Color Doppler Blood Flow Indices of the Superior Mesenteric Artery as an Early Predictor of Necrotizing Enterocolitis in Preterm Neonates

Abstract

Background: Necrotizing enterocolitis is the most common sever gastrointestinal emergency that affects premature newborns. It is often has a rapid onset with few signs that can be used to predict its occurrence. Its rapid onset and progression to morbidity and mortality initiates the researchers for seeking early diagnostic tools helping in detection infants at risk for development of the disease, for whom early preventive measures could be targeted. Previous studies have shown that high resistance patterns of mesenteric arterial Doppler flow velocimetry are associated with a significantly reduced tolerance to enteral feeding. Moreover, groups of infants deemed to be at increased risk of necrotizing enterocolitis tended to have high resistance patterns of flow in the superior mesenteric artery. AIM: To evaluate the Doppler blood flow indices of the superior mesenteric artery (SMA) in pre-term neonates at risk for developing necrotizing enterocolitis (NEC). Materials and Methods: This prospective study included 52 preterm neonates, whose gestational age was less than 34 weeks. All of the neonates were subjected to clinical assessments, laboratory investigations and color Doppler flow evaluation of the SMA (including PSV, EDV, RI and PI) on the first day of life. Necrotizing enterocolitis was diagnosed and classified based on Bell's staging criteria with Walsh and Kliegman's modifications. Clinical management and diagnosis of NEC were performed blind to the Doppler results. Statistical analysis was performed using the Mann-Whitney U test, and P-values less than or equal to 0.05 were statistically significant. Receiver operating characteristic (ROC) curves were used to determine the optimal threshold values of PSV, EDV, RI and PI, using MedCalc software, version 12.7.8.0. Results: The study included 52 preterm neonates, whose gestational age was less than 34 weeks. Twelve neonates (23%) developed NEC and were designated as group I, and the remaining 40 neonates (77%) were designated as group II. The median birth weights in groups I and II were 1000 and 1870 g, respectively, with a statistically significant difference of P < 0.05. Doppler indices of the SMA, peak systolic velocity (88.9 ±17 and 53 ±8.5 cm/s), end diastolic velocity (18.75±11.3 and 14.9±5.6 cm/s), resistive index (0.78±0.09 and 0.67±0.1) and pulsatility index (1.53±0.73 and 0.67 ± 0.15) were higher in group I than in group II, with statistically significant differences. Conclusion: Preterm infants with high resistance patterns of blood flow velocity in the SMA on the first day of life were at increased risk for developing necrotizing enterocolitis