New Guidelines for the Management of Extracranial Carotid Arterial Disease
Abstract & Commentary
By Harold L. Karpman, MD, FACC, FACP, Clinical Professor of Medicine, UCLA School of Medicine. Dr. Karpman serves on the speakers bureau for Forest Laboratories.
Synopsis: Duplex ultrasonography should be used in asymptomatic patients with known or suspected carotid arterial stenosis and should be considered for use in asymptomatic patients who have symptomatic peripheral arterial disease, coronary artery disease, or an atherosclerotic aortic aneurysm, and even in the asymptomatic patients who simply are at high cardiovascular risk.
Source: Brott TG, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS Guideline on the management of patients with extracranial carotid and vertebral artery disease: Executive summary. Circulation 2011;124:489-532.
The american college of cardiology foundation (ACCF) and the American Heart Association (AHA) have been jointly engaged in creating guidelines for cardiovascular disease since 1980. The 2011 update on the management of patients with extracranial carotid and vertebral artery disease1 includes contributions by members of the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, Society for Vascular Surgery, American Academy of Neurology, and Society of Cardiovascular Computed Tomography. The writing Task Force developed graded evidence-based recommendations using previously accepted and standardized techniques.2
The guidelines strongly recommend the use of duplex ultrasonography in asymptomatic patients with known or suspected carotid arterial stenosis and also indicated that its use should be considered to detect carotid arterial stenosis in asymptomatic patients who have symptomatic peripheral arterial disease, coronary artery disease, or an atherosclerotic aortic aneurysm, and even in the asymptomatic patients who simply are at high cardiovascular risk. Duplex ultrasonography is also recommended as the initial evaluation of patients with focal transient retinal or hemispheric neurological symptoms and the guidelines also recommend that magnetic resonance angiography (MRA) or computed tomography angiography (CTA) should be performed to detect carotid stenosis when sonography either cannot be obtained or yields equivocal or otherwise nondiagnostic results.
With respect to the recommendations for selection of patients for carotid revascularization, the guidelines recommend that patients at average or low surgical risk who have experienced nondisabling ischemic stroke or transient cerebral ischemic symptoms, including hemispheric events or amaurosis fugax, should undergo carotid endarterectomy (CEA) within 6 months of the episode if the diameter of the ipsilateral internal carotid artery is reduced by more than 70% on noninvasive imaging or by more than 50% on catheter angiography. Carotid arterial stenting (CAS) is recommended as an alternative to CEA for symptomatic patients who have an average or low risk of complications associated with endovascular intervention. The selection of asymptomatic patients for carotid revascularization should be guided by an assessment of the patient's comorbid conditions, life expectancy, and other individual factors involved in that patient's overall medical condition. It is considered reasonable to select CEA over CAS when revascularization is indicated, even in older patients when the arterial phleboanatomy is unfavorable for endovascular intervention and to select CAS over CEA when revascularization is indicated in patients whose neck anatomy is unfavorable for arterial surgery. Carotid revascularization is not recommended when the atherosclerotic lesion narrows the lumen by less than 50%, when the carotid artery is totally occluded on a chronic basis, or for patients with severe disability caused by cerebral infarction that precludes preservation of useful function.
Aspirin (81-325 mg daily) is recommended before a CEA and may be continued indefinitely postoperatively. After the first month following surgery, drug recommendations are that aspirin (75 to 325 mg daily), clopidogrel (75 mg daily), or a combination of low-dose aspirin plus extended-release dipyridamole (25 and 200 mg) twice daily should be administered for long-term prophylaxis against ischemic cardiovascular events. Before and after either CEA or CAS, antihypertensive medication is recommended if needed for control of blood pressure; smoking cessation should be recommended; diabetes should be carefully controlled; and the administration of statin lipid-lowering medication for prevention of ischemic events is reasonable irrespective of the serum lipid levels. The use of embolic protection devices during CAS can be beneficial to reduce the risk of stroke even when the risk of vascular injury is low. Noninvasive imaging of the extracranial carotid arterial system is reasonable 1 month, 6 months, and annually after revascularization to assess patency and exclude the development of new or contralateral lesions.
In patients with neurological symptoms referable to the posterior circulation and in those with a subclavian steal syndrome, noninvasive imaging by CTA or MRA rather than ultrasound imaging is appropriate for the initial evaluation for the detection of significant vertebral artery disease. If detected, vertebral artery atherosclerosis should be treated with lifestyle modification and medical therapy similar to the therapy administered to patients with extracranial carotid atherosclerosis.
Commentary
In summary, the 2011 Guideline on the Management of Patients with Extracranial Carotid and Vertebral Artery Disease1 is an extensive document written by a Task Force of 14 major cardiovascular organizations. The Task Force evaluated 368 references before writing the executive summary which is extremely thorough and has much more detail than could be included in this brief summary. Clinicians are strongly advised to consult this document for the more detailed recommendations of the Task Force.1
References
1. Brott TG, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS Guideline on the Management of Patients with Extracranial Carotid and Vertebral Artery Disease: Executive Summary. Circulation 2011;124:489-532.
2. ACCF/AHA. Task Force on Practice Guidelines. Manual for ACCF/AHA Guideline Writing Committees: Methodologies and Policies from the ACCF/AHA Task Force on Practice Guidelines. Available at: http://assets.cardio source.com/Methodology_Manual_for_ACC_AHA_Writing_Committees.pdf and http://circ.ahajournals.org/manual/. Accessed Oct. 1, 2011.