Researchers find diminishing returns in patient outcomes after endovascular thrombectomies pass 60-minute mark
The “Stroke Belt” refers to the swath of states in the Southeast where rates of stroke death are high, and according to the Department of Health and Environmental Control, South Carolina comes in at number six for the nation’s highest rates of stroke death.
A stroke occurs when blood flow to a particular area of the brain is cut off, which could be due to a clot, a blood vessel leak or the bursting of a brain aneurysm. Without enough oxygen, the cells in that part of the brain begin to die and can leave behind motor and cognitive deficits.
Timely removal of the blockage is vital when treating a stroke, and while the acceptable time to treatment has slowly lengthened with more effective thrombectomy techniques, physicians and surgeons must still act within 24 hours of the onset of stroke. Researchers at MUSC report in a recent paper in the Journal of the American College of Cardiology that the current standard of care for stroke should also factor in procedure time when considering surgical intervention.
“People will try once to remove the clot,” said Ali Alawieh, M.D., Ph.D., a neurosurgery researcher at MUSC who worked on the study under the direction of MUSC Division of Neuroendovascular Surgery Director Alejandro Spiotta, M.D. “They’ll then try two, three and even four times hoping for a successful attempt. The idea of the study is to look for a limit where you start doing more harm than good.”
By studying the number of attempts and the amount of time spent performing procedures, the team concluded that the likelihood of completing an endovascular thrombectomy without significantly increasing the risk for the patient decreases dramatically after the first 30-60 minutes, depending on the technique used. Complication rates increase by the minute after that.
Endovascular thrombectomies are performed using either stent retrievers (SRs) or aspiration thrombectomy (ADAPT). By comparing both techniques, Alawieh and Spiotta found that the most important detail to consider is the time spent manipulating the vessel. Using SRs, the golden time for the procedure is at the hour mark, and using ADAPT, it is a half-hour.
“We had noticed this trend at MUSC, but we wanted to know if it extended nationally,” said Alawieh. “As it turns out, it does. After that 30- to 60-minute mark, depending on the procedure, surgeons should reassess if the procedure is worth continuing.”
Because they are in the Stroke Belt, physicians at MUSC perform some of the largest numbers of endovascular thrombectomies in the country, totaling over 200 procedures a year. While rates of positive outcomes are highest with successful surgical intervention, patients may still recover some of the deficits with medical management.
This work involved a collaboration between MUSC and other centers across the country who are part of the Stroke Thrombectomy and Aneurysm Registry (STAR), a collaborative effort coordinated and initiated by MUSC to monitor outcomes in stroke patients nationally.
“Stroke intervention procedures are so effective in helping patients that it’s difficult for the physician to give up on a procedure when it’s not successful,” said Spiotta. “This work provides a potential stopping point.”
Progressnotes Summer 2019