Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Carotid Artery Revascularization
The management of carotid artery disease remains a topic of current investigation and vigorous debate regarding optimal treatments. Multiple prospective randomized controlled trials have compared the standard therapies, which include carotid endarterectomy (CEA), carotid artery stenting (CAS), and best medical therapy (BMT). In addition, hybrid procedures to treat carotid artery stenosis have been added to the therapeutic armamentarium. This chapter focuses on the evidence base, clinical decision making, and outcomes of the carotid revascularization techniques.
Indications for Carotid Revascularization
Symptomatic Patients
Based on the latest multisociety evidence-based guidelines, CEA is recommended as first-line treatment for most symptomatic patients with 50% to 99% internal carotid artery (ICA) stenosis. CAS is recommended for symptomatic patients with 50% to 99% stenosis who, for anatomic or medical reasons, are at high risk for CEA ( Box 31.1 ). BMT alone is recommended for patients with symptomatic ICA stenosis < 50%. The timing of carotid revascularization in symptomatic patients remains controversial. Concern over recurrent stroke following the initial event has resulted in a push toward early revascularization within 48 hours following initiation of symptoms. This is especially true for patients with stroke or profound symptoms of a transient ischemic attack (TIA). In contrast, the natural history of amaurosis fugax appears to be more benign. Patients who present with large infarcts on cerebral imaging, profound neurological impairment, or hemorrhage within the infarct should be considered for delayed revascularization between 2 and 14 days following initial presentation.
BOX 31.1
High-Surgical-Risk Criteria for Carotid Endarterectomy
-
Previous carotid endarterectomy
-
Previous neck dissection
-
Radiation therapy
-
Presence of stoma (tracheostomy/esophagostomy)
-
Lesion above second cervical vertebra (C2)
-
Contralateral cranial nerve injury
Asymptomatic Patients
CEA is recommended for patients with 70% to 99% asymptomatic ICA stenosis if the patient’s perioperative stroke and death rate is less than 3% and if the patient has at least a 3- to 5-year life expectancy. The use of CAS to treat asymptomatic patients is controversial. Currently CAS for asymptomatic patients is not reimbursed by Medicare outside of an Investigational Device Exemption (IDE)–approved clinical trial. However, CAS is frequently performed for asymptomatic patients at high anatomic risk for CEA. In addition, there are several large randomized trials demonstrating that CAS can be performed with a stroke and death rate of < 3% in standard-risk asymptomatic patients. The most representative is the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) ( Table 31.1 ). BMT alone is recommended for patients with asymptomatic stenosis of < 70% who are at high risk for intervention or with a life expectancy of < 3 years.
Table 31.1
CREST Study Results for Asymptomatic Patients
| CAS | CEA | P | |
|---|---|---|---|
| MI | 7 (1.2%) | 13 (2.2%) | .2 |
| All stroke | 15 (2.5%) | 8 (1.4%) | .15 |
| Major stroke | 3 (0.5%) | 2 (0.3%) | .66 |
| Minor stroke | 12 (2.0%) | 6 (1.0%) | .15 |
| Stroke + death | 15 (2.5%) | 8 (1.4%) | .15 |
| Stroke/death/MI | 21 (3.5%) | 21 (3.5%) | .96 |
CAS , Carotid artery stenting; CEA , carotid endarterectomy; CREST , Carotid Revascularization Endarterectomy Versus Stenting Trial; MI , myocardial infarction.
Last, the current data that inform decision making regarding the treatment of asymptomatic patients is dated and do not include rigorous BMT―using statins, improved blood pressure control, and antiplatelet therapy―which would be considered the current standard of care. Indications for when to perform CEA and when to perform carotid stent placement are discussed in greater detail below.
Preoperative Management
The perioperative guidelines of the American Heart Association (AHA) classify CEA as an intermediate-risk procedure. Preoperative cardiac assessment in patients undergoing CEA commonly includes a 12-lead electrocardiogram (EKG). Additional testing, such as a nuclear perfusion scans or dobutamine stress echocardiography, is based on the patient’s clinical profile, including the lesion’s risk for cardiovascular complications and stroke. It is recommended if the patient has three or more clinical risk factors (coronary artery disease [CAD], history of heart failure, diabetes mellitus, renal insufficiency), more in-depth cardiac risk assessment be considered. This is especially true for asymptomatic patients with critical carotid stenosis where the absolute risk reduction of stroke is lower than that in symptomatic patients. In a prospective trial, no medications have been shown to reduce perioperative outcomes. The preoperative medical management of patients undergoing CEA should include the chronic treatment for atherosclerosis, such as a statin. Interestingly in the PeriOperative ISchemic Evaluation-2 (POISE-2) trial, the addition of aspirin did not reduce adverse cardiovascular events in patients undergoing vascular surgery. Initiation of β-adrenergic blocking agents is not recommended either. However, if a patient is taking these agents they should not be discontinued, because withdrawal of a β-blocker is associated with an increase in cardiovascular events.
β-Blockers
According to the 2014 Clinical Practice Guidelines of the AHA and the American College of Cardiology, including data from 17 studies (16 randomized controlled trials), perioperative β-blockade started within 1 day or less before noncardiac surgery decreases nonfatal myocardial infarction (MI) but increases the risks of stroke, death, hypotension, and bradycardia. The current recommendation is to continue β-blockade in patients who are already on a β-blocker. There is a weak recommendation to start β-blockade in patients with a history of CAD or more than one clinical risk factor.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here