Background: Symptomatic vertebral artery (VA) stenosis has been associated with a markedly increased early risk of recurrent stroke. VA stenosis can be treated with stenting; however, there are few data from randomised controlled trials evaluating the efficacy of this treatment, and recent studies in intracranial stenosis have suggested that stenting may be associated with increased risk.
Objective: The Vertebral artery Ischaemia Stenting Trial (VIST) was established to compare the risks and benefits of vertebral angioplasty and stenting with best medical treatment (BMT) alone for recently symptomatic VA stenosis.
Design: VIST was a prospective, randomised, open, parallel, blinded end-point clinical trial.
Setting: The trial was performed in 14 hospitals in the UK.
Participants: Recruitment began on 23 October 2008 and follow-up ended on 1 March 2016, by which time every patient had been followed up for at least 1 year. Participants had to have symptomatic vertebral stenosis of at least 50% resulting from presumed atheromatous disease. Both patients and clinicians were aware of treatment allocation; however, an independent adjudication committee, masked to treatment allocation, assessed all primary and secondary end points.
Interventions: Participants were randomly assigned (1 : 1) to either vertebral angioplasty/stenting plus BMT (n = 91) or BMT alone (n = 88). A total of 182 patients were initially enrolled; however, three patients (two who withdrew after randomisation and one who did not attend after the initial randomisation visit) did not contribute any follow-up data and were excluded. None of these three patients had outcome events.
Main outcomes and measures: The primary end point was the occurrence of fatal or non-fatal stroke in any arterial territory during follow-up.
Results: The median follow-up was 3.5 (interquartile range 2.1-4.7) years. Of the 61 patients who were stented, 48 (78.7%) had extracranial stenosis and 13 (21.3%) had intracranial stenosis. No perioperative complications occurred with extracranial stenting; two strokes occurred during intracranial stenting. The primary end point occurred in five patients (including one fatal stroke) in the stent group and in 12 patients (including two fatal strokes) in the medical group (giving a hazard ratio of 0.40, 95% confidence interval 0.14 to 1.13; p = 0.08), with an absolute risk reduction of 25 strokes per 1000 person-years.
Limitations: The study was underpowered because it failed to reach target recruitment. The high rate of non-confirmation of stenosis in the stented group of the trial was a second limitation.
Conclusions: The trial found no difference in risk of the primary end point between the two groups.
Future: Post hoc analysis suggested that stenting could be associated with a reduced recurrent stroke risk in symptomatic VA and further studies are now required to confirm these findings, particularly in extracranial VA stenosis where complication rates with stenting were confirmed to be very low.
Trial registration: Current Controlled Trials ISRCTN95212240.
Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 41. See the NIHR Journals Library website for further project information. In addition, funding for the pilot phase was provided by the Stroke Association.
Keywords: POSTERIOR CIRCULATION; RANDOMISED CONTROLLED TRIAL; SECONDARY PREVENTION; STENTING; STROKE; VERTEBRAL ARTERY.
About one-quarter of all strokes occur in the back of the brain, which is supplied by the vertebral and basilar arteries. An important cause of stroke is a narrowing, or stenosis, of these arteries. It is known that patients who have a minor stroke due to narrowing of a vertebral artery (VA) have a high risk of a further stroke: as much as 30% in the next year. Stenosis of the VA can be treated with stenting, in which a wire mesh is put into the narrowed artery and opens it up. Many operations to insert a vertebral stent have been carried out worldwide with good technical results; however, it is not known whether it is better to treat vertebral stenosis with stenting or only tablets. The Vertebral artery Ischaemia Stenting Trial was a randomised controlled trial comparing vertebral stenting and best medical treatment (BMT) with BMT alone in patients who had suffered a minor stroke due to vertebral stenosis. Ninety-one patients had stenting and 88 had BMT alone. Patients were followed for an average of 3.5 years. It was planned to enrol 540 patients to the trial, but recruitment was slower than expected and funding for the study was halted; therefore, recruitment was stopped at 181 patients. There was no difference in the rate of recurrent stroke between patients who had stenting and those who had BMT alone. There was some evidence that stenting might be associated with a reduced risk of recurrent stroke, but the difference was not significant. The trial was limited by the failure to recruit the anticipated sample size. The results tell us that stenting is a possible treatment for vertebral stenosis; however, further trials are required to determine whether or not it is more effective at preventing recurrent stroke than BMT alone.