Cerebrovascular 3

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  1. Indirect Testing - Periorbital Capabilities
    Indicate external to internal carotid artery collateral flow due to ICA hemodynamically significant stenosis or occlusion
  2. Periorbital Testing Limitations
    • Only diagnostic with hemodynamically significant lesion
    • Cannot differentiate occlusion from tight lesion
    • Technique requires skill
  3. Periorbital Testing Position
    • Supine
    • Head or bed elevated slightly
    • Head on pillow
    • Eyes closed
  4. Periorbital Technique
    • 8-10 MHz Doppler CW probe
    • Locate frontal artery at inner canthus of eye
    • Flow should be antegrade
    • Series of superficial temporal and facial artery compressions are performed
    • Flow should remain antegrade throughout compressions

    Same procedures done on the supraorbital artery
  5. Periorbital Testing: Positive Response
    Flow in either the frontal and/or supraorbital arteries will reverse, stop, or significantly diminish flow when either superficial temporal and/or facial arteries are compressed. 

    All ipsilateral!
  6. Periorbital Testing: Negative Response
    Only minimal diminishment or augmentation of flow with compressions
  7. Periorbital Testing
    External to internal collateral carotid flow can also be verified with a 5 MHz CW probe when scanning the Opthalmic Artery

    • Flow toward the probe is normal
    • Flow away from the probe (reversed opthalmic) is abnormal and the collateral flow is verified
  8. Direct Testing: Duplex Scanning
    • Capabilities: Accurate way to localize arterial disease
    • Can differentiate occlusion from severe stenosis
    • Can follow progression of disease
    • Can determine plaque characteristics
  9. Soft Homogeneous Plaque
    • Fibrous plaque
    • Low to medium level echoes of similar appearance
    • Borders are smooth
  10. Calcification
    • Very bright, highly reflective echoes
    • Produces acoustic shadowing
  11. Ulcerated Plaque
    Plaque with a crater-like appearance
  12. Duplex Limitations
    • Incision
    • Size of 
    • Depth of vessel - superficial and deep
    • Course of vessel
    • Acoustic
  13. Duplex Overestimating
    May occur when:

    • Artifacts are mistaken for plaque or dissection
    • Flow in tortuous vessels are mistaken for stenoses
    • Bad doppler angle
  14. Duplex Underestimating
    May occur when:

    • Soft plaque is missed
    • Accelerated flow is missed
    • Length of plaque causes no acceleration of flow
  15. Duplex Postitioning
    • Reclining or supine
    • Towel under neck
    • Perform exam upright
  16. Duplex Transducers
    10, 7.5, or 5 MHz
  17. Duplex Planes
    • Anterior
    • Lateral
    • Posterolateral
    • Transverse
  18. Intra-Op Monitoring Capabilties
    • Identify problems immediately post endarterectomy
    • Intimal flaps
    • Platelet aggregation
    • Residual disease
    • Suture line stricture (narrowing can work like a stenosis)
  19. Intra-Op Technique
    • Transducer placed in sterile sleeve filled with gel
    • Wound filled with sterile gel
    • Scan settings adjusted as for regular carotid study (with 10-12 MHz probe)
  20. Transcranial Doppler Capabilties
    • Vasospasm monitoring
    • Indicate intracranial stenoses and/or occlusions
    • Assess collateral flow
    • Evaluate vasoconstriction
    • Indicate AVMs
    • Indicate brain death
  21. Moya Moya Disease
    • Means "puff of smoke" in Japanese
    • Collateral vessel development near occluded or nearly occluded vessels of the circle of willis
  22. Moya Moya TCD
    Demonstrates marked velocity reductions in the MCA and ACA bilaterally

    This is due to the fact that the lesions are long and not focal (which would produce velocity increases)
  23. TCD Limitations
    • Transtemporal window cannot always be used
    • Thickness of the temporal bone interferes
    • No anatomic landmarks so misidentification may occur
  24. TCD Positioning
    • Supine
    • Sitting
  25. TCD Windows
    Transorbital > Opthalmic Artery and Carotid Siphon

