ATHEROSCLEROTIC DISEASE OF THE CAROTID ARTERIES
Cerebrovascular accident (CVA) is the third leading cause of death in the United States, surpassed only by heart disease and malignancy.1 Stroke accounts for 10% to 12% of all deaths in industrialized countries. Almost one in four men and one in five women aged 45 years can expect to have a stroke if they live till 85 years of age. In a population of 1 million, 1600 people will have a stroke each year. Only 55% of these will survive 6 months, and a third of the survivors will have significant problems caring for themselves. As our population ages, the total number of people afflicted with stroke will continue to rise unless historic stroke rates decline in the future.2
The etiology of stroke is multifactorial. Ischemic stroke accounts for approximately 80% of all first-ever strokes, while intracerebral hemorrhage and subarachnoid hemorrhage are responsible for 10% and 5%, respectively. Of those strokes which are ischemic in nature, the majority are linked to complications of atheromatous plaques. The most frequent site of such an atheroma is the carotid bifurcation. Although the prevention of stroke in the general population has largely focused on the control of hypertension, a substantial number of strokes are preventable by the identification and treatment of carotid disease especially as the population ages.
Surgical endarterectomy of high-grade carotid lesions, both symptomatic and asymptomatic, has been identified as the treatment of choice for stroke prophylaxis in most patients when compared to "best medical therapy" (risk factor reduction and antiplatelet agents), as shown convincingly by the NASCET and ACAS studies.3,4 More careful inspection of their respective results suggest that the risk of disabling stroke or death was 1.9% in NASCET, with a 3.9% risk of minor stroke. In ACAS, the risk of major stroke or death was 0.6% when one excludes the 1.2% risk of stroke caused by diagnostic arteriography (Table 24-1). Subsequently, carotid endarterectomy (CEA) has been performed in increasing numbers of patients, and now represents the most frequent surgical procedure performed by vascular surgeons. Despite the proven efficacy of CEA in the prevention of ischemic stroke, great interest has been generated in carotid angioplasty and stenting (CAS) as an alternative to surgical therapy. This chapter will examine the current role of CEA in the treatment of patients with stenosis of the cervical carotid arteries, will analyze the concept of "high-risk" CEA, and will discuss the evolving role of CAS.
TABLE 24-1.Results of CEA for Symptomatic and Asymptomatic Carotid Stenosis ||Download (.pdf) TABLE 24-1. Results of CEA for Symptomatic and Asymptomatic Carotid Stenosis
| ||Mortality (%) ||Disabling Stroke (%) ||Minor Stroke (%) |
|Symptomatic disease |
| NASCET I† (>70% stenosis) ||0.6 ||1.3 ||3.9 |
| NASCET II‡ (50%–69% stenosis) ||1.2 ||1.6 ||4.0 |
|Asymptomatic disease |
| VA asymptomatic§ (>50% stenosis)...|