Tracheobronchial malformations in experimental esophageal atresia

Background: Malformations of the tracheobronchial tree may account for post operative respiratory symptoms in patients with esophageal atresia (EA). Th is study examines the respiratory tract in fetal rats with EA induced by Ad riamycin. Methods: Time-mated female rats were given either 2 mg/kg intraperitoneal A driamycin on gestational days 8 and 9 (adria group, n = 6) or no treatment (control group, n = 2), and the fetuses were recovered on day 21. Laryngo-t racheo bronchial tree was studied after transparentation and alcian blue-al izarin red staining that depicts the cartilage in blue and make the surroun ding tissues transparent. Results: There were no malformations in any of the 11 control animals studi ed. Conversely, 31 of 46 (67%) Adriamycin fetuses had EA with,distal TEF, T hese had more tracheal rings than controls (32 +/- 2 v 26 +/- 1.5, P < .05) at the expense of those of the mainstem bronchi (3.2 +/- 1 v 6.6 +/- 1.1 i n the right, P < .05 and 6.2 +/- 2.1 v 11 +/- 1.1 in the left, P < .05); Th ere were tracheal stenoses in 16 pups with EA (some severe and five double) , and all these had fragmented rings in the trachea or bronchi. In six case s there was an ectopic upper right bronchus, and 1 had a grossly abnormal l arynx. The malformations in the 15 Adriamycin-exposed fetuses without EA we re limited to some fragmented or mishaped rings. Conclusions: Laryngo-tracheobronchial malformations entailing the whole len gth of the tract a re very constant and severe in rats with EA and tracheoe sophageal fistula and correspond to an abnormal development of the tracheob ronchial anlage from the ventral foregut. Their nature and extent invite a careful investigation of the respiratory tracts in EA babies in whom they c ould be underscored. Copyright (C) 1999 by W.B. Saunders Company.