    Transtemoral > MCA ACA PCA

    Transforaminal/Transoccipital > VA BA
  26. TCD
    Compression and oscillation maneuvers may be used to help verify vessels
  27. TCD Intra-Op Capabilties
    Flow abnormalities during cerebrovascular and cardiovascular procedures are detected

    MCA monitoring for high intensity transient signals (HITS) or microembolic signals (MES)
  28. History of Carotid Surgery
    Prior to 1951, surgery included:

    • Carotid thrombectomy
    • Ligation/excision of carotid bifurcation
    • Intracranial carotid ligation
  29. First Carotid Reconstruction
    • Symptomatic patient with an ICA stenosis
    • Buenos Aires - 1951
    • 41, Male with recurrent TIAs
    • Partial resection of ICA with anastomosis or ECA to ICA
    • Concomitant cervical sympathectomy
  30. First Endarterectomy for Stroke Prevention
    • Michael Debakey, MD
    • Houston, TX - August 7, 1953
    • 53 year old male bus driver with right sided hemiparesis
  31. CV Surgery - Extracranial Occlusive Lesions
    • With occlusion - no surgery
    • Incision made with cautery
    • Dissection made down to carotid artery
    • Care taken not to disturb cranial nerves and ECA branch
    • Cerebral flow method must be determined
    •              Cross clamping or shunting
  32. CV Surgery - Cross Clamping
    • Done under local anesthesia
    • CCA ECA ICA occluded for 3 minutes
    • Patient asked to speak and move limbs on side affected by carotid lesion
    • If no evidence of impairment, assumed to have adequate intracranial collateral flow
    • 80-90% successful
  33. CV Surgery - Internal Shunt
    • Usually preferred method for surgery under general anesthesia
    • Shunt placed in vessel at both proximal and distal sites to lesion
    • To restore CV flow during endarterectomy
    • No clamping necessary other than shunt placement
  34. CV Surgery - Disadvantages to Shunting
    • Makes endarterectomy more cumbersome
    • Compromises visualization of distal end point of disease
    • Scuffing or distruption of distal intima during insertion
    • Possible introduction of air through shunt
    • Lesion is removed and artery incision site is closed
  35. CV Surgery - Kinking
    Area of kink removed and the vessel is resected
  36. FMD - Percutaneous Balloon Angioplasty
    • Groin approach
    • Brachial artery approach
  37. CV Surgery - Aneurysm
    • Ligation - not done anymore
    • Wrapping - prosethetic materials used to control expansion and limit risk of rupture
    • Resection - removal of aneurysmal section
  38. CV Surgery - Carotid Dissection
    • Heparin used more than surgical procedures
    • Thins blood so intima can heal
    • Surgical procedure - resection with graft
  39. CV Surgery - Carotid Body Tumor
    Group 1 - Minimal ICA involvement, tumor outside

    Group 2 - Partial involvement of ICA resection

    Group 3 - Lesions encircling ICA, dissection next to impossible, usually must resect using graft material
  40. CV Surgery - Complications
    • Extracranial hematoma
    • Infection
    • False aneurysm
    • Hypertension or hypotension
    •     Due to alternations in blood volume
    •     Due to peripheral vasoconstriction
    •     Due to cardiac dysfunction
  41. Carotid Stenting - Potential Benefits
    • Reduced complication rates
    • Less invasive
    • Can reach essentially all blockages
    • Very low restenosis rate (intimal hyperplasia)
    • Rapid return to daily life
  42. Contraindication for Carotid Stenting
    • Severly tortuous, calcified and atheromatous aortic arch vessels
    • Predunculated thrombus at the lesion site
    • Severe renal impairment
    • Recent stroke (3 weeks) should be placed on anticoagulants and antiplatelets for 1 month
    • Unable to tolerate antiplatelet for 1 month
  43. Contraindication for Carotid Stenting (2)
    • Potential atherosclerosis
    • Emboli protection/collection system
  44. Endarterectomy vs Stent Trials
    SAPPHIRE - Stenting and Angioplasty with Protection in Patients at High Risk for E

