RATIONALE - The role of the patent ductus arteriosus in the development of chronic lung disease in surfactant-treated premature newborns remains unclear.
OBJECTIVE - To examine the effects of ductus ligation on cardiopulmonary function and lung histopathology in premature primates.
METHODS - Baboons were delivered at 125 d, (term = 185 d) treated with surfactant, and ventilated for 14 d. Serial echocardiograms and pulmonary function tests were performed. Animals were randomized to ligation (n = 12) or no ligation (controls, n = 13) on Day 6 of life. Necropsy was performed on Day 14.
RESULTS - Compared with nonligated control animals, ligated animals had lower pulmonary-to-systemic flow ratios, higher systemic blood pressures, and improved indices of right and left ventricular performance. The ligated animals tended to have better compliance and ventilation indices for the last 3 d of the study. There were no differences between the groups in proinflammatory tracheal cytokines (interleukin [IL] 6 and IL-8), static lung compliance, or lung histology.
CONCLUSION - Although a persistent patent ductus arteriosus results in diminished cardiac function and increased ventilatory requirements at the end of the second week of life, ligation on Day 6 had no measurable effect on the histologic evolution of chronic lung injury in this 14-d baboon model.