Maturation of esophageal motility and esophagogastric junction in preterm infants

Background: Preterm infants commonly present with oral feeding problems. The role of maturation of esophageal bolus transport mechanisms herein remains unclear. Objectives: To characterize esophageal motility and function of esophagogastric junction (EGJ) during deglutitive swallowing in healthy preterm infants and to describe maturational changes. Methods: Four consecutive high-resolution manometry studies with impedance studies were performed weekly to investigate esophageal motility and EGJ function. Esophageal pressure topography and pressure-impedance metrics were derived. Mixed models with repeated measures were used for statistical analysis. Results: We analyzed 137 nutritive swallows from 36 motility studies in 10 preterm infants. The mean gestational age was 30.17 ± 0.94 weeks; the mean postmenstrual age at time point 1 and 4 was 34.42 ± 0.86 and 37.45 ± 1.16 weeks, respectively. Esophageal peristaltic wave patterns in response to nutritive swallows were observed in all patients. At later time points, esophageal body peristalsis became more rapid, evidenced by a faster distal contractile velocity and shorter distal latency (p = 0.002 and p < 0.0001, respectively). In addition, 4-s integrated relaxation pressures increased and distal contractile integral decreased at later time points (p = 0.003 and p = 0.021, respectively). Bolus clearance also improved at later age (p = 0.008). Conclusions: Preterm infants demonstrate peristaltic esophageal motility following nutritive swallows. However, alterations in esophageal bolus transport in relation to peristalsis are demonstrated. Peristaltic progression becomes more rapid, while deglutitive relaxation pressures increase with increasing age. These maturational changes may suggest further development of the enteric nervous system after birth in former preterm neonates.