A Longitudinal Study Of Maternal Cardiac Function In Twin Pregnancy Assessed By Ultrasound

Objective:To assess the twin pregnancies’s cardiac function using the conventional ultrasound and VVI technique, and analyze the relation between the variation and gestational ages.Methods:42women with twin pregnancy, who were considered fully meet the standard set underwent a vigorous selection process, through routine ultrasonic examinations, at the Second Xiangya Hospital, Central South University from April2012to April2013, were involved in the study, including28uncomplicated cases,14complicated cases(pre-eclampsia (n=4), SGA neonate (n=8) and both of them (n=2)). And each of the42women received serial maternal echocardiography at20-23weeks,26-29weeks and30-33weeks of the gestation. Patients were excluded if delivery took place prior34weeks. Cardiac findings were compared between patients with uneventful pregnancy outcome and those who developed one of the following complications:pre-eclampsia or gestational hypertension; small-for-gestational age (SGA) neonates (birth weight of one or both twins<10th centile for gestational age).Results:With the increasing of gestational age, the CO, HR and BP increased, while the TVR decreased in normal twin pregnancies, with extremely significant difference (P<0.001), however, the CO,HR,BP and TVR remained stale throughout the assessed pregnancy interval in twin pregnancies with complication. With the increasing of gestational age, the myocardial peak systolic strain and peak systolic strain rate of left ventricular increased in normal twin pregnancies, with significant difference (P<0.05), while that decreased in twin pregnancies with complication, but there was no significant differences (P>0.05).The cardiac output (CO) and stroke volume (SV) mean±standard deviation (SD) were significantly lower in twin pregnancies with complication than that in normal twin pregnancies, whereas the total vascular resistance (TVR) was higher, and the difference was significant (P<0.05). At each pregnancy stage, the myocardial segmental peak systolic strain and peak systolic strain rate of left ventricular in twin pregnancies with complication were lower than that in normal twin pregnancies with significant difference(p<0.05).Conclusion: With the increasing of gestational age, the CO、HR、BP rise, but the TVR decrease in normal twin pregnancies. Myocardial peak systolic strain and peak systolic strain rate of left ventricular increase, which is shown as typical longitudinal change. Yet, there was no significant change of the CO, HR, BP or TVR in twin pregnancies with complication, neither were the myocardial peak systolic strain and peak systolic strain rate of left ventricular, which even show the tendency of decline, moreover, significantly decline compare with normal twin pregnancies.