|Year : 2015 | Volume
| Issue : 1 | Page : 1-6
Early outcomes of carotid endarterectomy without shunting in patients with complete occlusion of the contralateral internal carotid artery
Mehmet Besir Akpinar, Ihsan Sami Uyar, Veysel Sahin, Funda Tetik, Halil Uc, Faik Fevzi Okur
Department of Cardiovascular Surgery, Medical Faculty, Sifa University, Izmir, Turkey
|Date of Web Publication||29-Nov-2014|
Mehmet Besir Akpinar
Department of Cardiovascular Surgery, Medical Faculty, Sifa University, Fevzipasa Bulvari No: 172/2 Konak. 35240, Izmir
Source of Support: None, Conflict of Interest: None
Aim: Shunting in carotid endarterectomy (CEA) is a controversial issue, which remains to be clarified in patients with contralateral carotid occlusion (CCO). In our clinic, CEA is performed under general anesthesia and without shunting. The present study aimed to discuss 30-day mortality and morbidity outcomes of CEA performed without shunting on 53 CCO cases. Materials and Methods: In our clinic, 415 CEA procedures were performed on 376 patients between the years 2005 and 2013. Among these patients, 53 (39 males and 14 females) with CCO who underwent isolated CEA were included in the study. All patients were operated on without shunting and under general anesthesia. Results: Of the patients, 31 were symptomatic (mean age, 63.2 5.1 years) and 22 were asymptomatic (mean age, 63.1 6.7 years). One (1.9%) patient died of postoperative myocardial infarction. Another patient (1.9%) developed stroke due to intracranial hemorrhage on the postoperative 6 th day. Transient ischemic attack was observed in 2 (3.8%) patients. Eight (15.1%) patients developed ipsilateral transient peripheral nerve injury, 1 (1.9%) patient developed hoarseness, and 5 (9.4%) patients developed organic brain injury. Conclusion: It was observed that CEA without shunting could be performed with an acceptable risk ratio under general anesthesia in cases with CCO.
Keywords: Carotid endarterectomy, carotid artery, stroke
|How to cite this article:|
Akpinar MB, Uyar IS, Sahin V, Tetik F, Uc H, Okur FF. Early outcomes of carotid endarterectomy without shunting in patients with complete occlusion of the contralateral internal carotid artery
. Sifa Med J 2015;2:1-6
|How to cite this URL:|
Akpinar MB, Uyar IS, Sahin V, Tetik F, Uc H, Okur FF. Early outcomes of carotid endarterectomy without shunting in patients with complete occlusion of the contralateral internal carotid artery
. Sifa Med J [serial online] 2015 [cited 2021 Apr 20];2:1-6. Available from: https://www.imjsu.org/text.asp?2015/2/1/1/145789
| Introduction|| |
Carotid endarterectomy (CEA) surgery was first performed in 1954 by Eastcott, Pickering and Rob; after being developed, it is being performed to prevent stroke in many centers.  However, the surgical procedure itself, which is performed to prevent stroke, has the risk for stroke.
Results of long-term follow-ups have demonstrated that CEA improves both ipsilateral and contralateral cerebral functions in patients with severe carotid artery stenosis concurrent with contralateral carotid artery occlusion (CCO), whether symptomatic or not. 
In the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and in the Asymptomatic Carotid Atherosclerosis Study (ACAS), CCO was demonstrated to be a risk factor likely to adversely affect the outcomes of CEA. , However, while some authors defend that presence of CCO increases the risk of CEA, numerous larger-scale studies have stated that presence of CCO only increases the incidence of shunting but does not cause an additional increase in morbidity or mortality risk. ,
Although the mechanism of potential neuronal damage in CEA remains unclear, in addition to microemboli and subclinical microinfarctions, intraoperative carotid artery clamping and associated decreased cerebral blood flow are known to play a major role in neuronal damage. 
Neurological complications in CEA are tried to be prevented by anesthesia procedures (local, general) and by optimizing neuromonitoring techniques. Several techniques have been developed to detect early neurological damage during CEA. While observation of bleeding from distal bed (back bleeding), measurement of stump pressure, transcranial Doppler, and near-infrared spectroscopy (NIRS) are used to test the adequacy of the vascular system, tests such as electroencephalography (EEG) and somatosensory-evoked potential (SSEP) monitoring are used to assess cerebral neuronal functions. , However, neither of these analyses have an absolute sensitivity and specificity yet. ,
Use of an intraluminal shunt has been recommended to reduce the complication rates during CEA. Nevertheless, there are different opinions on this issue due to the risk arising from shunting itself. ,, Some clinics routinely perform shunting whether or not monitoring is performed, whereas some other clinics perform shunting in selected cases, and some prefer not to perform shunting. 
