AKI and Kidney Replacement Therapy After Heart Transplantation: Epidemiology and Short-Term Outcomes

Background: Heart transplantation (HT) is the treatment of choice for patients with end stage heart failure. AKI requiring RRT after HT is common and severely affects clinical outcomes. We aim to evaluate the epidemiology and outcomes of HT-associated AKI requiring RRT. Methods: We conducted a single-centre analysis including HT patients at the University Hospital Policlinico, Bari, Italy between March 2022 and August 2024. We classified patients in two groups based on the need of RRT. The primary outcome was to assess the incidence of AKI requiring RRT and 30-day mortality. Logistic regression analyses were performed to assess risk factors for RRT and 30-day mortality. Results: 137 HT recipients were included in the study, representing one of the largest cohort in literature; 60 patients developed AKI requiring RRT (43.7%). Mean recipient age was 58 years. Days on waiting list for HT were higher in the no-RRT group. Patients in the RRT group presented a lower pre-HT eGFR (median eGFR 55.7 vs 69.1, p=0.009), while the rate of patients requiring ECMO (41.6% vs 14.2%, p<0.001) and RRT (RRT, 18.3% vs 2.5%, p=0.001) before HT was higher. All patients were treated with CRRT, with a median time of treatment of 19 days (IQR 4.7-36.7). 20 patients (20.4%) died at 30 days, with a higher percentage in the RRT group (40% vs 5.1%, p<0.001). In a multivariate analysis, the need of ECMO before (OR 3.16, 95%CI 1.13-8.78, p=0.027) and after HT (OR 10.38, 95%CI 4.24-25.38, p<0.001) were associated with the need of post-HT RRT. In a multivariate analysis, only the need of post-HT CRRT was independently associated with increased risk of mortality (OR 9.205, 95%CI 2.367–35.804, p=0.001). Conclusion: AKI requiring RRT was associated with high mortality rate and worse short-term outcomes in a large cohort of HT patients.