Carotid Surgery Update 2005

S.J.Fratesi MD, DABS, FRCS©,FICS,FACS

Supported by W.L. Gore & Assoc.

Key points in the evaluation of carotid stenosis

vUnderstand how/why strokes occur

vDetermine the risk of a primary stroke or a stroke recurrence

vDistinguish medical vs surgical treatments

vHow to monitor disease progression( medical vs surgical strategies)

BRAIN ATTACK

STROKE Transient IschemicAttack(TIA)

Stroke

An acute clinical event due to interruption of the cerebral circulation lasting more than 24 hours

If less than 24 hours called a TIA (transient ischemic attack)

Stroke facts

• The most common neuro illness in NA

• The leading cause of disability for adults

• The 3rd cause of death in adults following cardiac disease and cancer

Stroke mechanics• A cerebral infarct is an area of tissue

necrosis or death due to an obstruction of arterial flow due to either thrombosis, embolus or hemodynamic instability

• Normal cerebral flow=50-60ml/100grams of tissue /minute.Ischemia occurs at <30ml/100gms and tissue death if<10ml.

• In NA, there is a new stroke every minute

• In NA, a person dies from stroke every 3.5 minutes

• In NA, there are now 4million people who have had a stroke and are alive

• The chance of death with a stroke is 30%.Of those who survive the recurrence rate within the next 2 years is 30%

Stroke facts (continued)• On the rank and disability scale after

stroke, only 25% had a good outcome with a reasonable recovery

• Most stroke survivors still handicapped after one year will continue to require help

Stroke facts (continued)

• 40-60% of strokes are from extracranial carotid disease

• Stenosis > 50%……5% of the general population>60……10%>60 with known atherosclerotic risk facors….20% with known CAD and PVD

Stroke facts( continued )• Highest rate of strokes…> 80% stenosis

• Asymptomatic bruit…5% >age45, 10-15%>75

• Only 15-30% of strokes are preceded by a TIA

• CAROTID ENDARTERECTOMY first done 1954 is a natural extension of the disease.How do you screen for the disease and who should be offered the surgery?

Symptoms of Stroke/TIA

• Sudden numbness/weakness of face, arm,leg(usually one side)

• Sudden vision trouble(one/both eyes)• Sudden confusion,difficulty talking or

understanding• Sudden severe headache• Sudden difficulty with co-ordination,

walking or balance

Types of strokes• Ischemic stroke(80%) due to

thrombosis,embolus or hemodynamic instabilty.There is occlusion of the vessel leading to infarction

• Hemorrhagic stroke(20%) due to intracerebral or subarachnoid bleed(AVM or berry aneurysm.60% die the survivors usually are severely disabled

Incidence and prevalence of strokev400,000 ischemic strokes/year(US)

v75% first time v20% second time

v100,000 hemorrhagic strokes/year

vIn the US ,currently over 3 million surviving stroke patients

Incidence of Disabling neurological conditions

050,000

100,000150,000200,000250,000300,000350,000400,000450,000500,000

newcases/year

Parkinson'sBrain tumorEpilepsyAlzheimersSTROKE

Limitations of handicapped stroke survivors (AHA 1995*)

0%10%20%30%40%50%60%70%80%90%100%

walkingreadingshoppinghousework

Prevalence of disabling neurological conditions

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

currentcases inmillions

Alzheimer'sEpilepsySTROKE

Brain infarct-CT of head

Stroke due to” bleed” into the brain

Peripheral infarct..thrombotic

Major bleed into brain

Transient Ischemic AttacksA. Should never be ignored

B. Termed TIA or ministroke

C. Lasts <24 hours,usually<30 minutes

D. Needs immediate medical attention with investigation,drug or surgical therapy

Risk factors for stroke/TIAØHypertension

ØCigarette smoking

ØHeart disease

ØDiabetes

ØHyperlipidemia

LETS take a close lookat this carotid surgery stuff!

