Unexpected donor pulmonary embolism affects early outcomes after lung transplantation: A major mechanism of primary graft failure?

Objective: Primary graft failure remains a significant cause of morbidity and mortality after lung transplantation, and its mechanism is not understood. Previously 2 case reports described fatal primary graft failure due to donor-related unexpected pulmonary embolism. This study investigated the incidence, early outcome, and risk factors of unexpected pulmonary embolism in lung transplantation. Methods: An exploratory retrograde donor lung flush before implantation to diagnose pulmonary embolism (emboli group) or no pulmonary embolism (no-emboli group) was performed in 74 of 122 consecutive lung transplantations. Results: The incidence of macroscopic unexpected pulmonary embolism was 38% (28% clot and 9% fat). In the emboli group, significantly decreased oxygenation (P < .05), increased pulmonary vascular resistance (P < .001), an increased proportion of opacity on chest radiograph (P = .03), prolonged intubation (P < .001) and intensive care unit stay (P < .01), and decreased 1-year survival (P = .03) were seen after transplantation. In multivariate analysis, pulmonary embolism was an independent risk factor for prolonged intubation (hazard ratio, 2.42; P < .01). In logistic regression, death due to trauma with fracture and a smoking history of more than 20 pack-years were significant donor risk factors for pulmonary embolism (adjusted odds ratio, 8.77 and 5.64; P = .02 and .04, respectively). No deleterious effects of the exploratory flush were seen. Conclusions: Unexpected pulmonary embolism is relatively common, is potentially predicted by donor history (but not by arterial blood gas analysis or chest radiograph), and is associated with primary graft failure. Donor lungs with risk factors of pulmonary embolism should undergo an exploratory flush. When pulmonary embolism is diagnosed, further therapeutic strategies must be considered.