Carotid Endarterectomy

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Carotid Endarterectomy continued
  • 1Complication Overview:
    • Stroke
    • Postoperative TIAs
    • Seizures: frequency -- 0.4%-1% {possibly secondary to cerebral hyperperfusion, emboli, and/or intracerebral hemorrhage}
    • Postoperative carotid artery closure:  frequency = 0.8% to 2% 
    • Cranial nerve injury: 
      • Hypoglossal nerve injury sufficient to cause difficulty with speaking, chewing, swallowing due to tongue movement abnormalities  (risk= 1%)
      • Vagus or recurrent laryngeal nerve causing vocal cord paralysis (risk= 1%)
    • Headaches
    • Hypertension
  •  Morbidity/Mortality Factors
    •  Usually postoperative death (e.g., within two months following endarterectomy) after carotid endarterectomy is due to myocardial infarction{as opposed to neurological causes}
    • Mortality probability related to presence and extent of coronary vascular disease, i.e., patients without history or symptoms of coronary artery disease or had undergone coronary artery bypass surgery were at risk for significantly increased mortality {including cerebrovascular mortality causes}
  • Causes & time of occurrence of serious morbidity/mortality following carotid endarterectomy:
    •  Stroke (may occur during or after surgery): about 5% risk (mild to severe)
      •  Primary cause of postoperative stroke (immediate complication): carotid occlusion
        • also possible -- external & common carotid artery occlusions
          • palpation for superficial temporal pulse: indicative of external carotid flow
          • common carotid occlusion: usually secondary to internal or external branch occlusion
    •  Carotid hemorrhage -- special problems: reduced cerebral perfusion & airway occlusion
    •  Myocardial infarction (may occur during or after surgery)
    •  Other Complications:
      •  Cranial nerve damage-- frequency: 12%-17%
      •  Hypoglossal injury -- frequency 20% {hypoglossal injury may be asymptomatic; identified by direct Laryngoscopy; asymptomatic frequency = 33%}
        • Cause: coagulation of vein plexus surrounding the nerve
      •  Cricothyroid or thyroarytenoid dysfunction-- frequency 27.5%
      •  Operative site infection {most common Staphylococcus epidermidis; wound hematomas; postoperative embolization following arteriotomy site thrombus formation

 

 Peripheral vascular & visceral Insufficiency

  •  Atherosclerosis causes Lower limbs + abdominal major arterial vascular disease 
    • Consequences of atherosclerosis
      •  Occlusive disease
      •  Aneurysmal disease
  • Primary cause of morbidity/mortality: myocardial disease
  • Significant disability, pain, and organ failure ( e.g., kidneys): derivative of persistent intraoabdominal organ or lower-limb ischemia
  •  Morbidity in this patient group: High secondary to coronary vascular disease, diabetes, advanced age, hypertension and smoking
    • Postoperative management: difficult because of:
      • physiological lability
      • coaches
      • cardiac preload/afterload variations
    • Vascular Surgical outcome dependent on:
      1. Age
      2. coronary vascular disease severity
      3. nature of the surgery
      4. urgency of surgery
  • Preoperative Risk Assessment:
    • Possibly predictive: dipyridamole (Persantine) thallium scintigraphy (DTS)
      • may be useful in predicting in-hospital adverse events as well as long-term outcome2
    • Possibly predictive: Holter monitoring (ambulatory ECG monitoring)