The aim of the present study is to evaluate the 30-day mortality and morbidity outcomes of isolated CEA performed without shunting on 53 CCO patients. This is a single-institution retrospective descriptive study.
| Materials and Methods|| |
In our clinic, a total of 415 CEA procedures were performed on 376 patients due to carotid artery disease between the years 2005 and 2013. All of these cases were operated on without any shunt. Among these patients, 61 had complete occlusion of the contralateral carotid artery, of whom 8 had concomitant critical coronary artery stenosis. These 8 patients were excluded from the study since they underwent both CEA and coronary artery bypass graft (CABG) surgeries in the same session. Accordingly, all CCO patients who underwent isolated CEA (n = 53; 39 males and 14 females) were included in the study.
The patient group consisted of both symptomatic (n = 31, 58.5%; mean age, 63.2 ± 5.1 years) and asymptomatic (n = 22, 41.5%; mean age, 63.1 ± 6.7 years) patients.
Preoperative evaluation of the symptomatic patients revealed a history of transient ischemic attack (TIA) in 14 patients, a history of stroke in 9 patients, and a history of nonspecific vertigo, loss of balance, and amnesia in 8 patients. Of the patients with a history of stroke, 7 patients were observed to have contralateral hemiparesis (grade 2/5 in 4 patients and grade 1/5 in 3 patients) and 2 patients were observed to have ipsilateral hemiparesis (grade 2/5) of the complete occlusion site.
Independent risk factors (age, gender, coronary artery disease, peripheral artery disease, diabetes mellitus, and hypertension) likely to affect mortality and morbidity in the study patients are summarized in [Table 1].
|Table 1: Demographic data of patients with contralateral occlusion of the carotid artery|
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In our clinic, color Doppler screening of the carotid artery is routinely performed in all patients (regardless of risk factors) who would undergo CABG in order not to rule out those with critical carotid artery disease. All patients with asymptomatic carotid artery disease in the present study were those diagnosed during this screening.
Computed tomography (CT) angiography or digital angiography were performed for imaging of the arcus aorta and selective carotid artery system in patients in whom 60% and greater stenosis was detected by color Doppler ultrasonography. Patients with 60-70% ulcerated stenosis and with 70% and greater internal carotid artery stenosis were included in surgical treatment program.
All patients were operated on under general anesthesia. Induction was performed using 3-5 mg/kg sodium thiopental, 0.6 mg/kg atracurium, and 1-1.5 mg/kg fentanyl. Sevoflurane was used for inhalation anesthesia. Moderate hyperventilation (pCO 2 30-35 mmHg) was provided during respiration. Prior to cross-clamping, 3 μg/kg sodium thiopental was administered, and anesthesia maintenance was provided by 0.1-0.2 mg/kg atracurium and sevoflurane. Systolic blood pressure was tried to be maintained at 140-150 mmHg. Dexamethasone at a dose of 8 mg was administered intravenously just prior to cross-clamping and after removal of the cross-clamp. Intravenous heparin (100 U/kg) was administered while surrounding the carotid arteries with a tape, and heparin was completely neutralized by protamine after removal of the cross-clamp.
All patients were operated on by modified eversion technique as defined by Okur-Alayunt.  In this technique, an incision was made from the main carotid artery to the external carotid artery after preparation of the carotid artery system, and the plaques were removed. The internal carotid artery was not incised. The arteriotomy was primarily closed. Shunting was not performed in any of the patients. Measurements for cerebral vascular sufficiency or cerebral monitoring techniques were performed in none of the patients. In the postoperative period, all patients were transferred to the intensive care unit as intubated, and were then extubated there. Antiaggregant treatment (daily 150 mg acetyl salicylic acid) was given during preoperative and postoperative period to all the patients.
| Results|| |
In the demographic perspective, comorbid risk factors included hypertension in 26 (49.1%) patients, diabetes mellitus in 16 (30.2%) patients, and smoking history in 14 (26.4%) patients. CCO was approximately two times more prevalent in males than in females [Table 1]. Thirty-day mortality and morbidity outcomes in 53 patients with CCO who underwent CEA are presented in [Table 2].
