Do we really need patch and shunt for carotid endarterectomy? Karotis endarterektomide yama ve şanta gerçekten ihtiyacımız var mı?

Aim: The efficacy of carotid endarterectomy (CEA) for stroke prevention in asymptomatic and symptomatic patients is well known. We aimed to share long term follow up results for primary closure technique for CEA without shunting and investigated risk factors for complications in this patient group. Material and Methods: Between September 2013-2019, 122 patients with isolated CEA with primary closure were enrolled in this retrospective study. Dopppler ultrasound (DUSG) scanning was used as the primary imaging tool for the determination of residual and recurrent stenosis. During the follow-up period duplex ultrasonography was performed in the second month, sixth month and annually thereafter. Ipsilateral cerebrovascular events and mortalities were recorded during follow up period. Results: The mean age was 69,1 ± 7,1 (48-90) years. The median follow-up time was 47 (5 to 78) months. Hospital mortality was reported in 1 patient (0,8%). Early postoperative cerebrovascular accident were seen as ipsilateral disabling stroke in 1 patient (0,8%), ipsilateral non-disabling stroke in 1 patient (0,8%), reversible ischemic neurological deficit (RIND) in 1 patient (0,8%) and massive intracranial bleeding in 1 patient (0,8%). Late mortality was reported in 4 (3,3%) patients. 2 (1,6%) were cardiac reasons and 2 (1,6%) were non cardiac reasons. During the follow-up period ipsilateral cerebrovascular accident (CVA) were seen in 3 patients (2,5%) and these were; ipsilateral disabling stroke in 1 patient (0,8%), ipsilateral non-disabling stroke in 1 patient (0,8%), RIND in 1 patient (0,8%).According to the latest duplex scanning during follow up period 4 (3,3%) patients had below 50% restenosis, 2 (1,7%) patients had above 70% restenosis and 1 (0,8%) patient had total occlusion. Conclusion: Primary closure technique for CEA can be used in selected patients with acceptable early and late complication rates, low mortality and low restenosis rate.


Introduction
The efficacy of carotid endarterectomy (CEA) for stroke prevention in asymptomatic and symptomatic patients with severe carotid stenosis was shown in many studies. [1][2][3][4] American Heart Association (AHA) defines stroke and mortality rates threshold values for CEA in the light of many clinical studies. Threshold values for stroke are below 6% in symptomatic patients (above 50% stenosis proved by angiography) and below 3% in asymptomatic patients (above 60% stenosis proved by angiography) for CEA. [5] Today, there is no consensus about two basic subjects for severe asymptomatic or symptomatic carotid stenosis patients. First is which treatment strategy is the right choice CEA or carotid artery stenting (CAS) in this group of patients. Second is which option among primary closure, eversion, synthetic or autologous venous patch is the best choice while performing CEA.
In this study, we aimed to share long term follow up results for primary closure technique for isolated CEA without shunting and investigated risk factors for complications in this patient group.

