- Email: [email protected]
Single Center Experience With Modified Eversion Carotid Endarterectomy
Single Center Experience With Modified Eversion Carotid Endarterectomy Tze-Woei Tan, Albert K. Weyman, Siamak Barkhordarian, and Robert B. Patterson, Providence, Rhode Island
Background: Transaortic endarterectomy is a well-described technique for surgical revascularization of orificial atherosclerotic renovascular disease. Adopting this technique to carotid endarterectomy (CEA), modified eversion carotid endarterectomy (MECE), uses a traditional longitudinal arteriotomy that is confined to the bulb. This obviates the need for patch closure, simplifies the procedure, and permits easy conversion to traditional patch closure carotid endarterectomy (PCEA) for technical defects. We compared the safety and efficacy of this technique with PCEA. Methods: Three vascular surgeons performed 223 CEAs between July 2004 and December 2008 at a tertiary teaching hospital. Outcomes measured included perioperative stroke rate, morbidity rate, mortality rate, and late restenosis. The incidence of moderate (60-79%) and severe (80%) restenosis was examined at <6 weeks, 1 year, and 2 years after operation. All patients included in this study underwent follow-up for >12 months. Data were analyzed with Student’s t-test ( p < 0.05 ¼ significant). Results: CEA was performed for symptomatic disease in 40.4% (90/223) of patients. One surgeon performed MECE in 73.3% (99/135) of his patients during this period; the remaining patients (n ¼ 124) underwent traditional PCEA. Intraoperative completion duplex ultrasound was performed for all patients. In 5.1% (5/99) of the patients, MECE was converted to PCEA for residual flaps. Intraoperative carotid cross-clamping time was significantly shorter in the MECE group (29.2 minutes vs. 52.2 minutes, p < 0.05). For patients in the PCEA group, the overall mortality rate was 1.8% (4/223), and perioperative stroke rate was 1.4% (3/223). Overall morbidity was 7.2%, which was similar between the two groups. Late restenosis rate on duplex scan was 7.1% (1.0% severe stenosis), early occlusion occurred in one patient with PCEA, and the reintervention rate was 1.0% (2/196). The incidence of late restenosis was similar between the MECE and PCEA group (8.4% vs. 6.2%, p ¼ 0.55). Mean follow-up was 26.3 months for the MECE group and 29.4 months for the PCEA group. Conclusions: MECE is a safer alternative to conventional endarterectomy with a restenosis rate comparable with PCEA, offers the potential advantage of shorter clamping time, and obviates the need for patch closure.
INTRODUCTION Carotid endarterectomy (CEA) is the most effective treatment for prevention of stroke in atherosclerotic
Presented at the 20th Annual Winter Meeting of the Peripheral Vascular Surgery Society, Vail, CO, January 29-31, 2010. Providence Surgical Care Group, Warren Alpert School of Medicine, Brown University, Providence, RI. Correspondence to: Robert B. Paterson, MD, Providence Surgical Care Group, 486 Silver Spring, Providence, RI 02904, USA, E-mail: [email protected] Ann Vasc Surg 2011; 25: 87-93 DOI: 10.1016/j.avsg.2010.11.004 Ó Annals of Vascular Surgery Inc.
carotid artery stenosis.1-4 Surgical techniques for CEA have evolved in the last 50 years, traditionally performed with a longitudinal arteriotomy extending from the common carotid artery into the internal carotid artery (ICA). Patch closure is superior to primary closure with a lower risk of long-term stroke and carotid restenosis.5-8 Currently-practiced eversion carotid endarterectomy (ECEA) was first described by De Bakey et al. in 19599 and later modified by Kieny et al. in 1985.10 The purported benefits of ECEA include decreased operative time, avoidance of prosthetic material, and decreased rates of restenosis.8,11,12 Transaortic endarterectomy is a well-described technique for surgical revascularization of orificial 87
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Fig. 1. Technique of MECE. A Endarterectomy plane started using longitudinal arteriotomy that is confined to the bulb. The longitudinal arteriotomy ends (black
arrow) several millimeters before the end of the bulb (white arrow). B Endarterectomy continued cephalad into ICA by distal eversion over the atherosclerotic core.
atherosclerotic mesenteric and renovascular disease.13 By modifying this technique for carotid endarterectomy (MECE), a longitudinal arteriotomy can be used that is confined to the bulb without extension into the ICA. This obviates the need for patch closure, simplifies the procedure, requires less dissection and carotid manipulation as compared with ECEA, and permits easy conversion to traditional patch closure (PCEA) for technical defects. The goal of the present study is to compare the safety and efficacy of MECE with PCEA.
MECE group and 29.4 (12-62) months for the PCEA group. The study protocol was reviewed and approved by the Institutional Review Board. Primary outcome measures include perioperative stroke, overall morbidity, and overall mortality rates. Myocardial infarction was confirmed by positive electrocardiograph changes and elevated cardiac enzymes. Electrocardiography was performed routinely postoperatively and cardiac enzymes were detected on clinical suspicion. Other outcomes included late restenosis of the operated carotid artery and intraoperative carotid artery cross-clamping time. Postoperative duplex examination was performed at <6 weeks, 1 year, and to a maximum of 2 years after the operation. Moderate restenosis (60-79% reduction in vessel diameter) and severe restenosis (80%) were defined using duplex ultrasound criteria.14
MATERIALS AND METHODS A total of 227 CEAs were performed by three vascular surgeons between July 2004 and December 2008 at a tertiary teaching hospital. The indication for surgery, patient comorbidities, operative details, hospital stay, and outpatient follow-up were reviewed retrospectively from hospital and office charts as well as radiology and vascular laboratory records. Duplex imaging was the primary imaging modality used in recommending CEA, but did not influence choice of MECE versus PCEA, which was an intraoperative decision. Patients undergoing excision of carotid body tumor and carotid subclavian bypass were excluded. In this study, all patients were followed up for >12 months and for 23 of these patients (10.3%) follow-up was for <24 months; mean follow-up was 26.3 (12-49) months for the
Procedures MECE was performed under general anesthesia (laryngeal mask airway with cervical block or general endotracheal anesthesia). Carotid stump pressure and cerebral oximetry were used for monitoring and selective shunting. PCEA was performed either with cervical block with monitored anesthesia care or under general anesthesia with selective shunting using criteria described previously and a Hemashield patch was used for closure. MECE was performed
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Table I. Demographics and clinical features
Age (years) Male Coronary artery disease COPD DM Renal failure Hypertension Hyperlipidemia Peripheral vascular disease Smoker/ex-smoker
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
74.5 59.6% 63.6% 23.2% 25.3% 10.1% 96.0% 84.8% 20.2% 81.8%
72.5 49.2% 49.2% 11.3% 16.9% 8.9% 94.4% 72.6% 16.9% 74.2%
0.12 0.03 0.008 0.13 0.75 0.58 0.003 0.53 0.18
(45-90) (59/99) (63/99) (23/99) (25/99) (10/99) (95/99) (84/99) (20/99) (81/99)
(47-93) (61/124) (61/124) (14/124) (21/124) (11/124) (117/124) (90/124) (21/124) (92/124)
COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus.
