Study Finds Faster Way to Predict Life-Threatening Kidney Damage After Cardiac Surgery

A Yale-led team of researchers has completed the largest multi-center study to date, comparing and validating the performance of three kidney biomarkers to predict acute kidney injury or kidney failure faster in adult and pediatric cardiac-surgery patients. Their studies appear in the August 12 issue of the Journal of the American Society of Nephrology.

Acute kidney injury (AKI) is a common complication of cardiac surgery, and results in increased mortality. The researchers undertook these studies in order to speed the detection of AKI in cardiac surgery patients.

Kidney biomarkers or proteins are needed to help clinicians and scientists diagnose and measure acute kidney injury early during hospitalization.  Currently, clinicians measure serum creatinine levels in the body to determine kidney function, but this is not a good marker because it does not pick up early damage and injury to the kidney. 

The researchers, from the United States and Canada, are known as the Translational Research Investigating Biomarker End-Points in AKI consortium (TRIBE-AKI), a multidisciplinary group of academic investigators with expertise in pre-clinical, translational, epidemiologic and health services research.

The TRIBE-AKI study enrolled 1,200 adults and 300 children undergoing cardiac surgery, collecting more than 200,000 plasma (blood) and urine samples from these patients. They tested three new kidney biomarkers, known as urine IL-18, urine NGAL and plasma NGAL.

The study demonstrated that these three biomarkers or proteins identify kidney injury within 6 hours after surgery and 24-48 hours earlier than serum creatinine. In addition, the IL-18 and plasma NGAL biomarkers identified the adult patients that go on to develop severe kidney injury after cardiac surgery. Of the three biomarkers tested, urine IL-18 levels showed the strongest association (over a 6-fold increase in risk) with severe AKI in both adults and children. 

According to lead author and principal investigator Chirag Parikh, M.D., associate professor of nephrology at Yale School of Medicine and the Veterans Affairs Medical Center, “the findings support a paradigm change in the diagnosis of kidney diseases as there are no tests available at the present to assess the extent and severity of kidney injury. Measuring kidney injury with these biomarkers will provide clinicians with a greater window of time to treat patients and will identify high risk patients with severe kidney failure, potentially resulting in better short and long-term outcomes and decreasing mortality.”

Other researchers are Steven G. Coca of Yale and the Veteran Affairs Medical Center in West Haven; Kyaw Sint, Zhu Wang, Simon Li and Richard W. Kim of Yale;  Heather Thiessen-Philbrook of the University of Western Ontario;  Michael G. Shlipak of the San Francisco Veterans Administration Medical Center;  Jay L. Koyner of the University of Chicago;  Charles L. Edelstein of University of Colorado;  Prasad Devarajan of the Cincinnati Children’s Hospital Medical Center;  Uptal D. Patel of the Duke Clinical Research Institute;  Michael Zappitelli of the McGill University Health Center; Catherine D. Krawczeski of the Cincinnati Children’s Hospital Medical Center;  Cary S. Passik of Danbury Hospital and the University of Vermont;  Madhav Swaminathan of Duke University School of Medicine;  and Amit X. Garg of the University of Western Ontario.

The study was supported by a five-year, $4 million grant from the National Institutes of Health, the American Heart Association, the National Heart, Lung and Blood Institute.

For more information on TRIBE-AKI, please visit their website.

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