Examination of regional anesthesia for carotid endarterectomy Laura Pasin, MD,a Pasquale Nardelli, MD,a Giovanni Landoni, MD,a,b Guglielmo Cornero, MD,a Silvio Magrin, MD,a Yamume Tshomba, MD,b Roberto Chiesa, MD,b,c and Alberto Zangrillo, MD,a,b Milan, Italy Objective: Carotid endarterectomy is the most effective treatment for reducing the risk of stroke in patients with significant carotid stenosis. Few studies have focused on the failure rate of regional anesthesia. Methods: Data of all patients undergoing carotid endarterectomy (June 2009 to December 2014) in a single center were collected. Combined deep and superficial cervical plexus block or superficial plexus block alone was used according to the attending anesthesiologist’s choice and the patient’s characteristics (eg, dual antiplatelet or anticoagulation therapy). Intraoperative remifentanil (0.025-0.05 mg/kg/min) was administered to maintain an adequate level of comfort, responsiveness, and cooperation. General anesthesia was planned only in the case of major contraindications or the patient’s refusal of locoregional anesthesia. The primary end point of our study was the incidence of intraoperative conversion from locoregional to general anesthesia. Results: A total of 2463 carotid endarterectomies were included in the analysis. Regional anesthesia was initially chosen in 2439 patients, whereas 24 patients received planned general anesthesia. In seven cases, regional anesthesia was converted to general anesthesia because of severe agitation of the patient (before clamping in four cases, after carotid clamping in two cases, and after declamping in one case). A shunt was used in 302 patients (12.3%) because of neurologic deterioration at the carotid clamping test. Intraoperative complications were emergent repeated surgical procedures in 13 cases (0.53%) because of acute neurologic deterioration, 1 intraoperative acute myocardial infarction (0.04%), and 3 cases (0.04%) of hemodynamically relevant supraventricular tachyarrhythmia. No intraoperative death occurred. In-hospital mortality was 0.12% (three patients). Major stroke occurred in 23 patients (0.93%); minor stroke occurred in 16 patients (0.65%). The combined stroke and death rate was 1.62% (40 patients). Conclusions: In our practice, carotid endarterectomy under regional anesthesia is safe and associated with a very low rate of conversion to general anesthesia. (J Vasc Surg 2015;-:1-4.)
Surgical carotid endarterectomy still remains the most effective treatment for reducing the risk of stroke in patients with significant carotid stenosis.1,2 In fact, endovascular carotid stenting is associated with a higher incidence of perioperative and long-term minor stroke compared with carotid endarterectomy, although long-term functional outcome and risk of major stroke are comparable.3 Nowadays, both regional anesthesia and general anesthesia are widely used for patients undergoing carotid endarterectomy according to local standards. No technique for carotid endarterectomy is completely safe and perfect under all circumstances. One of the major complications of locoregional anesthesia is the need for urgent conversion to general anesthesia. Regardless of underlying cause of conversion, emergent intraoperative unplanned endotracheal From the Department of Anesthesia and Intensive Carea and Department of Vascular Surgery,c IRCCS San Raffaele Scientific Institute; and VitaSalute San Raffaele University.b Author conflict of interest: none. Additional material for this article may be found online at www.jvascsurg.org. Reprint requests: Laura Pasin, MD, Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2015 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.03.074
intubation of a patient under surgical drapes, with rotated head and an exposed or even clamped carotid, is very difficult and associated with major risks and hemodynamic instability. Locoregional anesthesia is the first-choice technique for patients undergoing carotid endarterectomy in our center. Because few studies focused on failure of regional anesthesia and its underlying causes, we decided to report our experience as a major center of vascular surgery. METHODS Data of all patients undergoing carotid endarterectomy between June 2009 and December 2014 in our center are presented. All patients signed a consent allowing scientific data management. Ethical Committee approval was waived according to Italian law. Exclusions were patients undergoing combined carotid endarterectomy and coronary artery bypass surgery and patients undergoing carotid percutaneous transluminal angioplasty through neck surgical incision. Carotid stenosis was graded according to the European Carotid Surgery Trial (ECST).4 The indication for surgery was ipsilateral severe (70%-99%) or moderate (50%-69%) carotid stenosis in symptomatic patients or high risk for future stroke (unstable carotid plaque or progression in the severity of asymptomatic carotid stenosis) in asymptomatic patients.5,6 Preoperative anticoagulation therapy was usually temporarily withheld, and a “heparin bridge” was provided during 1
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the perioperative period, according to the patient’s characteristics and risk of thromboembolic events. The last dose of heparin was usually administered the night before surgery. Superficial plexus block was performed in all patients receiving dual antiplatelet therapy or with unpaired coagulation profile. Combined deep and superficial cervical plexus block or superficial plexus block alone was performed according to the attending anesthesiologist’s choice. Patients received endovenous midazolam (0.2 mg/kg), and cervical plexus block was performed outside the operating room 20 minutes before surgical incision by one of a pool of eight specialized anesthesiologists. Heart rate, invasive blood pressure, pulse oximetry, and five-lead electrocardiography were monitored during execution of locoregional anesthesia and throughout surgery. Our anesthetic technique has been previously described in detail.7,8 Superficial cervical plexus block was