Normal reference ranges for cardiac valve cross-sectional areas in preterm infants

OBJECTIVE: To establish normal reference ranges for cardiac valve crosssectional areas (CSAs) in preterm infants and their correlation with gestational age, body weight, and chronological age. MATERIALS AND METHODS: In a prospective study, 268 preterm babies fulfilling the criteria for inclusion were examined. Echocardiograms were performed to measure aortic, pulmonary, mitral, and tricuspid valve CSAs on 0–6 day (s) of life and at weekly intervals until they reached 36 weeks. Gestational age was divided into three groups, 24–27, 28–31, and 32–35 weeks, and body weight was divided into five groups, ≤999, 1000–1499, 1500–1999, 2000–2499, and ≥2500 g. Overall group differences were compared for each period of life: 0–6 days and 1–2, 3–4, and ≥5 weeks. RESULTS: The mean gestational age was 29.8 (±2.38 standard deviation [SD]) weeks, ranging between 24 and 35 weeks, and the mean body weight was 1479 (±413 SD) g, ranging between 588 and 3380 g. All cardiac valve CSAs correlated well with body weight. A significant gradual increase was observed in all valve CSAs with body weight during each period of life. Overall, a progressive and significant increase in all valve CSAs was observed during the first 9 weeks of life. CONCLUSIONS: Cardiac valve CSAs were found to be significantly correlated with body weight. The study also provides reference data, which can be used as a normal reference tool for valve CSAs in preterm infants against gestational age, body weight, and chronological age.