The myocardial performance index in children after surgical correction of congenital malformations with intracardiac shunt.

Background: The lack of a simple and clinically useful method of myocardial function assessment makes it difficult to monitor patients after repair of congenital cardiac malformations. The myocardial performance index (MPI) introduced in 1995 by Chuwa Tei may help to precisely follow the course of postoperative myocardial function disturbances.

Aim: To assess the usefulness of MPI for cardiac function evaluation following surgical correction of congenital defects performed in cardiopulmonary bypass and to evaluate it's prognostic value.

Methods: This prospective study involved 73 children who underwent surgery for simple defects with intracardiac shunt--34 children with atrial septal defect (ASD) and 39 with ventricular septal defect (VSD). In the examined patient group, MPI and the parameters of cardiac index were measured in the early postoperative period. Then the results were correlated with congenital defect severity and postoperative course. The control group consisted of 77 healthy children.

Results: In the control group of healthy children, mean values of the right (RVMPI) and the left ventricular MPI (LVMPI) were 0.32+/-0.06 and 0.33+/-0.05, respectively. In children after ASD correction, MPI was elevated only for the right ventricle (mean value of 0.41+/-0.07). Meanwhile in children operated on for VSD, both the RVMPI and LVMPI values increased postoperatively. RVMPI reached a peak value on the 2nd postoperative day (0.48+/-0.20) while LVMPI reached a peak value between the 3rd and 5th day after surgery (0.49+/-0.10). A significant and strong correlation between severity of VSD and MPI values was observed. A marked correlation between MPI calculated on the 1st postoperative day and the course after surgery was also noted.

Conclusions: The MPI is a precise tool assessing both systolic and diastolic ventricular performance in the early postoperative period following surgical correction of a congenital defect with intracardiac shunt and is also a useful predictive factor of the postoperative course.