Managing carotid stenosis to prevent stroke

Author(s): Pamela Anderson, MSN, APN-BC, RN, CCRN; Terri Townsend, MA, RN, CCRN-CMC, CVRN, CMSRN; and Jennifer Schneider Davis, DNP, APRN-BC

Watch for warning signs to reduce risk.

Takeaways:

  • Approximately 87% of all strokes are ischemic, with 30% directly attributed to atherosclerosis of the internal carotid artery.
  • Within the first 3 months after a transient ischemic attack (TIA), 10% to 15% of patients will have a stroke, half of which occur within 48 hours of the initial TIA.
  • Modifiable risk factors associated with stroke include diabetes, obesity, lack of exercise, and smoking.

JAMES SMITH*, a 65-year-old white man, presents to his primary care provider (PCP) with symptoms consistent with a transient ischemic attack (TIA). He has had three transient episodes of left-eye blindness in the past 2 weeks and today experienced a fourth episode accompanied by right-arm numbness that lasted 30 minutes. Mr. Smith’s past medical history includes coronary artery disease, diabetes mellitus, tobacco use, and hypertension.

The PCP tells Mr. Smith that he may have had several TIAs and is at risk for a stroke. Mr. Smith is sent to the emergency department (ED), where the ED physician orders a carotid ultrasound (to evaluate for carotid stenosis), magnetic resonance imaging (MRI) of the brain (to assess for ischemia or infarct), electrocardiogram (to assess for cardiac arrhythmia), and lab work. The ED physician reviews Mr. Smith’s medication list, ensuring that he’s currently taking anti-platelet and statin therapy. The MRI is negative for a stroke, but Mr. Smith’s carotid duplex reveals velocities consistent with a critical carotid stenosis. Mr. Smith’s TIA symptoms are attributed to the stenosis, and he’s referred to a vascular surgeon who initiates dual anti-platelet therapy. The American Heart Association/American Stroke Association (AHA/ASA) recommends starting dual anti platelet therapy within 24 to 48 hours after a TIA and continuing these medications for 21 days. After 21 days, clopidogrel is continued for 90 days for secondary . prevention. As Mr. Smith has both carotid and coronary artery disease, he’ll continue lifelong antiplatelet therapy.
*Name is fictitious 

Carotid stenosis research

In an 8-year study on the prevalence and risk factors of asymptomatic carotid artery stenosis, Kaul and colleagues determined that carotid artery atherosclerosis is a major risk factor for stroke. Hypertension and diabetes also were noted as significant risk factors; 56% of participants with hypertension had a 2.5 times increased risk of ICA stenosis, and 55% of those with diabetes for 15 years or longer had a 6.2 times increased risk.

Baradaran and colleagues studied silent brain infarctions in patients with asymptomatic carotid artery atherosclerotic disease who had unilateral ICA stenosis of 50% or more. Their retrospective analysis of MRI or computed tomography images found that one-third of participants had evidence of silent brain infarctions on the same side as the ICA stenosis. The researchers state that their findings suggest atherosclerotic ICA stenosis is associated with an increased incidence of embolic occlusion in the anterior cerebral circulation. In addition, patients may report lack of carotid stenosis symptoms, but may have suffered at least one small, silent brain infarction. The researchers recommended examining the current treatment guidelines to evaluate if targeted therapy can decrease the risk of stroke. The results of this study indicate the importance of treating patients with carotid stenosis whether or not they have symptoms.

A review by Rubin and colleagues of several randomized controlled trials of carotid stenosis and stroke risk demonstrated that surgical intervention (carotid endarterectomy) provided effective secondary prevention in patients with more than 50% stenosis. However, the same report found that in asymptomatic patients with severe stenosis, endarterectomy effectiveness was significantly less than in symptomatic patients.

Stroke stats

In the United States, stroke is the principle cause of permanent long-term disability and is responsible for significant financial burden.

Approximately 7.2 million American adults experience a stroke within their lifetime (2.7% of the population, or one stroke every 40 seconds).
One of every 19 deaths is attributed to stroke.
Mobility is decreased in over 50% of individuals over 65 years old who survive a stroke.
An estimated $34 billion is spent annually on healthcare costs, medications, and missed work related to stroke.

