Cardiac Functions as a New Method for Evaluation of Fetal Anemia Pre and Post Intrauterine Fetal Blood Transfusion

INTRODUCTION

Circulatory changes associated with fetal anemia have an important role in maintaining sufficient tissue oxygenation. With fetal anemia, hyperdynamic circulation and increased cardiac output occurred. This is due to reduced the viscosity of blood, increased the contractility of heart, and peripheal vasodilatation due to hypoxia. In current practice, using Doppler in assessment of the peak systolic velocity (PSV) of the middle cerebral artery (MCA) is the main parameter in screening of fetal anemia. Severe fetal anemia causes continuous loss of adaptive mechanisms due to lack of oxygen delivered to the tissues. Finally, fetal acidosis results as a sequence of metabolic changes so increasing perinatal morbidity and mortality. Cardiac decompensation is not the principal mechanism involved in the development of overt fetal hydrops, however, severe anemia may cause cardiac ischemia, reduced contractility, and dysfunction. Myocardial performance index (MPI) is a noninvasive technique that evaluates systolic and diastolic cardiac function by pulsed Doppler. Tsutsumi et al. was the first described Fetal MPI evaluation then several studies have shown that it is a simple and replicable technique. Many have demonstrated significant changes in fetal MPI in intrauterine growth restriction, recipient fetuses of twin-twin transfusion syndrome, diabetes, and fetal inflammatory response syndrome. Similarly, fetal anemia causes changes in cardiac contractility and MPI as one of cardiac functions may have a role in the evaluation of disease severity and prognosis.

Patients and Methods:

This prospective study will be carried out at a tertiary referral center for fetal medicine (Fetal Medicine Unit, Cairo University, Egypt) from April 2017 till April 2018. Women with singleton pregnancies with Rh isoimmunization will be asked to participate in the study. Informed consent will be obtained from all participants. The ethical committee approval for the study will be from Bioethical Committee of the National Research Centre (number: 17 008, admission date: January 2017).

This will be a prospective study. Patients will be selected from Rh isoimmunized patients (positive titer of indirect coomb's test) who are scheduled to have intrauterine blood transfusion. This intrauterine blood transfusion is due to fetal anemia, and it is detected when the measurement of PSV (peak systolic velocity) of middle cerebral artery is more than 1.5 MoM (multiple of the median) according to Fetal Medicine unit of Cairo University protocol. All fetuses are free of structural and functional Fetal and echocardiographic anomaly scan.