Superior mesenteric artery blood flow in infants of very preterm and/or very low birthweight and related factors

Background Significant hemodynamic changes in preterm infants during early life could have consequences, especially on intestinal blood flow. Decreased of superior mesenteric artery (SMA) blood flow may lead to impairment in gut function and feeding intolerance. Objective To assess SMA blood flow velocity in very preterm and/or very low birth weight (VLBW) infants in early life and to elucidate potential influencing factors. Methods This cross-sectional study was conducted in the NICU at Cipto Mangunkusumo Hospital, Jakarta, including very preterm infants (28-32 wk GA) and/or VLBW (1,000-1,500 g) infants. Superior mesenteric artery (SMA) blood flow was evaluated by peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) measurement using Color Doppler ultrasonography (US) at <48 hours after birth. Maternal and neonatal characteristics that could be potentially associated with SMA blood flow were analyzed. Results We examined 156 infants eligible for inclusion. The PSV, EDV, and RI of SMA blood flow were not associated with gestational age or birth weight. Small for gestational age (SGA) infants had significantly lower median EDV [15.5 (range 0.0-32.8) vs. 19.4 (range 0.0-113.0), respectively; (P=0.003)] and higher RI [0.80 (range 0.58-1.00) vs. 0.78 (range 0.50-1.00), respectively; (P=0.009)] compared to appropriate for gestational age (AGA) subjects. Infants born to mothers with preeclampsia (PE) had lower median PSV [78.2 (range 32.0-163.0) vs. 89.7 (range 29.2-357.0), respectively; (P=0.038)]) and EDV [16.2 (range 0.0-48.5) vs. 19.4 (range 0.0-113.0), respectively; (P=0.022)] compared to those without maternal PE. Infants with absent/reverse end-diastolic velocity (AREDV) had a lower median EDV [16.9 (range 0.0- 32.4) vs. 19.4 (range 0.0-113.0), respectively; (P=0.041)] compared to those without AREDV. Furthermore, infants with hemodynamically significant patent ductus arteriosus (hs-PDA) had lower median EDV [16.2 (range 0.0-113.0) vs. 19.4 (range 0.0-71.1), respectively; (P=0.027)] but higher RI median [0.80 (range 0.50-1.00) vs. 0.78 (range 0.55-1.00), respectively; (P=0.032)] compared to those without hs-PDA. No difference in SMA blood flow across other factors was observed. Conclusion Superior mesenteric artery blood flow in very preterm and/or VLBW infants can be assessed using Color Doppler US by measuring PSV, EDV and RI. Changes in these parameters are significantly associated with SGA, preeclampsia, AREDV, and hs-PDA.