Material and Methods
All patients were operated by the same senior surgeon in two different centres. Patients who underwent staged, reverse staged and concomittant procedures were excluded from the study.
Clinical and demographic data were obtained from hospital records and office charts. Preoperative data were age, gender, hypertension, smoking, atherosclerotic cardiac disease, diabetes mellitus, peripheral vascular disease, family history, hyperlipidaemia, previous cardiac surgery, chronic obstructive pulmonary disease, chronic renal failure, atrial fibrillation and history of carotid artery disease symptoms (including disabling and non-disabling stroke, reversible ischemic neurologic deficit (RIND), transient ischemic attack (TIA), amaurosis fugax). Results of preoperative imaging (duplex ultrasonography (DUSG), computerized tomographic angiography (CTA), digital subtraction angiography (DSA) or conventional angiography) were also noted. Perioperative data including carotid artery clamping time, using of shunt, type of surgery (elective, emergent or urgent) were recorded.
Preoperative and postoperative DUSG examinations were performed by using a General Electric Logiq S7 Expert scanner equipped with 9L linear multi frequency transducer. The B-mode settings were adjusted to optimize the quality of the grey-scale images and the pulse repetition frequency used with colour Doppler flow imaging was adjusted according to the flow velocity.
The characteristics of the plaques were described in accordance with the Gray-Weale Classification. [6,7] The degree of stenosis involving the internal carotid artery (ICA) was described in accordance with the Society of Radiologists in Ultrasound Consensus Criteria reported by Grant et al. [8] All stenosis were confirmed by CTA or DSA or conventional angiography.
DUSG scanning was used as the primary imaging tool for the determination of residual and recurrent stenosis. During the follow-up period DUSG was performed in the second month, sixth month and annually thereafter. Restenosis which was found during follow-up period was classified as the same classifying criteria like preoperative period. Ipsilateral cerebrovascular events and mortalities were recorded during follow up period.
Emergent CEA was performed for revascularization of symptomatic patients within 2 weeks from stroke onset. Urgent CEA was performed within 6 hours from stroke onset. All patients signed standard informed consent forms for carotid endarterectomy and were informed about the potential risk of surgery.
All patients had dual anti-platelet (acetylsalicylic acid 100 mg and clopidogrel 75 mg) and anti hyperlipidemic therapy (atorvastatin 20 mg) during follow-up period.
Informed consent was obtained from all the patients participating in the study, and all the researchers signed the Declaration of Helsinki. Approval for the study was granted by the local ethics committee.

Surgical Technique
All procedures were performed under general anaesthesia. After positioning the patient, an incision was made anterior to the sternocleidomastoid muscle and exploration of common (CCA), external (ECA) and internal (ICA) carotid arteries was performed. After heparinisation (weight-based heparin dosing) (85 IU/kg), the vascular clamps were placed and arteriotomy was performed from CCA to ICA. Endarterectomy was applied and then atheromatous plaque was removed. A search for intimal flap was done and tacking sutures (with 7/0 non-absorbable polypropylene) was applied to the ICA if needed. If a large atheromatous plaque was protruding into the ECA, eversion endarterectomy technique was performed to the ECA. Finally the arteriotomy site was primarily repaired by 6/0 monofilament non-absorbable suture with continue technique under proper magnification. Protamine sulphate was not administered at the end of the procedure. After meticulous homeostasis and placement of minivac drain, wound closure and dressing was performed. For all patients conventionally accepted methods of determining the need of shunt insertion, including formal measurement of the ICA back flow and if needed back flow pressure were used. In this series all patients were operated without shunting. The vascular clamping time was recorded during the procedure.

Statistical Analysis
Data analyses were performed by using IBM SPSS Statistics version 17.0 software (IBM Corporation, Armonk, NY, USA). Whether the distributions of continuous variables were normally or not was determined by Kolmogorov Smirnov test. Continuous variables were shown as mean ± SD or median (min-max), where applicable. Number of cases and percentages were used for categorical data. While, the mean differences between groups were compared by Student's t test, otherwise, Mann Whitney U test was applied for not normally distributed data. Categorical variables were analysed by Fisher's exact test. A p value less than 0.05 was considered statistically significant.