Evidence-based medicine

Evidence based surgery

Levels of evidenceLevel 1…………data from randomized trials with low false(+) and low false(-)

Level 2…randomized but high false(+/-)

Level 3….data from randomized concurrent cohort studies

Level 4……data from randomized cohort studies

Level 5….anecdotal case studies

Strength of Recommendations

Grade A…..supported by Level 1 evidence

Grade B….supported by Level 2 evidence

Grade C…supported by Level 3,4 or 5 evidence

NASCET Study …stenosis >70%…….Ipsilateral stroke

0%

5%

10%

15%

20%

25%

30%

strokerate

surgicalmedical

European Study…symptomatic stenosis>70%…ipsilateral stroke

0%2%4%6%8%10%12%14%16%18%20%

strokerate

medicalsurgical

VA(Veterans) Study…stenosis >50%…ipsilateral stroke

0%2%4%6%8%10%12%14%16%18%20%

strokerate

medicalsurgical

Endarterectomy benefit..NASCET

stroke incidence

Carotid stenosis Absolute difference

90-99% 27%

80-89% 20%

70-79% 12%

Overall(18mos.) 18%

NASCET: surgery for symptoms

ØAbsolute risk reduction of 17 %

Ø# needed to treat: 6:1

NASCET Study…asymptomatic.. Stenosis>60%

0%

10%

20%

30%

40%

50%

60%

70%

strokereduction

allmenwomen

European study…asymptomatic>60% stenosis

0%

2%

4%

6%

8%

10%

12%

strokereduction

surgicalmedical

Asymptomatic carotid disease

ØAn asymptomatic bruit..1.5% stroke/year

ØAsymptomatic stenosis..1.3% stroke/year

ØStenosis >75 %..10.5%TIA/stroke/year

Asymptomatic Randomized Studies

ØCASANOVA...ASA/Persantine VS surgery...no benefit...but excluded>90 %

ØMACE.. terminated early ..morbidity but no ASA

ØVA trial favor surgery but not significant

ØACAS..60% stenosisabsolute reduction 5.9% (1 % /year)intent to treat 19:1 over 5 years

ACAS :risk <3%, survival>5 years

ØProven...ipsilateral stenosis > 60%(Grade A)

ØAcceptable > 60% stenosis with ACBG(Grade C)

ØUncertain >50% stenosis with ulcer (Grade C)

ACAS : 3-5 % risk

ØProven..none

ØAcceptable but not proven...stenosis> 75% ipsi/contrlateral

ØUncertain indications...ACBG unilateral/bilateral > 70%..ipsilateral stenosis >75%

ACAS : 5-10 % risk

ØProven...none

ØUncertain... ACBG ..unilateral/bilateral stenosis > 70%

Combined risk of stroke & death• 3% for asymptomatic patients

• 3-5% for TIA’s

• 7-10 % for previous stroke

• 10% for recurrent stenosis

SAH indications for surgical intervention ....asymptomatic

Ø > 80 % stenosis(duplex-MRA)

ØMale vs female

ØAnticipate 5 year survival

ØOptimized medical therapy

ØStatus of opposite carotid/ulcer

ØDisease progression

ØPersonal audit

Carotid bruit..meaning??

Carotid surgery..position

Antiplatelet Tx/risk reduction in patients with previous neuro event

Non fatal stroke/MI ,vascular death…..22%reduction

Vascular death/death from unknown causes…..14%

Death from any cause…16%

Non fatal stroke…23%

Non fatal MI…….36%

Anticoagulant use in “brain attacks”

Neuro event 1st Tx Option

TIA ….ASA 81mg-1300mg Ticlid/Plavix

TIA(ASA X )….Ticlid250mgbid *Coumadin

CrescendoTIA ….IV heparin ???enoxaparin

*!NR 2-3

Risk reduction for stroke after TIAqEvaluate and treat TIA

qAggressively treat BP(140/90<60,160/90>60)

qStop smoking

qAggressively treat CAD,CHF,arrhythmias and valvular heart disease

qAvoid excessive use of alcohol

qTreat hyperlidemia

qEncourage physical activity

Risk reduction (cont’d)

Estrogen should NOT be discontinued in post-menopausal women but OC should be in younger women otherwise a minimum Estrogen

Evaluation of ischemic event(the initial evaluation)

1)CBC,platelets,sed rate2)Chemistry(glucose/lipids)3)PT PTT INR4)ECG5)CT of head6)Non-invasive

study(Duplex,MRA or echocardiogram)

Diagnostics for TIA(if still uncertain)

1) Transthoracic/esophageal echo

2) Transcranial doppler

3) MRA

4) Cerebral angiography

5) Antiphospholipid antibodies

6) Ambulatory ECG

7) CSF exam

Diagnostics for TIA (cont’d)…if still uncertain

Rarely one must screen for a prothrombotic state.This would include Protein C,protein S ,antithrombin 3,protein electrophoresis and a collagen vascular screen

PRACTICE POINT

Cerebral angiography remains the present gold standard for the assessment of extracranial carotid stenosis

PRACTICE POINT

Duplex scanning has a95% sensitivity for hemodynamically significant stenosis

Consideration of carotid surgery

qAsymptomatic

qSymptomatic……TIA’s……Strokes

Do not delay surgery in a minor stroke patient with a normal CT or a small subcortical lesion on subsequent CT or MRI

Delay surgery by several weeks in a patient with a large clinical stroke or a moderate- sized infarct on CT

Who should be evaluated for carotid disease?

