Pulmonary Vein Flow Impedance: An Early Predictor of Cardiac Dysfunction in Intrauterine Growth Restriction

Abstract

Introduction: In intrauterine growth restriction (IUGR), increased uteroplacental vascular impedance contributes to preferential flow to left ventricle (LV), with consequent alteration of its compliance and increased left atrial (LA) pressure. Pulmonary vein pulsatility index (PVPI) reflects the increased impedance to LA filling and could be used as a cardiac monitoring parameter in IUGR. Material and Methods: A total of 27 IUGR fetuses (group 1), 28 fetuses with appropriate growth for gestational age from hypertensive mothers (group 2), and 28 controls (group 3) were studied. Pulsatility indices (PIs) of pulmonary veins and ductus venosus were calculated by Doppler echocardiography. Obstetric ultrasound was used to assess the PIs of uterine, umbilical, and middle cerebral arteries. Statistical analysis used analysis of variance, post-hoc Tukey, and Pearson’s tests. Results: Mean PVPI was higher in IUGR group (1.27 ± 0.39) when compared to groups 2 (1.02 ± 0.37; p = 0.01) and 3 (0.75 ± 0.12; p < 0.001). In group 2, moderate correlation between PVPI and ductus venosus pulsatility index (DVPI) was found but not between PVPI and cerebroplacental ratio (CPR). Discussion: Higher PVPI in IUGR reflects decreased LV compliance and altered LA dynamics. As LV dysfunction precedes right ventricle, our results suggest that PVPI could be an early echocardiographic parameter of fetal diastolic function in IUGR.

Fetal Pulmonary Vein Pulsatility Index in the Third Trimester of Pregnancy as a Predictor of Small for Gestational Age

“…The PVPI of the IUGR group was 1.27, that of the AGA fetuses from hypertensive mothers was 1.02, and that of the control group was 0.75. As a result, only the IUGR group showed higher PVPI compared with the other groups 5 . In a study conducted by Zielinsky et al, the PVPI among fetuses of diabetic mothers was higher than that among fetuses in the normoglycemic, healthy control group 28 .…”

“…This leads to a change in pulmonary venous blood flow. In situations in which the left ventricular compliance is reduced, the presystolic wave (a‐wave) of the pulmonary vein decreases, is absent, or reversed and the PVPI increases 5 …”

“…Decreased a‐waves in the ductus venosus can be used as parameters of severe fetal hypoxia 11,17,18 . However, these findings appear in the late stage of placental insufficiency 5 and could lead to missing the detection time for proper intervention. To improve perinatal outcomes, early predictors of placental insufficiency are needed.…”

“…PVPI could be another parameter that reflects myocardial performance. Recently, it has been reported that the PVPI increases in IUGR related to placental insufficiency 5,6 . Bravo‐Valenzuela et al reported that the average PVPI for normal birth weight was 0.83 and 1.31 in the IUGR group at 31 weeks 6 .…”

“…Pulmonary venous pulsatility index (PVPI) (peak systolic velocity minus pre‐systolic velocity/mean averaged maximum velocity) is useful for assessing the atrial dynamics. In the previous study, the average PVPI was found to be higher in the IUGR group than in the control group in late pregnancy 5,6 . However, the change in birth weight or perinatal outcome according to the PVPI has not been studied yet.…”