Acute Myeloma Kidney: free light chains removal associated with chemotherapy for patients and kidney survival

INTRODUCTION. Renal failure remains a principal cause of morbidity and mortality for patient with multiple myeloma. Among renal manifestation casts nephropathy (Myeloma Kidney) represents the most common. The aim of this study is to assess the efficacy and safety of the extracorporeal removal of free light chains by means of hemodialysis with double filter application in patients with Acute Myeloma Kidney associated with different schemas of chemotherapy. METHODS. Fourteen patients (M/F = 11/ 3) were considered in the study. Acute Myeloma Kidney affected all these patients. Ten patients underwent renal biopsy and 9 cases of myeloma cast nephropathy were diagnosed. The median age of the patients was 72 years (range ). Every patient underwent the chemotherapy together with the extracorporeal treatment for the removal of free light chains by using double filter. Hemodialytic treatments were scheduled three times a week and the hemodialysis dose was not related to the degree of the renal failure but to the removal of free light chains. The dialysis filter used were characterized by high adsorbitive properties: PMMA filter (polymethylmetacrylate; Filtryzer BK-F 2.1 m2 surface area) cut-off 20,000 daltons; PEPA filter (polyester polymer alloy FDX 210-GW, 2.1 m2 surface area) cut-off 35,000 daltons. Each dialysis session lasted 4 hours. Low molecular weight heparin was used as anticoagulation. During each session two dialyzers were used and the substitution of the filter was carried out at the second hour of the hemodialysis session. For each session the reduction rate of free light chains was calculated. Urine output, hemoglobin, platelets, white blood cell, renal function and electrolytes were assessed. RESULTS. Average number of dialytic session was 10. Median Reduction Rate for free light chains was 25 % (range 2.4% - 69%). There was no statistical significant difference in FLC reduction rate between PEPA double filter and PMMA double filter (median reduction rate 53% vs. 38%). Six patient involved in the study died because of the complications of multiple myeloma (infections, bone fractures, chronic kidney disease). They all required chronic hemodialysis. Eight patients survived: among these 6 restored their renal function and 2 required chronic hemodialysis treatment. DISCUSSION. Early removal of free light chains in patient with renal involvement associated with specific chemotherapy is a predictive factor of recovery of renal function and that the recovery of renal function is associated to a best outcome of the patient. The use of an extracorporeal treatment based on substitution of filter at the second hour of the dialytic session was assessed. The two types of filters (PMMA and PEPA) didn’t show statistical differences.