Although the 2018 U.S. stroke guidelines recommended extending the window for endovascular thrombectomy (EVT) to 24 hours in select stroke patients, a new meta-analysis in JAMA Neurology serves as a reminder that prompt treatment remains crucial for achieving successful reperfusion.
Each hour that passed from a patient’s arrival at a stroke EVT center to groin puncture reduced by 22 percent the odds of successful reperfusion, defined as a modified thrombolysis in cerebral infarction (mTICI) score of 2b or 3 after thrombectomy. Likewise, each hour from first imaging to groin puncture was linked to 26 percent lower odds of successful reperfusion.
The analysis included patient-level data from 728 participants in the EVT arms of randomized trials conducted by the HERMES (Highly Effective Reperfusion Using Multiple Endovascular Devices) group.
“Time is doubly important in the setting of AIS-LVO,” wrote lead author Romain Bourcier, MD, and colleagues, referring to acute ischemic stroke from large vessel occlusion. “First, the time to effective reperfusion is a major potentially modifiable factor associated with better clinical outcomes, and second, the intermediary outcome, the rate of successful reperfusion, is higher with faster in-hospital process times.”
The authors acknowledged their findings could be “confusing” in relation to the DAWN and DEFUSE 3 trials, which supported the recommendation for extending the thrombectomy window from six hours to 24 hours after stroke onset.
“Importantly, even if the reperfusion rate declines as time elapses, patients recanalized in later times continue to have better clinical outcome compared with those without reperfusion,” they wrote.
Bourcier et al. found the total time from stroke onset to groin puncture was linked to only an 8 percent reduction in the odds of reperfusion, which wasn’t deemed statistically significant. They suggested the more reliable reporting of time measurements within the hospital—compared to actual stroke onset—might explain why those in-hospital intervals were more strongly associated with reperfusion outcomes.
Another possibility, they said, is “several of the trials used imaging selection criteria to choose patients (thereby selecting those more likely to be slow progressors), and one trial examined an extended 12-hour eligibility window from stroke onset.”
The authors acknowledged the included studies featured different entry criteria and patient characteristics, potentially biasing the results. Also, procedural details, including device selection, weren’t analyzed.