Symptomatic patients• TIA’s

• Small strokes(lacunar)• Non-disabling cortical strokes(ica

anterior not vertebral posterior circulation)

• Opthalmic TIA’s (amaurosis fugax and possibly retinal emboli without

symptoms)

Who should be evaluated for carotid artery disease

Asymptomatic patients§ Cervical bruits§ Severe coronary artery disease pre-

CABG§ Severe peripheral vascular disease§ Prior carotid endarterectomy§ Carotid occlusion on opposite side§ Routine screening is not indicated before

cardiac/non-cardiac surgery?

What is the significance of acarotid bruit?

• Identifiable risk factor for coronary artery disease

• An indicator of systemic atherosclerosis• Does not predict the location or severity

of internal carotid artery disease• Correlates with an increased stroke rate

but does not correlate with location or mechanism of stroke

Diagnostic Imaging for Carotid stenosis

• Cerebral angiogram… the golden standard• Carotid duplex….the heir apparent

• MRI angio• Transcranial doppler• CT/CT angiography• Photon/Positron emission tomography

The indications for surgery in asymptomatic carotid surgery are quite complex....beware the data

Classification of neurological events

• Transient ischemic attack(TIA)/variant amaurosis fugax…. <24 hours

• Reversible neurological deficit(RIND)<3 weeks….no longer used

• Cerebral vascular accident(stroke)

• All of the above are considered some form of BRAIN ATTACK

Asymptomatic carotid stenosisqWhat degree of stenosis causes concern?

qWhat is the status of the other side?

qIs the patient really asymptomatic?

qWhat does the CT/MRI show?

qWhat are the associated co-morbid conditions and is the patient expected to live 5 years ?

Asymptomatic carotid stenosis

qMILD…..MODERATE…..SEVERE?qWhat is meant by Critical stenosis vs

severe carotid stenosis?

qWhat is the significance of the following? 1)systolic velocity 2)systolic velocity ratio 3)end diastolic velocity4)assessment of plaque integrity

Diagnostic workup for planned surgeryqDuplex scan of carotid arteries

qCT of brain depending on whether symptomatic or not

qMRI (angiography)

qStandard cerebral angiography

qThe appropriate haematological work-up

Color duplex (cont”d)

Color Doppler(Duplex)

Standard Duplex of carotid

Duplex criteria for stenosisGrade Peak systolic Peak diastolic Systolic ratio

Normal <110 cm/sec <40cm/sec <1.8cm/sec

Mild <110 <40 <1.8 (1-39% )

Moderate <130 40 <1.8 (40-59%)

Severe >130 >40 >1.8 (60-79%)

Critical >250 >100 >3.7 (80-99%)

Standard Digital subtraction Angiogram

MRA vs angio Circle of Willis

MRA angio

(Pseudo)occlusion..not seen on selective angio…”string sign”

MRA vs Digital Subraction Angiography

The culprit…atheroma at the carotid bifurcation

The notorious plaque

Circle of Willis

Shunt vs no shunt

1.Always shunt

2.Never shunt

3.Selectively shunt a)Stump pressuresb)EEGc)Transcranial dopplerd)Surgery under local

Types of shunts

Inlying vs outlying

Sizes 9-11 French(125cc/min)

Post-op complications• Neurological event

• Acute MI/death

• Baroreceptor dysfunction

• Hyperperfusion syndrome

• Difficult to control BP

• Hematoma• Parotitis• Infection• Aneurysm formation• Nerve

injuries(facial,greater auricular,hypoglossal,vagus and laryngeal branches

The importance of audits

üPersonal audit

üProfessional audit

üHigh vs low volume carotid surgeons..The greater Toronto experience

Carotid Stenting and Angioplasty

FORGET IT!!!!

Thrombolytic therapy in acute stroke?

Is the jury still out???

thrombolytic