Table II. Perioperative complications of patients
Death Stroke Combined stroke and death MI Hematoma CN injury ARF DVT
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
0% 0% 0% 4.04% 0% 0% 1.01% 1.01%
3.23% 2.42% 4.84% 3.23% 1.61% 0.81% 0% 0%
0.07 0.12 0.03 0.75 0.20 0.37 0.26 0.26
(0/99) (0/99) (0/99) (4/99)
(1/99) (1/99)
(4/124) (3/124) (6/124) (4/124) (2/124) (1/124)
MI, myocardial infarction; CN, cranial nerve; ARF, acute renal failure; DVT, deep venous thrombosis.
using a traditional longitudinal arteriotomy that was confined to the bulb (Fig. 1A) without extending the arteriotomy to the proximal ICA. After vascular control, the distal ICA was gently mobilized without the need for extensive dissection of the bifurcation and bulb, as with traditional ECEA. Endarterectomy was performed similar to the eversion technique15 by distal eversion of the adventitia over the atherosclerotic core and by removing the atheroma under direct vision (Fig. 1B). The endpoint was visualized and loose fibers were removed. In cases when the endpoint was not satisfactory by inspection or on intraoperative duplex scan, the arteriotomy was extended to the ICA and the procedure was converted to a traditional PCEA. The longitudinal arteriotomy was closed primarily with running fine monofilament suture. Intraoperative duplex ultrasound was performed for all CEAs in this study and MECE was converted to PCEA in cases when residual flap was noted on the endarterectomy endpoint. Statistical Methods Univariate comparisons of patient characteristics and outcomes were performed with Student’s t-test and c2 test; p values of <0.05 were assumed to be statistically significant.
RESULTS A total of 227 consecutive CEA were performed within the study period. Four patients were excluded from this study because of exclusion criteria stated previously. Three (1.35%) CEAs were performed in combination with coronary artery bypass graft. CEA was performed for symptomatic disease in 40.4% (90/223) of patients. One surgeon (R.B.P.) performed MECE in 73.3% (99/135) of his patients during this period; the remainder of his patients and all patients from the other two surgeons (n ¼ 124) underwent traditional PCEA. Conversion from MECE to PCEA was performed for 5.1% (5/99) of patients most commonly because of a distal flap at the endpoint on intraoperative duplex ultrasound. Based on intraoperative duplex findings, an additional two CEAs were reexplored because of residual flaps and one for no flow, and closed without conversion to PCEA. In the PCEA group, eight CEAs were reexplored - seven for residual flaps and one for no flow. Total reexploration rate for duplex findings was similar in both groups (MECE: 8/99 ¼ 8.08%, PCEA: 8/124 ¼ 6.45%, p ¼ 0.64). Patient demographics and comorbidities are listed in Table I. Patients in the MECE group had a significantly higher incidence of coronary artery disease and chronic
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Table III. Preoperative characteristics of patients
Symptomatic TIA Stroke Ipsilateral ICA stenosis 60-79% Ipsilateral ICA stenosis >80% Contralateral occlusion
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
30.30% 26.26% 4.04% 12.12% 87.88% 2.02%
48.39% 32.26% 16.13% 12.90% 87.10% 8.06%
0.006 0.33 0.003 0.86 0.86 0.05
(30/99) (26/99) (4/99) (12/99) (87/99) (2/99)
(60/124) (40/124) (20/124) (16/124) (108/124) (10/124)
TIA, transient ischemic attack; ICA, internal carotid artery.
Table IV. Overall restenosis and reintervention rate MECE
Restenosis rate (1 year) Occlusion (1 year) Restenosis rate (2 years) Severe restenosis rate (2 years) Reintervention rate (2 years)
3.0% 0% 8.4% 1.2% 1.2%
PCEA
(3/99) (7/83) (1/83) (1/83)
3.3% 0.8% 6.2% 0.9% 0.9%
p-value
(4/120) (1/120) (7/113) (1/113) (1/113)
0.89 0.36 0.55 0.83 0.83
Table V. Demographics and clinical features of patients for single surgeon who performed both procedures
Age (years) Male Coronary artery disease COPD DM Renal failure Hypertension Hyperlipidemia Peripheral vascular disease Smoker/ex-smoker
MECE (n ¼ 99)
PCEA (n ¼ 37)
p value
74.5 59.6% 63.6% 23.2% 25.3% 10.1% 96.0% 84.8% 20.2% 81.8%
70.5 56.8% 37.8% 13.5% 18.9% 8.1% 97.3% 64.9% 24.3% 86.5%
0.76 0.007 0.21 0.44 0.73 0.71 0.01 0.6 0.52
(45-90) (59/99) (63/99) (23/99) (25/99) (10/99) (95/99) (84/99) (20/99) (81/99)
(56-91) (21/37) (14/37) (5/37) (7/37) (3/37) (36/37) (24/37) (9/37) (32/37)
COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus.
obstructive pulmonary disease as compared with those in the PCEA group. The 30-day mortality rate for all patients was 1.8% (4/223), and perioperative stroke rate was 1.35% (3/223), all occurring in patients who underwent PCEA (Table II). Four patients died during the perioperative period, three from cardiac events, including cardiac arrest secondary to pulseless electrical activity and myocardial infarct. One death was due to an aspiration from massive stroke. Combined stroke and death rate was 4.8% in the PCEA group and was significantly higher than that of the MECE group ( p ¼ 0.03). Overall morbidity rate was 7.2% with similar rates between the two groups (Table II). Myocardial infarction occurred in eight of the total 223 (3.6%) patients; 4 of 99 (4.0%) in MECE and 4 of 124 (3.2%) in PCEA group, p ¼ 0.75.
