Review article DOI: 10.3345/kjp.2010.53.6.688 Korean J Pediatr 2010;53(6):688-693 Pulmonary hypertension in infants with broncho- pulmonary dysplasia Gi Beom Kim, M.D. Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Korea Received: 2 May 2010, Accepted: 13 May 2010 Corresponding Author: Gi Beom Kim, M.D. Department of Pediatrics, Seoul National University Children’s Hospital, 101 Daehang-Ro, Jongno-gu, Seoul 110-744, Korea Tel: +82-2-2072-0266, Fax: +82-2-743-3455 E-mail: ped9526@snu.ac.kr Copyright © 2010 by The Korean Pediatric Society An increase in the number of preterm infants and a decrease in the gestational age at birth have resulted in an increase in the number of patients with significant bronchopulmonary dysplasia (BPD) and secondary pulmonary hypertension (PH). PH contributes significantly to the high morbidity and mortality in the BPD patients. Therefore, regular monitoring for PH by using echocardiography and B-type natriuretic peptide (BNP) or N-terminal-proBNP must be conducted in the BPD patients with greater than moderate degree to prevent PH and to ensure early treatment if PH is present. In the BPD patients with significant PH, multi-modality treatment, including treatment for correcting an underlying disease, oxygen supply, use of diverse selective pulmonary vasodilators (inhaled nitric oxide, inhaled prostacyclins, sildenafil, and endothelin- receptor antagonist) and other methods, is mandatory. Key words: Pulmonary hypertension, Bronchopulmonary dysplasia, Vasodilator, Echocardiography, Brain natriuretic peptide This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by- nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction Bronchopulmonary dysplasia (BPD) was first described by Northway et al. (1967) as a chronic lung disease of preterm infants who required oxygen supply and mechanical ventilation for acute respiratory distress1). The introduction of prenatal steroid therapy, gentle ventilation techniques, exogenous surfactant treatment, and intensive treatment of patent ductus arteriosus have minimized severe lung injury and improved the survival rate in preterm infants over the 40 years since the introduction of the BPD concept. However, some infants with very low birth weight still develop BPD2). The overall incidence of BPD, which is characterized by the need for oxygen at 36 weeks of gestation, is about 30% for infants with birth weight less than 1,000 g in the United States3) and 9.7% for infants with birth weight less than 1,500 g analyzed in a Korean multicenter study4). Preterm infants with BPD usually have cardiovascular sequelae, such as pulmonary hypertension (PH), cor pulmonale with right ventricular (RV) hypertrophy, systemic hypertension, left ventricular hypertrophy, and development of systemic-to- pulmonary collateral vessels5). Among these cardiovascular sequelae, PH contributes significantly to the high morbidity and mortality in the BPD patients. Although little is known about the prevalence and mortality rate of PH, the prevalence of PH ranges from 8 to 25% and the mortality rate ranges from 14 to 50% in the BPD patients with PH6-9). This review focuses on the precise evaluation of the severity of PH and the recent progress in the treatment of PH in the BPD 688