performed with a 20-gauge needle by injection of ropivacaine 0.75% along the whole posterior border of the sternocleidomastoid muscle, subcutaneously. Deep cervical plexus block was performed as a triple injection technique at the level of the transverse processes of the higher cervical vertebrae (C2, C3, C4). We administered 4 or 5 mL of 0.75% ropivacaine for each injection, after a negative aspiration test result for blood. A total amount of ropivacaine 1.5 mg/ kg was allowed. Moreover, lidocaine 1% (4 mg/kg maximum) was used subcutaneously for incision line infiltration. Additional lidocaine (1%) was injected intraoperatively by surgeons if the patient reported pain or discomfort during the procedure. Intraoperative remifentanil (0.025-0.05 mg/kg/min) maintained an adequate level of comfort, responsiveness, and cooperation. Continuous endovenous infusion of nitroglycerin was titrated for blood pressure control during surgery. Additional clonidine or urapidil was administered if needed. On occasion, additional intraoperative midazolam or fentanyl was administered. General anesthesia was performed only in the case of major contraindications, such as an infection at the site of the block, a history of allergy to local anesthetics, or the patient’s refusal of locoregional anesthesia. Systemic heparinization (50 IU/kg) with an activated clotting time target >200 seconds was routinely used, and protamine 5 mg/kg was usually administered at the end of surgery. A shunt was selectively used in case of neurologic deterioration at the carotid cross-clamping test (a tolerance test of 1 minute before starting with the endarterectomy). The primary outcome of our study was the incidence of intraoperative conversion of locoregional to general anesthesia for any reason. Secondary outcomes were the incidences of major in-hospital cardiovascular and neurologic events and mortality. The incidences of myocardial infarction, hemodynamically relevant arrhythmias, need for reoperation, and intensive care unit (ICU) admission were recorded. Neurologic events were described as transient ischemic attacks and minor and major stokes (ischemic or hemorrhagic). Transient ischemic attack was defined as an event with symptoms lasting up to 24 hours. Major stroke was defined
as a nondisabling stroke with residual neurologic symptoms at hospital discharge. Minor stroke was defined as a stroke with symptoms lasting between 24 hours and hospital discharge. Statistical analysis. Descriptive statistics were used to present the study population and incidence of adverse events. The incidence of events and risk ratio with 95% confidence interval are presented. Data are presented as mean and numbers and percentages, standard deviation, or median and interquartile range. Between-groups comparisons were made with Student t-test, c2 test, or Fisher test, where appropriate. A P value < .05 was considered significant. Statistical analyses were performed with GraphPad Prism version 6.00 for Mac OS X (GraphPad Software, La Jolla, Calif). RESULTS A total of 2463 carotid endarterectomies in 2259 patients were performed during the study period and were included in the analysis. Demographic and clinical characteristics of the studied population are presented in Table I. Regional anesthesia was practiced in 2439 cases (99%), whereas 24 patients (1.0%) received planned general anesthesia. Two patients (0.08%) had a short episode of bradyasystole arrest immediately after cervical plexus block execution. Both episodes were attributed to a vagal reflex and resolved (with atropine administration in one case and chest thump in the other one). In the second case, surgery was postponed for 2 days. Another patient (0.04%) had seizures after block performance attributed to local anesthetic systemic toxicity or accidental vertebral injection. After a few minutes of loss of consciousness, the episode resolved without intervention, and the patient underwent surgery. In seven cases (0.28%), regional anesthesia was converted to general anesthesia. Two patients developed severe agitation before and two patients after skin incision but before clamping. In all these four cases, a shunt was used. In a fifth patient, a shunt was inserted because of neurologic deterioration at the carotid cross-clamping 1-minute test. A few minutes after shunt positioning, he became restless and agitated, requiring conversion to general anesthesia. At the end of surgery, the patient was successfully extubated without neurologic complications. On the second postoperative day, he suffered acute myocardial infarction requiring ICU admission. He was discharged after 14 days, in good condition. A sixth patient became restless and agitated after clamping, during carotid patch suture. In this case, a shunt was not used, and the patient was successfully extubated without neurologic complications at the end of surgery. A seventh patient developed loss of consciousness and desaturation after carotid declamping. At the end of surgery, he was admitted to the ICU, where he was extubated within a few hours without neurologic complications. Therefore, the risk of conversion from locoregional to general anesthesia in our institution (7 of 2439) is 0.28% (95%
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Table I. Characteristics of included patients Demographic characteristics Age 6 SD, years Male Medical history Hypertension Dyslipidemia History of neurologic events Stroke TIA Syncope Amaurosis Vertigo Other neurologic symptoms Type 2 diabetes mellitus Smoking history Renal insufficiency Chronic obstructive pulmonary disease Acute myocardial infarction PTCI or CABG
Table II. Incidence of in-hospital adverse events and mortality after 2463 procedures 71.7 6 8.23 1618 (65.7) 1869 1151 664 240 172 83 65 57 47 603 473 377 165 311 526
(75.9) (46.7) (27.0) (9.74) (6.98) (3.37) (2.64) (2.31) (1.91) (24.5) (19.2) (15.3) (6.70) (12.6) (21.4)
CABG, Coronary artery bypass graft; PTCI, percutaneous transluminal coronary intervention; SD, standard deviation; TIA, transient ischemic attack. Categorical variables are presented as number (%).