Preoperative carotid duplex indices and indications for CEA are summarized in Table III. Preoperative ipsilateral and contralateral ICA stenosis, including contralateral occlusion, was similar between the two groups. Overall, more patients underwent PCEA for symptomatic disease (48.4% vs. 30.3%, p ¼ 0.006) and had higher incidence of contralateral ICA occlusion (8.1% vs. 2.0%, p ¼ 0.05). There was one ICA occlusion after surgery and this early asymptomatic occlusion was found on the 6-week follow-up duplex ultrasound in a patient who underwent PCEA. Overall restenosis rate at 1-year follow-up was 3.2% (7/219) and late restenosis rate (2-year) was 7.1% (14/196). At the 2-year follow-up, the severe stenosis (80%) rate was 1.0% (2/196) and overall reintervention rate was 1.0% (2/196) (Table IV); the patient in the MECE group underwent redo CEA with
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Table VI. Preoperative characteristics of patients for single surgeon who performed both procedures
Symptomatic TIA Stroke Ipsilateral ICA stenosis 60-79% Ipsilateral ICA stenosis >80% Contralateral occlusion
MECE (n ¼ 99)
PCEA (n ¼ 37)
p value
30.30% 26.26% 4.04% 12.12% 87.88% 2.02%
59.5% 40.5% 59.5% 16.2% 83.8% 13.5%
0.002 0.11 <0.0001 0.53 0.53 0.007
(30/99) (26/99) (4/99) (12/99) (87/99) (2/99)
(22/37) (15/37) (22/37) (6/37) (31/37) (5/37)
TIA, transient ischemic attack; ICA, internal carotid artery.
Table VII. Perioperative complications of patients for single surgeon who performed both procedures
Death Stroke Combined stroke and death MI Hematoma CN injury ARF DVT
MECE (n ¼ 99)
PCEA (n ¼37)
p value
0% (0/99) 0% (0/99) 0% (0/99) 4.04% (4/99) 0% 0% 1.01% (1/99) 1.01% (1/99)
5.4% 2.7% 8.1% 0% 2.7% 0% 0% 0%
0.02 0.1 0.004 0.21 0.1 1.0 0.54 0.54
(2/37) (1/37) (3/37) (1/37)
MI, myocardial infarction; CN, cranial nerve; ARF, acute renal failure; DVT, deep venous thrombosis.
Table VIII. Late restenosis and reintervention rate for single surgeon who performed both procedures
Restenosis rate (2 years) Severe restenosis rate (2 years) Reintervention rate (2 years)
MECE (n ¼ 83)
PCEA (n ¼ 29)
p value
8.4% (7/83) 1.2% (1/83) 1.2% (1/83)
6.9% (2/29) 0% 0%
0.79 0.55 0.55
Hemashield patch closure, whereas the one in the PCEA group had carotid stent placement 12 months after the first surgery. Incidence of overall late restenosis was equivalent between the MECE and the PECE group (8.4% vs. 6.0%, p ¼ 0.50). One surgeon (R.B.P.) performed both MECE (n ¼ 99) and PCEA (n ¼ 37) procedures. Demographics and clinical features of his patients are listed in Table V. Patients in his MECE group had a higher incidence of coronary artery disease than the PCEA group. More patients in the PCEA group underwent surgery for symptomatic disease (Table VI) and had preoperative contralateral ICA occlusion (13.5% vs. 2.0%, p ¼ 0.007). Perioperative complications of his patients are listed in Table VII. His PCEA group had significantly higher incidence of perioperative mortality (5.4% vs. 0%, p ¼ 0.02) and combined stroke and death rate (8.1% vs. 0%, p ¼ 0.004). Incidence of late
restenosis and reintervention rate were similar between the MECE and the PECE group (8.4% vs. 6.9%, p ¼ 0.79) (Table VIII). Carotid shunt placement was required in 44.8% (100/223) of CEAs in this series, 6.1% (6/99) in the MECE patients and 75.8% (94/124) in the PCEA group, p<0.0001. Shunt placement rate was 57.8% for symptomatic patients and 36.0% for asymptomatic patients. The MECE group had an average carotid artery cross-clamping time of 29.2 (17-55) minutes, which was statistically shorter than the PCEA group, who had an average cross-clamping time of 52.2 (15-105) minutes, p ¼ 0.03 (Table IX).
DISCUSSION The safety and efficacy of ECEA has been validated in multiple randomized control trials,16,17 which have shown that ECEA is a safe and durable
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Table IX. Intraoperative carotid cross-clamping time and carotid shunt rate MECE (n ¼ 99)
Intraoperative carotid cross-clamping time Carotid shunt placement
29.2 (17-55) minutes 6.1% (6/99)
long-term treatment for ICA stenosis.18 Potential benefits of ECEA include avoidance of prosthetic patch for closure, lower restenosis rates, and shorter carotid cross-clamping times. This technique is especially useful when the ICA is coiled or kinked.10 However, the potential disadvantages of ECEA include difficulty in visualizing the endpoint, more extensive dissection in the vicinity of the bifurcation and bulb, and it is more technically demanding in cases when a shunt is required.19 Transaortic renal endarterectomy has been used for orificial atherosclerotic renovascular disease, particularly in conjunction with concomitant aortic surgery.13 By using MECE, a similar technique to transaortic orificial endarterectomy, CEA can be performed using a longitudinal arteriotomy that is confined to the carotid artery bulb. The arteriotomy is then closed primarily without a patch. The risk of narrowing the lumen of ICA is minimal by confining the arteriotomy to the carotid bulb, thus avoiding the necessity for patch closure. In this study, intraoperative completion carotid duplex ultrasound was performed for all patients; 5.1% of MECE were converted to PCEA because of technical defects that appeared most commonly as a distal flap at the endpoint on ultrasound. These patients, for whom MECE was converted to PCEA, were administered anticoagulants so as to minimize the risk of thromboembolism. There were no complications in this group of patients requiring conversion to PCEA. One surgeon (R.B.P.) in this study performed MECE in 73.3% of his patients during the study period. All his patients were considered for MECE irrespective of preoperative image findings; the decision to perform MECE or PCEA was decided intraoperatively. In all, 27% of his patients (36/133) underwent PCEA because of technical defects after MECE (5/36), a long arteriosclerotic plaque that precluded MECE, obligate carotid shunt placement (28/36), or an inadequate endpoint with attempted transarterial endarterectomy (2/36). In these cases, extension of the arteriotomy into the ICA was necessary to perform adequate endarterectomy and patch closure was performed.
