Predicting acute kidney injury risk post-surgery

21 July 2022

We are proud to supporting the work of Dr Bettina Wilm from the University of Liverpool through our Stoneygate awards. She is looking to improve the care of patients and reduce their risk of acute kidney injury (AKI) following surgery.

The problem

Thoracoabdominal aortic aneurysms (TAAA) (try saying that fast three times) are weaknesses in the main blood vessel taking blood from the heart down the body.

The weaknesses can cause bulges in the wall of the vessel and sometimes these can even burst. Surgery is performed to repair portions of the vessel and during surgery, blood is lost and re-introduced through sophisticated tubing and pumping systems. This transport of the blood through tubing and pumping machines can cause damage to the red blood cells. This can cause damage to the red blood cells. When damaged, the cells can rip open and spill the contents into the circulation. Some of these contents can cause problems for the kidney and result in acute kidney injury (AKI). Approximately 20-30% of patients undergoing surgery on the thoracoabdominal aorta develop AKI.

Dr Bettina Wilm

Taking the measurements

One of the main contents of a red blood cell is a protein called haemoglobin. Haemoglobin is responsible for carrying oxygen. When red blood cells are burst open, they release this haemoglobin into the blood. This is now known as ‘free haemoglobin’ and can be used to assess how much damage there is to the red blood cells.

Dr Bettina Wilm and her team at the University of Liverpool want to measure the amount of free haemoglobin in patients’ blood following surgery at Liverpool Heart and Chest NHS Trust. They will use this information to assess the level of risk for AKI. Using this data, they will get a better understanding of the link between red blood cell damage and AKI.

Additionally, Bettina and her team will use patient blood in her laboratory. They will treat kidney cells in a dish with blood from different patients. Looking at how the kidney cells respond to the patients’ blood will give information as to how AKI could be being caused.

What this means for kidney patients

By completing this work Bettina hopes to be able to accurately predict a patient’s risk of AKI following this type of surgery. This will hopefully help create a greater opportunity for preventative treatment. Using a small device called a Hemcheck patients can have their AKI risk assessed at the bedside and their care tailored accordingly.

Bettina said “We are delighted to receive this award. It will help our team, which includes perfusionists and cardiac surgeons at Liverpool Heart and Chest, to optimise conditions for blood perfusion for patients undergoing the serious aneurysm repair surgery.

"Our findings will allow us to determine those patients at risk of developing AKI and give them early preventative treatments. We hope that our research can reduce the number of cardiovascular patients who develop AKI and need to go into prolonged intensive care."