Norman Swan: Speaking of stroke, late last week at an international conference, a Melbourne team of researchers presented their findings from a trial of a new treatment for acute stroke.
Bruce Campbell is a neurologist at the Royal Melbourne Hospital and one of the researchers, I'll get him to explain.
Bruce Campbell: This is using an angiogram that many people will be familiar with from heart attacks where you put a small needle in the groin, feed a tube up into the brain in this case, and physically engage a clot using this metal cage, it's called a stent, to engage the clot and then retrieve it, which is a bit different to other treatments where we leave a stent in place.
Norman Swan: Before you did this trial, people would come in with a stroke and you hope that they get clot busting, and we've spoken about that before on the Health Report. Is this for people who have failed clot busting or what?
Bruce Campbell: That's an interesting question. Our attitude in this trial was to identify a proportion of patients who had big blocked vessels that we know the clot busting doesn't always work so well for. And then to give them a package of treatment which was a standard clot busting plus this angiographic clot removal procedure in the hope of getting their artery as quickly as possible.
Norman Swan: So just describe this person. They come into the Royal Melbourne by ambulance. What features do they have that you may think deserve this endovascular treatment?
Bruce Campbell: This is the more severe end of the stroke spectrum. These patients usually have a severe weakness down one side of their body, so they might not be able to move their arm and leg. Often they have no ability to talk. This is not someone just with a facial droop or a bit of numbness somewhere. And then it's very dependent on imaging. We do a CAT scan to exclude bleeding and then we do an extra study with some contrast that gets injected, a dye in the arm that shows us where the blood vessels are blocked. In this trial a key component was the use of CT perfusion, which is a more advanced CT technique where we look at where the blood flow is going, how much is getting to each part of the brain, and that gives us a very good idea of how much of the brain is actually something we can save and how much has already been irreversibly damaged.
In the EXTEND-IA trial, only 11% of our patients had dissolved the clot, with just the clot dissolving alone by the time they got to the angiogram, so that's pretty uncommon. So usually the clot is exactly where we left it at the time of the CT scan and then it's possible for the procedurals, which is not me, this is someone like Professor Peter Mitchell who is my co-principal investigator on the trial, go in with this technique and try and remove the clot.
Norman Swan: So tell me what you found?
Bruce Campbell: EXTEND-IA was a multicentre randomised controlled trial led out of the Royal Melbourne Hospital with myself and Professor Peter Mitchell as co-principal investigators, and it was conducted across 14 centres in Australia and New Zealand over about a two-year period. We were looking at this treatment in combination with the clot dissolving TPA treatment versus TPA alone, and it showed dramatic improvements in getting the artery open, so what we call reperfusion, restoring blood flow. And then that translated through to improved early neurological recovery at three days, and that also led to a longer-term good outcome at three months. So the proportion of patients with an independent outcome after these pretty severe strokes was 71% versus 40% in the TPA only group.