Carotid endarterectomy under local and/or regional anesthesia has less risk of myocardial infarction compared to general anesthesia: An analysis of national surgical quality improvement program database

Abstract

Multiple studies have evaluated the effect of anesthesia type on carotid endarterectomy with inconsistent results. Our study compared 30-day postoperative myocardial infarction, stroke, and mortality between carotid endarterectomy under local or regional anesthesia and carotid endarterectomy under general anesthesia utilizing National Surgical Quality Improvement Program database. All patients listed in National Surgical Quality Improvement Program database that underwent carotid endarterectomy under general anesthesia and local or regional anesthesia from 2005 to 2011 were included with the exception of patients undergoing simultaneous carotid endarterectomy and coronary artery bypass grafting. The data revealed substantial differences between the two groups compared, and these were adjusted using multiple logistic regression. Postoperative myocardial infarction, stroke, and death at 30 days were compared between the two groups. A total of 42,265 carotid endarterectomy cases were included. A total of 37,502 (88.7%) were performed under general anesthesia and 4763 (11.3%) under local or regional anesthesia. Carotid endarterectomy under local or regional anesthesia had a significantly decreased risk of 30-day postoperative myocardial infarction when compared to carotid endarterectomy under general anesthesia (0.4% vs 0.86%, p = 0.012). No statistically significant differences were found in postoperative stroke or mortality. Carotid endarterectomy under local or regional anesthesia carries a decreased risk of postoperative myocardial infarction when compared to carotid endarterectomy under general anesthesia. Therefore, patients at risk of postoperative myocardial infarction undergoing carotid endarterectomy, consideration of local or regional anesthesia may reduce that risk.

Keywords

Carotid endarterectomy local anesthesia regional anesthesia general anesthesia postoperative MI

Introduction

Carotid artery stenosis accounts for about 20% of ischemic strokes.¹ Carotid endarterectomy (CEA) was established as the procedure of choice for selected patients with carotid artery stenosis.^2–4 With carotid artery stenting (CAS) being presented as an alternative for CEA with less risk of postoperative myocardial infarction (MI), studying variables that affect CEA outcomes, specifically postoperative MI, has become more important than ever.⁵ An important variable that might affect CEA outcomes that was extensively evaluated over many decades is anesthesia type, which can be divided in the case of CEA into two groups: general anesthesia (GA) or regional or local anesthesia (LA). Our study aimed at studying the effect of anesthesia type on the 30-day postoperative major adverse events of carotid endarterectomy, namely MI, stroke, and death. Our hypothesis was CEA under LA has a lower incidence of postoperative MI compared to CEA under GA. The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was used to conduct the study.

Methods

The NSQIP database is a validated national multi-institutional database that is collected prospectively across surgical specialties by dedicated clinical reviewers.^6,7 NSQIP variables include preoperative risk factors, intra-operative information, and 30-day postoperative complications. Data are collected from medical records as well as by direct calls and/or mail to patients, and data accuracy is periodically audited by independent NSQIP reviewers.

The Institutional Review Board at Inova Health System determined that this study was exempt from review because patient identifiers are not included in the NSQIP dataset. All patients who underwent carotid endarterectomy (CPT code 35301) using general, regional, or local anesthesia from 2005 to 2011 were abstracted from the NSQIP database. Patients receiving a simultaneous coronary artery bypass grafting (CABG) procedure (CPT code 33510–33523, 33533–33536) were excluded from the analysis. “GA” is defined by NSQIP as “including IV (intravenous) anesthesia with intubation or Laryngeal Mask Airway,” LA is defined by NSQIP as “usually performed by the primary surgeon.” For the purpose of our study, LA was combined into the category of local anesthesia compared to GA. The primary outcome was 30-day postoperative MI. Additional outcomes include 30-day postoperative stroke and death.

