cardiovascular-agents and Persistent-Fetal-Circulation-Syndrome

The main cause of pulmonary hypertension in newborn babies results from the failure of the pulmonary circulation to dilate at birth, termed 'persistent pulmonary hypertension of the newborn' (PPHN). This syndrome is characterized by sustained elevation of pulmonary vascular resistance, causing extrapulmonary right-to-left shunting of blood across the ductus arteriosus and foramen ovale and severe hypoxaemia. It can also lead to life-threatening circulatory failure. There are many controversial and unresolved issues regarding the pathophysiology of PPHN, and these are discussed. PPHN is generally associated with factors such as congenital diaphragmatic hernia, birth asphyxia, sepsis, meconium aspiration and respiratory distress syndrome. However, the perinatal environment-exposure to nicotine and certain medications, maternal obesity and diabetes, epigenetics, painful stimuli and birth by Caesarean section-may also affect the maladaptation of the lung circulation at birth. In infants with PPHN, it is important to optimize circulatory function. Suggested management strategies for PPHN include: avoidance of environmental factors that worsen PPHN (e.g. noxious stimuli, lung overdistension); adequate lung recruitment and alveolar ventilation; inhaled nitric oxide (or sildenafil, if inhaled nitric oxide is not available); haemodynamic assessment; appropriate fluid and cardiovascular resuscitation and inotropic and vasoactive agents.

Topics: Adaptation, Physiological; Cardiovascular Agents; Cesarean Section; Environment; Extracorporeal Membrane Oxygenation; Female; Hemodynamics; Humans; Infant, Newborn; Maternal Exposure; Pain; Persistent Fetal Circulation Syndrome; Pregnancy; Pulmonary Circulation; Respiration, Artificial; Risk Factors; Stress, Physiological; Tobacco Smoke Pollution; Treatment Outcome

Pulmonary hypertension is associated with diverse cardiac, pulmonary, and systemic diseases in neonates, infants, and older children and contributes to significant morbidity and mortality. However, current approaches to caring for pediatric patients with pulmonary hypertension have been limited by the lack of consensus guidelines from experts in the field. In a joint effort from the American Heart Association and American Thoracic Society, a panel of experienced clinicians and clinician-scientists was assembled to review the current literature and to make recommendations on the diagnosis, evaluation, and treatment of pediatric pulmonary hypertension. This publication presents the results of extensive literature reviews, discussions, and formal scoring of recommendations for the care of children with pulmonary hypertension.

Topics: Cardiovascular Agents; Child; Child, Preschool; Combined Modality Therapy; Diagnostic Imaging; Disease Management; Extracorporeal Membrane Oxygenation; Genetic Counseling; Heart Defects, Congenital; Hernias, Diaphragmatic, Congenital; Humans; Hypertension, Pulmonary; Infant; Infant, Newborn; Lung; Lung Transplantation; Nitric Oxide; Oxygen Inhalation Therapy; Persistent Fetal Circulation Syndrome; Postoperative Complications; Respiration, Artificial; Ventilator-Induced Lung Injury

This study sought to determine the effect of combined treatment of hypoxia plus indomethacin on pulmonary vascular remodeling in fetal rats.. Hypoxia and indomethacin were used to treat pregnant rats during 19-21 days of gestation. The adventitia, media, and intima of pulmonary arteries from fetal rats were assessed. Western blots were used for determining the abundance of smooth muscle specific alpha-actin protein (α-SMA), elastin, and endothelial nitric oxide synthase (eNOS) in lung tissues. Plasma brain-type natriuretic peptide (BNP) levels, reflecting the increased right ventricular load or pulmonary arterial pressure, were detected.. The ratio of left ventricular free wall plus septum to right ventricular weight significantly increased in hypoxia plus indomethacin-treated group. The medial thickness percentage of pulmonary arteries of < 100 μm and ≥100 μm in diameter from hypoxia plus indomethacin-treated group was higher than that from control or single treatment group. Vascular elastin area percentage and immunostaining density of eNOS from the combined-treated group were higher than other groups. The relative abundance of α-SMA, elastin, and eNOS and plasma BNP levels in hypoxia plus indomethacin-treated group also significantly increased compared with other groups.. Hypoxia and indomethacin had synergistic effect on fetal pulmonary vascular remodeling. This rat model induced by combined treatments can mimic human persistent pulmonary hypertension of the newborn.

Topics: Actins; Animals; Animals, Newborn; Blotting, Western; Cardiovascular Agents; Disease Models, Animal; Elastin; Female; Humans; Hypoxia; Indomethacin; Infant, Newborn; Lung; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide Synthase Type III; Persistent Fetal Circulation Syndrome; Pulmonary Artery; Rats; Rats, Sprague-Dawley