Prognosis of premature infants with bronchopulmonary dysplasia at scholl age

Background and Aim: Bronchopulmonary dysplasia (BPD) is a clinical syndrome characterized by persistent oxygen demand, respiratory distress and accompanying radiological findings in premature babies. It is still the most common chronic respiratory system disease in infancy. Premature infants with BPD are at high risk for long term respiratory, neurodevelopmental, cardiovascular, auditory and visual sequelae and growth retardation. Clinical features of BPD, disease progression and long-term prognosis have changed very much with the development of new medical treatments and technology applied in neonatal intensive care units. Knowing the risks in the long term is important for proper monitoring and early treatment planning. However, information on long-term follow-up of BPD is limited. In this study, it was aimed to evaluate the prognosis of preterm born children with BPD in school age with new techniques and to identify possible risk factors related to long term sequelae. Materials and Methods: The premature cohort, born between 2005 and 2008 at Ege University Medical Faculty Hospital which was followed up after discharge for complications of prematurity and BPD, was evaluated at school ages (8-10 years) in this study. Twenty-three children with BPD (13 mild, 6 moderate, 1 severe) and 14 preterm born children without BPD were enrolled to the study with a healthy control group of composed of children at the same age and gender. Anthropometric and vital sign measurements were performed with appropriate techniques. Neurological assessment included Gross Motor Function Scale and Mizrahi scoring; respiratory assessment included spirometry, impulse oscillometry and exercise provocation tests, cardiovascular assessment included electrocardiogram, conventional, tissue doppler and speckle tracking echocardiography in addition to measurement of serum biomarkers (B-type Natriuretic Peptide, N-terminal Type B Natriuretic Peptide, Chitotriosidase, chitinase-like protein (YKL-40), high sensitivity C-reactive protein, myeloperoxidase (MPO), tumor necrosis factor- 6), interleukin-18 (IL-18), matrix metalloproteinase-1 (MMP1) and matrix metalloproteinase-9 (MMP9). Results: When anthropometric measurements are evaluated; the body weights of preterm born children with or without BPD were significantly lower than term controls (p <0.001, p = 0.027). There was no significant difference between the two groups in terms of height measurements (p = 0,348), while BPD preterm infants were significantly shorter than term infants (p <0.001). The head circumferences of infants with BPD were significantly lower than both preterm and term infants without BPD (p <0.001, p = 0.001). In the spirometry measurements, premature group without BPD had significantly lower FEF25-75% compared to BPD and term group (p = 0,035, p = 0,046). There was no significant difference between the groups in impulse oscillometry measurements. After exercise provocation; spirometry showed decreased FEV1 in both BPD and non-BPD preterms (p <0.001); decreased FEV1 / FVC and FEF25-75% in the premature group without BPD (p = 0.047, p <0.001); impulse oscillometry demonstrated only increased R 5 Hz measurements in the premature group without BPD when compared to the other groups (p = 0.005). Cerebral palsy was observed in 20% of the BPD group and 7.1% in the preterm group without BPD. The neurological disability in the BPD group was found to be 25% with the gross motor functioning scale and 35% with the Mizrahi clinical scoring scale. Conventional echocardiography showed that PAAT, which is an indicator of pulmonary hypertension, persisted high in addition to various structural changes in preterms with BPD (p = 0.003). Tissue Doppler echocardiography revealed significantly higher RVMPI BPD group than in the premature and term control group without BPD (p <0.001) as a global effect in the right ventricle. In the speckle tracking echocardiography; BPD group was found to be affected in right ventricle, left ventricle and interventricular septum. Postnatal corticosteroid therapy was associated with pulmonary hypertension findings and right ventricular myocardial performance indices. There was a positive correlation between NT-proBNP and RVMPI in the BPD group. In the BPD group, MMP1 was significantly higher as a proinflammatory marker (p <0.001). YKL-40 and MPO levels were higher in the preterms with and without BPD when compared to term controls. Conclusion: Preterm born children with or without BPD are leaner than term controls at school age. Additionally, the BPD group had lower height and head circumference. Neurological disabilities are more common in this group, consistent with smaller head circumference. In respiratory evaluations; regardless of BPD status, although the effects of preterm birth are faint, these influences become noticeable with exercise provocation. In patients with BPD, cardiovascular effects continue in school age and biochemical findings that may be precursors of adult cardiovascular disease have been found. Cardiovascular changes that were demonstrated in this study among school aged BPD patients with minimal or no respiratory findings, support the hypothesis that BPD is a vascular disease. Cardiovascular sequelae should be kept in mind in the long term follow up of patients with BPD.