One of the newest devices to surface for the treatment of acute ischaemic stroke is the EmboTrap from Neuravi. At the World Live Neurovascular Course (WLNC; 8–10 June, Chicago, USA) Osama Zaidat (Medical College of Wisconsin, Milwaukee, USA) and Tommy Andersson (AZ Groeninge, Kortrijk, Belgium and Karolinska University Hospital, Stockholm, Sweden) introduced the device and presented the results of the first 25 cases performed by Andersson and the team at Karolinska in Sweden.
Since the emergence of the positive results of intra-arterial treatment for acute ischaemic stroke from studies such as MR CLEAN, EXTEND-IA, ESCAPE and SWIFT PRIME it has become clear that despite trial design differences, each trial demonstrated a consistently positive treatment effect for endovascular therapy over medical therapy for large vessel occlusions. Comparing the trials, it also may be concluded that the more selective the patient inclusion, the more likely it is that there will be a good outcome. In MR CLEAN, for example, a much broader patient population was treated and fewer patients achieved a positive outcome as compared to EXTEND-IA and SWIFT PRIME, which both used advanced imaging to triage patients, treating a more selective patient population, and as a result there was a higher magnitude of positive clinical outcome.
Osama Zaidat pointed out that in those trials there was still on average 20–25% of patients who were not able to be revascularised. He also noted the importance of achieving full revascularisation in as few passes as possible, preferably TICI 3 in one pass. He explained that these kinds of challenges (rapid revascularisation with minimal manipulation, issues with distal embolisation and issues with the integration of the device with the clot) were what led to the concept of the EmboTrap device.
“The EmboTrap has this in mind, and it is one of the unique aspects that it focused on the clot research as well as the device and technical research. They studied the clot carefully and different types of clot, different clot composition, may be important factors in achieving recanalisation in a timely manner,” Zaidat said.
With the clot research in mind, the EmboTrap was designed as a three-component device: there is an inner channel to dilate the clot enough to facilitate a flow bypass; an open outer cage that is designed to engage the clot inside; and a distal fragment protection zone.
Tommy Andersson described his experience testing the EmboTrap device in the first 25 cases in Europe. He said, “What I like about this device is first of all, it is different, it is not just another stent retriever, it works in a different way and the company has really done its homework in testing lots of different clots to make it possible to retrieve soft, fresh clots to difficult, hard, fibrin-rich clots. It encapsulates the clot instead of penetrating it. It is not dependent on radial force or the penetration of the clot like the other devices, so it is conceptually different. Because it is not dependent on the radial force, there is very little friction when you advance the device, even if it is tortuous there is almost no friction at all. In addition, in terms of movement around the bends, it is very easy to control and because of its construction, the risk of losing fragments is probably less. Another good thing is that if you are going to use it, you can use it in exactly the same way you use a stent retriever. So the learning curve is quick.”
Andersson maintained that the goals of treatment are to have short procedure time, minimal distal/collateral emboli and minimal vessel complications. “Can I apply this to the cases that I have done? Yes. In the cases I have done I had TICI 2b/3 in one attempt in more than 80% of cases in Stockholm, and in Belgium I have done five cases and in four of them I had TICI 2b/3 in one attempt and in one case it was in two attempts. The procedure time was around 15-20 minutes, there were very few distal emboli and so far, there have been no obvious vessel complications,” he reported.
The EmboTrap will now be studied in a prospective US and European trial, ARISE II. The FDA IDE study will take place at 25 sites across Europe and the USA.