Kidney dysfunction after cardiac transplantation: does early acute kidney injury translate into inferior long-term patient and renal outcomes?

Impact of changing renal function, while waiting for a heart transplant, on post-transplant mortality and development of end stage kidney disease

Heart transplantation is a viable option for end stage heart disease but long-term complications such as chronic kidney disease are being increasingly recognized. We sought to investigate the effect of change in estimated glomerular filtration rate (eGFR) during the heart transplant waitlist period on post-transplant mortality and end stage kidney disease (ESKD). We analysed the United Network of Organ Sharing heart transplant database from 2000 to 2017. Multivariable Cox regression with restricted cubic splines and cumulative incidence competing risk (CICR) methods were used to compare the effects of change in eGFR on mortality and ESKD, respectively. A total of 19 412 patients met our inclusion criteria. Mortality increased with increasing loss of eGFR (adjusted hazard ratio increased from 1.02 [confidence interval (CI) 1.01-1.04, P = 0.008] for 10% loss to 1.15 (CI 1.06-1.26, P = 0.001) for 50% loss of eGFR. Similarly, risk of ESKD also increased monotonically with increasing loss of renal function [subdistribution hazard ratio increased from 1.12 (CI 1.09-1.14, P < 0.001) to 2.0 (CI 1.74-2.3, P < 0.001)] as loss of eGFR increased from 10% to 50%. Overall, we found that loss of >10% of eGFR resulted in higher risk of mortality and higher risk of ESKD.

Incidence, risk factors and clinical outcomes of acute kidney injury after heart transplantation: a retrospective single center study

Objectives

This study aimed to identify the incidence rate of Acute kidney injury (AKI) in our center and predict in-hospital mortality and long-term survival after heart transplantation (HTx).

Methods

This single-center, retrospective study from October 2009 and March 2020 analyzed the pre-, intra-, and postoperative characteristics of 95 patients who underwent HTx. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Risk factors were analyzed by multivariable logistic regression models. The log-rank test was used to compare long-term survival.

Results

Thirty-three (34.7%) patients developed AKI. The mortality in hospital in HTx patients with and without AKI were 21.21 and 6.45%, respectively (P < 0.05). Recipients in AKI who required renal replacement therapy (RRT) had a hospital mortality rate of 43.75% compared to 6.45% in those without AKI or RRT (P < 0.0001). A long cardiopulmonary bypass (CPB) time (OR:11.393, 95% CI: 2.183 to 59.465, P = 0.0039) was positively related to the occurrence of AKI. A high intraoperative urine volume (OR: 0.031, 95% CI: 0.005 to 0.212, P = 0.0004) was negatively correlated with AKI. AKI requiring RRT (OR, 11.348; 95% CI, 2.418–53.267, P = 0.002) was a risk factor for mortality in hospital. Overall survival in patients without AKI at 1 and 3 years was not different from that in patients with AKI (P = 0.096).

Conclusions

AKI is common after HTx. AKI requiring RRT could contribute powerful prognostic information to predict mortality in hospital. A long CPB time and low intraoperative urine volume are associated with the occurrence of AKI.