ECST 1998.
| Study characteristics | ||
| Methods | RCT ITT analysis Not censored at crossover Mean follow‐up: 6.1 years Minimum follow‐up: 4 months |
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| Participants | 3024 participants Europe and Australia 97 centres Sex: either Age: no restrictions Qualifying event: ischaemic cerebrovascular event (TIA, retinal infarction or non‐disabling ischaemic stroke), ipsilateral to carotid stenosis, within 6 months of randomisation Criteria: inclusion and exclusion criteria with 'uncertainty principle' Degree of stenosis: 67% to 99% (NASCET‐measured), 0% to 99% (ECST‐measured) Baseline demographics: mean age 63 years, 72% male, ischaemic heart disease (myocardial infarction or angina) 23%, diabetes 12% Prior neurological event: TIA 78%, stroke 50% | |
| Interventions | 'Carotid endarterectomy as soon as possible' versus 'avoid surgery if at all possible, for as long as possible' Co‐interventions: non‐protocolised usual care for both groups Co‐interventions described Crossover: medical to surgical crossover 3.5% within 1 year of randomisation; a further 8.3% of control patients underwent carotid endarterectomy subsequent to 1 year; surgical to medical crossover 3.4% | |
| Outcomes | Primary outcome: fatal or disabling ipsilateral ischaemic stroke Other outcomes: major stroke or surgical death, any major stroke, death from any cause, any major stroke or death, disabling or fatal stroke or surgical death, fatal stroke or surgical death Stroke was defined as a clinical syndrome characterised by rapidly developing symptoms, signs (or both) of focal, and at times global (applied to patients in deep coma and those with subarachnoid haemorrhage), loss of cerebral function lasting longer than 24 hours or leading to death with no apparent cause other than that of vascular origin Major stroke was a stroke as defined above, with symptoms lasting longer that 7 days Disabling stroke was a stroke that after 6 months was associated with disability as recorded on the modified Rankin scale of 3, 4, or 5 | |
| Funding source | UK Medical Research Council, the European Union Biomed programme, and the University of Oxford ICRF/MRC Clinical Trial Service Unit, England | |
| Notes | Adequate concealment Patients not blinded Clinicians not blinded External blinded review of outcomes Follow‐up: 99.8% Demographics: adequately reported and similar Principal investigator: Professor Charles Warlow, Division of Clinical Neurosciences, Western General Hospital, Edinburgh EH4 2XU, UK (e‐mail: charles.warow@ed.ac.uk) | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "Patients were randomised from a total of 80 centres in 14 European countries by telephone to the MRC/Imperial Cancer Research Fund Clinical Trial Service Unit (CTSU) at the University of Oxford. During the telephone call, enough information to identify the centre, the doctor, and the patient was entered into the CTSU computer" |
| Allocation concealment (selection bias) | Low risk | Quote: "As soon as this entry was complete, a treatment allocation to 'immediate surgery' or to 'no immediate surgery' was displayed, and that patient was then irrevocably in the trial, to be followed up until death" |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Comment: because of the nature of the intervention (surgical and non‐surgical groups), this RCT could not be blinded for surgeons or participants |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Comment: external blinded review of outcomes by independent assessor was performed, so this was unlikely to influence outcome measurement |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Comment: few participants (0.2%) were lost to follow‐up |
| Selective reporting (reporting bias) | Low risk | Comment: authors published findings on all the study outcomes (predefined) |
| Other bias | Low risk | |