The ACS NSQIP definition of MI includes the presence of one of the following: (a) electrocardiogram changes of ST elevation, new left bundle branch, or new q-wave in two or more contiguous leads; (b) new elevation in troponin level greater than three times the upper level of the reference range in the setting of suspected myocardial ischemia; or (c) physician diagnosis of MI. The definition of stroke according to ACS NSQIP is development of an embolic, thrombotic, or hemorrhagic vascular accident or stroke with motor, sensory, or cognitive dysfunction (e.g. hemiplegia, hemiparesis, aphasia, sensory deficit, and impaired memory) that persists for 24 or more hours. ACS NSQIP defines “stroke with neurological deficits” as a cerebrovascular accident with persistent residual motor, sensory, or cognitive dysfunction. In addition, “stroke with no neurological deficit” is defined as a cerebrovascular accident with neurologic deficit(s) lasting at least 30 min, but no current residual neurologic dysfunction or deficit. The mortality or postoperative death within 30 days of procedure is defined by ACS NSQIP as any death occurring within 30 days following surgery, regardless of cause, in or out of the hospital.

Postoperative MI, stroke, and death at 30 days were compared among patients receiving GA and patients receiving LA using simple and multiple logistic regression. Multiple logistic regression models were constructed using backward stepwise variable selection to determine whether anesthesia type was independently associated with postoperative outcomes after adjusting for relevant confounders. Potential confounding variables considered for the multivariable model were identified a priori and included gender, age, diabetes, smoking, dyspnea, revascularization or amputation for peripheral vascular disease, chronic obstructive pulmonary disease, congestive heart failure, MI, previous cardiac surgery, dialysis, transient ischemic attacks, history of stroke with or without neurological deficit, prior operation, and vascular surgeon subspecialty. Surgical specialty is defined by NSQIP not by board certification status but as designated by the surgeon performing the procedure. Statistical significance was assessed at α = 0.05. All analyses were performed using Stata/SE v.12 (College Station, TX).

Results

A total of 42,413 carotid endarterectomy cases were listed in the ACS NSQIP database from 2005 to 2011. Patients who had CEA and concurrent CABG (N = 148) were excluded. Of the remaining 42,265 CEAs, 37,502 (88.7%) were performed under GA and 4,763 (11.3%) were performed under LA. Selected preoperative variables and demographics were compared between the two study groups (Table 1). The GA group had a higher proportion of female patients, older age distribution, and higher proportion of smokers. Approximately one-quarter of patients in both anesthesia groups had preoperative TIA. Patients with history of stroke were more frequent in the GA group (with neurologic deficit: 16% vs. 14%, p = 0.001; without neurologic deficit: 9.2% vs. 8.3%, p = 0.04). Among surgeons performing CEA, 94.5% were vascular surgeons, 4.5% general surgeons, and the remaining 1% were neurosurgeons, thoracic, cardiac, orthopedics, and plastic surgeons. CEA under LA was more commonly performed by vascular surgeons 97%, compared to 94% for CEA under GA (p < 0.001).

Table 1.

Comparison of demographics and preoperative comorbidities by anesthesia type for patients who underwent carotid endarterectomy.

