Patients who have already had some degree of permanent loss of function in the brain due to stroke may benefit from reestablishing blood flow through a lifesaving procedure called mechanical thrombectomy, a recent study found.
Mechanical thrombectomy is minimally invasive and allows surgeons to gain access to an artery through a small incision. A catheter is threaded into an artery until it reaches the blood clot that is causing the stroke. The clot is removed through direct aspiration or by a stent retriever inserted into the catheter, reestablishing blood flow.
The study of 2,345 stroke patients, all of whom underwent this procedure to remove blood clots causing stroke symptoms, found that reestablishing blood flow could also help those who had permanent damage in the brain. This group of patients had previously been excused from large randomized trials evaluating mechanical thrombectomy because of concerns that the procedure would have no benefit.
Justin Mascitelli, MD, a neurosurgeon with The University of Texas Health Science Center at San Antonio (also called UT Health San Antonio), is a co-author of the study released Dec. 8 in the journal JAMA Network Open. He is also an assistant professor in the Department of Neurosurgery in the Joe R. and Teresa Lozano Long School of Medicine and serves as the director of the Neurosurgery Residency Program.
“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.
The study stems from the Stroke Thrombectomy and Aneurysm Registry that is led by the Medical University of South Carolina. 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 had blockage of the internal carotid artery or the M1 segment of the middle cerebral artery. Patients were graded on a 10-point scoring system. The scoring system, called the Alberta Stroke Program Early Computed Tomography Score, or ASPECTS, is based on the quantity of early ischemic (oxygen-depriving) changes on the patient’s first CT scan. A score of 10 indicates normal and a score of zero indicates ischemic changes in all regions included in the ASPECTS analysis. Most patients showed a functional outcome 90 days after the 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 five 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 a mechanical thrombectomy within six hours of stroke onset and patients who had it in an extended window up to 24 hours after the stroke onset had similar 90-day outcomes.