Reducing the risk of kidney injury during open heart surgery
A collaboration between researchers from Monash University and the Florey Institute of Neuroscience and Mental Health has found a promising way to reduce the risk that patients will develop life-threatening kidney injuries after open heart surgery.
Almost a quarter of patients who undergo heart surgery requiring cardiopulmonary
bypass (via the heart-lung machine) later develop acute kidney injury (AKI), greatly increasing their risk of dying in hospital or of developing chronic kidney disease.
The study was initiated by Professor Roger Evans from the Monash Biomedicine Discovery Institute. He said the inner part of the kidney, the medulla, suffers from a lack of oxygen (hypoxia) during heart surgery. This hypoxia damages the kidney tissue, potentially leading to acute kidney injury and possible later kidney failure.
The interdisciplinary team showed they could increase the delivery of oxygen to the kidney and thus avoid medullary hypoxia.
“We found that if we increased the rate that the heart-lung machine pumped blood around the body, or increased blood pressure, we improved oxygenation in the kidneys,” Professor Evans said.
The multidisciplinary study, published today in the journal Kidney International, was conducted using an animal model developed at the Florey Institute’s Pre-Clinical Critical Care Unit. According to Professor Evans, laboratory heads Professor Clive May and Dr Yugeesh Lankadeva have surgical and intensive care facilities for conducting these studies that are second to none in the world.
Using a breakthrough method that allows direct measurement of oxygen levels in kidney tissue during standard surgery, the team showed that the kidneys do indeed fail to receive enough oxygen. But this hypoxia can be avoided by simple changes to the usual way the heart-lung machine is used.
Cardiac surgeon Associate Professor Andrew Cochrane from Monash Health, perfusionist Mr Bruno Marino from Cellsaving and Perfusion Resources and Professor Rinaldo Bellomo from Austin Health were also instrumental in the study.
The researchers, who will soon start a clinical trial at Monash Health, believe their findings could eventually change standard practice during cardiac surgery.
“Just over a third of patients who develop severe AKI after cardiac surgery die in hospital. Even if AKI is mild, patients have a four-fold increased risk of dying in hospital. So we think our findings could lead to markedly improved treatment and better health outcomes for patients,” Professor Evans said.
The research was supported by the National Health and Medical Research Council of Australia (NHMRC) and the National Heart Foundation of Australia.
About the Monash Biomedicine Discovery Institute
Committed to making the discoveries that will relieve the future burden of disease, the newly established Monash Biomedicine Discovery Institute at Monash University brings together more than 120 internationally-renowned research teams. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.
About the Florey Institute
The Florey Institute of Neuroscience and Mental Health is one of the largest and highly respected brain research centres in the world. Our teams work on a range of serious diseases including stroke, epilepsy, Alzheimer’s, Parkinson’s and motor neurone diseases, depression, autism, schizophrenia, anxiety disorders and addiction. We are world leaders in imaging technology, stroke rehabilitation and large population studies to improve patient care around the world.