Covariates	GA		Local or regional anesthesia		Odds ratio	p-value^a
Covariates	Non-missing, N (%)	N (%)	Non-missing, N (%)	N (%)	Odds ratio	p-value^a
Total, N (%)	37,502 (100)	–	4763 (100)	–	–	–
Female, N (%)	37,436 (99.8)	15,380 (41)	4759 (99.9)	1836 (39)	0.90	<0.001
Age					–	<0.001
<60 years, N (%)	37,502 (100)	4,703 (13)	4763 (100)	500 (10)	–	–
60–79 years, N (%)	37,502 (100)	25,192 (67)	4763 (100)	3192 (67)	–	–
≥80 years, N (%)	37,502 (100)	7,607 (20)	4763 (100)	1,071 (22)	–	–
Diabetes					–	0.056
No, N (%)	37,502 (100)	26,885 (72)	4763 (100)	3445 (72)	–	–
Oral/non-insulin, N (%)	37,502 (100)	6,937 (18)	4763 (100)	902 (19)	–	–
Insulin-dependent, N (%)	37,502 (100)	3,680 (10)	4763 (100)	416 (8.7)	–	–
Smoker, N (%)	37,502 (100)	10,663 (28)	4763 (100)	1201 (25)	0.85	<0.001
Dyspnea					–	0.218
No, N (%)	37,502 (100)	30,569 (82)	4763 (100)	3922 (82)	–	–
Moderate exertion, N (%)	37,502 (100)	6,479 (17)	4763 (100)	794 (17)	–	–
At rest, N (%)	37,502 (100)	454 (1.2)	4763 (100)	47 (1.0)	–	–
Revascularization/amputation for PVD, N (%)	33,901 (90)	3,302 (10)	4298 (90)	366 (8.5)	0.86	0.010
COPD, N (%)	37,502 (100)	4,054 (11)	4763 (100)	448 (9.4)	0.86	0.003
Congestive heart failure, N (%)	37,502 (100)	382 (1.0)	4763 (100)	54 (1.1)	1.05	0.459
MI, N (%)	33,900 (90)	480 (1.4)	4298 (90)	51 (1.2)	0.84	0.226
Previous cardiac surgery, N (%)	33,900 (90)	7,604 (22)	4298 (90)	954 (22)	0.99	0.729
Dialysis, N (%)	37,502 (100)	396 (1.1)	4763 (100)	39 (1.0)	0.77	0.127
Transient ischemic attacks, N (%)	33,901 (90)	9,282 (27)	4298 (90)	1171 (27)	0.99	0.852
Stroke w/o neuro deficit, N (%)	33,901 (90)	5,328 (16)	4298 (90)	594 (14)	0.86	0.001
Stroke w/o neuro deficit, N (%)	33,901 (90)	3,125 (9.2)	4298 (90)	355 (8.3)	0.89	0.040
Prior operation, N (%)	32,127 (86)	389 (1.2)	4116 (86)	43 (1.0)	0.86	0.355
Vascular surgeon, N (%)	37,502 (100)	35,338 (94)	4763 (100)	4614 (97)	1.90	<0.001

p-values were calculated using Chi-square tests.

GA: general anesthesia; MI: myocardial infarction.

CEA under LA had a significantly decreased risk of 30-day postoperative MI when compared to CEA under GA (0.4% vs 0.9%, OR = 0.55, adjusted p = 0.012) (Table 2). In addition to GA, independent risk factors for postoperative MI were age, diabetes mellitus, dyspnea, revascularization or amputation for peripheral vascular disease, history of MI, and history of stroke with neurologic deficits (Table 3).

Table 2.

Odds ratios for 30-day MI, stroke and death after CEA under LA versus GA before and after controlling for confounding variables.

Outcome	Local/regional anesthesia N (%)	General anesthesia N (%)	Crude OR (95% CI)	p	Adjusted OR^a (95% CI)	p
MI	20 (0.4)	324 (0.9)	0.49 (0.3, 0.8)	0.002	0.55 (0.3, 0.9)	0.012
Stroke	66 (1.4)	591 (1.6)	0.88 (0.7, 1.1)	0.318	0.92 (0.7, 1.2)	0.540
Death	32 (0.7)	315 (0.8)	0.80 (0.5, 1.2)	0.226	0.92 (0.6, 1.3)	0.664

Multivariable logistic regression models were adjusted for statistically significant (α = 0.05) confounding variables. The MI model was adjusted for age, diabetes mellitus, dyspnea, history of MI, and history of stroke with neurologic deficit. The stroke model was adjusted for gender, diabetes mellitus, chronic obstructive pulmonary disease, history of transient ischemic attack, and history of stroke with and without neurologic deficit. The mortality model was adjusted for age, revascularization for peripheral vascular disease, chronic obstructive pulmonary disease, congestive heart failure, history of MI, dialysis, history of transient ischemic attack, history of stroke with neurologic deficit, and prior operation within 30 days.

MI: myocardial infarction.

Table 3.

