14.1 Goals

1. 
   

   Review the natural history of symptomatic carotid stenosis.

   
   
2. 
   

   Review and analyze the evidence supporting the indications for treatment of symptomatic carotid stenosis.

   
   
3. 
   

   Review and analyze risk factors favoring endovascular versus open treatment.

   
   
4. 
   

   Discuss the literature related to outcomes following treatment of symptomatic carotid stenosis.

14.2 Case Example

14.2.1 History of Present Illness

The patient is a 63-year-old male who presents immediately after an episode of acute onset vision loss in his right eye, which occurred while reading. He described it as a “black spot” in his right visual field that appeared suddenly. Full vision returned after approximately 2 minutes. The patient denied any associated pain, headache, nausea/vomiting, photophobia, recent trauma, illness, or cough, as well as any history of ocular disease or stroke.

Past medical history: Hypertension, hyperlipidemia, myocardial infarction (MI), chronic obstructive pulmonary disease.

Past surgical history: Cardiac stents.

Family history: Hypertension in parents.

Social history: Tobacco—two packs per day for 20 years; denies alcohol and illicit drugs.

Medications: Metoprolol, aspirin, plavix, atorvastatin.

Allergies: Penicillin (causes rash).

Review of systems: As per the above.

Neurological examination: Unremarkable.

Imaging studies: See figures. In Fig. 14.1, Fig. 14.2, and Fig. 14.3, digital subtraction angiography (DSA) shows severe stenosis of right common carotid artery.

14.3 Case Summary

1. 
   

   What factors influence the decision to offer a revascularization procedure to this patient?

   
   

   The major factors that support surgical treatment of the stenosis are the presence of symptoms, severity of the stenosis, the type of symptoms, and timing of presentation after symptom onset. Symptoms consistent with carotid stenosis should initiate imaging such as CT angiogram or four-vessel angiogram to evaluate severity of the stenosis, as well as studies to rule out other potential etiologies, such as isolated ophthalmologic issues, seizures, or multiple sclerosis. Based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET), patients presenting with symptomatic stenosis measuring 70 to 99% and treated with medical therapy had a 26% risk of any stroke at 2 years and a 13.1% risk of a major stroke or death at 2 years. ¹ The NASCET study data also showed a reduced risk of any stroke, major stroke, and fatal stroke when patients were treated with CEA over medical therapy alone in a center that routinely performs carotid interventions. ¹ Therefore, to avoid subsequent stroke, the patient with symptomatic carotid stenosis should be counseled to undergo treatment.

   
   

   The type of presenting symptoms can stratify high-risk and low-risk patients and help determine the type and timing of intervention. For a recent transient ischemic attack (TIA), some symptoms have been shown to confer a higher short-term risk of stroke. As determined by a secondary analysis of the NASCET trial data, patients who had a hemispheric TIA— defined as distinct neurological dysfunction lasting less than 24 hours—as the qualifying event experienced a higher risk of short-term stroke than those with hemispheric stroke. ² For these patients, the risk of stroke following the hemispheric TIA was 5.5% at 48 hours and 20.1% at 90 days. Comparatively, patients who presented after experiencing a hemispheric stroke (defined as stroke symptoms persisting beyond 24 hours) had only a 2.3% risk of stroke at 90 days. Of note, this 90-day stroke risk was not independently predicted by degree of stenosis.

   
   
2. 
   

   What patient factors would influence the decision to recommend CEA versus carotid angioplasty and stenting (CAS)?

   
   
   
   
   1. 
      

      Age—Patient’s age is an important consideration for determining the type of revascularization procedure. There are data showing that patients undergoing stenting over the age of 70 and endarterectomy over the age of 80 are considered high risk due to the risk of periprocedural stroke and risks of general anesthesia, respectively. To minimize the risks of general anesthesia, carotid stenting offers an alternative to patients who, due to age or other risk factors, are not candidates for general anesthesia. Some centers offer CEA without general anesthesia for this reason.

      
      
      
      
      1. 
         

         Patients aged 70 or older treated with CAS had a 12% risk of stroke or death within 120 days, compared to a 6% risk in those patients treated with CEA. ³ In addition, compared to the patients below the age of 60, patients above the age of 70 have a four times greater periprocedural risk following CAS. ⁴

         
         
      2. 
         

         Patients with greatly advanced age, defined as greater than or equal to 85 years, are at an especially increased risk of morbidity and mortality when undergoing general anesthesia. ⁵ In addition, patients aged 80 and older had higher rates of postoperative complications, and there were higher 30-day mortality rates among those who experienced complications. ⁶

      
      
   2. 
      

      Sex—Male patients with atherosclerotic stenosis have a fourfold greater risk for future stroke than similar female patients and therefore are more likely to benefit from CEA. ⁷

      
      
   3. 
      

      Ability to take antiplatelet drugs—Patients who are unable or unwilling to take antiplatelet drugs are better served with CEA because stent placement requires dual antiplatelet therapy to reduce the risk of perioperative complications, including stroke and in-stent thrombosis. ^{8 , 9 , 10} Patients can undergo CEA while taking either aspirin alone or dual antiplatelet medications.

      
      
   4. 
      

      Cardiovascular/Renal risk—As predicted by the Revised Cardiac Index for vascular surgery (which includes multiple risk factors such as hypertension, congestive heart failure, ischemic heart disease, cerebrovascular disease, insulin-dependent diabetes, renal failure, or age > 75), patients with three or more risk factors are at an increased risk of perioperative MI when undergoing vascular surgery; therefore, patients deemed to be high risk for vascular surgery may benefit more from CAS. ¹¹ On the other hand, stenting in patients with renal disease is an unfavorable option due to the need for contrast administration.

   
   
3. 
   

   What technical factors would influence the decision to pursue CEA versus CAS?

   
   
   
   
   1. 
      

      Surgical accessibility—Patients with a high carotid bifurcation (i.e., at the level of C2 or higher) may be better candidates for endovascular therapy; however, a high carotid lesion has not been associated with increased risk of cranial nerve injury with open surgery. ¹²

      
      
   2. 
      

      Prior CEA—Prior surgery to the region may make it more difficult to separate structures without incurring injury, especially nerve injury, due to the presence of scar tissue. ¹²

      
      
   3. 
      

      Other—Other features that may increase surgical difficulty include radiation to the head/neck region as well as prior neck surgery of any sort, both of which can lead to scarring and increase the risk of nerve injury as discussed above.

   
   
4. 
   

   What treatment, if any, should be pursued for the contralateral carotid artery?

   
   

   A staged CEA may be pursued for the contralateral carotid artery, to be performed following successful recovery from surgery on the symptomatic side first, if needed.

   
   
5. 
   

   What is the follow-up regimen?

   
   

   The first follow-up should occur around 2 weeks postoperatively to ensure proper wound healing and check for postoperative complications, including any further strokelike symptoms or to check for the evolution of any nerve injuries that may have occurred during surgery. At 3 months postoperatively, a carotid ultrasound should be done to evaluate the artery for any new stenosis or restenosis. If there is no evidence of stenosis on ultrasound, follow-up should proceed with an annual surveillance ultrasound. If restenosis has occurred, further evaluation should be undertaken with either CT angiography or catheter-based angiography.