Endovascular Removal of Clots Proven Successful in Clinical Stroke Trials
By Lindy Keane Carter
The American Heart Association is expected to issue a scientific statement this summer that recommends rapid endovascular clot retrieval in addition to standard of care in patients experiencing stroke secondary to large-artery occlusions. This is in response to the positive results of several recent landmark stroke thrombectomy trials, including the ESCAPE trial* (NCT01778335), for which MUSC Health served as a site.
ESCAPE is a multicenter, prospective, randomized controlled trial with blind outcome evaluation designed to test whether patients with acute ischemic stroke secondary to large-vessel occlusion would benefit from rapid endovascular treatment using retrievable stents (stentreivers) for clot removal in addition to standard of care (including intravenous thrombolysis).
Patients were selected based on computed tomography (CT) and CT angiography (CTA). Inclusion criteria included large proximal intracranial vessel occlusion with small-core ischemic infarct in the anterior brain (i.e., patients with blockages in the large vessels of the head and neck who had a small amount of dead brain but a large area of at-risk brain). The procedure consisted of obtaining a cerebral angiogram, delivering a stentreiver to the blockage in the brain’s artery through the endovascular system, and suctioning out the thrombus (blood clot).
Christine A. Holmstedt, D.O., Co-Director of MUSC Health’s Comprehensive Stroke & Cerebrovascular Center, was a co-investigator and co-author of the resulting report published in the New England Journal of Medicine (March 12, 2015; Epub ahead of print, February 11, 2015). “We found that patients who had this procedure—with or without tissue plasminogen activator—had significantly improved clinical outcomes and reduced mortality,” says Holmstedt. The stroke team’s goal was door to retrieval of the blood clot (and revascularization of the brain) in 90 minutes or less. The researchers found that the patients who had this procedure had a 50percent better outcome at 90 days.
The ESCAPE trial, which comprised 316 participants in 22 centers around the world, measured outcomes with the modified Rankin scale, which ranges from zero (no symptoms) to six (death). Functional independence (defined as a modified Rankin score of zero to two 90 days out) improved in 53percent of study patients undergoing thrombectomy vs 29.3percent of control patients.
“Although a very small number of patients will qualify for this procedure,” says Holmstedt, “it will have a tremendous impact because the patients who are candidates for endovascular thrombectomy are those patients who are having the most neurologically disabling strokes.”
Holmstedt recommends that these procedures be done at high-volume, comprehensive stroke centers, such as MUSC Health, where the stroke-dedicated teams have been trained to work together quickly, highly experienced endovascular interventional surgeons are readily available, and the brain imaging technology is accessible. This therapy will have ramifications for stroke system organization and Emergency Medical Services triaging to facilitate stroke patient transfers to appropriate levels of stroke care.