confidence interval, 0.14-0.59). No differences were found in demographic and preoperative clinical characteristics between patients who successfully underwent surgery under locoregional anesthesia and those patients who required conversion to general anesthesia (Supplementary Table, online only). Six surgeons contributed to the series. Surgical time was significantly longer in patients who underwent carotid endarterectomies under general anesthesia (78.2 6 19.5 vs 166.6 6 18.8 minutes; P < .01). Overall, a shunt was used in 287 patients (11.7%) undergoing locoregional anesthesia because of neurologic deterioration at the carotid cross-clamping test, but only the five patients described before were converted to general anesthesia. Three cases (0.12%) of intraoperative hemodynamically relevant supraventricular tachyarrhythmia were observed. No intraoperative deaths occurred. The following postoperative complications were noted. One patient (0.04%) suffered from intraoperative acute myocardial infarction and postoperative cardiogenic shock requiring percutaneous transluminal coronary angioplasty immediately after surgery, inotropic agents, intra-aortic balloon pump, ICU admission, and mechanical ventilation. On the third postoperative day, he underwent surgical revision for bleeding. During the 18 days of ICU stay, he suffered from minor stroke and pneumonia. He was discharged after 31 days, asymptomatic. One patient suffered from hemiplegia immediately after surgery. Therefore, he was admitted to the ICU, where he spent 24 hours, with nearly complete regression of neurologic deficit. Emergent repeated surgical procedures were performed in 13 patients (0.53%) because of acute neurologic deterioration immediately after surgery. Four of these patients required postoperative ICU admission for neurologic monitoring.
Postoperative adverse events Combined stroke and death Reoperation Bleeding Neurologic event Admission to ICU From the OR From the ward Major stroke Ischemic Hemorrhagic Minor stroke Transient ischemic attack Myocardial infarction Retinal artery thrombosis Surgery time, minutes Hospital stay 6 SD, days In-hospital mortality Caused by major stroke Caused by myocardial infarction
40 (1.62) 42 (1.70) 29 (1.18) 13 (0.53) 16 (0.65) 7 (0.28) 9 (0.36) 23 (0.93) 20 (0.81) 3 (0.12) 16 (0.65) 9 (0.36) 15 (0.61) 2 (0.08) 67 6 19 4.86 6 2.05 3 (0.12) 2 (0.08) 1 (0.04)
ICU, Intensive care unit; OR, operating room; SD, standard deviation. Categorical variables are presented as number (%).
In-hospital mortality was 0.12% (3 of 2463). The incidence of perioperative adverse events is reported in Table II. DISCUSSION This is the largest case series ever published focusing on conversion from cervical plexus block to general anesthesia for carotid endarterectomy. The overall conversion rate from locoregional to general anesthesia in our population was 7 of 2443 (0.28%), lower than the conversion rate reported in the literature. Reported indications for conversion from locoregional to general anesthesia are both surgery and anesthesia related. The most common anesthesia-related indications for conversion are block failure causing discomfort of the patient, pain and restlessness, claustrophobia, systemic toxicity of local anesthetics, airway obstruction due to cervical hematoma, accidental subarachnoid injection of local anesthetics, and diaphragmatic or vocal cord paralysis causing respiratory distress.9,10 On the contrary, the most common surgery-related indications for conversion to general anesthesia are loss of consciousness at carotid clamping and shunt-related complications (inadequate perfusion, air or plaque embolization, mechanical damage during shunt insertion or removal).11,12 In our study, restlessness and agitation, probably due to block failure or claustrophobia, were the most common reasons for conversion to general anesthesia (4 of 2463 of cases). Similar incidences of block failure were reported in other studies.9,13,14 As a major center of vascular surgery, our extremely low rate of conversion could be related to the very high volume of our institution. Moreover, even if we acknowledge that
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intraoperative supplemental local anesthesia administered by the surgeon might exceed suggested maximum doses, we did not observe cases of intraoperative local anesthetic systemic toxicity. Our positive results suggest that the combination of locoregional anesthesia with low-dose continued infusion of remifentanil is an effective and safe choice for anesthetic management of carotid endarterectomy. Also with regard to in-hospital outcome, the mortality rate in our population was significantly lower than the mortality rate reported in other studies. This is not surprising because low perioperative mortality in our hospital has been previously described.15 In considering perioperative morbidity, the incidence of postoperative cardiovascular events in our population is comparable to that reported in other large studies.14,16 On the contrary, we found a lower rate of in-hospital