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Brain Trauma Stroke


More recent prospective cohorts of medically treated patients with asymptomatic carotid stenosis have reported much lower stroke rates than these trials. A review of data collected from 11 studies showed that the average annual rates of ipsilateral or any other ischemic stroke in asymptomatic severe carotid stenosis fell significantly in the last three decades with medical management alone.34


It remains unknown whether


modern aggressive medical management would be better than, or equivalent to, revascularization in asymptomatic carotid stenosis, but it is an area which is gaining attention. Finally, it may be possible to identify patients at higher risk of stroke who then may be most likely to benefit from revascularization. Based upon the ACST study, progression of carotid atherosclerosis on serial Doppler ultrasound studies is associated with increased risk of first stroke.35


Furthermore, though not routinely


available at every hospital, prolonged microembolic signal detection with transcranial Doppler (TCD) ultrasound has been validated in a multicenter study to accurately stratify high- and low-risk patients with asymptomatic carotid stenosis.36


In summary, CEA can be recommended in men who have a life expectancy of at least five years with asymptomatic carotid stenosis of 60–99 %, provided the peri-operative risk of stroke and death is <3 %. In women, carotid revascularization can be considered, particularly if they are younger and have a low expected peri-procedural risk.


Carotid Angioplasty and Stenting in Asymptomatic Carotid Stenosis— Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy Besides CREST, as discussed earlier, another study that looked into the utility of CAS in asymptomatic patients was the Stenting and angioplasty with protection in patients at high risk for endarterectomy (SAPPHIRE) trial. SAPPHIRE randomized 334 high-surgical-risk patients to receive CAS with emboli protection device or endarterectomy to test the hypothesis that CAS was not inferior to endarterectomy. These patients had symptomatic carotid stenosis of ≥50 % or asymptomatic carotid stenosis of ≥80 %; however, more than 70 % of patients had asymptomatic carotid disease.37,38


Patients were considered high risk for


revascularization based upon age >80, pulmonary or cardiac disease, prior neck surgery, or radiation. The primary endpoint of the cumulative incidence of a major cardiovascular event at one year, which included a composite of peri-procedural death, stroke, or MI (within 30 days after the procedure), and/or death or ipsilateral stroke between 31 days and one year, was 12.2 % for CAS compared with 20.1 % for CEA (absolute difference 7.9 %, 95 % CI -0.7–16.4 %).


In the analysis of symptomatic patients with carotid stenosis (30 % in the CAS and 28 % in the endarterectomy group), the cumulative incidences of the primary endpoint at 30 days, and also one year, in both groups were non-significantly different (2.2 versus 9.3 %, p=0.18 at 30 days, and 16.8 versus 16.5 %, p=0.95 at one year). For patients with asymptomatic carotid stenosis (70 % in the CAS and 72 % in the endarterectomy group), the cumulative incidence of the primary endpoint in the peri-procedural period was 5.4 versus 10.2 % (p=0.20) in the CAS and CEA groups, respectively. SAPPHIRE hinted that CAS is not inferior to CEA in high-risk


patients, namely with contralateral carotid occlusion, neck irradiation, prior neck surgery, severe cardiac/pulmonary disease, recurrent stenosis post-CEA, and age more than 80 years.39


In patients ≥80 years old, a meta-analysis of 41 studies of either CEA or CAS showed that the stroke rate was significantly higher for CAS compared with CEA (7.0 versus 1.9 %); the relative risks of death or MI at 30 days were fairly similar.40


As mentioned above, half of the patients included in the CREST study had an asymptomatic carotid revascularization. For these patients, the stroke and death rates were 2.5 ± 0.6 % for CAS and 1.4 ± 0.5 % for CEA (HR 1.88, 95 % CI 0.79–4.42, p=0.15).


Conclusions


The decision to recommend carotid revascularization, by what method, and in what timeframe, needs to be done on an individual basis depending on specific patient characteristics and the availability of surgeons and interventionists with a high volume of procedures and a track record with an acceptable complication rate. The accompanying tables provide the current recommendations from the American Heart Association regarding carotid revascularization (see Tables 1 and 2). Clearly, the vast majority of patients with symptomatic carotid stenosis of 70–99 % will benefit from revascularization, which should be carried out as soon as possible, assuming that the first event was not a major stroke. In this setting, it appears that CEA is more beneficial compared with CAS when the lesion is surgically accessible. CAS may be a reasonable option in this setting if the lesion is surgically inaccessible, if there is restenosis post-CEA, radiation-induced stenosis, or underlying comorbidities increasing surgical risk, assuming that the expected peri-procedural risk remains less than 6 %.


CEA does offer benefit, compared with medical treatment, for asymptomatic carotid stenosis ranging between 60 and 99 %, provided the life expectancy goal of five years is met and the combined peri-operative risk of stroke or death associated with the procedure is less than 3 %, though the benefit is greater in men compared with women. Based on the most recent data from CREST, CAS may be a reasonable choice in patients with an asymptomatic stenosis, particularly for younger men.


Lastly, it is important to bear in mind that the trials comparing medical therapy with CEA were designed and implemented over the last three decades. During this time, there have been significant changes in medical management for the prevention of stroke. With the advent of newer antiplatelet agents, more powerful statins with more aggressive lipid goals, use of non-beta-blocker blood pressure medications with more aggressive goals, decreased prevalence of smoking, and increased awareness of diet and exercise, there is ample evidence that the risk of stroke from an otherwise asymptomatic carotid stenosis is less than the risk seen in prior CEA studies. In some patients with asymptomatic stenosis, aggressive medical management alone rather than CEA could be offered with serial non-invasive imaging studies to ensure that the stenosis is not progressing. Microembolic signal detection with TCD may also help to risk-stratify asymptomatic patients. n


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US NEUROLOGY


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