Yvo B. Roos:
I think it’s important to notice that everything we told today is only regarding patients which are directly presented to a comprehensive stroke center.
So all the six trials which were included in our meta-analysis, included only patients which were directly brought to a comprehensive stroke center, so a center capable of doing both intravenous treatments and endovascular treatment...
Yvo B. Roos:
I think it’s important to notice that everything we told today is only regarding patients which are directly presented to a comprehensive stroke center.
So all the six trials which were included in our meta-analysis, included only patients which were directly brought to a comprehensive stroke center, so a center capable of doing both intravenous treatments and endovascular treatment. So our data is not telling something about patients being transported to a primary stroke center. A primary stroke center capable of intravenous thrombolysis, the patients over there should be treated with intravenous thrombolysis when suitable as quickly as possible. That’s something I want to say upfront.
So what we did is that we took the data from the six trials all over the world, which were looking at the same thing, whether bridging therapy with intravenous thrombolysis and endovascular treatment was still, let’s say, better than going for direct thrombectomy.
And what we did is that we used all the data, we put it together. And well, what we saw is that the difference is not that different. Urs is going to tell you exactly what we did for the analysis. But the problem is that we are not talking about superiority of one of the other treatments, we’re talking about non-inferiority. And that’s always very difficult to understand.
When you talk about non-inferiority, you need to talk about the boundary of non-inferiority. In this case, we choose for a boundary of 5%, which was a boundary which we got from interviewing many, many, many experts in the world, we published a paper on that. And they said, “Well, if the treatment with going directly for endovascular treatment is not more than 5% different, then I would go for this direct treatment. But if you can’t show that the difference is, let’s say, less than 5%, if it’s going to be, then we should stick with the standard treatment, which is the combination.”
So we chose the 5% difference for this non-inferiority design and that’s how we started and that’s how we did the analysis and maybe Urs, you can tell what we did find.
Urs Fischer:
Yeah, thanks. So overall, there were 1,153 patients in direct mechanical thrombectomy arm and 1,160 patients received bridging thrombolysis.
So overall, there was on a first glimpse on the Grotta bars of the distribution of the modified Rankin Scale, there was a trend that patients with bridging thrombolysis perform better than patients treated with direct mechanical thrombectomy. However, the so-called adjusted common odds ratio was 0.89 and the 95-confidence interval was from 0.76 to 1.04. So this difference was not statistically significant.
However, we were not able to show the non-inferiority of the direct mechanical thrombectomy approach compared to bridging thrombolysis. So what does that mean and what is the clinical implication? Basically, we could not show that direct mechanical thrombectomy is better, however, we could also not show that it is equally effective. And therefore, most physicians in the future, they will continue treating patients with large vessel occlusion with intravenous thrombolysis and then will proceed with endovascular therapy.
However, if you look at the subgroups, the rates of good functional outcome defined as Modified Rankin Scale of 0 to 2 was 49% in the direct mechanical thrombectomy group and 51% in the bridging arm. So that’s only a difference of 2%, which was statistically not significant.
However, what we could show that successful reperfusion was significantly better in patients receiving bridging thrombolysis compared to direct mechanical thrombectomy. However, rates of any intracerebral hemorrhages were higher in the bridging arm than in the direct mechanical thrombectomy arm, but not symptomatic intracerebral hemorrhage.
So that means that if you treat patients with a large vessel occlusion, you have a small benefit regarding better reperfusion in patients with bridging thrombolysis, however, you have to pay that with an increased risk of any intracerebral hemorrhage.