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Article originally published by NeuroNews

The EMBOTRAP® family of revascularisation devices (CERENOVUS) is innovative within the stent retriever space due to its differentiated design based on a wealth of clot-science research. As a physician currently using EMBOTRAP in mechanical thrombectomy procedures to treat ischaemic stroke patients, Waleed Brinjikji (Mayo Clinic, Rochester, USA) is excited about the outstanding EMBOTRAP clinical outcomes from the recently published MASTRO I meta-analysis study, and believes these positive results are due in no small part to the work being done by the CERENOVUS Neuro Thromboembolic Initiative (NTI) and product development teams.

“I was actually invited to the first CLOT Summit meeting in 2015, and that is when I was introduced to all the clot-science work that NTI was doing,” Brinjikji recalls. “They were definitely ahead of the curve in terms of creating clot analogues that would mimic what goes on inside of our patients—and then devising devices specifically designed to extract clot based on this range of clot analogues.”

Brinjikji goes on to describe both the research being done by NTI, and the subsequent design of CERENOVUS’ neurovascular devices, as “very patient focused.” He iterates that this research has played a key role in changing neurointerventionists’ perceptions of the importance of clot science, from the selection of specific devices and techniques for a case, to understanding how certain clot characteristics impact stroke aetiologies and, ultimately, treatment outcomes.

The stroke-causing clots themselves—but also other factors, such as different vascular anatomies and pressure conditions—can all be replicated by researchers in the NTI labs, enabling optimised device design through “truly understanding the problem.”

“I would say that, if it was not for NTI at CERENOVUS, I do not think this whole field of clot science would have exploded over the past 10 years in the way it has,” Brinjikji adds. “CERENOVUS is clearly interested in bringing stroke science forward—for example, through the EXCELLENT registry and the [annual] CLOT Summit—and the ultimate goal here is to, at some point in the future, have tailored therapies based on clot [science].”

Brinjikji further posits that these efforts are helping to create “real, natural academic collaborations,” noting that the positive results of such collaborations can be seen in data from the ARISE II study and MASTRO I publication, both of which have demonstrated improved outcomes with CERENOVUS’ EMBOTRAP stent retriever versus those seen previously in the literature.

From insight to innovation

CERENOVUS via NTI has enabled the refinement and optimisation of the CERENOVUS portfolio of products. EMBOTRAP was the first device to benefit directly from this world-renowned research, and has undergone various iterations based on clot science—as well as physician feedback—over the past few years.

“They are designing devices tailored around the wide range of clots we encounter during our stroke thrombectomies, whether it is the red cell-rich clots that are more prone to fragmentation or the fibrin-rich clots that are a bit tougher to extract,” says Brinjikji.

Discussing the specific features that he feels set EMBOTRAP apart from other stent retrievers, Brinjikji first cites its closed distal end, which offers effective clot control and allows the operator to gain confidence that the clot has been secured in full. He also highlights its multi-segmented design, which aids in maintaining wall apposition while retrieving the clot, along with the inner channel, which can provide a reperfusion conduit.

I would say that, if it was not for NTI at CERENOVUS, I do not think this whole field of clot science would have exploded over the past 10 years in the way it has.

“The inner channel of the device is effective as a temporary bypass as you are leaving it [deployed] for a few minutes while retrieving clot,” he continues, “but I also noticed that it does a good job of almost pinning the clot between the tines of the EMBOTRAP stent retriever. Those are features that make it clear this has been designed with the clot in mind and ultimately provide consistently positive outcomes.

“The most important thing during a thrombectomy procedure is getting that first-pass TICI [thrombolysis in cerebral infarction] 3, and devices that allow you to achieve that, such as the EMBOTRAP, are essential.”

In Brinjikji’s view, EMBOTRAP’s aforementioned features result in an increased likelihood of consistently reaching that first-pass TICI 3 goal, and subsequently a greater chance of an excellent outcome for the patient, which is why the device is his first-line stent retriever of choice.

“It works very consistently,” he explains. “It is easily deliverable through your standard microcatheter, which is extremely important—even in tortuous anatomy, which is really nice. And, EMBOTRAP does produce high first-pass TICI 3 rates.”

Impact on clinical outcomes

One of the most recent and most telling pieces of evidence on EMBOTRAP, according to Brinjikji, is MASTRO I—a ‘living’ systematic review and meta-analysis that has already produced some positive data on the device’s capabilities but is also now set to be updated in the future to expand on these promising findings.

The meta-analysis sought to compare various safety and efficacy outcomes between EMBOTRAP, and two of the current stent retriever market leaders: Trevo (Stryker) and Solitaire (Medtronic). As Brinjikji points out, no randomised controlled trials (RCTs) offering direct comparisons between stent retriever devices have been completed to date, but—as a meta-analysis of observational studies in epidemiology (MOOSE) checklist-compliant study featuring a robust outlier analysis—MASTRO I is methodologically solid and offers the next best thing to an RCT.

“And the results almost speak for themselves,” he adds. “It is very exciting to see that there are indeed some differences in the efficacy and outcomes of patients treated with different types of stent retrievers—what the data suggest is that not all stent retrievers are the same. I think that the number-one message to take home, and the most important thing, was that we saw a statistically significantly better rate of 90-day mRS [modified Rankin scale] 0–2, compared to both Trevo and Solitaire, when using EMBOTRAP.”

More specifically, the meta-analysis found a 57.4% rate of mRS 0–2 with EMBOTRAP, versus 50% with Trevo (p=0.013) and 45.3% with Solitaire (p<0.001). EMBOTRAP also demonstrated a statistically significantly lower rate of symptomatic intracranial haemorrhage (sICH) compared to Solitaire (3.9% vs 7.75%; p=0.028). Hypothesising possible explanations for this, Brinjikji notes that numerically higher first-pass and TICI 3 rates seen with EMBOTRAP versus the other stent retrievers may be a contributing factor.

“When you look at the literature, EMBOTRAP provides extremely positive clinical and angiographic outcomes and, when you look at that, you have to say there is something special in the device design that is allowing us to achieve better outcomes,” he goes on. “And I think it all comes back to the clot science—the device was designed with clot science in mind.”

While he is quick to acknowledge the potential limitations of MASTRO I, such as its inclusion of observational studies and heterogeneity of data across the analysed studies, Brinjikji feels it constitutes an intriguing piece of evidence nonetheless.

“There are some single-centre or small multicentre studies being done to compare devices directly, so I think the field may be starting to move towards that, but in terms of the evidence we have right now it is pretty interesting—and I think MASTRO I at least provides some food for thought,” he concludes.

Waleed Brinjikji is an interventional neuroradiologist and associate professor of Radiology and Neurosurgery—and co-principal investigator of the Neurovascular Lab—at the Mayo Clinic in Rochester, USA. Brinjikji is a paid a consultant of CERENOVUS, part of Johnson & Johnson MedTech.