Simple Test May Prevent Kidney Injury After Heart Surgery

Monday, November 23, 2009

A simple blood test may allow earlier diagnosis of acute kidney injury (AKI) in children who undergo cardiac surgery with cardiopulmonary bypass. AKI occurs in at least 30 percent of these surgeries, which are most common major surgical procedures performed in hospitals around the world.

The test, which measures a biomarker called serum cystatin C, may enable diagnosis of acute kidney injury (AKI) as early as 12 hours after heart surgery with cardiopulmonary bypass, according to a new study conducted by Catherine Krawczeski, MD, a pediatric cardiologist at the Cincinnati Children’s Hospital Medical Center Heart Institute. In addition, cystatin C levels were shown to predict the severity and duration of AKI, which occurs frequently in adults and children after cardiopulmonary bypass.

Dr. Krawczeski presented her study on Tuesday, Nov. 16, at the annual meeting of the American Heart Association in Orlando.

“Cystatin C can predict AKI with reasonable certainty within 12 hours of cardiopulmonary bypass,” says Dr. Krawczeski. “It is highly accurate, commercially available and gives results several days before the problem otherwise would be detected. This could allow early intervention and improve patient outcomes.”

More than a million children and adults in the United States undergo cardiac surgery with bypass each year. Infants and children with congenital heart disease may be especially vulnerable to developing AKI, according to Dr. Krawczeski.

AKI affects up to 5 percent of hospitalized patients. In the critical care setting alone, about 6 percent of AKI requires dialysis. Of those, 60 percent die. Timing of treatment may be crucial to assure the best possible outcome.

“Early forms of AKI may be reversible, but treatment must be initiated within a ‘window of opportunity’,” says Dr. Krawczeski. “Experimental studies have identified interventions that may be used to prevent or treat AKI if instituted early in the disease process. The use of biomarkers such as cystatin C can help guide future therapeutic trials to test agents that may prevent or lessen the degree of injury.”

Dr. Krawczeski and her colleagues at Cincinnati Children’s studied 374 patients under the age of 18 who underwent cardiopulmonary bypass at Cincinnati Children’s between January 2004 and June 2007. Cystatin C as measured 12 hours after surgery not only predicted duration and severity of AKI but also length of hospital stay and mortality.

The study was supported by a grant from the National Institutes of Health. Collaborators on the study included Prasad Devarajan, MD, director of Division of Nephrology and Hypertension at Cincinnati Children’s.

About Cincinnati Children’s

Cincinnati Children’s Hospital Medical Center is one of 10 children’s hospitals in the United States to make the Honor Roll in U.S. News and World Reports 2009-10 America’s Best Children’s Hospitals issue. It is #1 ranked for digestive disorders and is also highly ranked for its expertise in respiratory diseases, cancer, neonatal care, heart care, neurosurgery, diabetes, orthopedics, kidney disorders and urology. One of the three largest children’s hospitals in the U.S., Cincinnati Children’s is affiliated with the University of Cincinnati College of Medicine and is one of the top two recipients of pediatric research grants from the National Institutes of Health.

President Barack Obama in June 2009 cited Cincinnati Children’s as an “island of excellence” in health care. For its achievements in transforming health care, Cincinnati Children’s is one of six U.S. hospitals since 2002 to be awarded the American Hospital Association-McKesson Quest for Quality Prize for leadership and innovation in quality, safety and commitment to patient care. The hospital is a national and international referral center for complex cases. Additional information can be found at www.cincinnatichildrens.org.