|Table 2: Early outcomes of carotid endarterectomy without shunting in patients with severe carotid artery stenosis concurrent with complete occlusion of the contralateral internal carotid artery|
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Complete occlusion was present in the right internal carotid artery in 29 patients and in the left internal carotid artery in 24 patients. There was 70% stenosis in the right vertebral artery in a patient with complete occlusion of the left internal carotid artery. One patient with complete occlusion of the right internal carotid artery had a 70% stenosis in the right vertebral artery and hypoplasia in the left vertebral artery. As it is shown in [Table 3], no significant stenosis was detected in vertebral artery systems of other patients.
|Table 3: Operative etiology of the patients. According to symptoms in patients with carotid artery disease distribution|
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In the intracranial cerebral artery system, the medial cerebral artery of the completely occluded side demonstrated filling from the contralateral carotid artery via Willis polygon in 36 (67.9%) patients.
The mean duration of cross-clamping was 18 ± 7 min.
One (1.9%) patient died of myocardial infarction on the postoperative 1 st day. One (1.9%) patient was re-hospitalized due to intracranial hemorrhage on the postoperative 6 th day. This patient had an ischemic stroke with the same site of the occluded carotid artery. The interval between the stroke and CEA was 45 days, and he had contralateral hemiparesis (grade 2/5) in the preoperative period. This patient developed 0/5 strength loss at the time of hemorrhage. Control brain tomography also revealed hemorrhage in the same region. The patient was followed-up with conservative treatment and discharged from hospital with hemiparesis (grade 3/5) on the 16 th day of hospitalization.
Two (3,8%) patients developed hemiparesis on the ipsilateral site of surgery. Postoperative diffusion weight MR images of the first patient revealed 3 mm and the seconad patient 5mm diamater acute ischemic areas on the occluded ICA site.
In 8 (15.1%) patients, symptoms associated with transient peripheral nerve injury (facial asymmetry, lingual deviation and dysphagia) were observed on the surgical site. Oral anti-inflammatory drug therapy (indomethacin at a dose of 50 mg/day) was commenced for these patients. This treatment was shifted to oral methylprednisolone treatment (4 mg/day) in 2 patients who showed no improvement within 5 days and the symptoms were observed to have disappeared completely on the control visit after 1 month.
One (1.9%) patient developed hoarseness that lasted for approximately 45 days.
Neurocognitive impairments were observed in 5 (9.4%) patients after 1-3 days of the CEA. Three of these 5 patients' ages were over 70 years. In these 5 patients, the mean duration of cross-clamping was 12 ± 4 min.
Neither of the patients developed bleeding, infection, or hematoma.
| Discussion|| |
Our treatment protocol for asymptomatic patients is specified in accordance with the criteria defined in the ACAS and in the Asymptomatic Carotid Atherosclerosis Study (ACST). Accordingly, 60-70% ulcerated stenotic lesions of the internal carotid artery and all 70% and greater stenosis were treated surgically.  Surgical treatment was not performed for carotid arteries with complete occlusion.
Use of shunts in CEA is a controversial issue. In our clinic, CEA is being performed since 2005 under general anesthesia without shunting.  The present study evaluated the patient group with CCO among patients who underwent CEA between the years 2005 and 2013. Accordingly, mortality rate was found to be 1.9% with 1 patient among 53 CCO patients who was operated on under general anesthesia without shunting. Evaluation of intracranial neurological complications revealed intracranial hemorrhage at a rate of 1.9%, transient neurological attack at a rate of 3.8%, and neurocognitive disorder at a rate of 9.4%.
The patient who died was the one with symptomatic CCO who was included in CABG surgery program. This patient awoke after CEA without any neurological deficit and was extubated, but died due to myocardial infarction developed during follow-up in the intensive care unit.
There are many studies evaluating CEA in patients with CCO. Most of these studies have compared patients with and without CCO and reported that intraoperative EEG changes are more remarkable in the CCO patient group in general; therefore, this patient group requires a higher rate of shunting. , Lacroix et al. reported the rate of shunt use to be 87% in patients with contralateral occlusion and 31% in patients without contralateral occlusion.  In that particular study, they reported the mortality rate to be 5.5% and the stroke rate to be 8%.  In the study by da Silva, the rate of shunt use was 83% and the combined stroke-mortality rate was 5.6% in patients with CCO. 
