Background: Bronchopulmonary dysplasia (BPD) is a common comorbidity of preterm infants less than 1,500 grams. When pulmonary hypertension (PHT) occurs concomitantly with BPD, the death rate is increasingly high. Established guideline for PHT screening in this specific group of infants may necessary.
Objective: To determine feasibility of the Chiang Mai University (CMU) guideline for screening of PHT in very low birth weight (VLBW) infants
Methods: This is a prospective study in VLBW infants who were admitted at Chiang Mai University hospital between 1st August 2019 and 30th September 2020. VLBW infants who had gestational age (GA) of 23+0-31+6 or BW of 400-1500 g. were performed echocardiography at 7, 28 days after birth and at postmenstrual age (PMA) 36 weeks. Blood sample were collected for N terminal pro B-type natriuretic peptide (NT-proBNP) at the same time. The exclusion criteria were congenital heart diseases (except patent ductus arteriosus, atrial septal defect, and ventricular septal defect), chromosome abnormality, and multiple anomalies. Demographic and clinical characteristic were recorded. Correlation coefficient were determined for NT-proBNP and tricuspid regurgitation (TR) gradient and left ventricular eccentric index (LVEI). Sensitivity and specificity and cut-off value of NT-proBNP were calculated.
Results: Ninety-five percent of PHT screening was successfully performed. From involving 33 patients, there was 10 PHT patients (30%). Nine of them (90%) had birth weight less than 1,000 g. PHT was identified in 23.8% of infants at 7 days of age, 19.4% of infants at 28 days of age, and 14.3% of infants at PMA 36 wk. Median of NT-proBNP in PHT group VS non-PHT group at 7 days of age was 12,634 pg/ml (IQR 1,754-28,489) VS. 1,656 pg/ml (IQR 916-3,270) (p = 0.013). Median of NT-proBNP in PHT group VS. Non-PHT group at 28 days of age was 8,548 pg/ml (IQR 1,225-15,466) VS 932 pg/ml (IQR 747-1,611) (p = 0.002). Median of NT-proBNP in PHT group VS. non-PHT group at PMA 36 wk. was 1,555 pg/ml (IQR 923-1,889) VS 1,861 pg/ml (IQR 925-2,855) (p = 0.411). Cut point of NT-proBNP for PHT at 7 days of age ≥ 1592.0 pg/ml (Sensitivity 100%, Specificity 50%, AUC 0.8, p=0.052, 95%CI 0.57-1.0), Cut point of NT-proBNP for PHT at 28 days of age ≥ 1,056.5 pg/ml (Sensitivity 100%, Specificity 54%, AUC 0.815, p=0.043, 95%CI 0.582-1.0). Cut point of NT-proBNP for PHT at PMA 36 wk. ≥ 709.0 pg/ml (Sensitivity 100%, Specificity 9%, AUC 0.375, p=0.467, 95%CI 0.09-0.66). NT-pro BNP had better correlation with LVEI (R = 0.370, p = .006) than TR gradient (R = 0.075, p =0.739).
Conclusions: There are feasible to perform PHT screening in group of infants less than 1,000 g. Using NT-pro BNP to screen PHT may be considered.
Keywords: Pulmonary hypertension, bronchopulmonary dysplasia, very low birth weight infant
