Mobile stroke response team visits patients to provide faster access to surgical treatment

Stroke patients were almost twice as likely to be functionally independent -; mobile and able to perform daily tasks -; 90 days after stroke if treated by a mobile stroke team who went there to perform mechanical clot removal, compared to those who were transferred to a stroke center for thrombectomy , according to research conducted within the Mount Sinai Health System and published today in Caress, a journal of the American Stroke Association, a division of the American Heart Association.

The study examines the results of a pilot program created by stroke specialists at Mount Sinai in New York. As part of this program, instead of transferring stroke patients to a stroke center, a mobile stroke intervention team (MIST) visited the patient to perform an endovascular thrombectomy, a procedure used to remove large blood clots in patients with acute ischemic stroke. The MIST team includes a neuro-interventionist, an assistant and a radiology technologist. The trial involved 226 patients who underwent endovascular thrombectomy at four hospitals in the Mount Sinai Health System between January 2017 and February 2020.

Drugs to dissolve large blood clots in the vessels in or leading to the brain are effective in about 15 to 20 percent of stroke cases. However, most patients with large vessel obstruction still require endovascular thrombectomy. Almost 90% of strokes are ischemic strokes, caused by blood clots in an artery that block normal blood flow and oxygen to the brain. Since 2015, endovascular thrombectomy has been the standard of care for the treatment of stroke. The biggest barrier for stroke patients today is timely access to this potentially life-saving procedure.

Less than 50 percent of Americans have direct access to endovascular thrombectomy, with the other half needing to be transferred to a thrombectomy-compatible hospital for treatment, often losing more than two hours of treatment. Every minute is precious in the treatment of stroke, and going to a center that offers thrombectomy is of crucial importance. The MIST model addresses this waste of time and brain health by providing faster access to this surgical treatment. “

Johanna Fifi, MD, Associate Director of Mount Sinai Cerebrovascular Center, Co-Director of Pediatric Brain Disorders and Associate Professor of Neurosurgery, Neurology and Radiology at Icahn School of Medicine at Mount Sinai and co-author of the study

Researchers looked at data from 226 patients who underwent endovascular thrombectomy at four Mount Sinai Health System hospitals (one is a certified full stroke center and three are thrombectomy-capable stroke centers). Of these, 106 patients were treated by the MIST team, and 120 were treated according to the current standard of care in hospitals without expertise in endovascular thrombectomy. Current standards are to treat patients with drugs to dissolve the clot and then transfer the patient to a hospital with the expertise to perform an endovascular thrombectomy. All patients in the analysis were functionally independent before having a stroke.

To assess the results, the researchers used the Modified Rankin Scale (mRS) and the National Institutes of Health Stroke Scale, two commonly used measures of the degree of disability or dependence in the daily activities of people with stroke. They analyzed the results of patients who were seen within six hours of stroke onset (early treatment window) and six hours after stroke symptoms (late window).

For patients treated in the early window, the rate of a good outcome (mRS less than 2; mobile and can perform daily tasks) three months after the event was significantly higher in patients in the MIST group (54%) compared to patients in the transferred group (28 percent). However, for patients treated in the late window, the results were similar, with 35% of patients in the MIST group having a good result at 90 days, compared to 41% in the transfer group.

“Ischemic strokes often progress rapidly and can cause serious damage, as the brain is deprived of blood and oxygen and brain tissue dies quickly, resulting in severe long-term disability or death,” Dr. Fifi. “Evaluating stroke patients in the early window means more rapidly progressing strokes are identified and treated.”

Data from the MIST trial were collected prospectively, however, the analysis was conducted retrospectively. The MIST program continues as more institutions and cities implement the model.