RESUMO
BACKGROUND: Very-low-birth-weight (VLBW) preterm neonates are vulnerable to patent ductus arteriosus (PDA), which might be related to high-resistance flow in the superior mesenteric artery (SMA), with decreased diastolic flow in situations of marked intestinal hypoperfusion. No previous studies have evaluated the portal vein and superior mesenteric vein (SMV) parameters to assess the PDA hemodynamic repercussions. OBJECTIVE: To assess mesenteric and portal flow in VLBW preterm neonates with or without PDA using serial Doppler ultrasonography (US). MATERIALS AND METHODS: We conducted a prospective longitudinal study on 61 VLBW preterm neonates submitted to 161 Doppler US exams, from 2 days to 20 days of age. RESULTS: All infants exhibited a progressive daily increase in the mean of the SMA diameter and systolic velocity, the portal vein diameter, the peak velocity, the mean velocity and the flow volume and of SMV diameter (P<0.05). The incidence of PDA was 37.7% (n=23) and infants with the disease revealed a smaller diameter, greater systolic velocity, lower diastolic velocity, and higher resistivity and pulsatility indices on SMA compared to those without PDA (P<0.05). Additionally, 47.8% (n=11) of infants with PDA exhibited absent or reversed end-diastolic flow in the SMA, and its resolution was seen among 54.5% (n=6) of these. Infants with PDA also exhibited lower values of portal vein diameter and flow volume and of SMV diameter (P<0.01). CONCLUSION: Doppler US enhances the understanding of mesenteric and portal flow, including the effects of PDA. The study of SMV and portal vein flow is proposed as a new parameter in PDA evaluation.