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					Endarterectomy
Present by Ri 張志富 Ri 戴君芙 Ri 陳婉瑜 Supervise by CR 劉治民

2008/8/12

Carotid artery stenosis
  

Atherosclerosis TIA & stroke Tx  Antiplatelet (Aspirin)  Endarterectomy  Stent

Endarterectomy
Indication (level I)
Symptomatic, stenosis> 70 %
Asymptomatic, stenosis>60%

Guideline for carotid endarterectomy. A statement for healthcare professionals from a special writing group of the stroke council, American Heart Association. Stroke. 1998;

Preoperative evaluation


CAD
 

Common in P’t with carotid stenosis AMI is leading mortality
CEA first: cardiac morbidity ↑ Coronary first: stroke risk ↑ Combine in unstable CAD with severe carotid stenosis



Staged or combined approach
 



Brown KR: Treatment of concomitant carotid and coronary artery disease: Decision-making regarding surgical options. J Cardiovasc Surg (Torino) 44:395–399, 2003.

General Anesthesia
 

Unpredictable BP response Induced hypertension:


 

10~20% above baseline Increase brain perfusion Myocardial ischemia

Regional Anesthesia 1
 





Allows continuous neurologic assessment Reduced need for shunting Greater stability of blood pressure and decreased vasopressor requirements No absolute contradiction to regional anesthesia

Regional Anesthesia 2


Disadvantage
No pharmacologic cerebral protection  patient panic, or seizure  airway inadequate in conversion


General or regional ?




No differences in perioperative stroke or death rate RA: fewer nonneurological, nonfatal complications

Papavasiliou AK, Magnadottir HB, Gonda T, et al: Clinical outcomes after carotid endarterectomy: Comparison of the use of regional and general anesthetics. J Neurosurg 92:291–296, 2000.

Intraoperative

management of hemodynamic change
Bradycardia Tachycardia Hypertension

and Hypotension

Cerebral

intraoperative protection
for the need of carotid shunt
patients

Monitoring
Awake EEG
Stump

pressure Cerebral oximetry
Others

Intraoperative management of hemodynamic change


Bradycardia and Hypotension
  



Carotid sinus manipulation Vagus tone↑ Myocardial infarct, neurological deficits Management
local anesthetics  temporary venous pacemakers  intravenous atropine  vasopressor


Local anesthetics
1% Lignocaine
2ml

Effect of lignocaine injection in carotid sinus on baroreceptor sensitivity during carotid endarterectomy Journal of Vascular Surgery Volume 39, Issue 6 , June 2004, Pages 1288-1294

Temporary venous pacemakers


37 balloon-assisted angioplasty and stent procedures



The pacemakers captured and maintained a rhythm in 23 (62%) of the 37 procedures and prevented symptomatic bradycardia and hypotension from occurring in all of the patients.
reduced the incidence of bradycardia and hypotension to only 3 (9%), as compared with the rate of 40 to 100% reported in the literature
Prevention of carotid angioplasty-induced bradycardia and hypotension with temporary venous pacemakers. Neurosurgery. 2001 Oct;49(4):814-20; discussion



Intravenous atropine

Carotid angioplasty and stent-induced bradycardia and hypotension: Impact of prophylactic atropine administration and prior carotid endarterectomy. J Vasc Surg. 2005 Jun;41(6)

Intraoperative management of hemodynamic change


Tachycardia
  



Stress, pain, catecholamine release Underlying CAD Myocardial infarct Management


Short-acting βblocker (eg. esmolol)

Prevention of tachycardia with atenolol pretreatment for carotid endarterectomy under cervical plexus blockade.






A double-blind, randomised, controlled trial of 40 patients 20 for placebo; 20 for 50 mg of atenolol two hours prior to surgery Tachycardia: 13/20 in the placebo group and 2/20 in the atenolol group (P < 0.01).
Anaesth Intensive Care. 1992 May;20(2):161-4.

Intraoperative management of hemodynamic change


Hypertension
  



Stress, pain, carotid body manipulation Sympathetic tone ↑ Underlying CAD, Myocardial infarct, cerebral hemorrhage Management
Nitroglycerin  Sodium nitroprusside


Cerebral intraoperative protection


Carotid shunt
Blood bypass from common to internal carotid artery  Complication:

 

Intimal flap arterial dissection Plaque emboli or air embolism

Cerebral intraoperative protection


Monitoring


Awake patients
Under regional anesthesia  Eye movement, speech, grasping, consciousness


Cerebral intraoperative protection


Monitoring


EEG
 

Theta and delta waves or disorganized rhythm Routine use of EEG was associated with apparent complete elimination of intraoperative strokes and less than 1% risk of perioperative strokes.

