COMPASS: Aspiration Similar to Stent Retriever in Stroke

Pauline Anderson

January 29, 2018

LOS ANGELES — Removing a clot by using aspiration is noninferior to removing it by stent retrieval in stroke patients, a new multicenter trial has found.

The results showed that an aspiration-first approach to clot removal achieves equivalent functional outcomes for patients with acute ischemic stroke compared with using a stent retriever first and that time to reperfusion, and quality of reperfusion, were similar for the two approaches.

These new findings should affect clinical practice, study author J. Mocco, MD, Mount Sinai Hospital, New York City, said at a media briefing here at the International Stroke Conference (ISC) 2018.

"There is now Level I evidence that stent retrievers and primary aspiration have equivalent clinical outcomes in emergent large vessel occlusion."

The study — COMparison of direct ASpiration vs Stent retrieval (COMPASS) — looked at two approaches: a direct aspiration first pass technique (ADAPT) and stent retrieval as first line (SRFL).

Both procedures involve inserting a guide catheter into the femoral artery in the groin and maneuvering it into the brain, aided by imaging. With the aspiration technique, a large-bore catheter is inserted into the area of the clot, which is then suctioned. The stent retriever approach uses a cage-like wire device to engage and remove the clot.

Both are helpful clot-removal tools, said Dr Mocco. "The question is, What do you start with?"  

The study enrolled 270 adult patients with acute ischemic stroke who were treated with the ADAPT approach (n = 134) or the SRFL approach (n = 136) within 6 hours of symptom onset at participating centers — all high-volume sites with "highly experienced practitioners," Dr Mocco said.

Among other things, study participants had to have a National Institutes of Health Stroke Scale score of more than 5, a large-vessel proximal occlusion (distal internal carotid artery through middle cerebral artery bifurcation), and a pre-event modified Rankin Scale (mRS) score of 0 to 1.

Preferred Technique

Each site submitted their last 20 cases. Treating physicians could use their preferred technique, but study organizers tried to include sites that were balanced in terms of preferred approach (ADAPT vs SRFL).

An analysis of the submitted cases showed that at six centers, at least 67% of cases were ADAPT, at another six centers, 67% or more of cases were SRFL; and at three centers, there was a mix of techniques with no apparent preference.

In terms of demographics, the two groups had an "excellent balance," noted Dr Mocco.

As for reperfusion rates, the percentage of patients achieving success (Thrombolysis in Cerebral Infarction [TICI] grade 2b or greater) with the primary modality was 83.2% in the aspiration group and 81.3% in the stent retrieval group (P = .75).

"What struck me in the data was that people didn't switch," said Dr Mocco. "The truth is, that happened very little."

Just over 20% of doctors in the aspiration group still used a stent retriever. "They either used It because they didn't quite get in there with just aspiration, or there was another clot somewhere else, or a little distal fragment."

The primary efficacy endpoint was functional outcome at 90 days, defined as an mRS score of 0 to 2. The analysis found that 49% of the SRFL group and 52% of the ADAPT group met this primary endpoint, with ADAPT being noninferior (P = .0014).

A secondary efficacy analysis found a similar shift in mRS distribution between the two groups at 90 days (odds ratio, 0.98; 95% confidence interval, 0.64 - 1.51).

The rate of TICI grade 2c or greater within 45 minutes of groin puncture was 50% in the ADAPT vs 44% in the SRFL group (P = .2998).

TICI grade 3 or greater within 45 minutes of puncture was seen in 34% of the ADAPT group vs 23% of the SRFL group (P = .0486).

Time from puncture to a TICI grade of 2b or greater was 22 minutes in ADAPT patients vs 33 minutes in SRFL patients (P = .0194)

"So the time to reperfusion was 11 minutes faster" with the aspiration technique, commented Dr Mocco.

At the end of the study, rates of TICI 2b, TICI 2c, and TICI 3 were 91.7%, 56.4%, and 37.6%, respectively, in the ADAPT group and 89%, 55.9%, and 28.7% in the SRFL group.

Safety endpoints — including 90-day all-cause mortality and intracranial hemorrhage within 24 hours —were similar in the two groups.

Equal Safety

"The safety data was completely equal; almost exactly so in many of the categories," said Dr Mocco.

He and his colleagues are still reviewing the cost analysis. But he told Medscape Medical News that, on the basis of anecdotal information, he believes that the aspiration route could be as much as 40% less costly than the stent retrieval approach.

He stressed, however, that the analysis is continuing and is "quite complex."

Is aspiration better for removing certain types of clots? Anecdotally, said Dr Mocco, this technique "seems to work really well" for clots at the top of the carotid artery, or in the basilar artery.

Large-scale registries might help determine which approach is best for which clots, he added.

Ralph L. Sacco, MD, professor and Olemberg Chair of Neurology and executive director of the McKnight Brain Institute and chief of neurology, Jackson Memorial Hospital, Miami, Florida, who attended the media briefing, agreed some clots might be more conducive to removal though aspiration and others by stent retrieval.

"Clot composition in an individual patient, and underlying pathophysiology, could potentially be important."

For example, said Dr Sacco, if the clot is cardioembolic or in a large vessel, it might make more sense to use aspiration, but when there's atherosclerotic disease and the clot is fibrous, stent retrieval might be wiser.

"This is the kind of the next-level study that we need to do, where we really get down to deciphering the type of patients" who might benefit from these different approaches.

Practice Patterns

In the meantime, the new results should sway practice patterns for some physicians.

"Now that we have this evidence for aspiration, I think that many more practitioners will start trying this technique," said Dr Mocco.

"They may try it and not like it and want to go back to stent retriever and that's fine, but I believe that now that this quality of evidence exists, there will be a dramatic shift in practice patterns."
Dr Mocco himself prefers starting with aspiration. "I personally think it's a little faster to do once you're trained" compared with stent retrieval. "It's a personal choice for me."

He hopes that the "very powerful and impressive" new evidence, which represents "amazing progress for patients," is taken into account when practice recommendations are updated.

Some interventionist neurologists attending the briefing weighed in on whether this new study is strong enough to warrant new guidelines.

For his part, Dr Sacco said it might provide level 1 or 2A evidence. "It's one trial, but it's a direct comparison and a large trial and has a lot of both primary and secondary outcomes," said Dr Sacco, adding that it's also a randomized comparison.

COMPASS reaffirmed the results of two previous multicenter randomized controlled trials: Penumbra's 3D Trial and the ASTER (Adapt versus StEnt Retriever) trial.

Results of another trial — PROMISE — also released here at ISC 2018, showed real-world safety and efficacy of ADAPT as a frontline approach in both revascularization rates and clinical outcomes.

Penumbra Inc funded the COMPASS trial. Dr Mocco received no payments from Penumbra and does not serve as a consultant to Penumbra. Penumbra has reimbursed him for some travel to scientific meetings for discussion of other trials over the past 3 years, but no honoraria or consulting fees were provided. Dr Mocco is a consultant for Rebound Medical, EndoStream, Cerebrotech Medical, Viseon, and Synchron. He is an investor in Apama, Viseon, TSP, Vastrax, EndoStream, Synchron, Cerebrotech Medical, Neurvana, NTI, and Serenity.

International Stroke Conference (ISC) 2018. Late-breaking abstract 4. Presented January 25, 2018.

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