High prevalence of pulmonary arterial thrombi in donor lungs rejected for transplantation

Donor hypoxemia is a common reason for the rejection of lungs for transplantation. Organ donors are at high risk for venous thromboembolism. Pulmonary arterial thrombosis could contribute to donor hypoxemia. The primary objective of this study was to prospectively quantify the incidence of pulmonary arterial thrombosis in organ donors whose lungs were rejected for transplantation. The secondary objective was to better define the spectrum of histologic abnormalities in the same group of lungs.

A complete gross pathologic and histologic analysis of whole lung specimens was done on lungs from 17 donors whose lungs were rejected for transplantation. Lungs had not been flushed with a pulmonary preservation solution.

Overall, 35% of the donors had gross or microscopic evidence of either pulmonary arterial thrombosis, pulmonary infarction, or both. Clinical characteristics, including oxygenation, were not significantly different between donors who had thrombi or infarction and donors who did not. Other pathologic findings included bronchopneumonia (focal or early in 4/17, moderate or severe in 8/17), respiratory bronchiolitis (7/17) and centriacinar emphysema (7/17).

Pulmonary arterial thrombosis and/or pulmonary infarction are very common in organ donors whose lungs are rejected for transplantation and might contribute to lung dysfunction both in lung donors and lung recipients. Further studies are needed to define the incidence of pulmonary arterial thrombosis in organ donors whose lungs are used for transplantation and to better assess the adverse clinical consequences of donor pulmonary arterial thrombosis in lung recipients.