major stroke compared with other studies.16,17 Our positive results could be helpful to those colleagues with less experience with cervical locoregional anesthesia who are interested in learning and applying this technique in their daily clinical practice. According to our experience, cervical plexus block, especially the superficial one, is an easy technique, with a rapid learning curve and with a low risk of complications. Leaving aside the purely technical aspects, we firmly believe that our successful regional anesthesia program is mainly built on a strong partnership between anesthesiologists and surgeons and on an effective communication with the patient. Limitations. We acknowledge, as a limitation of our study, that we did not routinely administer a structured pain or comfort survey to patients who underwent carotid endarterectomy under locoregional anesthesia in our center. Moreover, we did not collect data on differences in clinical outcome, amount of intraoperative local anesthetic supplementation, surgeons’ comments, and surgical time for patients who underwent carotid endarterectomy under superficial or combined deep-superficial cervical plexus block. In addition, we did not collect data on patients’ preoperative medications (statins, antiplatelet and anticoagulation therapies) and their impact on neurologic outcome and bleeding complications. Moreover, we acknowledge that our results cannot be generalized to institutions that do not routinely perform locoregional anesthesia for carotid endarterectomy. CONCLUSIONS Our study shows that in a high-volume center, carotid endarterectomy under locoregional anesthesia is safe and associated with a very low rate of conversion to general anesthesia. AUTHOR CONTRIBUTIONS Conception and design: LP, PN, GL, AZ Analysis and interpretation: LP, GL, RC, AZ Data collection: LP, PN, GC, SM, YT Writing the article: LP, PN, GL, YT Critical revision of the article: GC, SM, GL, YT, RC, AZ
Final approval of the article: LP, PN, GC, SM, GL, YT, RC, AZ Statistical analysis: LP, PN, GL Obtained funding: Not applicable Overall responsibility: LP 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;325:445-53. 2. European Carotid Surgery Trialists’ Collaborative Group. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet 1998;351:1379-87. 3. Bonati LH, Dobson J, Featherstone RL, Ederle J, van der Worp HB, de Borst GJ, et al. Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial. Lancet 2015;385:529-38. 4. Rothwell PM, Gutnikov SA, Warlow CP; European Carotid Surgery Trialist’s Collaboration. Reanalysis of the final results of the European Carotid Surgery Trial. Stroke 2003;34:514-23. 5. Brott TG, Halperin JL, Abbara S, Bacharach JM, Barr JD, Bush RL, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/ SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease. Stroke 2011;42:e464-540. 6. Paraskevas KI, Spence JD, Veith FJ, Nicolaides AN. Identifying which patients with asymptomatic carotid stenosis could benefit from intervention. Stroke 2014;45:3720-4. 7. Chiesa R, Melissano G, Castellano R, Tshomba Y, Marone EM, Civilini E, et al. Carotid endarterectomy: experience in 8743 cases. HSR Proc Intensive Care Cardiovasc Anesth 2009;1:33-45. 8. Collins VJ. Principles of anesthesiology. 2nd ed. Philadelphia: Lea & Febiger; 1978. p. 951-5. 9. Pandit JJ, Satya-Krishna R, Gration P. Superficial or deep cervical plexus block for carotid endarterectomy: a systematic review of complications. Br J Anaesth 2007;99:159-69. 10. Carling A, Simmonds M. Complications from regional anaesthesia for carotid endarterectomy. Br J Anaesth 2000;84:797-800. 11. Sundt TM Jr, Ebersold MJ, Sharbrough FW, Piepgras DG, Marsh WR, Messick JM. The risk-benefit ratio of intraoperative shunting during carotid endarterectomy. Ann Surg 1986;203:196-204. 12. Loftus CM, Dyste GN, Reinarz SJ, Hingtgen WL. Distal cervical carotid dissection after carotid endarterectomy: a complication of indwelling shunt? Neurosurgery 1986;19:441-5. 13. Hakl M, Michalek P, Sevcõk P, Pavlõkova J, Stern M. Regional anaesthesia for carotid endarterectomy: an audit over 10 years. Br J Anaesth 2007;99:415-20. 14. GALA Trial Collaborative Group, Lewis SC, Warlow CP, Bodenham AR, Colam B, Rothwell PM, Torgerson D, et al. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial. Lancet 2008;372:2132-42. 15. Landoni G, Pasin L, Monti G, Cabrini L, Beretta L, Zangrillo A. Towards zero perioperative mortality. Heart Lung Vessel 2013;5:133-6. 16. Sindjelic RP, Vlajkovic GP, Lucic M, Koncar I, Kostic D, Davidovic LB. Incidence of and indications for conversion of cervical plexus block to general anesthesia in patients undergoing carotid surgery: a single center experience. J Cardiovasc Surg 2015;56:441-6. 17. Hill MD, Brooks W, Mackey A, Clark WM, Meschia JF, Morrish WF, et al. Stroke after carotid stenting and endarterectomy in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST). Circulation 2012;126:3054-61. Submitted Feb 10, 2015; accepted Mar 24, 2015.
Additional material for this article may be found online at www.jvascsurg.org.
