Point-of-Care Echocardiography Unveils Misclassification of Acute Kidney Injury as Hepatorenal Syndrome

Abstract

Introduction: Fulfillment of the diagnostic criteria for ­hepatorenal syndrome type 1 (HRS-1) requires prior failure of 2 days of intravenous volume expansion and/or diuretic withdrawal. However, no parameter of volume status is used to guide the need for volume expansion in patients with suspected HRS-1. We hypothesized that point-of-care echocardiography (POCE) may better characterize the volume status in patients with acute kidney injury (AKI) and cirrhosis to ascertain or disprove the diagnosis of HRS-1. Methods: A pilot observational study was conducted to determine the clinical utility of POCE-based examination of inferior vena cava diameter (IVCD) and collapsibility index (IVCCI) to assess intravascular volume status in patients with cirrhosis and AKI who had been deemed adequately volume-repleted and thereby assigned a clinical diagnosis of HRS-1. Early improvement in kidney function was defined as ≥20% decrease in serum creatinine (sCr) at 48–72 h. Results: A total of 53 patients were included. The mean sCr at the time of volume assessment was 3.2 ± 1.5 mg/dL, and the mean Model for End-Stage Liver Disease score was 29 ± 8. Fifteen (23%) patients had an IVCD <1.3 cm and IVCCI >40% and were reclassified as fluid-depleted, 11 (21%) had an IVCD >2 cm and IVCCI <40% and were reclassified as fluid-expanded, and 8 (15%) had and IVCD <1.3 cm and IVCCI <40% and were reclassified as having intra-abdominal hypertension (IAH). Twelve (23%) patients exhibited early improvement in kidney function following a POCE-guided therapeutic maneuver, that is, volume expansion, diuresis, or paracentesis for those deemed fluid-depleted, fluid-expanded or having IAH, respectively. Conclusion: POCE-based assessment of volume status in cirrhotic individuals with AKI reveals marked heterogeneity. Unguided volume expansion in these patients may lead to premature or delayed diagnosis of HRS-1.