Results
Between September 2013-2019, 122 patients with isolated CEA with primary closure were enrolled in this study. All patients were operated by same senior surgeon in two different centres. 75 patients (61,5%) were male and 47 patients (38,5%) were female. The mean age was 69,1 ± 7,1 (48-90) years. Degree of stenosis in contralateral ICA was under 50% in all patients who had bilateral stenosis.
In addition to degree of stenosis, type of plaque and symptomatology of patient were also taken into consideration while deciding surgery. 6 patients with 50-70% stenosis were operated because of their symptoms and type 1 or type II plaques. Preoperative demographic variables, clinical features and preoperative ultrasonographic parameters of the patients listed in Table I.  Neck hematoma and bleeding were reported in patients who use clopidogrel during preoperative period but this was not statistically significant. Patient with postoperative ipsilateral disabling stroke was the one who was operated urgently within 6 hours of stroke onset.
According to the latest duplex scanning during follow up period 114 (94,2%) patients were normal, 4 (3,3%) patients had below 50% stenosis, 2 (1,7%) patients had above 70% stenosis and 1 (0,8%) patient had total occlusion. This patient was the one who had late disabling stroke complication. Operative and the follow-up data are listed in Table II. There is no statistically significant difference between preoperative variables and operative data when we compare patients who had late cerebrovascular accidents with had no complications.
When we compare patients who had restenosis after operation with patients with normal control DUSG, we found out that bilateral carotid artery stenosis was statistically significant in restenosis group (p=0,018). Also these patients, who had restenosis, had statistically significantly less type 2 plaque preoperatively (p=0,020). In addition to this, type 4 preoperative plaque was higher in restenosis group but this  Table III.
Patients who had cerebrovascular events during follow up period had higher PVD ratio than the others but this is not statistically significant (p=0,070).

Discussion
The primary goal in carotid artery revascularization is to prevent stroke in patients with carotid artery stenosis but there are two important questions which have not been answered yet. First one is CAS or CEA and the second one is which technique is most preferable while performing CEA.
On the basis of the extensive experience and several metaanalysis of randomized clinical trials comparing CAS with CEA disclosed no difference stroke or death rates in 30 days; in myocardial infarction (MI), stroke or death rates in 1 year. [9,10] In some studies, CAS was associated with a lower rate of MI and procedural morbidity such as cranial nerve injury [9], but others found CAS to be inferior to CEA or associated with higher rates of periprocedural stroke. [11,12] In some reports, there is near equivalence between CAS and CEA. [13,14] However, CEA has maintained superiority in most clinical trials and remains the best treatment option for most patients who require revascularization for carotid artery disease. And they have stated that; ≥ 70% recurrent stenosis was seen in 18 postoperative arteries (5.2%) (14 (8,6%) after primary closure and 4 (2,2%) after patch angioplasty), ≥ 50% recurrent stenosis was found in 31 arteries (8,9%) (22 (13,6%) after primary closure versus 9 (4,9%) arteries with patch closure).
They reported that only patch angioplasty was found to influence the restenosis rate. [15] Karen J. Ho et al. reported intermediate term outcome of CEA with bovine pericardial patch closure compared with Dacron patch and primary closure. They found that 30-day stroke and death were significantly lower in primary closure group.
When they compared groups about five year restenosis rates, they found out that patch closure (especially bovine patch closure) had better outcomes but they also stated that none of the variables proved significant predictors of restenosis. [16] Similarly, Efthymios et al. stated that there was no statistically significant difference among primary closure, patch closure and eversion closure about stroke and death rates. [17] In EVEREST (Eversion Carotid Endarterectomy Versus Standard Trials) study, 1353 patients were included and divided into two groups (678 patients in the conventional group, 675 patients in the eversion group). They found no statistical difference in late outcome (stroke, death and restenosis) between standard (patch and primary closure) and eversion CEA. Subgroup analysis showed that restenosis were statistically comparable) 2,8% vs 1,5%) for eversion and patch, respectively, while both significantly lower restenosis rates than primary closure. [18] In several studies, with respect to the technical component of the operation, there is consensus that patch closure is superior to primary closure. [18,19] On the other hand, there are many studies reported that primary closure technique is comparable and even superior to patch closure technique thanks to new medical treatment regimens and careful selection of patients. [20] Similarly, in our series, recurrent stenosis was seen in seven patients and only 3 of them serious (4 patients (3,3%) < 50% stenosis, 2 patients (1,7%) > 70% stenosis and 1 patient (0,8%) occlusion).

Study Limitations
This study is a retrospective, descriptive study and there is no control group of patients who underwent alternative techniques for comparison. Despite these, we believe that our study add useful information to the literature about safety and efficacy of primary closure technique for the CEA.

Conclusion
As a conclusion, primary closure technique for CEA can be used by experienced centres safely in selected patients with acceptable early and late complication rates, low mortality and low restenosis rate.