Historical Reference Page
This is a historical reference page. This trial preceded the modern evidence base. It is presented as a predecessor reference. See ATTENTION (2022) for the modern successor trial that established endovascular thrombectomy for basilar artery occlusion.
BASICS Trial: Basilar Artery International Cooperation Study: EVT vs Best Medical Treatment
In patients with acute basilar artery occlusion within 6 hours, does EVT plus best medical treatment improve 90-day favorable functional outcome (mRS 0-3) compared with best medical treatment alone?
Langezaal et al. (NEJM 2021) · doi:10.1056/NEJMoa2030297 · 300 patients
Population
Included
- Age 18 years or older
- CTA- or MRA-confirmed basilar artery occlusion
- Symptom onset or last known well within 6 hours
- No contraindication to EVT or best medical treatment
Excluded
- Bilateral fixed dilated pupils or GCS 5 or lower (catastrophic presentation)
- Large established infarct on baseline imaging
- Intracranial hemorrhage on baseline CT
- Pre-stroke severe disability (mRS 3 or greater)
- Contraindication to antiplatelet or antithrombotic therapy
Primary Outcome — mRS 0-3 at 90 Days
300 patients; EVT plus best medical treatment vs best medical treatment alone; basilar artery occlusion
In 300 patients with CTA- or MRA-confirmed basilar artery occlusion enrolled across 11 countries, EVT plus best medical treatment did not significantly improve favorable functional outcome (mRS 0-3) at 90 days compared with best medical treatment alone. mRS 0-3 was achieved in 44.2% (68 of 154) of the EVT group versus 37.7% (55 of 146) of the medical group (rate ratio 1.18, 95% CI 0.92 to 1.50, P=0.19). The confidence interval was wide and included a potential 50% relative increase in favorable outcomes with EVT, meaning the trial did not exclude a clinically meaningful benefit. Mortality was numerically lower in the EVT arm (38.0% vs 43.2%), though not statistically significant.
Visualization not shown for predecessor reference pages. See source paper for figures.
Trial Design
BASICS was an international open-label RCT enrolling patients with acute basilar artery occlusion at centers in Europe and Asia. Patients within 6 hours of onset (or last known well) with CTA- or MRA-confirmed basilar occlusion were randomized to EVT plus best medical treatment or best medical treatment alone. Best medical treatment included IV alteplase (0.9 mg/kg) if eligible; approximately 40% of the medical arm received alteplase. EVT could use any approved thrombectomy technique. The trial was designed to detect a 10-percentage-point difference in mRS 0-3 but the enrolled population had higher baseline severity than anticipated, limiting statistical power.
Safety
Symptomatic intracranial hemorrhage occurred in 4.5% of the EVT group versus 0.7% of the medical group (P=0.07). Mortality at 90 days was 38.0% EVT versus 43.2% medical, a non-significant difference. The sICH difference trended toward significance, consistent with reperfusion hemorrhage risk in the basilar territory.
Trial lineage
Endovascular therapy for basilar artery occlusion
BEST and BASICS were the first two RCTs in basilar-artery occlusion and both failed their primary frame — driven by substantial crossover in BEST and a control arm in BASICS that frequently received alteplase. ATTENTION and BAOCHE, both in Chinese populations, established benefit in 0-12 h and 6-24 h windows respectively and shifted guideline support toward EVT for basilar LVO.
- 2020BEST TrialNEUTRAL
First RCT of EVT for basilar artery occlusion. ITT primary (mRS 0-3 at 90 days): 42% vs 32% (OR 1.74, CI 0.81–3.74, p=0.23). Terminated early for crossover and low enrollment. Preceded ATTENTION (2022).
- 2021BASICS Trial· this pageNEUTRAL
Multinational RCT of EVT for basilar artery occlusion within 6 hours. Primary (mRS 0-3 at 90 days): 44.2% EVT vs 37.7% medical (RR 1.18, CI 0.92–1.50, P=0.19). Statistically negative; CI did not rule out meaningful benefit. Preceded ATTENTION (2022).
- 2022ATTENTION TrialPOSITIVE
Basilar artery thrombectomy within 12 hours; China trial.
- 2022BAOCHE TrialPOSITIVE
Basilar EVT 6–24 hours with imaging selection.