In their study, Julia et al. detected EEG changes in 25.8% of patients with CCO.  They reported that the rate of EEG changes decreased to 10.3% after the elevation of central blood pressure via pharmacological intervention and shunting was performed only in these patients, and the combined morbidity and mortality rate was 1.7% for CEA in CCO patients. The study by Julia et al. attracts attention as compared with the other studies since they performed shunting less frequently and the rate of morbidity and mortality was lower in CCO patients. 
Studies on shunt use have suggested that routine shunting increases morbidity due to shunting itself; thus, it should be "selectively" performed particularly in selected patients. ,, Potential additional complications reported due to shunt use include arterial dissection, bleeding, thrombosis, and air embolism.  Moreover, Howell reported that blood flow passing through the shunt lumen might fail to meet the needs of the brain.  Some clinical studies have demonstrated that shunt use during CEA has no remarkable effect in decreasing stroke and on 30-day morbidity and mortality. ,,
In the literature, there are studies reporting successful outcomes with the use of CEA without shunting in patients with CCO or with lesions of the contralateral carotid artery. ,, In their study involving 309 patients in whom CEA was performed without shunting, Ott et al. detected CCO in 22 patients but encountered no stroke in these patients.  Prioleau et al. reported a striking result that shunting had no effect in preventing stroke in CCO patients. 
General anesthesia has been demonstrated to have a protective effect on neurons against (cerebral) hypoxia. , It is obvious that cerebral protection becomes more important particularly in patients with CCO. Thiopental is an important and recommended agent for brain protection during brain-related surgeries, in conditions requiring neuroprotection, and in CEA surgeries. ,,, We also prefer general anesthesia during CEA due to its efficacy on cerebral protection and as it provides comfort both for the surgeon and the patient. As was mentioned under the subheading of "Anesthesia," we use thiopental as the anesthetic agent.
Shunting was not performed in the present study and the rates of mortality, intracranial hemorrhage, transient neurological attack, and neurocognitive disorder were found to be 1.9%, 1.9%, 3.8%, and 9.4%, respectively.
Neurocognitive disorder that could be considered as "organic brain injury" was observed in 5 patients. No motor deficit was noted in these patients. Three of these patients were aged over 70 years and had normal vertebral arteries, and the mean duration of cross-clamping was 12 ± 4 min in these patients. Brain CT was performed in one of these patients, in whom magnetic resonance imaging (MRI) could not be performed due to scoliosis, and no pathological finding was detected. The remaining 4 patients underwent diffusion brain MRI; 1 of these patients had a 4 mm diameter acute ischemia and senile atrophy in the frontal deep white matter of the complete occluded site; 1 patient had occipital millimetric acute ischemia on the site of endarterectomy, and the other 2 patients had no pathological finding except for senile atrophy. In these 5 patients, clinical improvement was provided by 3-10 days of haloperidol (3 mg/day) treatment in addition to routine antiaggregant treatment.
Eight patients developed ipsilateral facial asymmetry, lingual deviation, and dysphagia. No ischemic focus was detected on cerebral diffusion MRI of these patients. This complication might have been due to our attempts to reach to the 0.5 cm distal part of the atherosclerotic plaque. If the plaque persisted to continue to the distal part of the hypoglossal line, we hang the nervous with a silastic tape to reach the distal part of the internal carotid artery. And if any nerve crosses the carotid artery, we hang it. These tractions may cause to hypoglossal nerve, recurrent laryngeal nerve, and possibly the marginal mandibular branch of the 7th nerve. These patients with peripheral neural damage improved completely after treatment with non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin 50 mg oral/daily) and, if there was no response in 5 days, methylprednisolone (4 mg oral/daily) was given.
Hoarseness developed in 1 patient, of whom indirect laryngoscopy revealed unilateral vocal cord paralysis. This was defined as a separate complication since it is not related to the shunt usage or not and it might have resulted from periarterial surgical traction/manipulations, as well as from intubation.
Overall evaluation in terms of intracranial neurological damage revealed that 1 (1.9%) patient had intracranial hemorrhage, 2 (3.8%) patients had TIA, and 5 (9.4%) patients had organic brain damage. Based on these results, we are in the opinion that CEA under general anesthesia without shunting can be performed with an acceptable risk ratio in CCO patients.
Limitations of the study
First, the present study was not a comparative study. Second, pre- and postoperative neurological examinations of the patients were performed by a cardiovascular surgeon. Patients with neurological deficit on these examinations were referred to a neurologist. Thus, subclinical neurological deficits might have been overlooked.
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[Table 1], [Table 2], [Table 3]