Evidence map›Paper›PMID 34469763›Full record

Trial reportLancet (London, England)2021

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy.

Alison Halliday, Richard Bulbulia, Leo H Bonati, Johanna Chester, Andrea Cradduck-Bamford, Richard Peto, Hongchao Pan, ACST-2 Collaborative Group

Abstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Lancet (London, England), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 119 papers, 12 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
119citing papers in PubMed, 12 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

119 citing papers in PubMed, 12 syntheses or guidelines pooled it.

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  7. Carotid Artery Stenting With Double-Layer Stent: A Systematic Review and Meta-Analysis.Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists · 2024
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59 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

8 authors.

Alison HallidayNuffield Department of Population Health, University of Oxford, Oxford, UK; Nuffield Department of Surgery, University of Oxford, Oxford, UK. Electronic address: alison.halliday@ndph.ox.ac.uk.
Richard BulbuliaNuffield Department of Population Health, University of Oxford, Oxford, UK; Medical Research Council Population Health Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
Leo H BonatiDepartment of Neurology, University Hospital, Basel, Switzerland.
Johanna ChesterNuffield Department of Population Health, University of Oxford, Oxford, UK.
Andrea Cradduck-BamfordNuffield Department of Population Health, University of Oxford, Oxford, UK.
Richard PetoNuffield Department of Population Health, University of Oxford, Oxford, UK.
Hongchao PanNuffield Department of Population Health, University of Oxford, Oxford, UK; Medical Research Council Population Health Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
ACST-2 Collaborative Group

Funding

Cancer Research UK 16896
6 · The paper itself

Abstract

backgroundAmong asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence.

methodsACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362.

findingsBetween Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86-1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91-1·32; p=0·21).

interpretationSerious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable.

fundingUK Medical Research Council and Health Technology Assessment Programme.

Indexed as

AgedCarotid StenosisEndarterectomy, CarotidFemaleHumansMaleRisk FactorsStentsStrokeTime FactorsTreatment Outcome

Identifiers

PMID34469763
PMCPMC8473558

What Socratic holds

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LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.