COMPASS Trial: Aspiration as good as stent retrievers for large vessel clot removal in stroke

A new study, co-led by researchers at the Icahn School of Medicine at Mount Sinai and presented at the main event plenary session at the International Stroke Conference (ISC) 2018, has found that patients suffering a large vessel occlusion stroke (LVO), the most devastating kind of ischemic stroke, do just as well when treated with a direct aspiration first pass (ADAPT) approach than those treated with a stent retriever first-line (SRFL) approach. Stent retrievers are the current standard of care for mechanical thrombectomy in patients suffering acute ischemic strokes.

"Our data strongly demonstrates that the two approaches are clinically equivalent, meaning that patients do just as well when you start with aspiration, or clot suction, as when you start with a stent retriever to trap and pull out the clot," says J Mocco, MD, MS, Vice Chair of Neurosurgery and Director of the Cerebrovascular Center for the Mount Sinai Health System, who designed the study and presented the data at ISC 2018. "COMPASS is the first trial designed to compare patient functional outcome between these treatment approaches and we found that patients do equally well with either treatment."

Both the aspiration and stent retriever techniques are initiated by inserting a guide catheter into the femoral artery in the groin and guiding it up into the brain under image guidance. The aspiration approach involves passing a specialized aspiration catheter through the guide catheter, moving it directly to the lesion and then attaching it to an aspiration pump. Once attached to the aspiration system, the catheter is advanced into the proximal end of the clot, suction is initiated and the clot is either aspirated through the catheter or it becomes stuck at the catheter tip and is withdrawn back into the guide catheter. The stent retriever approach involves introducing a stent retriever, which resembles a tiny wire cage, through the guide catheter and moving it to the clot. The stent then opens up, traps the clot and the stent that contains the clot is removed through the guide catheter

Specifically, the COMPASS trial enrolled 270 patients into a prospective, randomized, open-label, blinded outcome assessment and core lab adjudicated trial to assess the clinical outcome of the patient, meaning how functional they were after treatment with either ADAPT using a large-diameter aspiration catheter (ACE™68) system, made by Penumbra Inc., or a stent retriever as first-line approach. To compare clinical outcomes, researchers used the modified rankin scale for neurologic activity (mRS), a standard measurement of the degree of disability or dependence in the daily activities of people who have suffered a stroke which runs from 0 (no symptoms at all) to 6 (dead). The data showed that the ADAPT technique was non-inferior to stent retrievers for treatment of large vessel occlusions with 52 percent of patients treated with Penumbra's aspiration system achieved the primary endpoint of functional independence (mRS 0-2) at 90 days compared with 49 percent of patients treated with stent retrievers. Revascularization speed demonstrated a non-significant trend in favor of aspiration with a 10-minute numeric advantage in achieving reperfusion success (p=0.0194). Quality of revascularization was comparable between the therapies, with the final rate of revascularization success (TICI 2b) being 92 percent and 89 percent, for ADAPT and stent retriever, respectively (p=0.54). Moreover, the percentage of patients achieving full reperfusion (TICI 3) was 38 percent for the ADAPT arm and 29 percent for the stent retriever arm (p=0.15).

Secondary safety endpoints presented, including embolization in new territory (ENT) and symptomatic intracranial hemorrhage (sICH), were not statistically different between the two arms.

A number of clinical trials published in 2015 demonstrated the superiority of endovascular thrombectomy (restoring blood flow to the brain by surgically removing the clot) over medical management (administration of clot busting drugs) for treatment of ischemic strokes. The majority of stoke thrombectomy data to date has focused on stent retrievers, leading many to believe that they represented the gold standard of thrombectomy devices, as reflected by recent American Heart Association/American Stroke Association guidelines. Results from this new study show that an aspiration-first strategy is at least as effective as using retrievable stents, and may even be faster, safer and cheaper.

"This study is very exciting because it shows that there are other ways to open the arteries that are just as effective and perhaps, less expensive. Whether you approach the brain clot with suction or whether you approach it with trapping and pulling it out, patients do equally well," says Dr. Mocco. "Stroke is a massive disease that is prevalent across the globe, so finding ways to provide these therapies to patients who need it in a cost-effective manner is going to be another great step forward in medicine."

Dr. Mocco designed the COMPASS trial in collaboration with leading stroke experts Aquilla Turk, DO, from The Medical University of South Carolina and Adnan Siddiqui, MD, from The University of Buffalo. The COMPASS trial was paid for by Penumbra but the trial was conducted independently by Dr. Mocco and his collaborators, who also handled all data analysis. The Mount Sinai Health System served as the international data coordinating center for the study.