ISC 2024 | Endovascular therapy for MeVO stroke: ongoing trials
Johanna Ospel, MD, University of Calgary, Calgary, Alberta, Canada, explains the uncertainty regarding the use of endovascular thrombectomy (EVT) in acute ischemic strokes due to medium vessel occlusions (MeVOs). In MeVO strokes (M2/3, A2/3, and P2/3 segment occlusions), the occluded vessel – and therefore area of ischemic damage – is smaller than in LVO stroke, meaning patients have better functional outcomes. Additionally, the smaller vessels are harder to get to and more fragile, making treatment more technically challenging. Dr Ospel notes that these factors mean there is less to gain and more to lose compared with LVO strokes, and more evidence is needed to shed light on the risk:benefit ratio. There is currently a lack of strong evidence of argue for or against the use of EVT in the setting of MeVOs, but several ongoing, large scale trials will address this question, including ESCAPE-MeVO (NCT05151172), DISTAL (NCT05029414), DISCOUNT (NCT05030142), and FRONTIER-AP. This interview took place during the International Stroke Conference 2024 in Phoenix, AZ.
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Transcript
It’s always a balance between risk and benefit in any treatment in medicine and MeVO thrombectomy is no exception. The challenge with a medium vessel occlusions is that the occluded vessel is smaller, meaning that the brain damage is also smaller compared to larger vessel occlusions. So patients do generally better even without any invasive treatment. And the other problem is that invasive treatment is harder in those distal occlusions because they’re smaller vessels, tinier and fragile, and it’s harder to get to those more peripherally located vessels...
It’s always a balance between risk and benefit in any treatment in medicine and MeVO thrombectomy is no exception. The challenge with a medium vessel occlusions is that the occluded vessel is smaller, meaning that the brain damage is also smaller compared to larger vessel occlusions. So patients do generally better even without any invasive treatment. And the other problem is that invasive treatment is harder in those distal occlusions because they’re smaller vessels, tinier and fragile, and it’s harder to get to those more peripherally located vessels. So the risk of accidentally perforating a vessel or dissecting a vessel with a wire or a catheter is higher.
So the benefits are lower, the risks are higher. And the question is where the tipping point is, so to speak. And that’s what we’re trying to find out with those trials. And then there are just technical challenges. For instance, catheters, they have a certain length. And the more peripheral you go in the brain, the longer your catheter has to be. And the current catheters, they’re mostly designed for large vessel occlusions that are more central. So sometimes you actually run out of catheter length and your catheter is just not long enough. So that problem hopefully will get solved because companies can design longer catheters. But at the time being, we have to deal with those kinds of issues as well.
There’s the trial that we’re running that’s ESCAPE-MeVO run from within Calgary, but there are sites in Canada, the US, Germany, Hungary and the UK. Then there’s DISTAL, that’s the Swiss trial which is running in Europe mainly. There is DISCOUNT which is a French trial. Then there is FRONTIER-AP – that’s an Australian trial. Then there’s another US trial that has a technical outcome, meaning reperfusion instead of a clinical outcome. And I think that’s all for now. I hope I didn’t forget any. But I think DISTAL, the Swiss trial and ESCAPE-MeVO, the Canadian one, they have enrolled most of most patients. So DISTAL has enrolled around 350 or so I think, ESCAPE-MeVO around 330, and then the French trial is kind of the next one. And I think they will all finish within 1 to 2 years from now and hopefully give us some answers.
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