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Monoclonal Gammopathies of Renal Significance (MGRS) are a rather heterogeneous group of renal disorders caused by a circulating monoclonal (MC) immunoglobulin (Ig) component, often in the absence of multiple myeloma (MM) or another clinically relevant lymphoproliferative disorder. Nevertheless, substantial kidney damage could occur, despite the "benign" features of the bone-marrow biopsy. One example is renal amyloidosis, often linked to a small clone of plasma cells, without the invasive features of MM. However, patients with amyloidosis may present with a nephrotic syndrome and renal failure, eventually leading to end-stage kidney disease. At the same time, other organs, such as the heart and the liver, may be severely damaged by Ig light chains or amyloid deposits, occasionally resulting in fatal arrhythmias and/or organ failure. Acute kidney injury (AKI) may as well result from massive excretion of MC proteins, with deposition disease in glomeruli or renal tubules, not rarely obstructed by luminal aggregates, or "casts". Proliferative glomerulonephritis with monoclonal Ig deposits is another, less frequent clinical presentation of an MGRS. The present review deals with the implications of MGRS for renal function and prognosis, and the potential of tools, such as the renal biopsy, for assessing clinical risk and guiding therapy of the underlying condition.
RESUMO
INTRODUCTION: Outflow stenosis is a frequent complication of vascular access for hemodialysis. It may cause increased pressure within the angioaccess along with reduced blood flow. Elective treatment is percutaneous transluminal angioplasty; however, when a long occlusion (>2 cm) occurs, success and mid-term patency of endovascular treatment are uncertain. We describe a case series of patients with long occlusion of elbow outflow complicating an otherwise excellent forearm arteriovenous fistula, treated by a bypass across the elbow through cubital vein transposition. PATIENTS AND METHODS: Six consecutive patients have been treated between 2015 and 2017; all were referred because of either low flow, increased venous pressure, excessive bleeding time, or recirculation and were examined by duplex ultrasound. A total of 83% of patients showed associated thrombosis within the access. All procedures were performed under loco-regional anesthesia and preventive hemostasis. Surgical thrombectomy was also performed when needed. RESULTS: Immediate success was obtained in all but two patients converted in veno-venous polytetrafluoroethylene bypass. Post-operative blood flow increased from 316 to 878 mL/min. All patients were dialyzed through the forearm access immediately the day after surgery, without the need for central vein catheter. Overall, 75% of patients needed a percutaneous transluminal angioplasty of the veno-venous anastomosis within 6 months. Primary and secondary patency at 12 and 24 months were 25%-0% and 100%-100%, respectively. CONCLUSION: Outflow reconstruction through the elbow bypass by cubital vein transposition is a valuable resource to rescue radiocephalic arteriovenous fistula complicated by outflow obstruction, avoiding the use of an interim central vein catheter. Endovascular treatment is vital to maintain functional patency in the mid- and long term.