Sources:
Centers for Disease Control and Prevention. Division for Heart Disease and Stroke Prevention: Stroke fact sheet. September 2017. cdc.gov/dhdsp/data_statistics/fact_sheets/fs_stroke.htm

Mozaffarian D, Benjamin EJ, Go AS, et al. Heart disease and stroke statistics—2016 update. Circulation. 2015;133(4):e38-e360. ahajournals.org/doi/full/10.1161/cir.0000000000000350#

TIA as warning sign

A TIA is a brief episode of neurologic deficit resulting from cerebral or retinal ischemia without evidence of cerebral infarction. The ASA calls a TIA a “warning stroke.” Within the first 3 months after a TIA, 10% to 15% of patients will have a stroke, half of which occur within 48 hours after the initial TIA, according to Khare and colleagues.

Because TIA symptoms typically resolve quickly, they’re frequently ignored, but this early warning sign of stroke should be taken seriously. An online AHA/ASA survey revealed that up to one-third of adults in the United States had experienced a TIA symptom but only 3% sought medical assistance. Public knowledge of TIA symptoms and recommended treatments may help reduce the financial burden and physical impairment from stroke caused by ICA stenosis.

Typical symptoms of a TIA or stroke resulting from carotid disease include amaurosis fugax (temporary monocular blindness caused by an embolus in the retinal artery), arm or leg weakness or paralysis, facial paralysis, or speech difficulties (slurred words or an inability to speak). Retinal examination can reveal Hollenhorst plaque (atherosclerotic embolus from the carotid arteries or the aorta). Dizziness, vertigo, and syncope are not caused by carotid stenosis and aren’t considered carotid occlusive disease symptoms. Patients with TIA symptoms should seek evaluation in the ED to help identify the cause of the TIA so that risk factors can be addressed and appropriate treatment initiated.

Carotid endarterectomy

Mr. Smith’s vascular surgeon reviews his ultrasound and recommends a computed tomography angiography (CTA) to confirm the findings and prepare for surgery. The CTA confirms the critical left ICA stenosis, and the surgeon recommends a left carotid endarterectomy to decrease future stroke risk.

Carotid endarterectomy is recommended for patients who have symptoms of a TIA or stroke and ultrasound or CTA evidence of carotid stenosis in the 70% to 99% range and for patients with asymptomatic carotid stenosis that’s 80% or more. The guidelines for carotid endarterectomy for symptomatic patients are endorsed by the AHA/ASA when the risk of mortality or perioperative stroke is less than 6% and for asymptomatic patients when stroke risk and perioperative mortality is less than 3%. The degree of internal carotid artery stenosis that a surgeon uses when deciding to perform a carotid endarterectomy may vary from one institution to another.

Postoperative monitoring

Mr. Smith undergoes the left carotid endarterectomy and is transferred to the intensive care unit (ICU) for postoperative care, which includes monitoring for complications.

After surgery, patients are at risk for several conditions and require close monitoring. Because the carotid baroreceptors are located near the carotid sinus (superior to the carotid bifurcation and site of a carotid endarterectomy), hypertension or hypotension may occur i the early postoperative period. Patients also may be at risk for intraoperative or postoperative stroke caused by embolization from disrupted plaque or a blood clot traveling to the brain from the carotid artery. Neurovascular assessment and vital signs are monitored to prevent hypertension (systolic blood pressure > 180 mmHg) and hypotension (systolic blood pressure < 90 mmHg or mean arterial pressure < 65 mmHg) according to guidelines from the Society for Vascular Nursing.

Other complications associated with carotid endarterectomy include neck hematoma, suture disruption, cerebral reperfusion syndrome, airway compromise, and cranial nerve injuries. Adequate control of hypertension can reduce the risk of neck hematoma, suture disruption, cerebral reperfusion syndrome, and airway compromise (caused by an expanding hematoma).

