Once again, a trial comparing endovascular therapy to medical treatment of stroke caused by basilar-artery occlusion found that endovascular treatment did not significantly improve outcome as measured by modified Rankin scale.
“In the intention-to-treat analysis, 68 of 154 patients (44.2%) in the endovascular treatment group had a favorable functional outcome (modified Rankin scale score, 0 to 3 at 90 days), as compared with 55 of 146 patients (37.7%) in the medical treatment group (risk ratio, 1.18; 95% confidence interval [CI], 0.92-1.50; P=0.19),” Lucianne C.M. Langezaal, MD, of St. Antonius Hospital, Nieuwegein, The Netherlands, and colleagues wrote in The New England Journal of Medicine.
The primary safety outcomes were symptomatic intracranial bleeding within three days of treatment and 90-day mortality. Bleeding was more common in the endovascular group, 4.5% versus 0.7% (P =0.06), and 90-day mortality was 38.3% in the endovascular arm versus 43.2% (P =0.29).
The authors noted two unexpected outcomes that may have contributed to the null findings: there was less symptomatic intracranial hemorrhage in the medical group than in previous trials of endovascular therapy in stroke, and the “incidence of basilar-artery patency at 24 hours in the medical group in our trial was also higher than in MR CLEAN (Multicenter Randomized Clinical Trail of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands), a large trial of endovascular treatment for patients with anterior circulation stroke.”
The median age of patients in the study was 67, and about half were women. The majority of patients had hypertension and about a third had diabetes. Twice as many patients in the endovascular arm (n=44) had atrial fibirillation. Langezaal et al mentioned this imbalance as a potential limitation but added that “adjustment for this imbalance did not substantially alter effect size between the groups.”
In an editorial, Marc Fischer, MD, of Beth Israel Deaconess Medical Center in Boston, pointed out that 98 of 124 patients who were eligible for BASICS but not enrolled actually went on to have endovascular therapy; however, the outcomes from those patients were not available. But if a substantial number of those 98 patients also had a modified Rankin score of 0 to 3 at 90 days, then “BASICS might have shown a clinically and statistically significant treatment effect, whereas if the converse had occurred, a lack of treatment benefit would have been reinforced. Furthermore, selection bias in the determination of which patients were enrolled probably was introduced because of the large percentage of patients who received endovascular therapy outside the trial.”
BEST was an endovascular therapy trial conducted in China that had a similar design to BASICS, and it too found more endovascular patients (42%) than medical therapy patients (32%) had Rankin scores of 0 to 3 at 9o days, but like BASICS that difference was not statistically significant. “An informal combination of the results of the two trials suggests that endovascular therapy in patients with vertebral and basilar-artery occlusion may be somewhat beneficial, but there is an important caveat that is similar to the one mentioned in BASICS. The outcomes in the 98 patients in BASICS who underwent screening for the trial but received endovascular therapy outside the trial would affect this combined analysis of the two trials. Without the availability of these outcomes, the conclusion remains that endovascular therapy in patients with basilar-artery occlusion is of unproven value,” Fisher wrote.
Additionally, Fisher noted that both BASICS and BEST did not employ advanced imaged on enrollment, “which would have resulted in the enrollment of patients who would have been likely to benefit from endovascular treatment, was not used. Other factors that may have influenced the outcome, such as the extent of the collateral circulation and thrombus on computed tomography (CT) or magnetic resonance angiography, were also not used for patient selection. Another factor that clouds interpretation of all trials involving patients with basilar-artery occlusion is the use of the modified Rankin scale as the outcome measure. This scale is an insensitive instrument in this context for determining whether a therapy is beneficial, because the brain stem is a compact structure in which many vital functions are subserved and small or medium-sized infarctions may lead to substantial disability.”
The researchers concluded that the door is not yet closed on endovascular intervention for strokes caused by basilar artery occlusion, saying “larger trials are needed to determine the efficacy and safety of endovascular therapy in patients with basilar-artery occlusion.”
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Be aware that outcoms of the BASICS trial do not support endovascular treatment of stroke caused by basilar-artery occlusion.
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A possible limitation of the BASICS trial was the lack of information from advanced imaging techniques.
Peggy Peck, Editor-in-Chief, BreakingMED™
Supported by the Dutch Heart Foundation, the Swiss Heart Foundation, the São Paulo Research Foundation, the National Council for Scientific and Technological Development in Brazil, the University Medical Center Utrecht, and St. Antonius Hospital Nieuwegein.
Langezaal had no disclosures.
Fisher reported personal fees from AstraZenca, Simere USA, Lumosa, and ALLM, outside the submitted work.
Cat ID: 130
Topic ID: 82,130,730,130,38,192,925
