Two studies published Aug. 28 in Lancet Neurology provide long-term data showing that for patients with carotid stenosis, endarterectomy could be a better option than balloon angioplasty with or without stenting (endovascular treatment). 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.
Lead author of both studies Martin M Brown, PhD, from University College London and the National Hospital for Neurology and Neurosurgery in London, and colleagues from the CAVATAS investigators group noted that carotid atherosclerosis causes about 20 percent of all strokes and the narrowing is severe enough to warrant surgery in 5-10 percent of stroke and transient ischemic attack (TIA) patients.
While studies comparing surgery and endovascular treatment have been published, the authors said that none has provided long-term follow-up data on the risks of the procedures. 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 (251 patients) or endovascular treatment (253).
The researchers found that within 30 days of treatment, there were more minor strokes that lasted less than seven days in the endovascular treatment group (eight) than in the surgery group (one). Following the 30-day perioperative period, they found an eight-year incidence of ipsilateral stroke was higher in the endovascular treatment group (11.3 percent) than the surgery group (8.6 percent).
The combined endpoint of stroke or TIA also occurred more in the endovascular treatment group (19.3 percent) than the surgery group (17.2 percent). “However, none of the post-operative differences in stroke outcomes was statistically significant,” researchers wrote.
Based on their findings, the authors concluded that “[m]ore 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 study examined patients who had been followed for a median of five years, and who had had a neck ultrasound to examine the carotid artery for restenosis at annual intervals. They found that the estimated incidence of severe restenosis (70 percent or more) was three times more likely in the endovascular group than in the surgery group: 31 percent versus 10 percent.
Brown and colleagues found that patients whose endovascular treatment involved stenting rather than just angioplasty alone were less than half as likely to develop restenosis; while those who smoked were more than twice as likely to develop severe restenosis 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 percent) than those with no restenosis (11 percent).
Based on the results of this study, the CAVATAS investigators concluded that restenosis is approximately “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 revascularization."
In an accompanying commentary, Peter M Rothwell, PhD, from John Radcliffe Hospital in Oxford, England, wrote that a “meta-analysis of all the available data on long-term outcome in randomized trials of endovascular treatment versus endarterectomy for symptomatic carotid stenosis now shows a significantly worse outcome after endovascular treatment.”
He said that 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 general anesthetic versus local anesthetic for carotid surgery trial—that endarterectomy can be done at least as safely under local anesthetic as it is under general anesthetic—should influence patients' preferences."