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

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.

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.

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).

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.