BACKGROUND: Lung transplantation has proven to be an effective treatment option for end-stage lung disease. However, early and late complications following transplantation remain significant causes of high mortality.
OBJECTIVE: In this review, we focus on the time of onset in primary graft dysfunction and rejection complications, as well as emphasize the role of imaging manifestations and pathological features in early diagnosis, thus assisting clinicians in the early detection and treatment of posttransplant complications and improving patient quality of life and survival.
METHODS: We searched electronic databases such as PubMed, Web of Science, and EMBASE. We used the following search terms: lung transplantation complications, primary graft dysfunction, acute rejection, chronic lung allograft dysfunction, radiological findings, and diagnosis and treatment.
CONCLUSIONS: Primary graft dysfunction, surgical complications, immune rejection, infections, and neoplasms represent major posttransplant complications. As the main posttransplant survival limitation, chronic lung allograft dysfunction has a characteristic imaging presentation; nevertheless, the clinical and imaging manifestations are often complex and overlap, so it is essential to understand the temporal evolution of these complications to narrow the differential diagnosis for early treatment to improve prognosis.

BACKGROUND: Bronchiolitis obliterans syndrome (BOS) is one of the most severe complications and the leading cause of late mortality and morbidity after lung transplantation (LT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). No approved treatment for BOS is available. This review aimed to systematically identify and summarise the findings regarding the relationship between FEV1 decline and mortality in patients who developed BOS following LT or allo-HSCT.
METHODS: A systematic literature search was performed in the Medline, Embase and Cochrane reviews databases. Of the 501 potential studies identified 25 met inclusion criteria and were analysed.
RESULTS: Overall, 13 studies reported a relationship between FEV1 and mortality, and 12 studies reported both mortality and FEV1 results but did not investigate the relationship between them. There was heterogeneity in the analyses, which investigated the relationship between FEV1 decline and mortality across the studies in terms of levels of lung functioning, comparison to a control group, treatment, and statistical methodology; nevertheless, a clear and consistent increase in the risk of death associated with FEV1 decrease was seen in the analysed studies.
CONCLUSIONS: The systematic literature review identified studies and findings that support a relationship between FEV1 and mortality, with a decrease in FEV1 being statistically associated with increased risk of death. Knowing that lower FEV1 levels are associated with higher mortality rates may help assess the condition of a patient with BOS and monitor future treatment effectiveness. However, more evidence is needed to further investigate this relationship and to verify its clinical usefulness.

Lung transplantation is a treatment option in end-stage lung disease. Complications can develop along a continuum in the immediate or longer post-transplant period, including surgical and technical complications, primary graft dysfunction, rejection, infections, post-transplant lymphoproliferative disorder, and recurrence of the primary disease. These complications have overlapping clinical and imaging features and often co-exist. Time of onset after transplant is helpful in narrowing the differential diagnosis. In the early post transplantation period, imaging findings are non-specific and need to be interpreted in the context of the clinical picture and other investigations. In contrast, imaging plays a key role in diagnosing and monitoring patients with chronic lung allograft dysfunction. The goal of this article is to review primary graft dysfunction, acute rejection, and chronic rejection with emphasis on the role of imaging, pathology findings, and differential diagnosis.