IMPROVED ULTRASTRUCTURAL LUNG PRESERVATION WITH PROSTAGLANDIN-E1 AS DONOR PRETREATMENT IN A PRIMATE MODEL OF HEART-LUNG TRANSPLANTATION

Donor pretreatment with prostaglandin E1 as a pulmonary vasodilator ha s developed as a simple, effective means to provide excellent preserva tion in heart-lung transplantation. This study was undertaken to inves tigate the degree of ultrastructural preservation of the lung with pro staglandin El and other pulmonary vasodilators in a primate heart-lung transplantation model. Heart-lung transplantation was performed in 14 African green monkeys. Donor cardiac preservation was achieved with c old crystalloid cardioplegic solution (10 ml/kg). Lung preservation wa s achieved with cold, modified Euro-Collins solution delivered into th e main pulmonary artery (60 ml/kg total). Vasodilator agents were admi nistered intravenously 15 minutes before aortic crossclamping. The hea rt-lung grafts were stored at 4-degrees-C for 6 hours. Three groups of animals were studied: five donors with prostaglandin E1 (0.1 to 4.0 m ug/kg per minute five donors with prostacyclin (0.1 to 0.35 mug/kg per minute), and four donors with nitroprusside (0.8 to 5.0 mug/kg per mi nute). After transplantation, arterial blood gas measurements and lung biopsies were performed at 1- and 3-hour intervals. Five formalin blo cks per specimen were sectioned for hematoxylin and eosin staining. Ce llular preservation and endothelial cell swelling were evaluated with electron microscopy. The specimens were graded for alveolar hemorrhage , endothelial cell swelling, and cellular preservation (grade 0, minim al, to grade 3, severe) and a mean score was obtained for each preserv ative agent. Prostaglandin E1-treated specimens demonstrated the least amount of endothelial swelling (mean score of 1.0) compared with pros tacyclin- and nitroprusside-treated specimens (mean scores of 1.4 and 2.7, respectively). All nitroprusside-treated specimens demonstrated m oderate to severe endothelial cell swelling. Interstitial and alveolar hemorrhage was noted in poorly preserved specimens, but there were no significant differences between groups. We conclude that prostaglandi n E1 provides improved cellular preservation by decreasing the extent of endothelial cell swelling as observed on electron microscopy.