Alveolar capillary dysplasia: a cause of persistent pulmonary hypertension of the newborn

Abstract

alveolar capillary dysplasia should be ruled out in all newborn infants presenting severe idiopathic pulmonary hypertension associated with malformations. Open lung biopsy may prevent from using costly, invasive and probably ineffective procedures such as extracorporeal membrane oxygenation.

Alveolar Capillary Dysplasia

“…Furthermore, it seems likely that some cases originally classified as idiopathic persistent pulmonary hypertension of the newborn (PPHN) may actually have been ACD/MPV (14,20). A slight male predominance (60%) has appeared in reported cases (21,22). No geographic pattern is apparent; cases have been distributed worldwide.…”

“…Extrapulmonary findings are present in 50 to 80% of cases (10,14,21,25,30,33,34). Therefore, an infant with unexplained respiratory failure and structural abnormalities of the genitourinary, gastrointestinal, or cardiovascular systems should be evaluated for ACD/MPV (10,33).…”

“…More than 90% of affected infants are born at term (17,21), and in greater than 60% of cases, onset of cyanosis and respiratory failure occurs within 48 hours of birth (9,23). In a recent review of 21 cases of ACD/MPV from England, Melly and colleagues (24) proposed that the severity of disruption in capillary density and lack of contact with the alveolar epithelium may be two major factors that determine clinical course and prognosis, and they ascribed the potential for survival beyond the neonatal period in a minority of patients to higher capillary density and apposition.…”

Misplaced pulmonary arteries in an adult patient with pulmonary hypertension

“…Vascular endothelial growth factors have also been implicated as a potential mechanism [24,25]. Arterial muscularisation may be a primary anomaly related to abnormal vascular development [26] or secondary to regional hypoxaemia resulting from intrapulmonary shunting via gas exchange through the arteriovenular wall [19,27]. Cullinane et al [28] proposed that the arterial changes were the primary abnormality, possibly caused by a teratogenic exposure in utero, with pulmonary vasoconstriction leading to failure of normal angiogenesis.…”

Fetal lung lesions: a new classification of fetal lung dysplasia

“…This group of 'lung dysplasias' are indeed thought to represent diffuse abnormal development of the lungs in-utero, but without the presence of a mass lesion. They include alveolar capillary dysplasia, with or without misalignment of the pulmonary vessels 9,10 , rhabdomyomatous dysplasia of the newborn lung 11 and several other conditions often considered under this umbrella classification, such as pulmonary alveolar proteinosis 12 , including surfactant protein deficiencies, and so-called early onset chronic pneumonitis of infancy 13 . Therefore, the introduction of several further categories of 'fetal lung dysplasia' to encompass essentially all developmental pulmonary anomalies would appear to have little benefit.…”