Groundbreaking stroke study leads the way

Buying time to let the brain heal itself naturally following an acute stroke is the cornerstone of research being undertaken by the Hunter Medical Research Institute (HMRI) Stroke Research Group.

Led by Associate Professor Chris Levi from Hunter New England Health, the group is working in collaboration with a team from Harbin Medical University in Northern China on cutting-edge techniques that cool the brain and reduce – sometimes completely – the impact of stroke.

By cooling the brain, the body's metabolic demand, and in turn the brain's oxygen demand, is reduced, giving the affected cells more time to stay alive and decrease the chance of permanent damage.

Called neuro-suspension, the state induced by cooling gives the brain precious extra time for the blood clot blocking the artery and causing the stroke to dissolve naturally or with medication.

Levi said neuro-cooling was a routine treatment following cardiac arrest, proving an effective way of slowing damage to the brain.

"In stroke, unless the clot can be removed or it dissolves naturally, blood flow stops permanently to a small section of the brain and the survival rate of the affected cells is not high," Levi said.

"We only have about six to eight hours where we can intervene, cool the brain and treat the clot."

The randomised trial will examine two methods of cooling and, using high-technology neuro-imaging, measure the results for comparison purposes.

The researchers will also record how much at-risk brain tissue, measured at baseline, is actually salvaged as a result of cooling.

"These advanced imaging techniques will give us proof of concept," Levi said.

At Harbin Medical University, researchers are focusing on evaluating the effectiveness of a cooling helmet to treat the brain locally.

The Newcastle team is investigating intravascular technology which cools the blood through the whole body.

As the patient is cooled, the skin is protected with a warming blanket and medication is given to reset the body’s thermoregulatory system and shivering reflex. Body temperature can be reduced from 37°C to the desired temperature of 33°C within an hour.

During the trial, patients will be cooled for 24 hours and then slowly warmed again. For eligible patients, medication will be given to help dissolve the clot during the cooling process. The remaining cohort will be cooled and given time to heal naturally.

"Cooling is likely to be the most powerful neuro-protectant treatment we have at the moment."

Levi said the Harbin collaboration would allow researchers from the two research teams to compare the results of the different techniques.

"The cooling helmet is a non-invasive treatment and does not require us to suppress shivering," he said. "Through the collaboration, we can share outcome measures, pool our knowledge and compare the benefits of each method."

Stroke is a significant health issue today. Twenty per cent of acute stroke patients die in the first month following a stroke and half of the survivors suffer irreparable damage.

This innovative research will go towards reducing the devastating and debilitating impacts of the disease.

Professor Levi’s research is supported by grants from the National Heart Foundation and the Hunter Medical Research Institute including sponsorship from the Brain Foundation, the Greaves Family, Mrs Ferma McLean, the Dr Andrew Lojszczyk Memorial Grant and corporate and community donations to HMRI.