Elsevier

The Lancet Neurology

Volume 8, Issue 8, August 2009, Pages 724-730
The Lancet Neurology

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Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS): a prospective registry study

https://doi.org/10.1016/S1474-4422(09)70173-5Get rights and content

Summary

Background

Treatment strategies for acute basilar artery occlusion (BAO) are based on case series and data that have been extrapolated from stroke intervention trials in other cerebrovascular territories, and information on the efficacy of different treatments in unselected patients with BAO is scarce. We therefore assessed outcomes and differences in treatment response after BAO.

Methods

The Basilar Artery International Cooperation Study (BASICS) is a prospective, observational registry of consecutive patients who presented with an acute symptomatic and radiologically confirmed BAO between November 1, 2002, and October 1, 2007. Stroke severity at time of treatment was dichotomised as severe (coma, locked-in state, or tetraplegia) or mild to moderate (any deficit that was less than severe). Outcome was assessed at 1 month. Poor outcome was defined as a modified Rankin scale score of 4 or 5, or death. Patients were divided into three groups according to the treatment they received: antithrombotic treatment only (AT), which comprised antiplatelet drugs or systemic anticoagulation; primary intravenous thrombolysis (IVT), including subsequent intra-arterial thrombolysis; or intra-arterial therapy (IAT), which comprised thrombolysis, mechanical thrombectomy, stenting, or a combination of these approaches. Risk ratios (RR) for treatment effects were adjusted for age, the severity of neurological deficits at the time of treatment, time to treatment, prodromal minor stroke, location of the occlusion, and diabetes.

Findings

619 patients were entered in the registry. 27 patients were excluded from the analyses because they did not receive AT, IVT, or IAT, and all had a poor outcome. Of the 592 patients who were analysed, 183 were treated with only AT, 121 with IVT, and 288 with IAT. Overall, 402 (68%) of the analysed patients had a poor outcome. No statistically significant superiority was found for any treatment strategy. Compared with outcome after AT, patients with a mild-to-moderate deficit (n=245) had about the same risk of poor outcome after IVT (adjusted RR 0·94, 95% CI 0·60–1·45) or after IAT (adjusted RR 1·29, 0·97–1·72) but had a worse outcome after IAT compared with IVT (adjusted RR 1·49, 1·00–2·23). Compared with AT, patients with a severe deficit (n=347) had a lower risk of poor outcome after IVT (adjusted RR 0·88, 0·76–1·01) or IAT (adjusted RR 0·94, 0·86–1·02), whereas outcomes were similar after treatment with IAT or IVT (adjusted RR 1·06, 0·91–1·22).

Interpretation

Most patients in the BASICS registry received IAT. Our results do not support unequivocal superiority of IAT over IVT, and the efficacy of IAT versus IVT in patients with an acute BAO needs to be assessed in a randomised controlled trial.

Funding

Department of Neurology, University Medical Center Utrecht.

Introduction

Stroke is the leading cause of disability in developed countries.1 Posterior circulation stroke accounts for about 20% of all ischaemic strokes. The basilar artery, which is the main vessel of the posterior circulation, supplies most of the brainstem and occipital lobes and part of the cerebellum and thalami. Owing to different degrees of involvement of the brainstem, patients with acute basilar artery occlusion (BAO) can present with symptoms that vary from isolated cranial nerve palsies or hemiplegia to the locked-in state or coma. Despite recent advances in the treatment of acute stroke, the rate of death or disability associated with BAO is almost 80%.2, 3, 4

Randomised trials have shown the safety and efficacy of intravenous thrombolysis (IVT) given within 4·5 h of the onset of the symptoms of acute ischaemic stroke and intra-arterial thrombolysis given within 6 h.5, 6, 7, 8, 9, 10 Unfortunately, the results of these randomised acute stroke trials do not directly apply to patients with an acute BAO because only few, if any, of these patients were included. BAO has not been studied in isolation in randomised clinical trials because of its low incidence: only about 5% of all patients who have thrombolysis for stroke have BAO.4, 11 We are aware of only one randomised trial of treatment in patients with an acute BAO, which was terminated prematurely because of poor recruitment.12 Case series of patients with BAO found the outcomes of patients treated with antithrombotic therapy (AT), IVT, or intra-arterial therapy (IAT) were similar.2, 13 The primary aim of the Basilar Artery International Cooperation Study (BASICS) was to obtain a better understanding of outcomes after acute BAO and to study potential differences in treatment response in anticipation of a definitive randomised controlled trial of acute treatment in these patients.

Section snippets

Patients

BASICS was a prospective, observational, international registry of consecutive patients aged 18 years or older who presented with an acute symptomatic and radiologically confirmed BAO.14 Patients were eligible for entry if they presented with symptoms or signs attributable to disruption of the posterior circulation, and had a BAO as confirmed by CT angiography (CTA), magnetic resonance angiography (MRA), or conventional contrast angiography. BAO was defined as complete obstruction of flow in

Results

619 patients from 48 centres in Europe (41), South America (3), North America (2), Australia (1), and the middle east (1) were included in the registry. Participating centres and the number of patients recruited per centre are listed at the end of the paper. One centre was excluded from participation in the registry because not all pertinent data on consecutive patients were being recorded.

183 patients were treated with AT, 121 with IVT, and 288 with IAT. Of the patients treated with IVT, 80

Discussion

This is a prospective, international observational study of consecutive patients who presented with an acute symptomatic BAO. Although, to date, no data from a randomised controlled trial support the use of IAT for BAO, IAT was by far the most commonly used treatment type in our registry. Almost 50% of patients were treated with primary IAT: 56% of patients with a severe deficit and 38% of patients with a mild-to-moderate deficit. Additionally, 7% were treated with IVT followed by IAT.

Our

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BASICS study group members listed at end of report.

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