Comparison of demographics and preoperative comorbidities by post-operative MI for patients who underwent carotid endarterectomy.

Covariates	No MI, N (%)	MI, N (%)	Adjusted odds ratio (95% CI)	p-value^a
Total, N (%)	–	–
Local/regional anesthesia, N (%)	4,743 (11)	20 (5.8)	0.55 (0.34, 0.87)	0.012
Female, N (%)	17,073 (41)	143 (42)	–	–
Age			–	–
<60 years, N (%)	5,179 (12)	24 (7.0)	Ref	Ref
60–79 years, N (%)	28,176 (67)	208 (61)	1.44 (0.93, 2.23)	0.103
≥80 years, N (%)	8,567 (20)	111 (32)	2.87 (1.81, 4.54)	<0.001
Diabetes			–	–
No, N (%)	30,121 (72)	209 (61)	Ref	Ref
Oral/non-insulin, N (%)	7,762 (19)	77 (22)	1.46 (1.10, 1.94)	0.009
Insulin-dependent, N (%)	4,039 (10)	57 (17)	2.01 (1.45, 2.79)	<0.001
Smoker, N (%)	11,771 (28)	93 (27)	–	–
Dyspnea			–	–
No, N (%)	34,235 (82)	256 (75)	Ref	Ref
Moderate exertion, N (%)	7,192 (17)	81 (24)	1.57 (1.21, 2.05)	0.001
At rest, N (%)	495 (1)	6 (1.7)	1.56 (0.68, 3.57)	0.291
Revascularization/amputation for PVD, N (%)	3,625 (10)	43 (15)	1.57 (1.13, 2.18)	0.007
COPD, N (%)	4,454 (11)	48 (14)	–	–
Congestive heart failure, N (%)	430 (1.2)	6 (1.7)	–	–
MI, N (%)	518 (1.4)	13 (4.5)	2.96 (1.67, 5.25)	<0.001
Previous cardiac surgery, N (%)	8,473 (22)	85 (29)	–	–
Dialysis, N (%)	428 (1.0)	7 (2.0)	–	–
Transient ischemic attacks, N (%)	10,374 (27)	79 (27)	–	–
Stroke w/o neuro deficit, N (%)	5,862 (15)	60 (21)	1.39 (1.04, 1.85)	0.024
Stroke w/o neuro deficit, N (%)	3,444 (9.1)	36 (12)	–	–
Prior operation, N (%)	430 (1.2)	2 (0.7)	–	–
Vascular surgeon, N (%)	39,622 (95)	330 (96)	–	–

p-values were calculated using multivariable logistic regression, adjusted for other variables retained in the model.

*Proportions may not sum to 100 due to rounding.

MI: myocardial infarction.

No statistically significant difference was found when comparing postoperative stroke rate and death between GA and LA groups (Table 2). The incidence of 30-day postoperative stroke for CEA under GA was 1.6% compared to 1.4% for CEA under LA. In addition to anesthesia type, the postoperative stroke multivariable logistic regression model included adjustment for gender, diabetes mellitus, chronic obstructive pulmonary disease, history of transient ischemic attack, and history of stroke with and without neurologic deficit.

The incidence of 30-day postoperative death for CEA under LA was 0.7% compared to 0.8% for GA (Table 2). Confounding variables included in the multivariable logistic regression model predicting 30-day mortality were age, revascularization for peripheral vascular disease, chronic obstructive pulmonary disease, congestive heart failure, history of MI, dialysis, history of transient ischemic attack, history of stroke with neurologic deficit, and prior operation within 30 days.

Discussion

Anesthesia type in carotid endarterectomy has been previously studied. The use of local anesthesia to perform the procedure is viewed by many vascular surgeons as a less-invasive procedure compared to GA. The advantages of CEA under LA compared to GA include intraoperative awake neurologic monitoring, which allows more judicious use of shunting, better cerebrovascular autoregulation, and better hemodynamic stability compared to CEA under GA.^8–10 Our study aimed to utilize the multi-center prospectively collected ACS NSQIP database with the purpose of obtaining a large enough sample that has the power to reveal any differences in major adverse outcomes between CEA under GA compared to LA. Our study suggests a decreased incidence of postoperative MI in the LA group compared to GA (0.4% vs 0.9%, respectively, p = 0.012). No statistically significant differences were noted in death or stroke rates between anesthesia types.

