Mechanical Thrombectomy in and Outside the REVASCAT Trial
Is there a difference in outcome for stroke patients treated with endovascular thrombectomy (EVT) in a clinic trial versus those treated with EVT outside the trial?
The REVASCAT (Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke due to Anterior Circulation Large Vessel Occlusion Presenting Within 8-Hours of Symptom Onset) trial randomized acute stroke patients to best medical therapy, including intravenous (IV) tissue plasminogen activator (tPA) or best medical therapy plus EVT. It was conducted at four hospitals in Catalonia from November 2012 through December 2014. It was stopped after a planned interim analysis due to lack of equipoise as concurrent studies were published showing the benefit of EVT. All stroke patients in Catalonia are tracked in a mandatory registry (SONIIA). The registry has near complete capture (>99.9%) of stroke cases and includes clinical, imaging, and outcome data. All patients treated with EVT, including inpatients and those enrolled in the REVASCAT trial, were included in SONIIA.
Patients treated with EVT were identified in SONIIA, and the REVASCAT inclusion criteria were applied to identify patients enrolled in the trial. As some laboratory and imaging data that may have excluded patients from REVASCAT were not available in SONIIA, the number of patients identified as being eligible for REVASCAT may be overestimated. At the REVASCAT hospitals, the same teams treated patients within and outside the trial.
There were 504 patients treated with EVT in Catalonia during the REVASCAT trial period, of which 103 were treated in the trial. Thirty-eight patients who were eligible for the trial were treated with EVT outside the trial. In the population, 84.4% of eligible patients were treated in REVASCAT.
Patients treated with EVT outside of REVASCAT were older, had more baseline disability, and had basilar and distal middle cerebral artery (MCA) occlusions (all exclusion criteria for the trial). Recanalization rates were similar between those patients included in the trial and those treated outside the trial. There were more hemorrhages in the patients with basilar and distal MCA occlusion, but the overall numbers were small. Mortality was higher in the patients with basilar occlusion. The 3-month functional outcomes were similar in patients treated with EVT in REVASCAT when compared with those treated outside the trial.
The REVASCAT trial enrolled close to 85% of eligible patients, and patients treated outside the trial had similar outcomes to those treated in the trial.
EVT has become the standard of care for acute stroke patients with large artery occlusion because it is safe and reduces disability. There have been concerns about the generalizability of the studies showing the effectiveness of EVT, and this study speaks to those concerns. REVASCAT included about 85% of patients eligible for EVT. The majority of patients not enrolled in the trial did not meet inclusion criteria due to age, pre-stroke functional status, or location of vessel occlusion. Despite these differences, patients treated with EVT outside REVASCAT had similar outcomes to those patients treated in the trial.
While these results are encouraging regarding the generalizability of EVT, some caution is warranted. In Catalonia, EVT is performed at Comprehensive Stroke Centers and these results may not apply to patients treated in other facilities. In addition, as there is a strong relationship between time to treatment and outcome in stroke, systems of stroke care are important. In Catalonia, systems of stroke care may be better organized to rapidly identify and transport patients to centers that can perform EVT when compared with other parts of the world.
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