Potentially Modifiable Predictors for Renal Replacement Therapy in Patients with Cardiac Surgery Associated-Acute Kidney Injury: a Propensity Score-Matched Case-Control Study.

Wuhua Jiang,Jie Teng,Jiarui Xu,Zhe Luo,Bo Shen,Yimei Wang

doi:10.21470/1678-9741-2018-0206

Abstract

ObjectiveTo discover potentially modifiable perioperative predictors for renal replacement therapy (RRT) in patients with cardiac surgery-associated acute kidney injury (CSA-AKI).MethodsA cohort of 1773 consecutive cardiac surgery patients with postoperative acute kidney injury (AKI) from January 2013 to December 2015 were included retrospectively. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The primary outcome was CSA-AKI requiring renal replacement therapy (AKI-RRT). The initiation of RRT was based on clinical judgment regarding severe volume overload, metabolic abnormality (e.g., acidosis, hyperkalemia), and oliguria. Patients with AKI-RRT were matched 1:1 with patients without AKI-RRT by a propensity score, to exclude the influence of patients' demographics, comorbidities, and baseline renal function. Multivariable regression was performed to identify the predictors in the matched sample.ResultsAKI-RRT occurred in 4.4% of the entire cohort (n=78/1773), with 28.2% of in-hospital mortality (n=22/78). With the propensity score, 78 pairs of patients were matched 1:1 and the variables found to be predictors of AKI-RRT included the contrast exposure within 3 days before surgery (odds ratio [OR]=2.932), central venous pressure (CVP) >10 mmHg on intensive care unit (ICU) admission (OR=1.646 per mmHg increase), and erythrocyte transfusions on the 1st day of surgery (OR=1.742 per unit increase).ConclusionAKI-RRT is associated with high mortality. The potentially modifiable predictors found in this study require concern and interventions to prevent CSA-AKI patients from worsening prognosis.

Highlights

Acute kidney injury (AKI) is one of the prevalent complications after cardiac surgery, with reported incidences over 30%, while mortality increases fourfold and even a slight renal function decrease can influence short- and long-term survival rates after cardiac surgery[1]
The potentially modifiable predictors found in this study require concern and interventions to prevent cardiac surgery-associated acute kidney injury (CSA-AKI) patients from worsening prognosis
Several modifiable risk factors have been reported participating in the pathophysiology of CSA-AKI or AKI-renal replacement therapy (RRT)[5,6,7,8,9]

Summary

Introduction

Acute kidney injury (AKI) is one of the prevalent complications after cardiac surgery, with reported incidences over 30%, while mortality increases fourfold and even a slight renal function decrease can influence short- and long-term survival rates after cardiac surgery[1]. There have been several studies[2,3,4] identifying predictors for cardiac surgery-associated acute kidney injury (CSA-AKI) or AKI renal replacement therapy (RRT), including age, gender, preoperative renal function dysfunction, and comorbidities (e.g. hypertension, diabetes mellitus), whereas most of the predictors are unmodifiable and their clinical significance are limited. If analyzed along with unmodifiable predictors, the significance of the modifiable predictors can be concealed due to their lower occurrence, but their association with worsening renal function will be useful for prevention, even if AKI will develop inevitably.

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Results

Discussion

Conclusion