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Supplementary Table (online only). Demographic and preoperative clinical characteristics of patients who successfully underwent surgery under locoregional anesthesia and of patients who required conversion to general anesthesia Locoregional anesthesia
No. of procedures Demographic characteristics Age, years Male Medical history Hypertension Dyslipidemia Type 2 diabetes mellitus History of neurologic events Stroke TIA Syncope Amaurosis Vertigo Other neurologic symptoms Smoking history Renal insufficiency COPD Myocardial infarction PTCI or CABG
Total
General anesthesia
Not converted to general anesthesia
Converted to general anesthesia
2463
24
2432
7
71.7 6 8.23 1618 (65.7)
68.4 6 9.89 15 (62.5)
71.8 6 8.21 1597 (65.7)
1869 1151 603 664 240 172 83 65 57 47 473 377 165 311 526
(75.9) (46.7) (24.5) (27.0) (9.74) (6.98) (3.37) (2.64) (2.31) (1.91) (19.2) (15.3) (6.70) (12.6) (21.4)
13 10 5 10 5 1 2 1 1 3 3 1 3 3
(54.2) (41.7) (20.8) (41.7) (20.8) (4.17) (8.33) 0 (4.17) (4.17) (12.5) (12.5) (4.2) (12.5) (12.5)
1851 1140 598 652 234 171 81 64 56 46 467 372 164 306 520
(76.1) (46.9) (24.6) (26.8) (9.62) (7.03) (3.33) (2.63) (2.30) (1.89) (19.2) (15.3) (6.74) (12.6) (21.4)
P value
75.6 6 8.73 6 (85.7)
.22 .43
5 (71.4) 1 (14.3) 0 2 (28.6) 1 (14.3) 0 0 1 (14.3) 0 0 3 (42.9) 2 (28.6) 0 2 (28.6) 3 (42.9)
.68 .13 .21 .99 .51 .99 .99 .17 .99 .99 .14 .29 .99 .22 .17
CABG, Coronary artery bypass graft; COPD, chronic obstructive pulmonary disease; PTCI, percutaneous transluminal coronary intervention; TIA, transient ischemic attack. Categorical variables are presented as number (%).
Surgical carotid endarterectomy still remains the most effective treatment for reducing the risk of stroke in patients with significant carotid stenosis.1,2 In fact, endovascular carotid stenting is associated with a higher incidence of perioperative and long-term minor stroke compared with carotid endarterectomy, although long-term functional outcome and risk of major stroke are comparable.3 Nowadays, both regional anesthesia and general anesthesia are widely used for patients undergoing carotid endarterectomy according to local standards. No technique for carotid endarterectomy is completely safe and perfect under all circumstances. One of the major complications of locoregional anesthesia is the need for urgent conversion to general anesthesia. Regardless of underlying cause of conversion, emergent intraoperative unplanned endotracheal From the Department of Anesthesia and Intensive Carea and Department of Vascular Surgery,c IRCCS San Raffaele Scientific Institute; and VitaSalute San Raffaele University.b Author conflict of interest: none. Additional material for this article may be found online at www.jvascsurg.org. Reprint requests: Laura Pasin, MD, Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2015 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.03.074
intubation of a patient under surgical drapes, with rotated head and an exposed or even clamped carotid, is very difficult and associated with major risks and hemodynamic instability. Locoregional anesthesia is the first-choice technique for patients undergoing carotid endarterectomy in our center. Because few studies focused on failure of regional anesthesia and its underlying causes, we decided to report our experience as a major center of vascular surgery. METHODS Data of all patients undergoing carotid endarterectomy between June 2009 and December 2014 in our center are presented. All patients signed a consent allowing scientific data management. Ethical Committee approval was waived according to Italian law. Exclusions were patients undergoing combined carotid endarterectomy and coronary artery bypass surgery and patients undergoing carotid percutaneous transluminal angioplasty through neck surgical incision. Carotid stenosis was graded according to the European Carotid Surgery Trial (ECST).4 The indication for surgery was ipsilateral severe (70%-99%) or moderate (50%-69%) carotid stenosis in symptomatic patients or high risk for future stroke (unstable carotid plaque or progression in the severity of asymptomatic carotid stenosis) in asymptomatic patients.5,6 Preoperative anticoagulation therapy was usually temporarily withheld, and a “heparin bridge” was provided during 1
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the perioperative period, according to the patient’s characteristics and risk of thromboembolic events. The last dose of heparin was usually administered the night before surgery. Superficial plexus block was performed in all patients receiving dual antiplatelet therapy or with unpaired coagulation profile. Combined deep and superficial cervical plexus block or superficial plexus block alone was performed according to the attending anesthesiologist’s choice. Patients received endovenous midazolam (0.2 mg/kg), and cervical plexus block was performed outside the operating room 20 minutes before surgical incision by one of a pool of eight specialized anesthesiologists. Heart rate, invasive blood pressure, pulse oximetry, and five-lead electrocardiography were monitored during execution of locoregional anesthesia and throughout surgery. Our anesthetic technique has been previously described in detail.7,8 Superficial cervical plexus block was performed with a 20-gauge needle by injection of ropivacaine 0.75% along the whole posterior border of the sternocleidomastoid muscle, subcutaneously. Deep cervical plexus block was performed as a triple injection technique at the level of the transverse processes of the higher cervical vertebrae (C2, C3, C4). We administered 4 or 5 mL of 0.75% ropivacaine for each injection, after a negative aspiration test result for blood. A total amount of ropivacaine 1.5 mg/ kg was allowed. Moreover, lidocaine 1% (4 mg/kg maximum) was used subcutaneously for incision line infiltration. Additional lidocaine (1%) was injected intraoperatively by surgeons if the patient reported pain or discomfort during the procedure. Intraoperative remifentanil (0.025-0.05 mg/kg/min) maintained an adequate level of comfort, responsiveness, and cooperation. Continuous endovenous infusion of nitroglycerin was titrated for blood pressure control during surgery. Additional clonidine or urapidil was administered if needed. On occasion, additional intraoperative midazolam or fentanyl was administered. General anesthesia was performed only in the case of major contraindications, such as an infection at the site of the block, a history of allergy to local anesthetics, or the patient’s refusal of locoregional anesthesia. Systemic heparinization (50 IU/kg) with an activated clotting time target >200 seconds was routinely used, and protamine 5 mg/kg was usually administered at the end of surgery. A shunt was selectively used in case of neurologic deterioration at the carotid cross-clamping test (a tolerance test of 1 minute before starting with the endarterectomy). The primary outcome of our study was the incidence of intraoperative conversion of locoregional to general anesthesia for any reason. Secondary outcomes were the incidences of major in-hospital cardiovascular and neurologic events and mortality. The incidences of myocardial infarction, hemodynamically relevant arrhythmias, need for reoperation, and intensive care unit (ICU) admission were recorded. Neurologic events were described as transient ischemic attacks and minor and major stokes (ischemic or hemorrhagic). Transient ischemic attack was defined as an event with symptoms lasting up to 24 hours. Major stroke was defined
