Cerebral resistive indices and intraventricular hemorrhage in premature neonates < 29 weeks’ gestation: a pilot prospective cohort study

In extremely preterm newborns, intraventricular hemorrhage (IVH) greatly influences neurodevelopmental outcomes. Preterm newborns who later develop IVH might have altered cerebral blood flow (CBF) as measured by resistive index (RI) on Doppler ultrasound. Knowledge regarding RI in extremely premature infants remains limited. This pilot prospective cohort study aimed to evaluate the association between early cerebral RI (within the first 36 h of life) and the occurrence of IVH in preterm infants born at < 29 weeks’ gestation. Prospective cohort study in which cranial Doppler was performed in preterm infants < 29 weeks at < 36 h of age and between 5 and 7 days of age. CBF velocities and RI were measured. Clinical and demographic factors were also assessed. Statistical analyses included Pearson’s chi-square exact test, independent t-test, Mann-Whitney U exact test, and Pearson’s and Spearman’s correlations when appropriate. Multiple regression and receiver operating characteristics (ROC) analysis were used to examine the association between RI and IVH. Statistical significance was set at p < 0.05. Of the 30 enrolled infants, 27% developed an IVH. RI and peak systolic/end diastolic velocity ratio measured at < 36 h of life for the neonates with IVH were significantly higher than that for the non-IVH group (0.70(± 0.04) and 3.37(± 0.46) vs. 0.65(± 0.05) and 2.91(± 0.39); p = 0.02 and 0.01, respectively). Multiple regression showed RI amongst babies with IVH was higher by 0.05 when adjusted for other clinical variables (p = 0.01). Exploratory ROC analysis yielded an area under the curve (AUC) of 0.76, suggesting moderate discriminatory ability of RI to distinguish infants who developed IVH. These differences were not statistically significant when measured at 5–7 days. RI had no significant correlation with antenatal steroid use, delayed cord clamping, or presence of hemodynamically significant patent ductus arteriosus. Higher cerebral RI measured within the first 36 h of life was associated with IVH in this pilot study. These findings are preliminary and should be interpreted cautiously due to the small sample size and the exploratory nature of the study. Larger multicenter trials with serial measurements are needed to validate RI as a predictive marker for IVH.