WCN 2021 | Endovascular interventions in small strokes
Jan Gralla, MD, Inselspital, University Hospital Bern, Bern, Switzerland, discusses endovascular interventions in small strokes. Several types of strokes have been shown to benefit from endovascular mechanical thrombectomy (MT). In peripheral small vessel stroke and in primary vessel occlusions which are non-eligible for intravenous thrombolytics (IVT), MT is often the only treatment option. Similarly, patients with large vessel occlusions have been shown to benefit from recanalization with MT. Nevertheless, few randomized controlled clinical trials have been conducted to demonstrate the benefit of endovascular interventions in small strokes. Such interventions include direct aspiration and stent retriever thrombectomy and intra-arterial thrombolysis (IAT). Magnetic resonance imaging (MRI) can be used to determine which patients will benefit from recanalization and should therefore be used in clinical trials to ensure accurate results. Finally, Prof. Gralla highlights key studies evaluating endovascular interventions in medium and small vessel occlusions in the primary and secondary settings. This interview took place during the XXV World Congress of Neurology.
Transcript (edited for clarity)
It’s a very interesting topic because since we have the large randomized control trials in 2014, the large vessel occlusions are, I wouldn’t say so, but at least there has been shown lots of potential for mechanical thrombectomy and endovascular interventions. For peripheral strokes, small vessel stroke, this is a bit more complicated because patients present with few neurological deficits because of the smaller, smaller territory, the vessels themselves are smaller as well than in [inaudible]...
It’s a very interesting topic because since we have the large randomized control trials in 2014, the large vessel occlusions are, I wouldn’t say so, but at least there has been shown lots of potential for mechanical thrombectomy and endovascular interventions. For peripheral strokes, small vessel stroke, this is a bit more complicated because patients present with few neurological deficits because of the smaller, smaller territory, the vessels themselves are smaller as well than in [inaudible]. It’s much more interesting to see whether endovascular treatment is successful there as well, but definitely it’s an important topic because some patients don’t have any other possibility than endovascular treatment. So far there are a couple of randomized control trials on their way. Basically, we can distinguish between two different categories of small vessel stroke. One is the primary occlusion, so patients present with this particular occlusion from the beginning and they are either non-eligible for IV thrombolytics.
So again, we don’t have any other treatment possibility or they have dislodged thrombus of larger thrombus from the proximal vessel to this distal vessel under IV treatment. Nevertheless, they present with an occlusion distally to the largest so the small vessel. The other group are those in which the large vessel occlusion has been recanalized by using endovascular thrombectomy, for example, and there’s a remaining embolus in both categories so far, a single-arm prospective or retrospective studies have shown that endovascular treatment or more general recanalization is helpful, but this has not been shown on a randomized control level for each group yet. I think the techniques are pretty similar to what we use in large vascular occlusions. So the endovascular techniques are either stent retriever thrombectomy with all its pros and cons in combination with local aspiration or in combination with a Lugar catheter, then direct aspiration, which from my point of view has some potential there because the mechanical force that we apply to this vessel territory might be less.
And then the third option, which I think might be very interesting is intra-arterial thrombolysis (IAT) either on the basis of IA-rtPA as standard or formally with urokinase or with new approaches such as tenecteplase. So three different approaches, two mechanically and one pharmacological pharmaceutical intervention. Well, I think the most tricky part is we know that IV thrombolytics are very effective there. So from my feeling, this might not be the group in which we’re going to investigate mechanical thrombectomy first. So the patient is eligible for IV thrombolytics, I think that’s a very good target to go for these small vessel diseases or small vessel strokes. As we have learned from previous stroke studies especially the imaging of the remaining vital tissue, meaning the penumbra will be crucial to determine what kind of techniques is successful. So I think if we go into studies, you have to be sure that the overall population is not blurred by patients who cannot gain any benefit from recanalization at all.
So I think the imaging will be a crucial point here. I think in the end, we have seen so many surprises, randomized controlled trials in the recent years, and basically weeks there has to be a randomized controlled trial on these different topics. So primary, small vessel occlusions, secondary, small vessel occlusions, and they’re on their way, so we look at two randomized controlled trials on medium and small vessel occlusions in the primary setting and there is a new trial which has recently been supported by the Swiss National Foundation called Techno with tenecteplase in the secondary occlusions after thrombectomy. I think this is what we have to look at what we have seen so far, make any thrombectomy or let’s say the endovascular treatment of stroke can be very successful if conducted in a clear setting with a clear procedural pathway and a clear way of doing it, which device to use when.
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Disclosures
Global PI of STAR and Swift Direct (Medtronic)