The increased rate of postoperative MI observed in CEA under GA might be explained by the higher incidence of hypotension and hemodynamic instability in this population.^9,10 Hypotension in CEA under GA is multi-factorial and can include direct cardiac effects, such as decreases in cardiac preload or suppression of the sympathetic nervous system.^10,11 In addition to hypotension, GA agents can induce a thrombophilic state that may further contribute to the development of MI.^12,13

A lower MI rate for patients undergoing CEA with LA has been reported by several smaller non-randomized studies.^14–17 However, these improved outcomes' advantages were not translated into clinical outcomes, as data collected from systematic reviews have not revealed any differences in postoperative major adverse events,. This includes any differences in MI rates when comparing CEA under LA with GA.^18,19 Furthermore, the largest randomized trial to date (GALA), with multiple noted limitations,²⁰ revealed no differences in primary outcomes between CEA under GA and CEA under LA, despite a statistically significant increase in hemodynamic instability in the CEA under GA group.²¹ The GALA trial, however, had its limitations. First, patients who were considered to be “high risk” by surgeons and anesthetists were excluded. Second, the number of postoperative major adverse events (stroke, MI, or death) were lower than anticipated by the conductors of the trial, with less adverse events for CEA under LA (4.5%), but not statistically significant as compared to CEA under GA (4.8%). Finally, the GALA recruited 3526 subjects falling short of their anticipated sample of 5000. While authors of the GALA trial concluded that the sample size of 5000 would likely not have changed the results of the trial, they acknowledge that the above-stated factors reduced the power of the study. Given the relatively low occurrence of the major adverse events after CEA under LA or GA, comparing the outcomes of two groups will be largely affected by the power of the study, which was reduced in the GALA trial.²¹

Our study had comparable outcomes with other large analyses performed using the NSQIP database, which have reported GA with CEA as an independent risk factor for postoperative MI.^22,23 Another NSQIP analysis including 24,716 patients from 2005 to 2009 that analyzed composite stroke, MI, and death rate based on anesthesia type revealed no difference in outcomes between regional and GA but shorter anesthesia time for regional anesthesia patients who were also more likely to be discharged the next day.²⁴ Compared to the study by Schechter et al.,²⁴ our study had a larger sample and therefore more power to reveal differences between the outcomes of the two groups that might have not been accounted for in a smaller sample.

Other risk factors that independently increased the postoperative MI risk in our study after adjustment with a multivariable logistic regression model include age more than 80 years old, diabetes mellitus, dyspnea upon moderate exertion, peripheral vascular disease (PVD), history of stroke with neurologic deficits, and a history of MI. History of MI being a significant predictor for development of postoperative MI in our study correlates with clinical models such as the modified Goldman criteria or Eagle criteria, which identify it as a major cardiac risk factor in non-cardiac surgery.^25,26 The other risk factors found in our study, which significantly correlated with postoperative MI and are included in the Eagle criteria, are advanced age (more than 80 in our study compared to age more than 70 in the Eagle criteria), diabetes mellitus, and history of stroke.²⁶

With post-CEA MI being the primary outcome of our study, it is important to mention that postoperative MI in vascular surgery not only affects the immediate postoperative period but also may be a predictor of long-term mortality.²⁷ Therefore, the incidence of post-CEA MI can have devastating short-term and long-term effects on patients. Consequently, the above risk factors identified in our study, along with the modified Goldman or Eagle's criteria, might help identify patients at increased risk of postoperative MI after CEA, and therefore these patients should be considered candidates for CAS or CEA under LA, with the latter having the advantage of less risk of postoperative stroke.⁵

