Changes in fetal myocardial performance index following intravascular transfusion: preliminary report

Abstract

Objective: To investigate the changes in fetal left ventricle myocardial performance index (MPI) following intrauterine intravascular transfusion (IUT). Methods: Prospective study, including 25 IUT performed in 13 singleton pregnancies with maternal Rh D alloimmune disease. Left ventricle MPI was evaluated prior to transfusion and repeated 24h after each procedure. Delta MPI was calculated as the difference between post- and pre-transfusion MPI z-scores. Multilevel regression analysis was used to examine the association between delta MPI and gestational age at procedure, fetal middle cerebral artery peak velocity MoM, pre- and post-MPI and hemoglobin z-score values, the volume of blood transfused and feto-placental volume percentage expansion. Adjustments were made for repeated measurements within the same fetus, and across different time points. The significance level was set as 0.05. Results: MPI z-score values increased significantly following transfusion (delta MPI = 1.10 +/- 2.47, p = 0.036). Delta MPI showed a significant correlation with gestational age at transfusion (r = -0.47, p = 0.018), pre-transfusion MPI z-score (r = -0.50, p = 0.012) and feto-placental volume percentage expansion (r = -0.41, p = 0.044). Conclusion: Left ventricle MPI increases significantly after intrauterine blood transfusion and greater changes are associated with procedures at an earlier gestational age, lower pre-transfusion MPI z-scores and smaller feto-placental volume expansion.