PCEA (n ¼ 124)
52.2 (15-105) minutes 75.8% (94/124)
p value
0.03 <0.0001
Although some claim safety and feasibility of shunt placement with ECEA,15,16 one of the concerns with ECEA is the difficulty with shunt placement.20 We have similarly noted that shunt placement is more technically demanding with MECE. Although we have successfully used ICA shunting with MECE in the early part of our experience without any complications related to shunt placement, it is currently our preference to convert to longitudinal arteriotomy and traditional patch closure in cases when shunt placement is needed, especially for patients with a history of recent stroke and contralateral ICA occlusion21-24 so as to minimize the total ischemic time. This accounts for the shunt rate for the PCEA group (76%) being significantly higher than the MECE patients (6%) in this study, as well as the greater percentage (48%) of symptomatic patients in the PCEA cohort. Kumar et al. recently reported their experience with modified eversion carotid endarterectomy,25 confirming low perioperative mortality and morbidity rate. Their reported 2-year severe restenosis rate of 0.92% and rate of conversion to PCEA were similar to our experience. They questioned the clinical value for shunt placement with brief carotid cross-clamping time in their study and relatively low overall shunt use (2.7%), mainly for patient with severe contralateral disease. We disagree on the basis of stump pressure criteria, and feel that there remains a role for carotid shunting, especially in patients with severe contralateral disease, contralateral occlusion, and history of recent stroke.21-24 Our current practice is to perform traditional PCEA when shunting is required. There are several limitations to our study. It is a retrospective review of single center data, and the sample size is most likely not large enough to definitively determine the superiority of one technique over the other. However, this study showed no differences in perioperative mortality, stroke rate, and postoperative ICA restenosis rate between the two groups. We demonstrated good and equivalent results between the two techniques in our center with statistically shorter carotid cross-
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clamping time in the MECE group. Although carotid cross-clamping time is not known to be associated with worst morbidity or mortality, it can be associated with higher incidence of early restenosis after carotid endarterectomy.26 A second limitation of this study is the selective and heterogeneous nature of patients who underwent MECE; more likely to be asymptomatic patients with severe ICA stenosis as compared with the PCEA group and most likely skewed by the preference for PCEA when carotid shunting is difficult. All MECE were performed by a single surgeon in this study with preference toward MECE in his patients. We recognize this potential bias within the study, but our data suggests that, with experience, MECE has the potential benefit of simplifying the procedure and remains a safe, expeditious, and effective technique for treatment of atherosclerotic ICA stenosis.
Modified eversion carotid endarterectomy
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10.
11.
12.
13.
14.
15.
CONCLUSION MECE has the advantage of short carotid crossclamping time, avoidance for patch, and less dissection as compared with conventional ECEA for atherosclerotic carotid disease, and is a safe alternative to PCEA with a comparable restenosis rate. REFERENCES 1. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991;325:445-453. 2. Executive committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid stenosis. JAMA 1995;273:1421-1428. 3. European Carotid Surgery Trialists’ Collaborative Group. Randomized trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet 1998;351:1379-1387. 4. Halliday A, Mansfield A, Marro J, et al. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomized control trial. Lancet 2004;363:1491-1502. 5. Bond R, Rerkasem K, AbuRahma AF, Naylor AR, Rothwell PM. Patch angioplasty versus primary closure for carotid endarterectomy. Cochrane Database Syst Rev 2004;2:CD000160. 6. Manheim D, Weller B, Vahadim E, Karmeli R. Carotid endarterectomy with a polyurethane patch versus primary closure: a randomized study. J Vasc Surg 2005;41:403-407. 7. Bond R, Rerkasem K, Naylor AR, Aburahma AF, Rothwell PM. Systemic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy. J Vasc Surg 2004;40:1126-1135. 8. Byrne J, Feustel P, Darling RC III. Primary closure, routine patching, and eversion endarterectomy: what is the current
16.
17.
18. 19.
20.
21. 22.
23.
24.
25.
26.
93
state of the literature supporting use of these techniques? Semin Vasc Surg 2007;20:226-235. De Bakey ME, Crawford ES, Cooley DA, Morris GC Jr. Surgical considerations of occlusive disease of innominate, carotid, subclavian, and vertebral arteries. Ann Surg 1959;149:690-710. Kieny R, Hirsch D, Seiller C, Thiranos JC, Petit H. Does carotid eversion endarterectomy and reimplantation reduce the risk of restenosis? Ann Vasc Surg 1993;7:407-413. Darling RC III, Shah DM, Chang BB, et al. Carotid endarterectomy using the eversion technique. Semin Vasc Surg 2000;13:4-9. Cao P, De Rango P, Zannetti S. Eversion vs conventional carotid endarterectomy: a systemic review. Eur J Vasc Endovasc Surg 2002;23:195-201. Clair DG, Belkin M, Whittemore AD, Mannick JA, Donaldson MC. Safety and efficacy of transaortic renal endarterectomy as an adjunct to aortic surgery. J Vasc Surg 1995;21:926-933. Grant EG, Benson CB, Moneta GL, et al. Carotid artery stenosis: gray-scale and Doppler US diagnosisdSociety of Radiologists in Ultrasound Consensus Conference. Radiology 2003;229:340-346. Shah DM, Darling RC III, Chang BB, et al. Carotid endarterectomy by eversion technique, its safety and durability. Ann Surg 1998;228:471-478. Cao P, Giordano G, De Rango P, et al. A randomized study on eversion versus standard carotid endarterectomy. Study design and preliminary results: the Everest Trial 1998. J Vasc Surg 1998;27:595-605. Cao P, Giordano G, De Rango P, et al. Eversion versus conventional carotid endarterectomy: late results of a prospective multicenter randomized trial. J Vasc Surg 2000;31:19-30. Black JH III, Ricotta JJ, Jones CE. Long-term results of eversion carotid endarterectomy. Ann Vasc Surg 2010;24:92-99. Green RM, Greenberg R, Illig K, Shortell C, Ouriel K. Eversion endarterectomy for the carotid artery: technical considerations and recurrent stenoses. J Vasc Surg 2000;32: 1052-1061. Crawford RS, Chung TK, Hodgman T, Pedraza JD, Corey M, Cambria RP. Restenosis after eversion vs. patch closure carotid endarterectomy. J Vasc Surg 2007;46:41-48. Baker WH, Dorner DB, Barnes RW. Carotid endarterectomy: is an indwelling shunt necessary? Surgery 1977;82:312-316. Graham AM, Gewertz BL, Zarins CK. Predicting cerebral ischemia during carotid endarterectomy. Arch Surg 1986;121:595-598. Lawrence PF, Alves JC, Jicha D, Bhirangi K, Dobrin PB. Incidence, timing, and causes of cerebral ischemia during carotid endarterectomy with regional anesthesia. J Vasc Surg 1998;27:329-337. Sundt TM, Ebersold MJ, Sharbrough FW, Piepgras DG, Marsh WR, Messick JM Jr. The risk-benefit ratio of intraoperative shunting during carotid endarterectomy. Relevancy to operative and postoperative results and complications. Ann Surg 1986;203:196-204. Kumar S, Porter C, Hager E, et al. Modified eversion carotid endarterectomy. Presented at: 37th Annual Meeting, Society for Clinical Vascular Surgery, March 18-21, 2008, Ft Lauderdale, FL. Malek LA, Malek AK, Leszczynski J, et al. Carotid clamping time as a risk factor for early restenosis after carotid endarterectomy. Eur J Vasc Endovasc Surg 2005;30: 143-146.