Although cerebral reperfusion syndrome is rare, it’s the most common cause of intracranial hemorrhage and seizure activity in the first 2 weeks after carotid endarterectomy. Nurses should be aware of carotid reperfusion symptoms to ensure prompt treatment. Symptoms include severe ipsilateral (same side as the carotid endarterectomy) headache, focal contralateral (opposite side) neurologic symptoms, hypertension, or seizure. The nurse should notify the patient’s provider and administer medication to control hypertension, headache, and/or seizure activity as ordered. Rigorous blood pressure control also is required, and a neurologist may be consulted to assist with management.

Cranial nerve injuries associated with carotid endarterectomy include the facial (VII), vagus (X), accessory (XI), glossopharyngeal (IX), and hypoglossal (XII) nerves, with vagus and hypoglossal the most common. Signs of vagus nerve injury are dysphagia or hoarseness; signs of hypoglossal nerve injury include tongue deviation to the operative side. Neurologic and cranial nerve assessments should be performed according to the organization’s protocol.

Medical management for stroke prevention

Medical management for stroke prevention targets both surgical and nonsurgical candidates who have stroke risk factors. Outpatient carotid stenosis management focuses on reducing stroke risk with antiplatelet/antithrombotic, antihypertensive, and hypercholesterolemia (statin) therapy; smoking cessation; diabetes management; and exercise. (See Modifiable risk factors.)

Modifiable risk factors

Modifiable risk factors associated with stroke include diabetes, obesity, lack of exercise, and smoking.

American Diabetes Association recommendations

The American Diabetes Association (ADA) recommends these lifestyle changes as integral to lowering atherosclerotic cardiovascular disease risk in patients with diabetes:

reduced-calorie diet high in fruits and vegetables (eight to 10 servings a day)
restricted sodium consumption (< 2,300 mg/day)
limited alcohol consumption (two drinks daily or less for men and one drink daily or less for women)
increased activity.

The ADA also recommends the following:
In general, for a patient who’s overweight, an initial weight-loss goal of 10% of
baseline weight is encouraged over 6 months. If the patient reaches this initial goal, additional weight-loss goals can be established when necessary.
In patients with diabetes who are hospitalized after an ischemic stroke, target blood glucose should be between 140 to 180 mg/dL.
Because smoking increases the risk of stroke, patients should be counseled on smoking cessation and use of nicotine products and oral smoking-cessation medications.

American Heart Association recommendations

The American Heart Association (AHA) recommends the following lifestyle changes for all Americans, but each person’s 10-year atherosclerotic cardiovascular risk should be calculated to individualize treatment parameters for maximum benefit and to avoid overtreatment.

Consume a heart-healthy diet that includes fish, legumes, fruits, vegetables, and nuts. The Mediterranean diet has demonstrated a reduction in mortality from all causes.
Limit sweetened beverages, processed meat products, and refined carbohydrates.
Limit sodium consumption to < 2,000 mg daily.
Avoid trans fats.
Engage in regular physical activity (150 minutes weekly of moderate activity or 75 minutes weekly of vigorous activity).

Antiplatelet/antithrombotic therapy

Single antiplatelet therapy with aspirin is recommended to prevent coronary events in patients with ICA stenosis who are asymptomatic and don’t have a history of stroke. For patients with non-cardioembolic acute ischemic stroke, aspirin and extended-release dipyridamole and clopidogrel have shown efficacy. Early antiplatelet therapy with aspirin (81 to 325 mg) should be started within the first 48 hours of symptom presentation, before surgical intervention, and continued after surgery.

Antihypertensive therapy

Good blood pressure control is essential to stroke prevention. In patients who are neurologically stable, a blood pressure goal of < 140/90 mmHg is considered safe and reasonable to maintain for long-term control.

Hypercholesterolemia (statin) therapy

Statin therapy is recommended for primary and secondary prevention of atherosclerotic cardiovascular disease (ASCVD). According to the 2018 American College of Cardiology (ACC)/AHA guidelines for treating blood cholesterol, high-intensity statin therapy is recommended to reduce ASCVD in adults younger than 75 years old. The AHA/ASA also recommends assessing the coronary artery calcium (CAC) score (with a noninvasive heart scan) in patients over 40 years old with uncertain risk status. CAC scores range from 0 (low risk) to >100 (an indication to start statin therapy).

