Future management of carotid stenosis: role of urgent carotid interventions in the acutely symptomatic carotid patient and best medical therapy for asymptomatic carotid disease

Abstract

Background: Stroke is the fourth leading cause of death in the United States, leading to devastating disability. Most strokes are ischemic, and nearly one-third of these are caused by carotid disease. The primary mechanism of carotid-related stroke is an atheroembolic event from an unstable atherosclerotic plaque rupture. In the 1990s, randomized trials demonstrated the benefit of carotid endarterectomy (CEA) in reducing the risk of stroke in both symptomatic and asymptomatic carotid disease.

Methods: We review best medical therapy (BMT) for asymptomatic carotid disease and recent randomized trials comparing CEA and carotid angioplasty stenting (CAS), and we discuss the role of urgent carotid interventions in patients with acute neurologic symptoms.

Results: In 2010, 2 large trials demonstrated the efficacy of CAS in select patients, although CAS was associated with an increased procedural stroke risk compared to CEA. An age effect was observed; patients >75 years do worse with CAS compared to CEA. As BMT has evolved in the past decade, a future trial (CREST-2) will address whether BMT is equal to intervention (CEA or CAS) in asymptomatic carotid disease. In a subgroup of patients with asymptomatic carotid disease, CEA plus BMT will likely remain the mainstay therapy for carotid disease compared to BMT alone. CEA and CAS will continue to play complementary roles in the future, as CAS will be done in select patients in whom CEA cannot be undertaken because of high-risk anatomical or medical conditions. Finally, a role for urgent carotid interventions in a select group of patients who present with acute neurologic symptoms is developing as a way to prevent recurrent stroke after an initial carotid plaque rupture event.

Conclusion: CAS has an increasingly higher risk of stroke with advancing age. Patients treated with CAS have a 1.76-fold increased risk of stroke (95% CI, 1.35-2.31) with each 10-year increase in age. No such age effect is seen in patients treated with CEA. Age is a critical variable in making informed choices regarding treatment of severe carotid artery stenosis.

Keywords: Carotid angioplasty stenting; carotid disease; carotid endarterectomy; carotid stenosis.

Figure 1.

Algorithm for the management of >50% carotid stenosis. Carotid endarterectomy (CEA) may be undertaken safely in the majority of asymptomatic and symptomatic patients. In symptomatic disease, if stenosis is <50% and all other sources of cerebral ischemia have been ruled out, best medical therapy should be utilized. However, if the symptoms recur (such as in cases with an ulcerated carotid plaque), a CEA may be undertaken. *An ultrasound is the preferred way to image asymptomatic carotid and symptomatic carotid stenosis, and computed tomography angiography (CTA) is not recommended routinely for imaging the patient with asymptomatic disease unless an intervention is planned; in these cases, an ultrasound may suffice prior to CEA. CAS, carotid angioplasty stenting; MRI/MRA, magnetic resonance imaging/magnetic resonance angiography (of the head and neck).

Figure 2.

Magnetic resonance imaging demonstrates several small foci of restricted diffusion within the right occipital, parietal, and frontal lobes compatible with small areas of embolic infarction.

Figure 3.

A computed tomography perfusion scan shows increased mean transit time and decreased blood flow with maintained blood volume involving the majority of the right cerebral hemisphere, suggesting possible ischemic penumbra from slow vascular blood flow. No evidence suggests significant core infarction. There is relative sparing of the right anterior cerebral artery territory likely via collateral flow from the anterior communicating artery.

Figure 4.

A sagittal representative computed tomography angiography image of the left internal carotid artery shows an atherosclerotic plaque resulting in high-grade 90% stenosis approximately 1.5 cm distal to the bifurcation and spanning a distance of approximately 3.5 cm along the vessel course. Superimposed thrombus is also noted in this region.