Value of Renal Histology for Predicting Cardiorenal Outcomes in Patients Listed for Cardiac Transplantation

Abstract

<h3>Purpose</h3> Cardiorenal syndrome is associated with excess morbidity and mortality, particularly in patients requiring durable mechanical circulatory support or cardiac transplantation. There are minimal data regarding predictors of renal outcomes in these patients and identifying those who may benefit from dual organ-transplantation. <h3>Methods</h3> We identified 18-patients with renal histology supporting the diagnosis of cardiorenal syndrome, from 665 consecutive patients listed for cardiac transplantation between 2010-2019. These were prospectively analysed for glomerular, tubular, interstitial and arteriolar changes as shown in table 1, tallied to give a severity score. The primary outcome, major adverse kidney events (MAKE), was a composite of death, need for renal replacement therapy (RRT), drop in estimated glomerular filtration rate (eGFR) >50% or stage V chronic kidney disease occurring prior to transplantation for the baseline cohort, and following transplantation for the transplanted cohort. The secondary outcomes included the individual components of MAKE at the two different time points. <h3>Results</h3> Mean age 52.3, 22% female. 5 patients did not survive to transplant (2 of these died on ventricular assist device). 1 patient had successful heart-kidney transplant. MAKE occurred in 7/17 of baseline; this was associated with a higher severity score, mean 5 vs. 2.3, p=0.03. There was no difference in age, creatinine or eGFR at biopsy. MAKE following transplantation occurred in 8/13 patients. There were no significant associations with this outcome. MAKE in the baseline cohort was primarily driven by need for RRT (mean 5.2 vs. 2.5, p=0.04). Contrary to limited previous literature, interstitial fibrosis did not predict any outcome, whilst presence of glomerular ischaemic changes, tubular atrophy and arteriosclerosis were associated with pre-transplant MAKE. <h3>Conclusion</h3> More severe renal histology prior cardiac transplantation are associated with adverse renal endpoints.