Reducing risk

After surgery, Mr. Smith is neurologically intact and has stable vital signs. He’s discharged 24 hours after his ICU stay. Because Mr. Smith has known atherosclerosis, a statin medication and aspirin are prescribed at discharge. He also receives education about smoking cessation and the various pharmacologic therapies available.

Currently, the United States Preventive Services Task Force recommends against screening for asymptomatic carotid stenosis. However, ACC/AHA guidelines recommend cardiovascular risk assessments (age, cholesterol, gender, ethnicity, blood pressure screening, diabetes, and tobacco use) in all adults to help reduce cardiovascular events and stroke risk associated with ICA stenosis.

Pamela Anderson is an adult nurse practitioner in vascular surgery at St. Vincent Medical Group in Indianapolis, Indiana. Terri Townsend is a staff educator for cardiovascular and outpatient services at Community Hospital in Anderson, Indiana. Jennifer Schneider Davis is an adult nurse practitioner at the Ball State University Student Health Center in Muncie, Indiana.

Selected references

American Diabetes Association. Cardiovascular disease and risk management: Standards of medical care in diabetes—2019. Diabetes Care. 2019;42(suppl 1):S103-123.

Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;140(11):e596-646.

Ballotta E, Toniato A, Da Roit A, Baracchini C. Clinical outcomes of carotid endarterectomy in symptomatic and asymptomatic patients with ipsilateral intracranial stenosis. World J Surg. 2015;39(11):2823-30.

Baradaran H, Gialdini G, Mtui E, Askin G, Kamel H, Gupta A. Silent brain infarction in patients with asymptomatic carotid artery atherosclerotic disease. Stroke. 2016;47(5): 1368-70.

Benjamin EJ, Blaha MJ, Chiuve SE, et al. Correction to: Heart disease and stroke statistics— 2017 update: A report from the American Heart Association. Circulation. 2017; 136(10):e196.

De Borst GJ. Commentary on “Cranial nerve injury after carotid endarterectomy: Incidence, risk factors, and time trends.” Eur J Vasc Endovasc Surg. 2017;53(3):336.

Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: A report of the American College of Cardiology/American Association Task Force on Clinical Practice Guidelines. Circulation. 2019; 139(25):e1082-1143.

Kaul S, Alladi S, Mridula KR, et al. Prevalence and risk factors of asymptomatic carotid artery stenosis in Indian population: An 8-year follow-up study. Neurol India. 2017;65(2):279-85.

Khare S. Risk factors of transient ischemic attack: An overview. J Midlife Health. 2016; 7(1):2-7.

Meschia JF, Klaas JP, Brown RD, Brott TG. Evaluation and management of atherosclerotic carotid stenosis. Mayo Clin Proc. 2017; 92(7):1144-57.

Ooi YC, Gonzalez NR. Management of extracranial carotid artery disease. Cardiol Clin. 2015;33(1):1-35.

Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2018;49(3):e46-110.

Rich K, Treat-Jacobson D, DeVeaux T, et al. Society for Vascular Nursing carotid endarterectomy (CEA) updated nursing clinical practice guideline. March 2017. svnnet.org/wp-content/uploads/2017/06/SVN-CEA-Guideline-Final-6.12.17.pdf

Rubenfire M. 2018 ACC/AHA multisociety guideline on the management of blood cholesterol. American College of Cardiology. November 10, 2018. acc.org/latest-in-cardiology/ten-points-to-remember/2018/11/09/14/28/2018-guideline-on-management-of-bloodcholesterol

Rubin MN, Barrett KM, Brott TG, Meschia JF. Asymptomatic carotid stenosis: What we can learn from the next generation of randomized clinical trials. JRSM Cardiovasc Dis. 2014;3:1-8.

2 COMMENTS

  1. Kathy,
    I have worked for two large hospital systems in Indiana. Both hospitals used the ICU to monitor any patient who has undergone a carotid endarterectomy or a carotid stent. There can be a great deal of variation in management of patients with vascular conditions/surgeries depending on the geographic location of hospital.
    Do your staff members receive additional training for the care of the vascular patient or heart patients on your floor?

    Pam

  2. How common is it to use the ICU for post-op monitoring? We use a Heart & Vascular Unit (HVU) at my hospital. We are not considered a step-down unit, just another Med-Surg unit.

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