#1827 Myeloma cast nephropathy: is high cut-off hemodialysis effective?

Abstract

Abstract Background and Aims Light-chain cast nephropathy is the result of intra-tubular precipitation of light-chains produced by a multiple myeloma. Treatment often includes high cut-off filters hemodialysis (HCO) with the purpose of purifying these chains until the chemotherapy response is achieved. The main goal of this study is to analyze our experience and determine if there is a correlation between the amount of chain purified and the conservation of renal function. Method We conducted a retrospective study that includes all patients suffering from myeloma cast nephropathy treated with hemodialysis in our hospital between 2008 and 2023. HCO filters were used in all of the cases and the diagnosis was established by clinical criteria. In the early stages of the study, only those patients who required kidney replacement therapy underwent dialysis. However, in recent years some cases which did not meet the renal replacement criteria were included. Results 27 patients received the treatment, 59,3% were male and the average age was 68,7+/-8 years. Even though the average of glomerular filtration rate (GFR) previous to the myeloma was 72,65+/-20ml/min, it should be underlined that 8 of them suffered from 3-4 stage chronic kidney disease. The mean follow-up was 55 months, after which 16 had passed away. 59,3% were kappa gammapathy and 75% of them had bone disease. Chemotherapy schemes were variable (85% included Bortezomib). The average of dialysis sessions was 8+/-3,8. 7 patients continued undergoing conventional hemodialysis during the hospital stay but only one of them remained in chronic dialysis. The average GFR at the beginning was 12,2+/-7ml/min. Despite the improvement of the renal function, when compared to the previous GFR, a statistically significant reduction in both hospital discharge (43,67ml/min) and after 1- and 2-year periods (51,94 and 39,91ml/min) was observed. No differences in renal function between patients who started dialysis prematurely (GFR>10ml/min) and those who did not were noticed. The light-chain reduction ratio in each dialysis was examined; it was remarkably variable (2-87%). In order to establish a connection between the amount of chain purified and the preservation of renal function, we conducted a correlation analysis between the intra-dialysis reduction of chains and the GFR at hospital discharge and after 1-year, but not statistically interrelations were observed (p=0,376 and 0,633 respectively). Lastly, no connection between the intra-dialysis light-chain reduction and the loss of GFR was detected. Conclusion In patients with myeloma cast nephropathy, a higher purification of light-chains in HCO hemodialysis is not associated with a better preservation of renal function.