as a nondisabling stroke with residual neurologic symptoms at hospital discharge. Minor stroke was defined as a stroke with symptoms lasting between 24 hours and hospital discharge. Statistical analysis. Descriptive statistics were used to present the study population and incidence of adverse events. The incidence of events and risk ratio with 95% confidence interval are presented. Data are presented as mean and numbers and percentages, standard deviation, or median and interquartile range. Between-groups comparisons were made with Student t-test, c2 test, or Fisher test, where appropriate. A P value < .05 was considered significant. Statistical analyses were performed with GraphPad Prism version 6.00 for Mac OS X (GraphPad Software, La Jolla, Calif). RESULTS A total of 2463 carotid endarterectomies in 2259 patients were performed during the study period and were included in the analysis. Demographic and clinical characteristics of the studied population are presented in Table I. Regional anesthesia was practiced in 2439 cases (99%), whereas 24 patients (1.0%) received planned general anesthesia. Two patients (0.08%) had a short episode of bradyasystole arrest immediately after cervical plexus block execution. Both episodes were attributed to a vagal reflex and resolved (with atropine administration in one case and chest thump in the other one). In the second case, surgery was postponed for 2 days. Another patient (0.04%) had seizures after block performance attributed to local anesthetic systemic toxicity or accidental vertebral injection. After a few minutes of loss of consciousness, the episode resolved without intervention, and the patient underwent surgery. In seven cases (0.28%), regional anesthesia was converted to general anesthesia. Two patients developed severe agitation before and two patients after skin incision but before clamping. In all these four cases, a shunt was used. In a fifth patient, a shunt was inserted because of neurologic deterioration at the carotid cross-clamping 1-minute test. A few minutes after shunt positioning, he became restless and agitated, requiring conversion to general anesthesia. At the end of surgery, the patient was successfully extubated without neurologic complications. On the second postoperative day, he suffered acute myocardial infarction requiring ICU admission. He was discharged after 14 days, in good condition. A sixth patient became restless and agitated after clamping, during carotid patch suture. In this case, a shunt was not used, and the patient was successfully extubated without neurologic complications at the end of surgery. A seventh patient developed loss of consciousness and desaturation after carotid declamping. At the end of surgery, he was admitted to the ICU, where he was extubated within a few hours without neurologic complications. Therefore, the risk of conversion from locoregional to general anesthesia in our institution (7 of 2439) is 0.28% (95%
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Table I. Characteristics of included patients Demographic characteristics Age 6 SD, years Male Medical history Hypertension Dyslipidemia History of neurologic events Stroke TIA Syncope Amaurosis Vertigo Other neurologic symptoms Type 2 diabetes mellitus Smoking history Renal insufficiency Chronic obstructive pulmonary disease Acute myocardial infarction PTCI or CABG
Table II. Incidence of in-hospital adverse events and mortality after 2463 procedures 71.7 6 8.23 1618 (65.7) 1869 1151 664 240 172 83 65 57 47 603 473 377 165 311 526
(75.9) (46.7) (27.0) (9.74) (6.98) (3.37) (2.64) (2.31) (1.91) (24.5) (19.2) (15.3) (6.70) (12.6) (21.4)
CABG, Coronary artery bypass graft; PTCI, percutaneous transluminal coronary intervention; SD, standard deviation; TIA, transient ischemic attack. Categorical variables are presented as number (%).
confidence interval, 0.14-0.59). No differences were found in demographic and preoperative clinical characteristics between patients who successfully underwent surgery under locoregional anesthesia and those patients who required conversion to general anesthesia (Supplementary Table, online only). Six surgeons contributed to the series. Surgical time was significantly longer in patients who underwent carotid endarterectomies under general anesthesia (78.2 6 19.5 vs 166.6 6 18.8 minutes; P < .01). Overall, a shunt was used in 287 patients (11.7%) undergoing locoregional anesthesia because of neurologic deterioration at the carotid cross-clamping test, but only the five patients described before were converted to general anesthesia. Three cases (0.12%) of intraoperative hemodynamically relevant supraventricular tachyarrhythmia were observed. No intraoperative deaths occurred. The following postoperative complications were noted. One patient (0.04%) suffered from intraoperative acute myocardial infarction and postoperative cardiogenic shock requiring percutaneous transluminal coronary angioplasty immediately after surgery, inotropic agents, intra-aortic balloon pump, ICU admission, and mechanical ventilation. On the third postoperative day, he underwent surgical revision for bleeding. During the 18 days of ICU stay, he suffered from minor stroke and pneumonia. He was discharged after 31 days, asymptomatic. One patient suffered from hemiplegia immediately after surgery. Therefore, he was admitted to the ICU, where he spent 24 hours, with nearly complete regression of neurologic deficit. Emergent repeated surgical procedures were performed in 13 patients (0.53%) because of acute neurologic deterioration immediately after surgery. Four of these patients required postoperative ICU admission for neurologic monitoring.
