By Adnan H Siddiqui, Elad I Levy, L Nelson Hopkins and Kenneth V Snyder
Our group of Neurosurgery at University at Buffalo, New York, USA, has been performing carotid endarterectomy for more than 30 years and carotid artery stenting since 1994. We have participated in virtually all carotid artery stenting trials in the USA and have been co-principal investigators or executive committee members for most. Our experience includes over 2000 carotid endarterectomy and 3000 carotid artery stenting procedures. The largest and most comprehensive randomised trial to date has been the CREST trial (Carotid revascularisation endarterectomy vs. stenting), which demonstrated equivalence overall with more minor strokes with carotid artery stenting and more myocardial infarctions with carotid endarterectomy, in spite of first-generation technology and limited experience. Myocardial infarction had a significant impact on long-term mortality, as did major stroke. Patients with minor strokes after carotid artery stenting improved significantly at six and 12 months, and these strokes did not have an impact on long term-survival. Moreover, CREST commenced only six years after carotid artery stenting was first performed in the USA. Carotid artery stenting results improved in the latter half of the trial as experience and judgment improved. So what have the trials taught us about the usefulness of carotid artery stenting?
Experience and judgment are important. Experience must be significant(performance of >70 cases) for patients to benefit, according to the analysis of the CAPTURE 2 data (Carotid ACCULINK/ACCUNET post approval trial to uncover rare events) conducted by Gray and colleagues. Embolic protection adds benefit given the over 20% stroke rate when embolic protection cannot be used in carotid artery stenting. Younger patients (<68 years) seem to fare better with carotid artery stenting in CREST although experience suggests that if care is taken to avoid tortuous arch or carotid anatomy, elderly patients fare well with carotid artery stenting. Again, judgment counts.
Recent neurologic symptoms and hypoechoic plaques on ultrasound are often associated with plaque rupture with plaques containing resolving haematoma (liquid material) and fresh clot, and affected patients seem better with carotid endarterectomy in most trials. However, recent carotid artery stenting studies with proximal embolic protection have shown better results and less magnetic resonance imaging abnormalities postprocedure. Cranial nerve abnormalities occurred in 5% of carotid endarterectomies. Carotid artery stenting may be preferable in patients with existing cranial nerve injuries, for example, those with vocal cord paresis from previous carotid endarterectomy.
Patients with high-risk features for carotid endarterectomy, such as significant medical comorbidities, recurrent stenosis, poor collateral circulation, and surgically ‘inaccessible’ lesions (for example, distal plaque extension or obese endomorphic body habitus), all appear to benefit from carotid artery stenting, that is, avoidance of carotid endarterectomy.
What is especially encouraging about our experience so far is the fact that carotid artery stenting seems to nicely complement carotid endarterectomy in most cases where carotid endarterectomy poses increased risk.Carotid artery stenting is as durable and protective (from stroke) and has similar restenosis rates compared with carotid endarterectomy. Given favourable anatomy, carotid artery stenting under local anaesthesia is faster with less impact on patient physiology and results in earlier discharge (usually 24 hours) than carotid endarterectomy, which is usually performed under general anaesthesia. Decision-making at our weekly multidisciplinary peer review conference is usually straightforward when we look at the various pros and cons. Carotid endarterectomy is a good procedure and patients and physicians are at a serious disadvantage when both procedures are not available.
L Nelson Hopkins is professor and chairman of Neurosurgery and professor of Radiology School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
Elad I Levy is professor of Neurosurgery and Radiology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
Adnan H Siddiqui is professor of Neurosurgery and Radiology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
Kenneth V Snyder is assistant professor of Neurosurgery, Radiology, and Neurology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.