Public Release: 

Mount Sinai researchers lead trial showing aspiration is equally effective as, and significantly cheaper than, traditional stent retriever approach for clot removal

The Mount Sinai Hospital / Mount Sinai School of Medicine

Sucking a clot directly out of the artery in patients experiencing a stroke is just as effective as, and significantly cheaper than, removing it by use of a stent, according to a study co-led by researchers at the Icahn School of Medicine at Mount Sinai and published in print March 9 in The Lancet.

The study, known as COMPASS, concerned large vessel occlusion stroke, the most devastating kind of ischemic stroke. It compared the direct aspiration first pass (ADAPT) approach to the current standard of care, stent retriever first-line (SRFL), for mechanical clot removal (thrombectomy) in patients suffering acute ischemic strokes.

"Our data strongly demonstrates that the two approaches have comparable clinical results, 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 and senior author of the study. "COMPASS is the first prospective randomized trial designed to compare both patient outcome and cost between these treatment approaches, and we found that patients do equally well with the aspiration approach, which is significantly cheaper."

Both 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-first approach involves passing a specialized aspiration microcatheter through the guide catheter, moving it directly to the lesion, and then attaching it to an aspiration pump. Once attached to the suction system, the catheter is advanced into the 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is initiated, and the clot is either aspirated through the catheter or it becomes stuck at the catheter tip and is withdrawn back into the guide catheter.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 SRFL 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 and traps the clot, and then both are removed through the guide catheter.

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 (ACE68 ™) system, made by Penumbra Inc., or an SRFL 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: 51.5 percent of patients treated with Penumbra's aspiration system achieved the primary endpoint of independence (mRS 0-2) at 90 days compared with 49.3 percent of patients treated with stent retrievers. Final revascularization rates were also similar for the two study groups: 91.7 percent of patients treated with aspiration achieved TICI compared to 90.4 percent with stent retrievers (p=0.83). Moreover, the percentage of patients achieving TICI 3 was 37.6 percent for the ADAPT arm and 27.2 percent for the stent retriever arm (p=0.09).

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

Using prespecified device-related procedural cost analyses, the COMPASS trial showed that the aspiration-first cohort had significantly lower device costs across all analysis methods. When using aggregate supply chain data as the primary source and list price as the secondary source, the aspiration-first group had a mean $4,541 reduction in the cost of devices used compared with the stent retriever first line group. When using list price as the primary source and aggregate supply chain data as the secondary source, the aspiration-first group had a mean $5,074 reduction in the cost of devices used. Furthermore, the reduction in median device costs was even greater ($6157.40 and $6,838, respectively) (p<0.0001 for all price comparisons).

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. However, the majority of stroke thrombectomy data to date has been based on the stent retriever approach, leading many to believe that stent retrievers represented the gold standard of thrombectomy devices, as reflected by recent American Heart Association/American Stroke Association guidelines.

"This study is very exciting because it shows that there are other ways to open the arteries that are just as effective and importantly, 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 horrible 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 a great step forward in medicine."


Dr. Mocco designed the COMPASS trial in collaboration with leading doctors Aquilla Turk, DO, from the Medical University of South Carolina and Adnan Siddiqui, MD, PhD, from the University at 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.

Post embargo, the study can be accessed at:

About the Mount Sinai Health System

The Mount Sinai Health System is New York City's largest integrated delivery system, encompassing eight hospitals, a leading medical school, and a vast network of ambulatory practices throughout the greater New York region. Mount Sinai's vision is to produce the safest care, the highest quality, the highest satisfaction, the best access and the best value of any health system in the nation. The Health System includes approximately 7,480 primary and specialty care physicians; 11 joint-venture ambulatory surgery centers; more than 410 ambulatory practices throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and 31 affiliated community health centers. The Icahn School of Medicine is one of three medical schools that have earned distinction by multiple indicators: ranked in the top 20 by U.S. News & World Report's "Best Medical Schools", aligned with a U.S. News & World Report's "Honor Roll" Hospital, No. 12 in the nation for National Institutes of Health funding, and among the top 10 most innovative research institutions as ranked by the journal Nature in its Nature Innovation Index. This reflects a special level of excellence in education, clinical practice, and research. The Mount Sinai Hospital is ranked No. 18 on U.S. News & World Report's "Honor Roll" of top U.S. hospitals; it is one of the nation's top 20 hospitals in Cardiology/Heart Surgery, Gastroenterology/GI Surgery, Geriatrics, Nephrology, and Neurology/Neurosurgery, and in the top 50 in six other specialties in the 2018-2019 "Best Hospitals" issue. Mount Sinai's Kravis Children's Hospital also is ranked nationally in five out of ten pediatric specialties by U.S. News & World Report. The New York Eye and Ear Infirmary of Mount Sinai is ranked 11th nationally for Ophthalmology and 44th for Ear, Nose, and Throat. Mount Sinai Beth Israel, Mount Sinai St. Luke's, Mount Sinai West, and South Nassau Communities Hospital are ranked regionally.

For more information, visit, or find Mount Sinai on Facebook, Twitter and YouTube.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.