Clot-removal procedures can help more stroke patients than previously thought

Image of skull and brain of stroke patient

Study reviewed data from thousands of patients who had mechanical thrombectomy.

Contact: Will Sansom, (210) 567-2579,

SAN ANTONIO (Dec. 10, 2021) — A study of 2,345 stroke patients, all of whom underwent mechanical thrombectomy to remove blood clots from the brain causing stroke symptoms, found that re-establishing blood flow through this lifesaving procedure may also help a population of patients who have already sustained some degree of permanent stroke in the brain. This group of patients had previously been excluded from large randomized trials evaluating mechanical thrombectomy due to concerns that the procedure would be futile.

Justin Mascitelli, MD

Justin Mascitelli, MD, of The University of Texas Health Science Center at San Antonio (also referred to as UT Health San Antonio), is a co-author of the study released Dec. 8 in the journal JAMA Network Open. “What we learned from this investigation is that a group of patients previously not expected to benefit from mechanical thrombectomy could indeed achieve substantial independence with successful mechanical thrombectomy and reestablishment of blood flow,” Dr. Mascitelli said.

Mechanical thrombectomy is a set of procedures by which surgeons gain access to an artery through a small incision, thread a catheter to a clot and remove the clot either through direct aspiration or by insertion of a device called a stent retriever. The stent retriever is deployed within the clot and then carefully withdrawn from the brain, removing the blockage and restoring circulation.

The study was derived from the Stroke Thrombectomy and Aneurysm Registry (STAR) that is led by the Medical University of South Carolina (MUSC). The registry includes databases of 28 stroke centers in the U.S., Europe and Asia. The 2,345 patients were treated with mechanical thrombectomy between Jan. 1, 2016 and Dec. 31, 2020.

All patients presented with blockage of the internal carotid artery or the M1 segment of the middle cerebral artery. Patients were graded on a 10-point scoring system called ASPECTS (Alberta Stroke Program Early Computed Tomography Score). ASPECTS is based on the quantity of early ischemic (oxygen-depriving) changes on the patient’s first computed tomography (CT) scan. A score of 10 indicates normal and a score of zero indicates ischemic changes in all regions included in the ASPECTS analysis. The primary outcome was functional outcome at 90 days post thrombectomy.

Out of the entire patient cohort, 213 patients (9.1%) had an ASPECTS score of 2 to 5. Of these patients, 22% achieved favorable 90-day outcomes after mechanical thrombectomy. Reestablishment of blood flow, called “recanalization” by stroke specialists, was essential. “Patients who achieved successful recanalization were nearly 5 times more likely to achieve favorable outcomes compared with patients who had unsuccessful recanalization,” the authors wrote.

The study also found that patients who had mechanical thrombectomy early (within 0-6 hours of stroke onset) and patients who had it in an extended window (6-24 hours) had similar 90-day outcomes.

At UT Health San Antonio, Dr. Mascitelli is assistant professor in the Department of Neurosurgery of the Joe R. and Teresa Lozano Long School of Medicine. He also serves as the Neurosurgery Residency Program director.

Outcomes of Mechanical Thrombectomy for Patients With Stroke Presenting With Low Alberta Stroke Program Early Computed Tomography Score in the Early and Extended Window

Eyad Almallouhi, MD; Sami Al Kasab, MD; Zachary Hubbard, MD; Eric C. Bass, DO; Guilherme Porto, MD; Ali Alawieh, MD, PhD; Reda Chalhoub, BS; Pascal M. Jabbour, MD; Robert M. Starke, MD; Stacey Q. Wolfe, MD; Adam S. Arthur, MD, MPH; Edgar Samaniego, MD; Ilko Maier, MD; Brian M. Howard, MD; Ansaar Rai, MD; Min S. Park, MD; Justin Mascitelli, MD; Marios Psychogios, MD; Reade De Leacy, MD; Travis Dumont, MD; Michael R. Levitt, MD; Adam Polifka, MD; Joshua Osbun, MD; Roberto Crosa, MD; Joon-Tae Kim, MD, PhD; Walter Casagrande, MD; Shinichi Yoshimura, MD, PhD; Charles Matouk, MD; Peter T Kan, MD; Richard W Williamson, MD; Benjamin Gory, MD, PhD; Maxim Mokin, MD, PhD; Isabel Fragata, MD, PhD; Osama Zaidat, MD; Albert J. Yoo, MD, PhD; Alejandro M. Spiotta, MD; for the Stroke Thrombectomy and Aneurysm Registry (STAR) Collaborators

First published:  JAMA Network Open, Dec. 8, 2021

The University of Texas Health Science Center at San Antonio, also referred to as UT Health San Antonio, is one of the country’s leading health sciences universities and is designated as a Hispanic-Serving Institution by the U.S. Department of Education. With missions of teaching, research, patient care and community engagement, its schools of medicine, nursing, dentistry, health professions and graduate biomedical sciences have graduated 39,700 alumni who are leading change, advancing their fields, and renewing hope for patients and their families throughout South Texas and the world. To learn about the many ways “We make lives better®,” visit

Stay connected with The University of Texas Health Science Center at San Antonio on FacebookTwitterLinkedInInstagram and YouTube.

Share This Article!