Thrombectomy improves functional outcomes for patients with acute stroke due to basilar artery occlusion

1. In this randomized clinical trial, thrombectomy for stroke due to basilar artery occlusion led to a higher proportion of patients with good functional outcomes at 90 days when compared to usual management.

2. Thrombectomy did not reduce mortality rate within 90 days and was associated with procedural complications and cerebral hemorrhages compared to controls.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Stroke due to basilar artery occlusion is associated with a poor prognosis. While endovascular thrombectomy improves patient outcomes for acute stroke due to occlusion in the anterior circulation, little is known about the efficacy of thrombectomy for occlusion in the posterior circulation, such as that in the basilar artery. This randomized control trial evaluated the efficacy and safety of endovascular thrombectomy and medical therapy compared to medical therapy alone in patients with acute ischemic stroke due to basilar artery occlusion. Patient functional status was evaluated at 90 days using the modified Ranking scale. The primary efficacy outcome was changed from a modified Rankin Scale score of zero to four, to zero to three due to emerging evidence from other clinical trials that were not available at the time of protocol design. Good functional status, defined by a modified Ranking scale score of zero to three, was observed in significantly more patients in the thrombectomy group compared to the control group. Basilar artery patency at 24 hours was also observed in significantly more patients in the thrombectomy group compared to the control group. Notably, the incidence of symptomatic intracranial hemorrhage at 24 hours was significantly higher in the thrombectomy group compared to the control group. Mortality at 90 days was not significant between groups. As a limitation, patient recruitment criteria and the primary outcome of the study were changed during the trial, which may lead to bias in results. The study population consisted of the Han Chinese population, which may reduce generalizability to other populations.

Click here to read the study in NEJM

Relevant Reading: Endovascular Therapy for Stroke Due to Basilar-Artery Occlusion

In-Depth [randomized controlled trial]: In the present randomized control trial, adults aged 18 to 80 with occlusion of the basilar artery (n=218) were randomized in a 1:1 ratio to receive thrombectomy and medical therapy (n=110) or medical therapy alone (n=108). Treatments were administered within six to 24 hours after symptom onset. Patients were followed for 90 days. While inclusion criteria included a National Institutes of Health Stroke Scale (NIHSS) score of 10 or higher, patients with an NIHSS score of six or higher were included due to slow initial recruitment. The primary outcome of a modified Rankin Scale score of zero to four was later changed to zero to three midtrial due to new evidence from similar trials showing that the updated range is more meaningful to patient function. At baseline, patient characteristics were similar between groups, with the median NIHSS score being 20. At 90 days, 46% and 24% of patients in the thrombectomy and control groups, respectively, achieved the primary outcome (adjusted rate ratio, 1.81 (95% confidence interval [CI], 1.26 to 2.60; p<0.001). The original primary outcome was achieved in 55% and 43% of patients in the thrombectomy and control groups, respectively (adjusted rate ratio, 1.21; 95% CI, 0.95 to 1.54). Successful reperfusion in the thrombectomy group, defined as modified Thrombolysis in Myocardial Infarction (TICI) category of 2b or 3, was observed in 88% of the patients. Basilar artery patency, assessed with imaging, was observed in 92% and 19% of patients in the thrombectomy and control groups, respectively. For safety outcomes, the incidence of symptomatic intracranial hemorrhage at 24 hours was higher in the thrombectomy (6%) than in the control (1%) group (unadjusted risk ratio, 5.18; 95% CI, 0.64 to 42.18). Mortality at 90 days was not significant between groups (31% and 42% in the thrombectomy and control groups, respectively). This study suggests that thrombectomy may improve functional status at 90 days for patients with acute stroke due to basilar artery occlusion, but may also increase the risk of cerebral hemorrhages.

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