Interventional Neuroradiology

confidence interval from 10 to 50%. Although this relative reduction in stroke risk seems impressive, the absolute benefit is small because the risk of stroke without surgery for asymptomatic stenosis is so low. It is necessary to operate on 50 patients to prevent one stroke, implying a perioperative complication rate of 2%. This is not always achievable, even in the best hands. Charles Warlow, in a BMJ editorial in 1998 [33], concludes that for most patients receiving average treatment, the argument is against surgery for asymptomatic carotid stenosis. This argument is easily extrapolated to carotid angioplasty plus or minus stenting.

There are many disadvantages to conventional surgery apart from the perioperative stroke risk. Risks include myocardial infarction, pulmonary embolism, pneumonia, deep vein thrombosis, the side effects of anesthesia and the discomfort of intubation. Cranial nerve palsy also carries risks of significant morbidity, particularly involving the hypoglossal nerve. One of these complications affects at least 10% of patients after carotid endarterectomy.

Whether percutaneous transluminal angio-plasty (PTA) plus or minus stenting of the carotid has a place in the routine management of carotid atherosclerosis is still very controversial. There is need for further, ideally randomized, trials between surgery and endovascular treatments. Primary stenting is favored over angioplasty. PTA plus or minus stenting for carotid stenosis has the great advantage of being performed under local anesthesia, avoiding the perils of general anesthesia and the discomfort of an incision in the neck. Carotid angioplasty and stenting can be performed under minimal neuroleptic analgesia and, apart from occasional transient pain on inflation of the balloon, the discomfort of a successful angioplasty is no more than that associated with routine angiography. The patient can be discharged after 24 hours or, in some centers, if the patient is fit, the procedure can be performed as a day case.

The only randomized clinical trial to investigate the risks and benefits of PTA for carotid stenosis in comparison with conventional surgery, the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), finished in 1997 [33a]. The trial randomized over 500 patients between surgery and angio-plasty between 1992 and 1997. There was no significant difference in the risk of stroke or death related to the procedure between surgery and angioplasty. The rate of any stroke lasting more than 7 days or death within 30 days of first treatment was approximately 10% in both the surgery and endovascular groups. Preliminary analysis of long-term survival showed no difference in the rate of ipsilateral stroke or any disabling stroke in patients up to 3 years after randomization. In CAVATAS, the rates of stroke and death within 30 days in both groups are higher than those reported in the literature but not significantly different from ECST (rate of 7.5%). Long-term follow up is not yet available. Hopefully, centers will continue to follow up CAVATAS-enrolled patients. Long-term 5-year outcome data for angioplasty are scant in the literature. Only when we know how good endovascular treatment is at preventing stroke and death will we be truly able to recommend it.

New randomised trials comparing carotid stenting with carotid endarterectomy are currently ongoing during 2004: the Carotid Revas-cularisation Endarterectomy versus Stent Trial (CREST) in North America; the Endarterectomy versus Angioplasty in Patients with Severe Symptomatic Carotid Stenosis (EVA-3S) in France; the Stent Protected Percutaneous Angioplasty versus Carotid Endarterectomy (SPACE) in Germany and Austria; the follow-up to the CAVATAS trial, the International Carotid Stenting Study (ICSS) (CAVATAS2 International). It is hoped when these series are analysed that we will be able to have more information as to whether stenting is both as efficacious and durable as carotid endarterectomy. With respect to published series, complication rates from angioplasty and stenting vary from 0-70%. However, data from several series of over 500 patients give a similar risk of stroke and death during carotid PTA as that found as a result of carotid endarterectomy in NASCET and ECST. The mean stroke rate at the time of procedure for these series was 1.5% for minor or non-disabling stroke and 2.1% for major stroke or death, resulting in an overall stroke rate of 3.6%.

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