    CREST - Carotid Revascularization Endarterectomy vs Stent

    Carotid Endarterectomy (CEA) and Carotid Artery Stenting (CAS) have similar net outcomes though the individual risks vary, lower stroke with CEA and lower MI with CAS. Younger patients have improved efficacy with CAS and older patients have improved efficacy with CEA
  45. Stroke Prevention
    • Antihypertensive drugs
    • Reduce
    • Cessation of smoking
    • Weight
    • Anticoagulation therapy
    •     For occlusive disease, atrial fibrillation,    
    •     and heart
    •     Aspirin or persantine
  46. Stroke Treatment
    • Surgery - endarterectomy or stenting
    • Drugs - tPA with protocol
    •    Approved for acute stokes, blood clots 
    •    Risk of bleeding, benefits outweigh risks
    •    Must be given 3 hours after onset or not    
    •    effective
    • Hospital care
    • Rehab
  47. Stroke Rehab is Dependent on:
    • Extent of brain that is affected
    • Survivor's attitude
    • Rehab team's skill
    • Cooperation of family and friends
    • People with the least impairment benefit most
  48. Stoke Rehab Goals
    • Reduce dependence on others
    • Improve physical ability
    • Re-teach old skills
    • Teach new skills when old are not recoverable
    • Maintain and improve patients physical condition
  49. Stroke Rehab Education of Family:
    • Must teach family what stroke survivors are going through
    • Must explain what disabilties will affect patient
    • Must explain what the family is going to expect
    • Must explain how to handle potential problems
  50. Carotid Intima-Media Thickness (CIMT)
    Because coronary heart disease is the leading cause of death in the US, primary prevention of cardiovascular events is a priority

    If atherosclerosis plaque develops in one vessel of the body, plaque is probably developing in other arteries. The primary concern is the coronary arteries.

    Autopsy studies in young people with atherosclerotic plaque shows a correlation with cardiovascular risk factors
  51. The Framingham Global Risk Assessment Model
    • Started in 1948
    • 5,209 men and women, 30 to 62 were studied to determine patterns within the development of CVD
    • Restudied every 2 years
    • Instrumental in finding risk factors
  52. The Framingham Cardiac Risk Score
    Uses Age, Sex, Total Cholesterol, HDL, BP, HX of Diabetes, and a HX of Smoking to predict a 10 year CHD risk
  53. Framingham to CIMT
    Framingham uses age to calculate atherosclerotic burden
  54. MCA
    • Transtemporal
    • 3-4cm
    • Toward
    • Same
    • 55+-12
    • Obliteration or Diminishment
  55. ACA/MCA Bifurcation
    • Transtemporal
    • 5-6.5cm
    • Bidirectional
    • Identical to ACA/MCA
  56. ACA
    • Transtemporal
    • 6.5-7cm
    • 8 @ both ACAs
    • Anterior and Superior
    • 50+-11
    • Obliteration, Diminishment, or Reversal
  57. PCA (1)
    • Transtemporal
    • 5-6.5cm
    • Toward
    • Posterior and Inferior 
    • 39+-10
    • No change, Augment, Diminishment, Obliteration
  58. PCA (2)
    • Transtemporal
    • 5-6.5cm
    • Away
    • Posterior and Inferior
    • 40+-10
    • No change, Obliteration, Diminishment
  59. TICA
    • Transtemporal
    • Toward 
    • Inferior
    • 39+-9
    • Obliteration or Reversal
  60. OA
    • Transorbital
    • 40-60cm
    • Toward 
    • Obliteration
  61. Carotid Siphon
    • Transorbital
    • 6-8cm
    • Away, Bidirectional, or Toward
    • 41+-11, 47+-14
    • Obliteration, Reversal
  62. VA
    • Transforamenal
    • 6-9cm
    • Away
    • 38+-10
  63. BA
    • Transforamenal
    • 8-12cm...9.5cm
    • Away
    • 41+-10
Card Set:
Cerebrovascular 3
2013-06-07 03:38:43

Test 3
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