Management of chronic rejection after lung transplantation

Outcomes after lung transplantation are limited by chronic lung allograft dysfunction (CLAD). The incidence of CLAD is high, and its clinical course tends to be progressive over time, culminating in graft failure and death. Indeed, CLAD is the leading cause of death beyond the first year after lung transplantation. Therapy for CLAD has been limited by a lack of high-quality studies to guide management. In this review, we will discuss the diagnosis of CLAD in light of the recent changes to definitions and will discuss the current clinical evidence available for treatment. Recently, the diagnosis of CLAD has been subdivided into bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). The current evidence for treatment of CLAD mainly revolves around treatment of BOS with more limited data existing for RAS. The best supported treatment to date for CLAD is the macrolide antibiotic azithromycin which has been associated with a small improvement in lung function in a minority of patients. Other therapies that have more limited data include switching immunosuppression from cyclosporine to tacrolimus, fundoplication for gastroesophageal reflux, montelukast, extracorporeal photopheresis (ECP), aerosolized cyclosporine, cytolytic anti-lymphocyte therapies, total lymphoid irradiation (TLI) and the antifibrotic agent pirfenidone. Most of these treatments are supported by case series and observational studies. Finally, we will discuss the role of retransplantation for CLAD.

Lung protective ventilation based on donor size is associated with a lower risk of severe primary graft dysfunction after lung transplantation

BACKGROUND

Mechanical ventilation immediately after lung transplantation may impact the development of primary graft dysfunction (PGD), particularly in cases of donor-recipient size mismatch as ventilation is typically based on recipient rather than donor size.

METHODS

We conducted a retrospective cohort study of adult bilateral lung transplant recipients at our center between January 2010 and January 2017. We defined donor-based lung protective ventilation (dLPV) as 6 to 8 ml/kg of donor ideal body weight and plateau pressure <30 cm H₂O. We calculated the donor-recipient predicted total lung capacity (pTLC) ratio and used logistic regression to examine relationships between pTLC ratio, dLPV and PGD grade 3 at 48 to 72 hours. We used Cox proportional hazards modelling to examine the relationship between pTLC ratio, dLPV and 1-year survival.

RESULTS

The cohort included 373 recipients; 24 (6.4%) developed PGD grade 3 at 48 to 72 hours, and 213 (57.3%) received dLPV. Mean pTLC ratio was 1.04 ± 0.18. dLPV was associated with significantly lower risks of PGD grade 3 (OR = 0.44; 95% CI: 0.29-0.68, p < 0.001) and 1-year mortality (HR = 0.49; 95% CI: 0.29-0.8, p = 0.018). There was a significant association between pTLC ratio and the risk of PGD grade 3, but this was attenuated by the use of dLPV.

CONCLUSIONS

dLPV is associated with decreased risk of PGD grade 3 at 48 to 72 hours and decreased 1-year mortality. Additionally, dLPV attenuates the association between pTLC and both PGD grade 3 and 1-year mortality. Donor-based ventilation strategies may help to mitigate the risk of PGD and other adverse outcomes associated with size mismatch after lung transplantation.