Postoperative adverse events Combined stroke and death Reoperation Bleeding Neurologic event Admission to ICU From the OR From the ward Major stroke Ischemic Hemorrhagic Minor stroke Transient ischemic attack Myocardial infarction Retinal artery thrombosis Surgery time, minutes Hospital stay 6 SD, days In-hospital mortality Caused by major stroke Caused by myocardial infarction
40 (1.62) 42 (1.70) 29 (1.18) 13 (0.53) 16 (0.65) 7 (0.28) 9 (0.36) 23 (0.93) 20 (0.81) 3 (0.12) 16 (0.65) 9 (0.36) 15 (0.61) 2 (0.08) 67 6 19 4.86 6 2.05 3 (0.12) 2 (0.08) 1 (0.04)
ICU, Intensive care unit; OR, operating room; SD, standard deviation. Categorical variables are presented as number (%).
In-hospital mortality was 0.12% (3 of 2463). The incidence of perioperative adverse events is reported in Table II. DISCUSSION This is the largest case series ever published focusing on conversion from cervical plexus block to general anesthesia for carotid endarterectomy. The overall conversion rate from locoregional to general anesthesia in our population was 7 of 2443 (0.28%), lower than the conversion rate reported in the literature. Reported indications for conversion from locoregional to general anesthesia are both surgery and anesthesia related. The most common anesthesia-related indications for conversion are block failure causing discomfort of the patient, pain and restlessness, claustrophobia, systemic toxicity of local anesthetics, airway obstruction due to cervical hematoma, accidental subarachnoid injection of local anesthetics, and diaphragmatic or vocal cord paralysis causing respiratory distress.9,10 On the contrary, the most common surgery-related indications for conversion to general anesthesia are loss of consciousness at carotid clamping and shunt-related complications (inadequate perfusion, air or plaque embolization, mechanical damage during shunt insertion or removal).11,12 In our study, restlessness and agitation, probably due to block failure or claustrophobia, were the most common reasons for conversion to general anesthesia (4 of 2463 of cases). Similar incidences of block failure were reported in other studies.9,13,14 As a major center of vascular surgery, our extremely low rate of conversion could be related to the very high volume of our institution. Moreover, even if we acknowledge that
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intraoperative supplemental local anesthesia administered by the surgeon might exceed suggested maximum doses, we did not observe cases of intraoperative local anesthetic systemic toxicity. Our positive results suggest that the combination of locoregional anesthesia with low-dose continued infusion of remifentanil is an effective and safe choice for anesthetic management of carotid endarterectomy. Also with regard to in-hospital outcome, the mortality rate in our population was significantly lower than the mortality rate reported in other studies. This is not surprising because low perioperative mortality in our hospital has been previously described.15 In considering perioperative morbidity, the incidence of postoperative cardiovascular events in our population is comparable to that reported in other large studies.14,16 On the contrary, we found a lower rate of in-hospital major stroke compared with other studies.16,17 Our positive results could be helpful to those colleagues with less experience with cervical locoregional anesthesia who are interested in learning and applying this technique in their daily clinical practice. According to our experience, cervical plexus block, especially the superficial one, is an easy technique, with a rapid learning curve and with a low risk of complications. Leaving aside the purely technical aspects, we firmly believe that our successful regional anesthesia program is mainly built on a strong partnership between anesthesiologists and surgeons and on an effective communication with the patient. Limitations. We acknowledge, as a limitation of our study, that we did not routinely administer a structured pain or comfort survey to patients who underwent carotid endarterectomy under locoregional anesthesia in our center. Moreover, we did not collect data on differences in clinical outcome, amount of intraoperative local anesthetic supplementation, surgeons’ comments, and surgical time for patients who underwent carotid endarterectomy under superficial or combined deep-superficial cervical plexus block. In addition, we did not collect data on patients’ preoperative medications (statins, antiplatelet and anticoagulation therapies) and their impact on neurologic outcome and bleeding complications. Moreover, we acknowledge that our results cannot be generalized to institutions that do not routinely perform locoregional anesthesia for carotid endarterectomy. CONCLUSIONS Our study shows that in a high-volume center, carotid endarterectomy under locoregional anesthesia is safe and associated with a very low rate of conversion to general anesthesia. AUTHOR CONTRIBUTIONS Conception and design: LP, PN, GL, AZ Analysis and interpretation: LP, GL, RC, AZ Data collection: LP, PN, GC, SM, YT Writing the article: LP, PN, GL, YT Critical revision of the article: GC, SM, GL, YT, RC, AZ
