[Show abstract][Hide abstract] ABSTRACT: To evaluate the efficacy of University of Wisconsin (UW) solution for lung preservation, we performed canine lung allotransplantation with lungs preserved in UW solution. Donor lungs from eight dogs were flushed with UW solution and lungs from four dogs with Euro-Collins solution, and these were preserved for 24 hr in cold storage at 4-6 degrees C. All recipient dogs were given cyclosporine at a dose of 20 mg/kg/day until death. None of the four dogs that received a lung allograft flushed with Euro-Collins solution survived contralateral pulmonary artery and bronchial occlusion. All eight dogs that received a lung allograft flushed with UW solution were alive between 8 and 21 days postoperatively. Six of them survived until pulmonary function tests were performed. The engrafted lungs functioned well until death between days 10 and 21 posttransplantation. The PaO2 was 428 +/- 26 prior to transplantation, 317 +/- 140 at 60 min after transplantation, and 382 +/- 76 mmHg at 10 to 21 days after transplantation. In the other two dogs, the grafted lungs functioned poorly, and macroscopically revealed diffuse organizing pneumonia. We conclude that UW solution is useful for up to 24 hr of cold preservation prior to lung allografting. However, we recommend that lungs preserved with UW solution be transplanted within 24 hr, because, despite adequate function, microscopic damage occurs in the grafted lung.