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Patients who have material causing narrowing in neck artery removed rather than angioplasty have lower chance of narrowing recurring and subsequent stroke (CAVATAS study)

Lancet

Two Articles published Online First and in the October edition of the Lancet Neurology provide long-term data that show that, for patients with a narrowing of the carotid artery supplying blood to brain (carotid stenosis), removal of the material causing the narrowing(endarterectomy [surgery]) could be a better option than balloon angioplasty with or without stenting (endovascular treatment [ET]). Surgery reduces the risk of both short-term and long-term stroke, and reduces the risk of repeat stenosis--which itself reduces the risk of stroke. The articles are written by Professor Martin M Brown, UCL Institute of Neurology, The National Hospital for Neurology and Neurosurgery, London, UK, and colleagues from the CAVATAS investigators group.

Narrowing of the carotid artery due to deposits of fatty material (atherosclerosis) is one of the main causes of stroke and its less serious sister-ailment, transient ischaemic attack (TIA). Carotid atherosclerosis causes about 20% of all strokes and the narrowing is severe enough to warrant surgery in 5-10% of stroke and TIA patients. Surgery (carotid endarterectomy) involves removal of the fatty deposits in the artery through an incision in the neck. The surgeon clamps the carotid artery and may put in a temporary bypass (shunt) to try and prevent stroke during the operation. He or she then cuts out the fatty deposits from the wall of the artery, then removes the clamps and shunt, and sews up the incision. Endarterectomy is often done under general anaesthetic (but can be done under local anaesthetic). Endovascular treatment involves dilation of the narrowed portion of the artery by inflation of a balloon inside the artery (angioplasty) with or without insertion of a wire mesh (stenting) to hold open the artery from inside. The balloon and/or the stent are threaded up to the neck through a narrow tube (catheter) inserted into a groin artery under local anaesthesia. While studies comparing surgery and ET have been published, none has provided long-term follow-up data on the risks of these procedures for patients. The first paper looked at 504 patients who, between 1992 and 1997, presented at a participating hospital with confirmed carotid stenosis which was equally suitable for treatment with either surgery (received by 251 patients) or ET (253).

The researchers found that within 30 days of treatment, there were more minor strokes that lasted less than 7 days in the ET group (8) than in the surgery group (1). Following the 30-day post-treatment (perioperative) period, the 8-year incidence of ipsilateral stroke (stroke on the same side as the carotid stenosis) was higher in the ET group (11.3%) than the surgery group (8.6%). The combined endpoint of stroke or TIA also occurred more in the ET group (19.3%) than the surgery group (17.2%). However, none of the post-operative differences in stroke outcomes were statistically significant.

The authors conclude: "More patients had stroke during follow-up in the endovascular group than in the surgical group, but the rate of ipsilateral non-perioperative stroke was low in both groups and none of the differences in the stroke outcome measures was significant. However, the study was underpowered and the confidence intervals were wide. More long-term data are needed from the ongoing stenting versus endarterectomy trials."

The second paper looked at patients who had been followed up for a median of five years, and who had had a neck ultrasound to examine the carotid artery for recurrence of stenosis (restenosis) at annual intervals. They found that the estimated incidence of severe restenosis (narrowing of 70% or more of the artery) was 31% in the ET group and 10% in the surgery group; thus three times more likely for the patients who received ET. Patients whose ET involved stenting rather than just angioplasty alone were less than half as likely to develop restensosis; while those who smoked were more than twice as likely to develop severe restensois as those who did not. Finally, patients who developed severe restenosis in the year after treatment were more than twice as likely to go on to suffer ipsilateral stroke or TIA within five years (23%) than those with no restenosis (11%).

The authors conclude: "Restenosis is about three times more common after endovascular treatment than after endarterectomy and is associated with recurrent ipsilateral cerebrovascular symptoms; however, the risk of recurrent ipsilateral stroke is low. Further data are required from ongoing trials of stenting versus endarterectomy to ascertain if long-term ultrasound follow-up is necessary after carotid revascularisation."

In an accompanying Reflection and Reaction comment, Professor Peter M Rothwell, John Radcliffe Hospital, Oxford, UK, says: "A meta-analysis of all the available data on long-term outcome in randomised trials of endovascular treatment versus endarterectomy for symptomatic carotid stenosis now shows a significantly worse outcome after endovascular treatment*. Carotid stenting could still be used, at least in patients with inoperable stenosis or if patients strongly prefer endovascular treatment, although the recent finding of the GALA (general anaesthetic versus local anaesthetic for carotid surgery) trial--that endarterectomy can be done at least as safely under local anaesthetic as it is under general anaesthetic--should influence patients' preferences."

He adds that, pending the publication of results of two other recently completed trials, 'The routine use of stenting in patients with recent symptoms of carotid stenosis who are suitable for endarterectomy can no longer be justified'.

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Professor Martin M Brown, UCL Institute of Neurology, The National Hospital for Neurology and Neurosurgery, London, UK. T) +44 7701 007446 E) m.brown@ion.ucl.ac.uk

Professor Peter M Rothwell, John Radcliffe Hospital, Oxford, UK contact best via e-mail E) peter.rothwell@clneuro.ox.ac.uk

For full Articles and Reflection and Reaction, see: http://press.thelancet.com/tlncavatas.pdf

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