Background: Transaortic endarterectomy is a well-described technique for surgical revascularization of orificial atherosclerotic renovascular disease. Adopting this technique to carotid endarterectomy (CEA), modified eversion carotid endarterectomy (MECE), uses a traditional longitudinal arteriotomy that is confined to the bulb. This obviates the need for patch closure, simplifies the procedure, and permits easy conversion to traditional patch closure carotid endarterectomy (PCEA) for technical defects. We compared the safety and efficacy of this technique with PCEA. Methods: Three vascular surgeons performed 223 CEAs between July 2004 and December 2008 at a tertiary teaching hospital. Outcomes measured included perioperative stroke rate, morbidity rate, mortality rate, and late restenosis. The incidence of moderate (60-79%) and severe (80%) restenosis was examined at <6 weeks, 1 year, and 2 years after operation. All patients included in this study underwent follow-up for >12 months. Data were analyzed with Student’s t-test ( p < 0.05 ¼ significant). Results: CEA was performed for symptomatic disease in 40.4% (90/223) of patients. One surgeon performed MECE in 73.3% (99/135) of his patients during this period; the remaining patients (n ¼ 124) underwent traditional PCEA. Intraoperative completion duplex ultrasound was performed for all patients. In 5.1% (5/99) of the patients, MECE was converted to PCEA for residual flaps. Intraoperative carotid cross-clamping time was significantly shorter in the MECE group (29.2 minutes vs. 52.2 minutes, p < 0.05). For patients in the PCEA group, the overall mortality rate was 1.8% (4/223), and perioperative stroke rate was 1.4% (3/223). Overall morbidity was 7.2%, which was similar between the two groups. Late restenosis rate on duplex scan was 7.1% (1.0% severe stenosis), early occlusion occurred in one patient with PCEA, and the reintervention rate was 1.0% (2/196). The incidence of late restenosis was similar between the MECE and PCEA group (8.4% vs. 6.2%, p ¼ 0.55). Mean follow-up was 26.3 months for the MECE group and 29.4 months for the PCEA group. Conclusions: MECE is a safer alternative to conventional endarterectomy with a restenosis rate comparable with PCEA, offers the potential advantage of shorter clamping time, and obviates the need for patch closure.
INTRODUCTION Carotid endarterectomy (CEA) is the most effective treatment for prevention of stroke in atherosclerotic
Presented at the 20th Annual Winter Meeting of the Peripheral Vascular Surgery Society, Vail, CO, January 29-31, 2010. Providence Surgical Care Group, Warren Alpert School of Medicine, Brown University, Providence, RI. Correspondence to: Robert B. Paterson, MD, Providence Surgical Care Group, 486 Silver Spring, Providence, RI 02904, USA, E-mail: [email protected] Ann Vasc Surg 2011; 25: 87-93 DOI: 10.1016/j.avsg.2010.11.004 Ó Annals of Vascular Surgery Inc.
carotid artery stenosis.1-4 Surgical techniques for CEA have evolved in the last 50 years, traditionally performed with a longitudinal arteriotomy extending from the common carotid artery into the internal carotid artery (ICA). Patch closure is superior to primary closure with a lower risk of long-term stroke and carotid restenosis.5-8 Currently-practiced eversion carotid endarterectomy (ECEA) was first described by De Bakey et al. in 19599 and later modified by Kieny et al. in 1985.10 The purported benefits of ECEA include decreased operative time, avoidance of prosthetic material, and decreased rates of restenosis.8,11,12 Transaortic endarterectomy is a well-described technique for surgical revascularization of orificial 87
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Fig. 1. Technique of MECE. A Endarterectomy plane started using longitudinal arteriotomy that is confined to the bulb. The longitudinal arteriotomy ends (black
arrow) several millimeters before the end of the bulb (white arrow). B Endarterectomy continued cephalad into ICA by distal eversion over the atherosclerotic core.
atherosclerotic mesenteric and renovascular disease.13 By modifying this technique for carotid endarterectomy (MECE), a longitudinal arteriotomy can be used that is confined to the bulb without extension into the ICA. This obviates the need for patch closure, simplifies the procedure, requires less dissection and carotid manipulation as compared with ECEA, and permits easy conversion to traditional patch closure (PCEA) for technical defects. The goal of the present study is to compare the safety and efficacy of MECE with PCEA.
MECE group and 29.4 (12-62) months for the PCEA group. The study protocol was reviewed and approved by the Institutional Review Board. Primary outcome measures include perioperative stroke, overall morbidity, and overall mortality rates. Myocardial infarction was confirmed by positive electrocardiograph changes and elevated cardiac enzymes. Electrocardiography was performed routinely postoperatively and cardiac enzymes were detected on clinical suspicion. Other outcomes included late restenosis of the operated carotid artery and intraoperative carotid artery cross-clamping time. Postoperative duplex examination was performed at <6 weeks, 1 year, and to a maximum of 2 years after the operation. Moderate restenosis (60-79% reduction in vessel diameter) and severe restenosis (80%) were defined using duplex ultrasound criteria.14
MATERIALS AND METHODS A total of 227 CEAs were performed by three vascular surgeons between July 2004 and December 2008 at a tertiary teaching hospital. The indication for surgery, patient comorbidities, operative details, hospital stay, and outpatient follow-up were reviewed retrospectively from hospital and office charts as well as radiology and vascular laboratory records. Duplex imaging was the primary imaging modality used in recommending CEA, but did not influence choice of MECE versus PCEA, which was an intraoperative decision. Patients undergoing excision of carotid body tumor and carotid subclavian bypass were excluded. In this study, all patients were followed up for >12 months and for 23 of these patients (10.3%) follow-up was for <24 months; mean follow-up was 26.3 (12-49) months for the
Procedures MECE was performed under general anesthesia (laryngeal mask airway with cervical block or general endotracheal anesthesia). Carotid stump pressure and cerebral oximetry were used for monitoring and selective shunting. PCEA was performed either with cervical block with monitored anesthesia care or under general anesthesia with selective shunting using criteria described previously and a Hemashield patch was used for closure. MECE was performed
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Table I. Demographics and clinical features
Age (years) Male Coronary artery disease COPD DM Renal failure Hypertension Hyperlipidemia Peripheral vascular disease Smoker/ex-smoker
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
74.5 59.6% 63.6% 23.2% 25.3% 10.1% 96.0% 84.8% 20.2% 81.8%
72.5 49.2% 49.2% 11.3% 16.9% 8.9% 94.4% 72.6% 16.9% 74.2%
0.12 0.03 0.008 0.13 0.75 0.58 0.003 0.53 0.18
(45-90) (59/99) (63/99) (23/99) (25/99) (10/99) (95/99) (84/99) (20/99) (81/99)
(47-93) (61/124) (61/124) (14/124) (21/124) (11/124) (117/124) (90/124) (21/124) (92/124)
COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus.