Occlusive Peripheral Vascular Disease

  • Overview: Three major groupings describing pathophysiological characteristics, prognosis and outcome
  Type I 
Limited to aortic bifurcation & common iliacs Local form of disease Common in male smokers (age group: 40-55 years of age)
Presentation: Thighs and hip claudication* 5-year survival: 90% Minimal coronary vascular disease/cerebrovascular disease in this group
  • 3*Intermittent claudication:
    • Calf muscle pain (and less frequently in the buttock or thigh) at a reproducible exercise level
      • asymmetrical pain common
    • 4Diagnosis Steps
      1. Complete history; determine if pain is reproducible & resolves with rest
      2.  Physical Exam: checking for evidence of systemic atherosclerosis
        • check pulses {carotid, brachial, & radial} 
        • examine femoral pulses
        • check dorsalis pedis pulses (absent about 10% of normal individuals)
        • palpate/auscultate abdomen for  bruits/aneurysm
        • examine feet for thin, atrophic skin, cracks between toes & toenail thickening
      3.  Additional tests for selective patients
        • Noninvasive vascular analysis to assess disease severity & location
          1.  Doppler ankle-brachial index
            • Ankle-brachial index (ABI)= (ankle systolic blood pressure)/(arm systolic blood pressure)
          2.  Segmental pressures
          3.  Pulse volume recording waveform
          4.  Doppler waveform analysis, duplex imaging, exercise Doppler studies
          5.  Treadmill exercise testing with treadmill set at an angle
  • "The iliac vessels of a 65 year-old man presenting with increasing right calf claudication (two blocks) are seen in this angiogram.  The patient had a prior left femoral popliteal bypass, bilateral carotid endarterectomy and history of coronary artery disease"-- courtesy of vesalius (http://www.vesalius.com), used with permission
  • "The femoral vessels show the bypass graft on the left, occlusion of the right superficial femoral and stenosis of the right profunda 2 cm beyond its origin" -- courtesy of vesalius (http://www.vesalius.com), used with permission
  •  aType II Peripheral Vascular Disease
    • Diffuse aorticoiliac disease {multiple levels}
    • Significant coexistence of:
      • coronary vascular disease
      • cerebrovascular disease
    • Patient profile:
      • relatively older patient
      • smoker
      • diabetic
      • hypertensive
      • hyperlipidemic
    • Common Clinical Findings
      • Lower extremity ischemic ulcers 
      • Lower extremity claudication (severe)
    •   Outcome:
      • 5 yr. survival following surgical intervention: 80%
      • Characterized by coronary/cerebrovascular disease incidence
  •    aType III Peripheral Vascular Disease
    • Most advanced disease: 5-year survival = 65% secondary to significant small vessel disease {small vessels are not surgically accessible}
    • Characteristics:
      • femoral-popliteal involvement
      • tibial vascular involvement
      • more common in women than men
      • often associated with diabetes mellitus
    • Clinical Course:
      •  complicated due to other systemic disease processes
    •  Mortality frequency
      • Cause: cardiac disease/dysfunction [independent to whether primary presentation is aneurysmal or occlusive major vascular disease]
        •  Occlusive disease: mortality due to cardiac dysfunction: 64%-79%
        •  Overall mortality rate for carotid endarterectomy = 2%-3%
        •  Surgical mortality rate for occlusive major vascular disease usually >/= 4%

 

 

  • aPrimary Reference: Katz, J.,  Evaluation Risk Assessment of Patients with Vascular Disease in Principles and Practice of Anesthesiology (Longnecker, D.E., Tinker, J.H. Morgan, Jr., G. E., eds)  Mosby, St. Louis, Mo., pp. 201-218, 1998.
  • 1 UCLA Neurosurgery: Cerebrovascular & Stroke Diseases & Disorders -- Carotid Stenosis (http://www.neurosurgery.medsch.ucla.edu/Diagnoses/Cerebrovascular/CerebroDis_3.html)
  • 2Fleisher, LA, Rosenbaum, SH, Nelson, AH, et al: Preoperative dipyridamole thallium imaging and ambulatory electrocardiographic monitoring as a predictor of perioperative cardiac events and long-term outcome, Anesthesiology, 83 (5): 906-917, 1995. note: second sourced reference from Primary Reference above.
  • 3Peripheral vascular diseases: arterial diseases. In: The Merck Manual of Geriatrics, second edition, Portland OR: CMC Research Inc.; 1996
  • 4Hirsch, AT, Munnings, F. Intermittent claudication: steps for evaluation management.  The physician and Sports Medicine.  1993; 21:125-131.

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