Final approval of the article: LP, PN, GC, SM, GL, YT, RC, AZ Statistical analysis: LP, PN, GL Obtained funding: Not applicable Overall responsibility: LP 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;325:445-53. 2. European Carotid Surgery Trialists’ Collaborative Group. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet 1998;351:1379-87. 3. Bonati LH, Dobson J, Featherstone RL, Ederle J, van der Worp HB, de Borst GJ, et al. Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial. Lancet 2015;385:529-38. 4. Rothwell PM, Gutnikov SA, Warlow CP; European Carotid Surgery Trialist’s Collaboration. Reanalysis of the final results of the European Carotid Surgery Trial. Stroke 2003;34:514-23. 5. Brott TG, Halperin JL, Abbara S, Bacharach JM, Barr JD, Bush RL, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/ SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease. Stroke 2011;42:e464-540. 6. Paraskevas KI, Spence JD, Veith FJ, Nicolaides AN. Identifying which patients with asymptomatic carotid stenosis could benefit from intervention. Stroke 2014;45:3720-4. 7. Chiesa R, Melissano G, Castellano R, Tshomba Y, Marone EM, Civilini E, et al. Carotid endarterectomy: experience in 8743 cases. HSR Proc Intensive Care Cardiovasc Anesth 2009;1:33-45. 8. Collins VJ. Principles of anesthesiology. 2nd ed. Philadelphia: Lea & Febiger; 1978. p. 951-5. 9. Pandit JJ, Satya-Krishna R, Gration P. Superficial or deep cervical plexus block for carotid endarterectomy: a systematic review of complications. Br J Anaesth 2007;99:159-69. 10. Carling A, Simmonds M. Complications from regional anaesthesia for carotid endarterectomy. Br J Anaesth 2000;84:797-800. 11. Sundt TM Jr, Ebersold MJ, Sharbrough FW, Piepgras DG, Marsh WR, Messick JM. The risk-benefit ratio of intraoperative shunting during carotid endarterectomy. Ann Surg 1986;203:196-204. 12. Loftus CM, Dyste GN, Reinarz SJ, Hingtgen WL. Distal cervical carotid dissection after carotid endarterectomy: a complication of indwelling shunt? Neurosurgery 1986;19:441-5. 13. Hakl M, Michalek P, Sevcõk P, Pavlõkova J, Stern M. Regional anaesthesia for carotid endarterectomy: an audit over 10 years. Br J Anaesth 2007;99:415-20. 14. GALA Trial Collaborative Group, Lewis SC, Warlow CP, Bodenham AR, Colam B, Rothwell PM, Torgerson D, et al. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial. Lancet 2008;372:2132-42. 15. Landoni G, Pasin L, Monti G, Cabrini L, Beretta L, Zangrillo A. Towards zero perioperative mortality. Heart Lung Vessel 2013;5:133-6. 16. Sindjelic RP, Vlajkovic GP, Lucic M, Koncar I, Kostic D, Davidovic LB. Incidence of and indications for conversion of cervical plexus block to general anesthesia in patients undergoing carotid surgery: a single center experience. J Cardiovasc Surg 2015;56:441-6. 17. Hill MD, Brooks W, Mackey A, Clark WM, Meschia JF, Morrish WF, et al. Stroke after carotid stenting and endarterectomy in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST). Circulation 2012;126:3054-61. Submitted Feb 10, 2015; accepted Mar 24, 2015.
Additional material for this article may be found online at www.jvascsurg.org.
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Supplementary Table (online only). Demographic and preoperative clinical characteristics of patients who successfully underwent surgery under locoregional anesthesia and of patients who required conversion to general anesthesia Locoregional anesthesia
No. of procedures Demographic characteristics Age, years Male Medical history Hypertension Dyslipidemia Type 2 diabetes mellitus History of neurologic events Stroke TIA Syncope Amaurosis Vertigo Other neurologic symptoms Smoking history Renal insufficiency COPD Myocardial infarction PTCI or CABG
Total
General anesthesia
Not converted to general anesthesia
Converted to general anesthesia
2463
24
2432
7
71.7 6 8.23 1618 (65.7)
68.4 6 9.89 15 (62.5)
71.8 6 8.21 1597 (65.7)
1869 1151 603 664 240 172 83 65 57 47 473 377 165 311 526
(75.9) (46.7) (24.5) (27.0) (9.74) (6.98) (3.37) (2.64) (2.31) (1.91) (19.2) (15.3) (6.70) (12.6) (21.4)
13 10 5 10 5 1 2 1 1 3 3 1 3 3
(54.2) (41.7) (20.8) (41.7) (20.8) (4.17) (8.33) 0 (4.17) (4.17) (12.5) (12.5) (4.2) (12.5) (12.5)
1851 1140 598 652 234 171 81 64 56 46 467 372 164 306 520
(76.1) (46.9) (24.6) (26.8) (9.62) (7.03) (3.33) (2.63) (2.30) (1.89) (19.2) (15.3) (6.74) (12.6) (21.4)
P value
75.6 6 8.73 6 (85.7)
.22 .43
5 (71.4) 1 (14.3) 0 2 (28.6) 1 (14.3) 0 0 1 (14.3) 0 0 3 (42.9) 2 (28.6) 0 2 (28.6) 3 (42.9)
.68 .13 .21 .99 .51 .99 .99 .17 .99 .99 .14 .29 .99 .22 .17
CABG, Coronary artery bypass graft; COPD, chronic obstructive pulmonary disease; PTCI, percutaneous transluminal coronary intervention; TIA, transient ischemic attack. Categorical variables are presented as number (%).