Carotid endarterectomy with routine electroencephalography and selective shunting: Influence of contralateral internal carotid artery occlusion and utility in prevention of perioperative strokes. J Vasc Surg. 2002 Jun;35(6):1114-22

Comparison of simultaneous electroencephalographic and mental status monitoring during carotid endarterectomy with regional anesthesia
Journal of Vascular Surgery Volume 28, Issue 6 , December 1998, Pages 1014-1023

Cerebral intraoperative protection


Monitoring  Stump pressure  Circle of Willis ↔ ICA  Threshold: 30-50 mmHg



Correlation of carotid artery stump pressure and neurologic changes during 474 carotid endarterectomies performed in awake patients.


Using 40 mm Hg systolic as a threshold, the need for shunting (15%) and the false-negative rate (1.0%) for SP in our series were equivalent to the results of EEG monitoring during CEA reported in the literature.

J Vasc Surg. 2005 Oct;42(4):684-9.

Cerebral intraoperative protection


Monitoring  Cerebral oximetry  Regional cerebral oxygen saturation  Could not identify a threshold that can be used alone to predict the need for shunt placement

A clinical evaluation of near-infrared cerebral oximetry in the awake patient to monitor cerebral perfusion during carotid endarterectomy. J Clin Anesth. 2005 Sep;17(6):426-30.

P=0.01

Cerebral intraoperative protection


Others  Arterial blood pressure  Preoperative level or slightly higher  Normocapnia  Hypothermia  Volatile anesthetics and barbiturates  Avoid nitrous oxide: ↑postoperative myocardial ischemia  Induction drugs  Sodium thiopental  Propofol  Etomidate

SSEP
 







The response of the sensory cortex Able to detect subcortical sensory pathway ischemia Decreased regional cerebral blood flow (< 12 mL/100 g of brain tissue per minute) No specific physiologic marker influenced amplitude Not been definitivelyJournal of Anesthesia 51:937-941 (2004) established Canadian

Transcranial Doppler (TCD)
 









Continuous measurement of blood flow Detection of microembolic events Peri-op: shunt function, malfunction, and incidence of emboli during shunt insertion Post-op: early postoperative embolization, hyperperfusion syndrome Technical difficulties Outcome has not Annals of Vascular Surgery Inc. 2005,11 January been reported

Postoperative Considerations
 

 

Postoperative stroke Postoperative hypertension & hypotension Hyperperfusion syndrome Others

Postoperative stroke
Cause  Plaque emboli  Platelet aggregates  Poor cerebral protection  Relative hypotension

Evaluation and treatment








Recovery room or intraoperative ultrasound The optimal time to heparinize ? Percutaneous transluminal carotid angioplasty with stenting Thrombolytic therapy

Postoperative hypertension




 

Poorly controlled preoperative hypertension Surgical denervation of the carotid sinus baroreceptors General anesthesia > Regional anesthesia Neurologic and cardiac complications

Postoperative hypotension
 

 


As frequently as hypertension Carotid sinus baroreceptor hypersensitivity or reactivation Regional anesthesia > General anesthesia Myocardial and cerebral ischemia Fluids and vasopressors

Hyperperfusion syndrome








Abrupt increase in blood flow with loss of autoregulation Occurs several days after sugery Moderate (20 to 44 %) increases in ipsilateral cerebral blood flow (by PWI) Absence of increases in middle cerebral artery flow velocity (by TCD)

Risk Factors
 

 

High-grade (>80%) carotid stenosis Recent cerebral infarction Reduced CBF or cerebral vasoreactivity Severe postoperative hypertension

Symptoms and Signs
 

 


Headache Focal motor seizures Focal neuralogic sign Intracerebral hemorrhage Brain edema

Treatment






Strict control of postoperative hypertension (SBP<150mmHg) Intravenous labetalol, nitroprusside, and nitroglycerin Most postoperative BP lability resolves in the first 24 hours

Others
 

 


Nerve injury Wound hematoma Respiratory distress Infection Parotitis

Prognosis


Predictors of mortality
  

 

Age Male sex Diabetes mellitus Systemic hypertension Cigarette smoking

References
1.

2. 3.

Miller: Miller's Anesthesia, 6th ed Anesthesiology Clinics of North America Volume 22 • Number 2 • June 2004 James P Greelish, Emile R Mohler, III, Ronald M Fairman, for carotid endarterectomy (Cochrane review). The Cochrane Library. Issue 2 Oxford: Update Software; 2006.

Thank you for your attention


				
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