Table II. Perioperative complications of patients
Death Stroke Combined stroke and death MI Hematoma CN injury ARF DVT
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
0% 0% 0% 4.04% 0% 0% 1.01% 1.01%
3.23% 2.42% 4.84% 3.23% 1.61% 0.81% 0% 0%
0.07 0.12 0.03 0.75 0.20 0.37 0.26 0.26
(0/99) (0/99) (0/99) (4/99)
(1/99) (1/99)
(4/124) (3/124) (6/124) (4/124) (2/124) (1/124)
MI, myocardial infarction; CN, cranial nerve; ARF, acute renal failure; DVT, deep venous thrombosis.
using a traditional longitudinal arteriotomy that was confined to the bulb (Fig. 1A) without extending the arteriotomy to the proximal ICA. After vascular control, the distal ICA was gently mobilized without the need for extensive dissection of the bifurcation and bulb, as with traditional ECEA. Endarterectomy was performed similar to the eversion technique15 by distal eversion of the adventitia over the atherosclerotic core and by removing the atheroma under direct vision (Fig. 1B). The endpoint was visualized and loose fibers were removed. In cases when the endpoint was not satisfactory by inspection or on intraoperative duplex scan, the arteriotomy was extended to the ICA and the procedure was converted to a traditional PCEA. The longitudinal arteriotomy was closed primarily with running fine monofilament suture. Intraoperative duplex ultrasound was performed for all CEAs in this study and MECE was converted to PCEA in cases when residual flap was noted on the endarterectomy endpoint. Statistical Methods Univariate comparisons of patient characteristics and outcomes were performed with Student’s t-test and c2 test; p values of <0.05 were assumed to be statistically significant.
RESULTS A total of 227 consecutive CEA were performed within the study period. Four patients were excluded from this study because of exclusion criteria stated previously. Three (1.35%) CEAs were performed in combination with coronary artery bypass graft. CEA was performed for symptomatic disease in 40.4% (90/223) of patients. One surgeon (R.B.P.) performed MECE in 73.3% (99/135) of his patients during this period; the remainder of his patients and all patients from the other two surgeons (n ¼ 124) underwent traditional PCEA. Conversion from MECE to PCEA was performed for 5.1% (5/99) of patients most commonly because of a distal flap at the endpoint on intraoperative duplex ultrasound. Based on intraoperative duplex findings, an additional two CEAs were reexplored because of residual flaps and one for no flow, and closed without conversion to PCEA. In the PCEA group, eight CEAs were reexplored - seven for residual flaps and one for no flow. Total reexploration rate for duplex findings was similar in both groups (MECE: 8/99 ¼ 8.08%, PCEA: 8/124 ¼ 6.45%, p ¼ 0.64). Patient demographics and comorbidities are listed in Table I. Patients in the MECE group had a significantly higher incidence of coronary artery disease and chronic
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Table III. Preoperative characteristics of patients
Symptomatic TIA Stroke Ipsilateral ICA stenosis 60-79% Ipsilateral ICA stenosis >80% Contralateral occlusion
MECE (n ¼ 99)
PCEA (n ¼ 124)
p value
30.30% 26.26% 4.04% 12.12% 87.88% 2.02%
48.39% 32.26% 16.13% 12.90% 87.10% 8.06%
0.006 0.33 0.003 0.86 0.86 0.05
(30/99) (26/99) (4/99) (12/99) (87/99) (2/99)
(60/124) (40/124) (20/124) (16/124) (108/124) (10/124)
TIA, transient ischemic attack; ICA, internal carotid artery.
Table IV. Overall restenosis and reintervention rate MECE
Restenosis rate (1 year) Occlusion (1 year) Restenosis rate (2 years) Severe restenosis rate (2 years) Reintervention rate (2 years)
3.0% 0% 8.4% 1.2% 1.2%
PCEA
(3/99) (7/83) (1/83) (1/83)
3.3% 0.8% 6.2% 0.9% 0.9%
p-value
(4/120) (1/120) (7/113) (1/113) (1/113)
0.89 0.36 0.55 0.83 0.83
Table V. Demographics and clinical features of patients for single surgeon who performed both procedures
Age (years) Male Coronary artery disease COPD DM Renal failure Hypertension Hyperlipidemia Peripheral vascular disease Smoker/ex-smoker
MECE (n ¼ 99)
PCEA (n ¼ 37)
p value
74.5 59.6% 63.6% 23.2% 25.3% 10.1% 96.0% 84.8% 20.2% 81.8%
70.5 56.8% 37.8% 13.5% 18.9% 8.1% 97.3% 64.9% 24.3% 86.5%
0.76 0.007 0.21 0.44 0.73 0.71 0.01 0.6 0.52
(45-90) (59/99) (63/99) (23/99) (25/99) (10/99) (95/99) (84/99) (20/99) (81/99)
(56-91) (21/37) (14/37) (5/37) (7/37) (3/37) (36/37) (24/37) (9/37) (32/37)
COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus.
obstructive pulmonary disease as compared with those in the PCEA group. The 30-day mortality rate for all patients was 1.8% (4/223), and perioperative stroke rate was 1.35% (3/223), all occurring in patients who underwent PCEA (Table II). Four patients died during the perioperative period, three from cardiac events, including cardiac arrest secondary to pulseless electrical activity and myocardial infarct. One death was due to an aspiration from massive stroke. Combined stroke and death rate was 4.8% in the PCEA group and was significantly higher than that of the MECE group ( p ¼ 0.03). Overall morbidity rate was 7.2% with similar rates between the two groups (Table II). Myocardial infarction occurred in eight of the total 223 (3.6%) patients; 4 of 99 (4.0%) in MECE and 4 of 124 (3.2%) in PCEA group, p ¼ 0.75.
