Clinical Trial: Evaluating Novel Biomarkers in Acute Kidney Injury

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Evaluating the Utility of Urinary Proteomics and Novel Biomarkers in Acute Kidney Injury

Brief Summary:

The investigators have a new technique of looking at urine to see whether it contains protein fragments that are released by damaged kidneys. These fragments seem to be more accurate than the current blood tests that the investigators use to diagnose renal failure. This technique needs to be validated with a group of patients that have a relatively high incidence of renal failure, cardiopulmonary bypass.

The investigators hypothesise that using novel markers of renal dysfunction will identify patients who go on to develop renal failure earlier, and in a higher number than the standard blood tests.

The investigators aim to collect urine from patients before going onto bypass, and then at Day 1 and Day 2 after bypass. This urine will be analysed for protein fragments, as well as other new markers of renal dysfunction. The investigators will also take blood at baseline and for the first two days in Cardiac Intensive Care, and compare the accuracy of the new tests with the 'gold standard' that is creatinine.

Detailed Summary:

The diagnosis of acute renal failure has been problematic, with a review showing 35 working definitions being used in the literature. This lack of clarity gave rise to the ADQI group creating the terminology of acute kidney injury (AKI). AKI has been used to give foundation to both the RIFLE and AKIN criteria, which have been shown to perform well in predicting critical care and hospital mortality. Their criteria are based on measuring increases of serum creatinine from baseline levels, and tallying this with weight-based urinary volumes. Problems with these techniques lie in having accurate baseline creatinine values, with the MDRD formula often proving inaccurate. Criticisms have also been levelled at using serum creatinine at all, given its variance with different body-mass compositions and fluid-balance status, as well as its relatively late rise in AKI compared to its utility in chronic renal failure.

Many novel biomarkers have been investigated in AKI, either serum or urine (cystatin-C, Il-18, KIM-1, NGAL). Results have been varied, with potential problems being lack of specificity to AKI, cost and the heterogeneous nature of patient populations in the various studies. NGAL has emerged as potentially the most specific to early AKI and additionally a number of commercially available assays are now available. Interest has been shown in the use of biomarker panels, allowing for improved sensitivity, albeit at a higher cost. Urinary proteomic analysis has been used as an investigative technique for AKI for the last ten years, but diverse populations and lack of blinding hampered early studies. A recent paper used techniques developed by collaborators on this proposal to improve the performance of proteomic assays, with impressive performance of these assays when looking at critically ill patients with AKI.

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Sponsor: Dr Robert Docking

Current Primary Outcome: Development of acute kidney injury [ Time Frame: Within two days of cardiopulmonary bypass ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: University of Glasgow

Dates:
Date Received: April 3, 2012
Date Started: November 2012
Date Completion:
Last Updated: May 26, 2015
Last Verified: May 2015