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Abstract Background and Aims Thrombotic microangiopathy (TMA) is a rare but severe complication following lung transplantation. The pathogenesis is poorly understood, involving endothelial damage and various risk factors, including calcineurin inhibitor (CNI) toxicity. We aimed to evaluate diagnostic accuracy, identify risk factors for and assess the renal and overall survival of TMA in this patient group. Method We performed a retrospective study of patients with TMA after lung transplant between 01/01/2000-01/01/2021. Matching controls were selected based on underlying lung disease, age, gender, CMV risk, and immunosuppressive regimen. Overall survival and baseline data (age, gender) were collected for the whole lung transplant group. Results A total of 29 TMA cases (2.9%) were identified out of 1025 lung transplantations. 48% of patients had a complete hematological assessment with Coombs testing as the most frequent (52%) missing test. The median time from transplantation to TMA was 5.9 months. 76% of the episodes occurred before 12 months. 77% of patients had organ damage with acute kidney injury in 72%. At the time of TMA 38% of patients had a cytomegalovirus (CMV) infection. Arterial hypertension was found in 31% and acute rejection in 11%. The immunosuppressive scheme consisted of tacrolimus/mycophenolate mofetil and corticosteroids in the majority of cases (56%). Tacrolimus (n = 22) and cyclosporine (n = 7) trough levels were respectively 11.8 and 207 µg/l at the time of TMA. Treatment consisted of change in immunosuppressive regimen (72%), 31% received plasmapheresis. When comparing the TMA patients with the control group a higher rate of donor specific antibodies were found (11% vs 1%), a lower median time till chronic lung allograft dysfunction (37 m vs 91 m) and a higher prevalence of end-stage renal disease (24% vs 6%) and overall death (97% vs 44%) with mortality being significantly higher (p 0.01). Fig. 1 illustrates the overall outcome. Conclusion This study illustrates the clinical characteristics and outcomes of TMA after lung transplantation. Even though the prevalence is low the effects are deleterious with acute kidney injury in the majority of cases and higher risk of end-stage renal disease and mortality. Our study emphasizes the need for higher further research into risk factors, and therapeutic strategies to prevent and improve patient outcomes. Furthermore, the findings underscore the importance of vigilant monitoring and tailored interventions for TMA in lung transplant patients.
Rosseels et al. (Wed,) studied this question.