Histopathologic and Radiologic Assessment of Unused Donor Lungs: When to Decline or Not?

Abstract

Donor organ shortage, in combination with a 70% decline rate of offered donor lungs, results in significant wait list mortality and time with poor quality of life. Assessing donor lungs for transplant suitability is based on donors' history, gas exchange, chest X-ray, bronchoscopy, and in situ visual inspection; but donor lung acceptance remains subjective. We performed an in depth histopathologic and radiologic assessment of retrieved but unused donor lungs. We assessed 62 donor lungs not used for transplantation for various reasons between 2010 and 2019. These lungs were air-inflated, frozen, scanned with computed tomography, systematically sampled on 4 different locations, assessed macroscopically and microscopically by two experienced lung pathologists and by an experienced thoracic radiologist, all blinded for the reason of decline. Reasons for non-use are summarized in the figure. Thirty-nine (63%) lungs were not used for allograft-related reasons. In 13/39 (33%) lungs, the reason for decline could not be confirmed by histologic assessment (emboli, n=7; pneumonia, n=3; contusion, n=2; emphysema, n=1), in an additional 8/39 (21%) lungs, histologic abnormalities were only considered focal and mild (emphysema, n=5; pneumonia, n=3). In 16/39 (41%) lungs, radiology could not confirm the reason for decline. Twenty-three (37%) of 62 unused donor lungs were not transplanted due to extra pulmonary causes, of which 3 (13%) lungs displayed severe histologic abnormalities (pneumonia, n=2; emphysema, n=1), in addition to mild emphysema in 9 (39%) lungs and mild bronchopneumonia in 1 lung (4%). Radiology revealed ground-glass opacities in 8/23 (35%) and emphysema in 4/23 (17%) of these donor lungs. Histologic and radiologic assessment of unused donor lungs revealed substantial discrepancy with the clinical reason for decline. Prior chest CT imaging and frozen sections in selected cases might contribute to adequate donor assessment and augment current yield of donor lungs.