Analysis of postoperative stroke and mortality rate after CEA revealed that anesthesia type did not affect those two outcomes. Factors that increased postoperative stroke risk in our study after adjustment with multivariable logistic regression model were symptomatic carotid stenosis, history of TIA, history of stroke without neurologic deficit, and history of stroke with neurologic deficit. Other risk factors that increased the postoperative stroke risk were insulin-dependent diabetes mellitus and COPD. In addition, important variables that predicted mortality after adjustment with multivariable logistic regression model were advanced age, PVD, COPD, CHF, history of MI, being on dialysis, and stroke with neurologic deficit. As noted above, our study patients with symptomatic carotid disease (TIA, stroke without neurologic deficit, and stroke with neurologic deficit) were at increased risk for developing postoperative stroke compared to asymptomatic patients with carotid stenosis. Stroke with neurologic deficit was also noted to be an independent risk factor for post-CEA MI and death. The increase in the rate of major adverse events (MI, stroke, or death) found in the patients with symptomatic compared to asymptomatic carotid artery stenosis correlates with multiple studies revealing favorable outcomes in the latter group.^2,3

Finally, our study had several limitations similar to other studies performed with the NSQIP dataset. These include the lack of randomization, multiple surgeons, the lack of carotid endarterectomy intraoperative information in the database (including intraoperative hemodynamic instability, intraoperative heart rate, shunt usage, and the degree of carotid artery stenosis), and the inability to assess quality of life or functional outcome from the dataset. In addition, the NSQIP database is designed for quality improvement and not to accurately compare two study groups; therefore, the data are not designed to be stratified for patient presentation and comorbidities, which can affect the accuracy of the analysis. Besides, the sample discrepancy between CEA under GA compared to CEA under LA might affect the analyzed outcomes, given the relatively low incidence of MI in both groups. Additionally, given the nature of the study, there were no standardized postoperative protocols for diagnosing MI such as routine postoperative EKG, and cardiac enzymes as was the case in multiple prospective trials including the CREST trial, which might have attributed to the relatively low incidence of reported MI in the NSQIP database. Other limitations include the inability to collect intraoperative events pertinent to local anesthesia group from NSQIP dataset such as patient anxiety or discomfort during the operation. Another limitation is the presence of relatively more comorbid conditions in the CEA under GA group with more smokers, more COPD, and more patients with history of stroke. These comorbidities were accounted for by the multivariate analysis model. Other limitations include the lack of standard postoperative care or protocol, such as the frequency of statin usage postoperatively, the usage of antiplatelet agents (which can be dual, single, or none), blood pressure control, and other postoperative care factors that cannot be controlled with our type of study.

Conclusion

In conclusion, our NSQIP study analysis suggests that CEA performed under GA has an increased risk of postoperative MI. Therefore, along with controlling other cardiac risk factors, electing CEA under local or regional anesthesia for patients at risk of postoperative MI may reduce that risk.

Footnotes

Acknowledgments

Presented as poster presentation at Society for Vascular Surgery Annual Meeting May 2013, San Francisco. Also presented as plenary session at Eastern Vascular Society 27th Annual Meeting September 2013, West Virginia.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflict of interest

None declared.

References

Petty

Brown

Jr Whisnant

. Ischemic stroke subtypes: a population-based study of incidence and risk factors. Stroke 1999; 30: 2513–2516.

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.

Rothwell

Eliasziw

Gutnikov

. Analysis of pooled data from the randomised controlled trials of endarterectomy for symptomatic carotid stenosis. Lancet 2003; 361: 107–116.

Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European carotid surgery trial (ECST). Lancet 1998; 351: 1379–1387.

Mantese

Timaran

Chiu

. The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST): stenting versus carotid endarterectomy for carotid disease. Stroke 2010; 41: S31–34. .

Davis

Pierce

Henderson

. Assessment of the reliability of data collected for the Department of Veterans Affairs National Surgical Quality Improvement Program. J Am Coll Surg 2007; 204: 550–560.