Preoperative carotid duplex indices and indications for CEA are summarized in Table III. Preoperative ipsilateral and contralateral ICA stenosis, including contralateral occlusion, was similar between the two groups. Overall, more patients underwent PCEA for symptomatic disease (48.4% vs. 30.3%, p ¼ 0.006) and had higher incidence of contralateral ICA occlusion (8.1% vs. 2.0%, p ¼ 0.05). There was one ICA occlusion after surgery and this early asymptomatic occlusion was found on the 6-week follow-up duplex ultrasound in a patient who underwent PCEA. Overall restenosis rate at 1-year follow-up was 3.2% (7/219) and late restenosis rate (2-year) was 7.1% (14/196). At the 2-year follow-up, the severe stenosis (80%) rate was 1.0% (2/196) and overall reintervention rate was 1.0% (2/196) (Table IV); the patient in the MECE group underwent redo CEA with
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Table VI. Preoperative characteristics of patients for single surgeon who performed both procedures
Symptomatic TIA Stroke Ipsilateral ICA stenosis 60-79% Ipsilateral ICA stenosis >80% Contralateral occlusion
MECE (n ¼ 99)
PCEA (n ¼ 37)
p value
30.30% 26.26% 4.04% 12.12% 87.88% 2.02%
59.5% 40.5% 59.5% 16.2% 83.8% 13.5%
0.002 0.11 <0.0001 0.53 0.53 0.007
(30/99) (26/99) (4/99) (12/99) (87/99) (2/99)
(22/37) (15/37) (22/37) (6/37) (31/37) (5/37)
TIA, transient ischemic attack; ICA, internal carotid artery.
Table VII. Perioperative complications of patients for single surgeon who performed both procedures
Death Stroke Combined stroke and death MI Hematoma CN injury ARF DVT
MECE (n ¼ 99)
PCEA (n ¼37)
p value
0% (0/99) 0% (0/99) 0% (0/99) 4.04% (4/99) 0% 0% 1.01% (1/99) 1.01% (1/99)
5.4% 2.7% 8.1% 0% 2.7% 0% 0% 0%
0.02 0.1 0.004 0.21 0.1 1.0 0.54 0.54
(2/37) (1/37) (3/37) (1/37)
MI, myocardial infarction; CN, cranial nerve; ARF, acute renal failure; DVT, deep venous thrombosis.
Table VIII. Late restenosis and reintervention rate for single surgeon who performed both procedures
Restenosis rate (2 years) Severe restenosis rate (2 years) Reintervention rate (2 years)
MECE (n ¼ 83)
PCEA (n ¼ 29)
p value
8.4% (7/83) 1.2% (1/83) 1.2% (1/83)
6.9% (2/29) 0% 0%
0.79 0.55 0.55
Hemashield patch closure, whereas the one in the PCEA group had carotid stent placement 12 months after the first surgery. Incidence of overall late restenosis was equivalent between the MECE and the PECE group (8.4% vs. 6.0%, p ¼ 0.50). One surgeon (R.B.P.) performed both MECE (n ¼ 99) and PCEA (n ¼ 37) procedures. Demographics and clinical features of his patients are listed in Table V. Patients in his MECE group had a higher incidence of coronary artery disease than the PCEA group. More patients in the PCEA group underwent surgery for symptomatic disease (Table VI) and had preoperative contralateral ICA occlusion (13.5% vs. 2.0%, p ¼ 0.007). Perioperative complications of his patients are listed in Table VII. His PCEA group had significantly higher incidence of perioperative mortality (5.4% vs. 0%, p ¼ 0.02) and combined stroke and death rate (8.1% vs. 0%, p ¼ 0.004). Incidence of late
restenosis and reintervention rate were similar between the MECE and the PECE group (8.4% vs. 6.9%, p ¼ 0.79) (Table VIII). Carotid shunt placement was required in 44.8% (100/223) of CEAs in this series, 6.1% (6/99) in the MECE patients and 75.8% (94/124) in the PCEA group, p<0.0001. Shunt placement rate was 57.8% for symptomatic patients and 36.0% for asymptomatic patients. The MECE group had an average carotid artery cross-clamping time of 29.2 (17-55) minutes, which was statistically shorter than the PCEA group, who had an average cross-clamping time of 52.2 (15-105) minutes, p ¼ 0.03 (Table IX).
DISCUSSION The safety and efficacy of ECEA has been validated in multiple randomized control trials,16,17 which have shown that ECEA is a safe and durable
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Table IX. Intraoperative carotid cross-clamping time and carotid shunt rate MECE (n ¼ 99)
Intraoperative carotid cross-clamping time Carotid shunt placement
29.2 (17-55) minutes 6.1% (6/99)
long-term treatment for ICA stenosis.18 Potential benefits of ECEA include avoidance of prosthetic patch for closure, lower restenosis rates, and shorter carotid cross-clamping times. This technique is especially useful when the ICA is coiled or kinked.10 However, the potential disadvantages of ECEA include difficulty in visualizing the endpoint, more extensive dissection in the vicinity of the bifurcation and bulb, and it is more technically demanding in cases when a shunt is required.19 Transaortic renal endarterectomy has been used for orificial atherosclerotic renovascular disease, particularly in conjunction with concomitant aortic surgery.13 By using MECE, a similar technique to transaortic orificial endarterectomy, CEA can be performed using a longitudinal arteriotomy that is confined to the carotid artery bulb. The arteriotomy is then closed primarily without a patch. The risk of narrowing the lumen of ICA is minimal by confining the arteriotomy to the carotid bulb, thus avoiding the necessity for patch closure. In this study, intraoperative completion carotid duplex ultrasound was performed for all patients; 5.1% of MECE were converted to PCEA because of technical defects that appeared most commonly as a distal flap at the endpoint on ultrasound. These patients, for whom MECE was converted to PCEA, were administered anticoagulants so as to minimize the risk of thromboembolism. There were no complications in this group of patients requiring conversion to PCEA. One surgeon (R.B.P.) in this study performed MECE in 73.3% of his patients during the study period. All his patients were considered for MECE irrespective of preoperative image findings; the decision to perform MECE or PCEA was decided intraoperatively. In all, 27% of his patients (36/133) underwent PCEA because of technical defects after MECE (5/36), a long arteriosclerotic plaque that precluded MECE, obligate carotid shunt placement (28/36), or an inadequate endpoint with attempted transarterial endarterectomy (2/36). In these cases, extension of the arteriotomy into the ICA was necessary to perform adequate endarterectomy and patch closure was performed.
