The Effect of Acute Kidney Injury on Coagulation Parameters in Patients with Decompensated Cirrhosis

Abstract

Introduction: It is now accepted that the coagulopathy of chronic liver disease represents a tenuous “rebalanced state” of hemostasis. There is mounting evidence that clinical events disrupt this balance leading to bleeding or thrombosis. We aimed to investigate the effects of acute kidney injury (AKI) on hemostasis in cirrhotic patients by comparing conventional laboratory tests in patients with cirrhosis to a global coagulation assay (rotational thromoelastometry, ROTEM). Methods: Patients with decompensated cirrhosis admitted to the hospital were screened for participation. Patients were excluded if they were on therapeutic anticoagulation or had a known inherited coagulation disorder. A total of 25 patients were enrolled into 2 groups, those with AKI and cirrhosis and those without AKI. All but one patient had Childs-Turcotte-Pugh C cirrhosis (16/16 without AKI, 8/9 patients with AKI). Blood samples were obtained by a phlebotomist with standard technique. Blood was analyzed within two hours by trained technicians using ROTEM. Other common labs were performed in the central medical laboratory. Data on patient characteristics were obtained from the medical record. Results: The two groups were similar in characteristics except for elevated BUN (61.6 vs 16.7, P=0.0002), creatinine (Cr) (2.78 vs 0.91, P=0.0001), and albumin (3.27 vs 2.70, P=0.009) in the patients with AKI compared to those without. Conventional coagulation indices including platelets, INR and fibrinogen were similar between the groups. Clotting time (CT), clot formation time (CFT) and maximal clot formation time (MCF) were similar between the two groups. Analysis of the entire cohort revealed a positive correlation of platelet count and MCF (r=0.59, P=0.002) and a negative correlation between fibrinogen and CFT (r=-0.45, P=0.02). BUN level and Cr level also had a positive correlation with CT (BUN: r=0.38, p 0.06; Cr: r=0.5, p 0.01). Conclusion: AKI in patients with cirrhosis does not predictably alter common clinical laboratory coagulation parameters. In global coagulation testing using ROTEM, the MCF and CFT remain closely related to platelet and fibrinogen levels in decompensated cirrhosis patients with or without AKI. However, elevation of BUN and creatinine is correlated with prolonged CT. Further analysis in larger cohorts is necessary to better understand the clinical implications of these findings.