Carotid artery endarterectomy
Carotid artery endarterectomy is widely used on the carotid artery of the neck as a way to reduce the risk of stroke, particularly when the carotid artery is narrowed by more than 70%. A carotid endarterectomy may itself cause a stroke at the time of operation.
Endarterectomy is also used as a supplement to a vein bypass graft to open up distal segments.
Pulmonary hypertension caused by chronic thromboembolic disease (CTEPH) may be amenable to pulmonary thromboendarterectomy of the pulmonary artery. This is a highly specialized procedure.
Carotid artery stenosis (CS) is a major cause of ischemic stroke. Treatment of CS consists of best medical treatment and carotid revascularization (CR), including carotid endarterectomy (CEA) and carotid artery stenting (CAS). Both CR techniques have their own procedural risks. Therefore, selection of the appropriate treatment for patients with CS is relatively complicated. Many studies and guidelines have reported the efficacy of each treatment for both symptomatic and asymptomatic patients. However, the results are still controversial, especially concerning the efficacy and safety of CEA and CAS 1).
Carotid endarterectomy is a surgical procedure to remove the atheromatous plaque material, or blockage, in the lining of an artery constricted by the buildup of soft/hardening deposits. It is carried out by separating the plaque from the arterial wall.
Atherosclerotic stenosis of the internal carotid artery causes 10–15% of all strokes. Carotid endarterectomy lowers the long-term risk of stroke in patients with symptomatic carotid artery stenosis 2) 3).
Carotid endarterectomy (CEA) is a common, well-developed surgical procedure.
Technique: Carotid endarterectomy is safe, effective, and durable, but can we make it better? 4).
Pre-op risk factors for CEA
Identifying patients at high risk for complications after CEA has proven challenging. Typically, the exclusion criteria from studies are cited, but in most cases, these are simply patients that were not included in the study because it was the investigators’ perception that these patients might be “high risk.” Therefore these risk factors are not validated. They are included here for completeness. NASCET and ACAS: age > 80 years, prior ipsilateral CEA, prior contralateral CEA within 4 months, prior neck XRT, tandem lesion larger than target lesion, other conditions that could cause symptoms (atrial fibrillation, prior stroke with persistent major deficit, valvular heart disease), major organ failure, uncontrolled hypertension or diabetes mellitus, and significant coronary artery disease 5) 6)
The SAPPHIRE Trial (Stenting and Angioplasty with Protection in Patients at High-Risk for Endarterectomy): patients with clinically significant cardiac disease (CHF, abnormal stress test, or need for open-heart surgery), severe pulmonary disease, contralateral carotid occlusion, contralateral laryngeal-nerve palsy, previous radical neck surgery or neck XRT, recurrent stenosis after endarterectomy, and age > 80 years 7).
The ARCHeR Trial (ACCULINK for Revascularization of Carotids in High-Risk patients) also included patients with tracheostomy, spinal immobility, and dialysis-dependant renal failure 8).
Anesthesia and monitoring
Most (but not all) surgeons monitor some parameter of neurologic function during carotid endarterectomy, and will alter technique (e.g. insert a vascular shunt) if there is evidence of hemodynamic intolerance of carotid clamping (only occurs in ≈ 1–4%).
patient movement during procedure (often exacerbated by sedation and alterations in CBF), lack of cerebral protection from anesthetic and adjunctive agents. The only prospective randomized study found no di erence between local and general anesthesia 11). The multicenter, randomized controlled General Anesthesia versus Local Anesthesia (GALA) Trial 12) found no significant differences in the prevention of stroke, MI, or death for either anesthetic technique. Subgroup analysis showed trends (not statistically significant) favoring local anesthesia for perioperative death, event-free survival at 1 year, and patients with contralateral occlusion. Local anesthesia was associated with a significant reduction of shunt insertion 13).
A Cochrane Database Review found no evidence from randomized trials to favor either anesthetic technique 14)
- general anesthesia, possibly including barbiturates (thiopental boluses of 125–250 mg until 15– 30 second burst suppression on EEG, followed by small bolus injections or constant infusion to 15)
a) EEG monitoring
b) SSEP monitoring
c) measurement of distal stump pressure after CCA occlusion (unreliable), e.g. using a shunt if stump pressure <25 mm Hg
d) transcranial Doppler
Both general anesthesia and local anesthesia are used in the University Hospital Pilsen for carotid endarterectomy (CEA). The decision as to which anesthetic technique to use during surgery is made individually.
The satisfaction of a group of 205 patients with regard to anesthesia used and their future preferences were evaluated prospectively through a questionnaire. The reasons for dissatisfaction were assessed.
CEA was performed under general anesthesia (GA) in 159 cases (77.6%) and under local anesthesia (LA) in 46 cases (22.4%). In the GA group, 148 patients (93.1%) were satisfied; 30 patients (65.2%) in the LA group were satisfied (p < 0.0001). The reason for dissatisfaction with GA were postoperative nausea and vomiting (7 patients), postoperative psychological alteration (3), and fear of GA (1). The reasons for dissatisfaction with LA were intraoperative pain (9 patients), intraoperative discomfort and stress (5), and intraoperative breathing problems (2). Of the GA group, 154 (96.9%) patients would prefer GA again, and of the LA group, 28 (60.9%) patients would prefer LA if operated on again (p < 0.0001). Overall, 172 patients (83.9%) would prefer GA in the future, and 33 patients (16.1%) would prefer LA.
Overall patient satisfaction with CEA performed under both GA and LA is high. Nevertheless, in the GA group, patient satisfaction and future preference were significantly higher. Both GA and LA have advantages and disadvantages for CEA. An optimal approach is to make use of both anesthetic techniques based on their individual indications and patient preference 16).
In addition to routine, the following should be checked:
- change in neurologic status due to cerebral dysfunction, including:
a) pronator drift(R/O new hemiparesis)
b) signs of dysphasia (especially for left-sided surgery)
c) mimetic muscle symmetry (assesses facial nerve function)
- pupil diameter and reaction (R/O stroke, Horner syndrome)
- severe H/A (especially unilateral) > may indicate hyperperfusion syndrome
STA pulses (R/O external carotid occlusion)
tongue deviation (R/O hypoglossal nerve injury)
symmetry of lips (R/O weakness of lower lip depressors due to retraction of marginal mandibular branch of the facial nerve against mandible usually resolves in 6–12 wks, must differentiate from central VII palsy due to stroke)
check for hoarseness (R/O recurrent laryngeal nerve injury)
assess for a hematoma in operative site: note any tracheal deviation, dysphagia
A bovine placenta training model for CEA is inexpensive and readily available and closely resembles human carotid arteries. The model can provide a convenient and valuable simulation and practice addition for vascular surgery training 17).
Citation analysis on carotid endarterectomy has witnessed a marked shift in the publication trends from studying the outcome and complications to comparing carotid artery stenting with endarterectomy. This analysis is a good introductory article to physicians interested in this topic, as it summarizes the highly impactful articles and enlists the most-cited RCT on CEA 18).