PCEA (n ¼ 124)
52.2 (15-105) minutes 75.8% (94/124)
p value
0.03 <0.0001
Although some claim safety and feasibility of shunt placement with ECEA,15,16 one of the concerns with ECEA is the difficulty with shunt placement.20 We have similarly noted that shunt placement is more technically demanding with MECE. Although we have successfully used ICA shunting with MECE in the early part of our experience without any complications related to shunt placement, it is currently our preference to convert to longitudinal arteriotomy and traditional patch closure in cases when shunt placement is needed, especially for patients with a history of recent stroke and contralateral ICA occlusion21-24 so as to minimize the total ischemic time. This accounts for the shunt rate for the PCEA group (76%) being significantly higher than the MECE patients (6%) in this study, as well as the greater percentage (48%) of symptomatic patients in the PCEA cohort. Kumar et al. recently reported their experience with modified eversion carotid endarterectomy,25 confirming low perioperative mortality and morbidity rate. Their reported 2-year severe restenosis rate of 0.92% and rate of conversion to PCEA were similar to our experience. They questioned the clinical value for shunt placement with brief carotid cross-clamping time in their study and relatively low overall shunt use (2.7%), mainly for patient with severe contralateral disease. We disagree on the basis of stump pressure criteria, and feel that there remains a role for carotid shunting, especially in patients with severe contralateral disease, contralateral occlusion, and history of recent stroke.21-24 Our current practice is to perform traditional PCEA when shunting is required. There are several limitations to our study. It is a retrospective review of single center data, and the sample size is most likely not large enough to definitively determine the superiority of one technique over the other. However, this study showed no differences in perioperative mortality, stroke rate, and postoperative ICA restenosis rate between the two groups. We demonstrated good and equivalent results between the two techniques in our center with statistically shorter carotid cross-
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clamping time in the MECE group. Although carotid cross-clamping time is not known to be associated with worst morbidity or mortality, it can be associated with higher incidence of early restenosis after carotid endarterectomy.26 A second limitation of this study is the selective and heterogeneous nature of patients who underwent MECE; more likely to be asymptomatic patients with severe ICA stenosis as compared with the PCEA group and most likely skewed by the preference for PCEA when carotid shunting is difficult. All MECE were performed by a single surgeon in this study with preference toward MECE in his patients. We recognize this potential bias within the study, but our data suggests that, with experience, MECE has the potential benefit of simplifying the procedure and remains a safe, expeditious, and effective technique for treatment of atherosclerotic ICA stenosis.
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10.
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15.
CONCLUSION MECE has the advantage of short carotid crossclamping time, avoidance for patch, and less dissection as compared with conventional ECEA for atherosclerotic carotid disease, and is a safe alternative to PCEA with a comparable restenosis rate. REFERENCES 1. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991;325:445-453. 2. Executive committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid stenosis. JAMA 1995;273:1421-1428. 3. European Carotid Surgery Trialists’ Collaborative Group. Randomized trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet 1998;351:1379-1387. 4. Halliday A, Mansfield A, Marro J, et al. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomized control trial. Lancet 2004;363:1491-1502. 5. Bond R, Rerkasem K, AbuRahma AF, Naylor AR, Rothwell PM. Patch angioplasty versus primary closure for carotid endarterectomy. Cochrane Database Syst Rev 2004;2:CD000160. 6. Manheim D, Weller B, Vahadim E, Karmeli R. Carotid endarterectomy with a polyurethane patch versus primary closure: a randomized study. J Vasc Surg 2005;41:403-407. 7. Bond R, Rerkasem K, Naylor AR, Aburahma AF, Rothwell PM. Systemic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy. J Vasc Surg 2004;40:1126-1135. 8. Byrne J, Feustel P, Darling RC III. Primary closure, routine patching, and eversion endarterectomy: what is the current
16.
17.
18. 19.
20.
21. 22.
23.
24.
25.
26.
93
state of the literature supporting use of these techniques? Semin Vasc Surg 2007;20:226-235. De Bakey ME, Crawford ES, Cooley DA, Morris GC Jr. Surgical considerations of occlusive disease of innominate, carotid, subclavian, and vertebral arteries. Ann Surg 1959;149:690-710. Kieny R, Hirsch D, Seiller C, Thiranos JC, Petit H. Does carotid eversion endarterectomy and reimplantation reduce the risk of restenosis? Ann Vasc Surg 1993;7:407-413. Darling RC III, Shah DM, Chang BB, et al. Carotid endarterectomy using the eversion technique. Semin Vasc Surg 2000;13:4-9. Cao P, De Rango P, Zannetti S. Eversion vs conventional carotid endarterectomy: a systemic review. Eur J Vasc Endovasc Surg 2002;23:195-201. Clair DG, Belkin M, Whittemore AD, Mannick JA, Donaldson MC. Safety and efficacy of transaortic renal endarterectomy as an adjunct to aortic surgery. J Vasc Surg 1995;21:926-933. Grant EG, Benson CB, Moneta GL, et al. Carotid artery stenosis: gray-scale and Doppler US diagnosisdSociety of Radiologists in Ultrasound Consensus Conference. Radiology 2003;229:340-346. Shah DM, Darling RC III, Chang BB, et al. Carotid endarterectomy by eversion technique, its safety and durability. Ann Surg 1998;228:471-478. Cao P, Giordano G, De Rango P, et al. A randomized study on eversion versus standard carotid endarterectomy. Study design and preliminary results: the Everest Trial 1998. J Vasc Surg 1998;27:595-605. Cao P, Giordano G, De Rango P, et al. Eversion versus conventional carotid endarterectomy: late results of a prospective multicenter randomized trial. J Vasc Surg 2000;31:19-30. Black JH III, Ricotta JJ, Jones CE. Long-term results of eversion carotid endarterectomy. Ann Vasc Surg 2010;24:92-99. Green RM, Greenberg R, Illig K, Shortell C, Ouriel K. Eversion endarterectomy for the carotid artery: technical considerations and recurrent stenoses. J Vasc Surg 2000;32: 1052-1061. Crawford RS, Chung TK, Hodgman T, Pedraza JD, Corey M, Cambria RP. Restenosis after eversion vs. patch closure carotid endarterectomy. J Vasc Surg 2007;46:41-48. Baker WH, Dorner DB, Barnes RW. Carotid endarterectomy: is an indwelling shunt necessary? Surgery 1977;82:312-316. Graham AM, Gewertz BL, Zarins CK. Predicting cerebral ischemia during carotid endarterectomy. Arch Surg 1986;121:595-598. Lawrence PF, Alves JC, Jicha D, Bhirangi K, Dobrin PB. Incidence, timing, and causes of cerebral ischemia during carotid endarterectomy with regional anesthesia. J Vasc Surg 1998;27:329-337. Sundt TM, Ebersold MJ, Sharbrough FW, Piepgras DG, Marsh WR, Messick JM Jr. The risk-benefit ratio of intraoperative shunting during carotid endarterectomy. Relevancy to operative and postoperative results and complications. Ann Surg 1986;203:196-204. Kumar S, Porter C, Hager E, et al. Modified eversion carotid endarterectomy. Presented at: 37th Annual Meeting, Society for Clinical Vascular Surgery, March 18-21, 2008, Ft Lauderdale, FL. Malek LA, Malek AK, Leszczynski J, et al. Carotid clamping time as a risk factor for early restenosis after carotid endarterectomy. Eur J Vasc Endovasc Surg 2005;30: 143-146.