and then 2, 10, and 20 minutes after cross-clamp application. A final MPI was measured after unclamping of the aorta. As compared with baseline, cross-clamp application initially worsened MPI within 2 minutes and then MPI improved to baseline after 10 minutes of cross-clamp application. The MPI improved significantly after unclamping of the aorta.ConclusionsThe authors observed a temporal variation in global myocardial function after the application of a cross-clamp in the suprarenal position. There was transient deterioration of global myocardial function (the prolongation of MPI) 2 minutes after cross-clamp application, which improved within 10 minutes. Myocardial function returned to baseline after unclamping the aorta.