MO378WHAT LIES BENEATH ANTICOAGULATION-RELATED ACUTE KIDNEY INJURY

Abstract

Abstract Background and Aims Acute kidney injury (AKI) secondary to glomerular hemorrhage in the context of overanticoagulation, commonly known as anticoagulant-related nephropathy (ARN), is a relatively novel recognized entity. Preexisting or underlying kidney disease seems to be a predisposing factor; however, few studies have described histologic findings in patients with ARN. We aimed to examine underlying kidney pathology in patients on oral anticoagulation who presented an episode of AKI with hematuria in whom a kidney biopsy was performed. Method Spanish retrospective observational multicenter case study in patients treated with oral anticoagulants who developed macroscopic or intense hematuria followed by AKI. Only patients with available kidney biopsy specimens were included. Histologic findings and clinical data throughout follow-up were analyzed. The main outcome was to describe pathologic findings in kidney biopsy specimens of patients with clinical suspicion of ARN. The secondary outcome was to assess kidney outcomes during follow-up. Results Twenty-four patients were included with a median age of 76 years (interquartile range [IQR] 64-81) and a follow-up period of 10.1 (IQR 1.3-41.1) months. 79% were male, 22 (91%) had hypertension and 9 (37%) were diabetic. Most cases (91%) were on anticoagulation with vitamin K antagonists. At admission, 87% of cases presented gross hematuria with a median serum creatinine (SCr) of 4.2 mg/dl and a median INR of 2.3. During follow-up, median highest (peak) SCr was 6.3 mg/dl and 11 (45%) patients required acute dialysis. Kidney biopsy showed that all patients except one had an underlying nephropathy (confirmed IgA nephropathy in 16 [66.7%], probable IgA nephropathy in 2, diabetic nephropathy in 3, nephrosclerosis in 1, and idiopathic nodular glomerulosclerosis in 1). Tubules filled with red cells and red cell casts were observed in 66.7% of the cases and acute tubular necrosis in 70.8%. Management included anticoagulation withdrawal in 14 cases (58.3%) and immunosuppressive treatment with corticosteroids (n = 17 [70.8%]) and mycophenolic acid (n = 5 [20.8%]). At 12 weeks after discharge, 11 patients had >50% decrease in SCr (with respect to peak SCr), 6 had <50% decrease and 5 were on chronic dialysis. Conclusion IgA nephropathy was the most common underlying kidney disease in our biopsy-proven series of ARN, in which a significant percentage of patients did not achieve kidney function recovery.