Histologic Identification of Prominent Intrapulmonary Anastomotic Vessels in Severe Congenital Diaphragmatic Hernia.

[congenital diaphragmatic hernia]

To determine whether prominent intrapulmonary anastomotic vessels (IPAVs ) or bronchopulmonary "shunt " vessels can be identified in lungs from infants with fatal congenital diaphragmatic hernia (CDH ).We performed histology with immunostaining for CD 31 (endothelium ) and D 2 -40 (lymphatics ), along with high -precision 3 -dimensional (3 D ) reconstruction on lung tissue from 9 patients who died with CDH .E ach patient with CDH required mechanical ventilation , cardiotonic support , and pulmonary hypertension (PH )-targeted drug therapy . All patients were diagnosed with severe PH by echocardiography , and 5 received extracorporeal membrane oxygenation therapy . Death occurred at a median age of 24 days (range , 10 -150 days ) from refractory hypoxemia with severe PH , pneumonia , or tension pneumothorax . Histology showed decreased alveolarization with pulmonary vascular disease . In each patient , prominent IPAVs were identified as engorged , thin -walled vessels that connected pulmonary veins with microvessels surrounding pulmonary arteries and airways in lungs ipsilateral and contralateral to the CDH . Prominent anastomoses between pulmonary arteries and bronchial arteries were noted as well . The 3 D reconstruction studies demonstrated that IPAVs connect pulmonary vasculature to systemic (bronchial ) vessels both at the arterial and venous side .Histology and 3 D reconstruction identified prominent bronchopulmonary vascular anastamoses in the lungs of infants who died with severe CDH . We speculate that IPAVs connecting pulmonary and bronchial arteries contribute to refractory hypoxemia in severe CDH .