Khuri

Daley

Henderson

. The Department of Veterans Affairs' NSQIP: the first national, validated, outcome-based, risk-adjusted, and peer-controlled program for the measurement and enhancement of the quality of surgical care. National VA Surgical Quality Improvement Program. Ann Surg 1998; 228: 491–507.

McCleary

Dearden

Dickson

. The differing effects of regional and general anaesthesia on cerebral metabolism during carotid endarterectomy. Eur J Vasc Endovasc Surg 1996; 12: 173–181.

Eibes

Gross

. The influence of anesthetic technique on perioperative blood pressure control after carotid endarterectomy. Am Surg 2000; 66: 641–647.

10.

Stoneham

Thompson

. Arterial pressure management and carotid endarterectomy. Br J Anaesth 2009; 102: 442–452.

11.

Scheffer

Ten Voorde

Karemaker

. Effects of thiopentone, etomidate and propofol on beat-to-beat cardiovascular signals in man. Anaesthesia 1993; 48: 849–855.

12.

Badner

Beattie

Freeman

. Nitrous oxide-induced increased homocysteine concentrations are associated with increased postoperative myocardial ischemia in patients undergoing carotid endarterectomy. Anesth Analg 2000; 91: 1073–1079.

13.

Rosenfeld

Beattie

Christopherson

. The effects of different anesthetic regimens on fibrinolysis and the development of postoperative arterial thrombosis. Perioperative Ischemia Randomized Anesthesia Trial Study Group. Anesthesiology 1993; 79: 435–443.

14.

Allen

Anderson

Rubin

. The influence of anesthetic technique on perioperative complications after carotid endarterectomy. J Vasc Surg 1994; 19: 834–842. discussion: 42–43.

15.

Watts

Lin

Bush

. The impact of anesthetic modality on the outcome of carotid endarterectomy. Am J Surg 2004; 188: 741–747.

16.

Sternbach

Illig

Zhang

. Hemodynamic benefits of regional anesthesia for carotid endarterectomy. J Vasc Surg 2002; 35: 333–339.

17.

Becquemin

Paris

Valverde

. Carotid surgery. Is regional anesthesia always appropriate? J Cardiovasc Surg 1991; 32: 5928.

18.

Rerkasem

Rothwell

. Local versus general anaesthesia for carotid endarterectomy. Cochr Database Syst Rev 2008, pp. CD000126.

19.

Tangkanakul

Counsell

Warlow

. Local versus general anaesthesia in carotid endarterectomy: a systematic review of the evidence. Eur J Vasc Endovasc Surg 1997; 13: 491–499.

20.

Paraskevas

Mikhailidis

Bell

. The GALA trial: will it influence clinical practice? Vasc Endovascular Surg 2009; 43: 429–432.

21.

Lewis

Warlow

Bodenham

. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomized controlled trial. Lancet 2008; 372: 2132–2142.

22.

Leichtle

Mouawad

Welch

. Outcomes of carotid endarterectomy under general and regional anesthesia from the American College of Surgeons' National Surgical Quality Improvement Program. J Vasc Surg 2012; 56: 81–83.

23.

Woo

Garg

Hye

. Contemporary results of carotid endarterectomy for asymptomatic carotid stenosis. Stroke 2010; 41: 975–979.

24.

Schechter

Shortell

Scarborough

. Regional versus general anesthesia for carotid endarterectomy: the American College of Surgeons National Surgical Quality Improvement Program perspective. Surgery 2012; 152: 309–314.

25.

Detsky

Abrams

McLaughlin

. Predicting cardiac complications in patients undergoing non-cardiac surgery. J Gen Intern Med 1986; 1: 211–219.

26.

Eagle

Berger

Calkins

. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J Am Coll Cardiol 2002; 39: 542–553.

27.

Landesberg

Shatz

Akopnik

. Association of cardiac troponin, CK-MB, and postoperative myocardial ischemia with long-term survival after major vascular surgery. J Am Coll Cardiol 2003; 42: 1547–1554.