carotid artery disease-1
Post on 02-Apr-2018
229 Views
Preview:
TRANSCRIPT
-
7/27/2019 Carotid Artery Disease-1
1/40
CAROTID ARTERY
DISEASE
Vic Vernenkar, D.O.
St. Barnabas HospitalDept. of Surgery
-
7/27/2019 Carotid Artery Disease-1
2/40
Epidemiology
3rd most common cause of death in the US
Most common cause of long term disability
500,000 CVAs annuallyContributes 200,000 deaths annually
Of those that survive, 2/3 have disability,
1/3 require hospitalization for it.
16 trillion$ a year in costs
-
7/27/2019 Carotid Artery Disease-1
3/40
Risk Factors
Nontreatable
Age
Ethnicity
GenderFamily History
Genetics
-
7/27/2019 Carotid Artery Disease-1
4/40
Risk Factors
Treatable
Hypertension
TIAs
Previous CVAsAsx Bruit or Stenosis
Cardiac Disease
Aortic Arch
atheromatosis
Diabetes Mellitus
Cigarette Smoking
fibrinogen,homocysteine
anticardiolipin
Oral contraceptives
Obesity
-
7/27/2019 Carotid Artery Disease-1
5/40
Anatomy
Brain 2% of body weight but 17% of CO
and 20% of O2 supply.so neural tissue
can become necrotic within minutesBranches of aortic arch; inominate
(Brachiocephalic), L common carotid and L
subclavian.
-
7/27/2019 Carotid Artery Disease-1
6/40
Anatomy
Inominate branches to form R subclavian
and R common carotid.
10% of population L common comes ofinominate.
-
7/27/2019 Carotid Artery Disease-1
7/40
Anatomy
Brain supplied by 2 internals and 2 vertebrals. The
internal supply 80-90% of total blood flow.
The common carotids bifurcate at angle of
mandible into external and internal.
Branches if external are lingual, ascending
pharyngeal, superior thyroid, occipital, posterior
auricular. The terminal branches are int. maxillaryand superficial temporal a.
-
7/27/2019 Carotid Artery Disease-1
8/40
Anatomy
Extensive collaterals between external and
vertebrals in case of occlusion
Periorbital collaterals connect throughophthalmic artery to internal carotid in case
of occlusion in neck.
Extensive side to side collaterals between Land R externals and L and R vertebrals.
-
7/27/2019 Carotid Artery Disease-1
9/40
Anatomy
Internals branch into anterior cerebral andmiddle cerebral arteries
The L and R middle cerebrals connect at thecircle of Willis via anterior and posteriorcommunicating arteries.
15% have no connections between ant and
post cerebral circulations, 35% lackconnection between the two hemispheres.
-
7/27/2019 Carotid Artery Disease-1
10/40
Anatomy
Vertebrals arise from first portion of
subclavian artery and enter 6th cervical
vertebra and ascend in foramen. Unite toform Basilar artery. The Basilar terminates
as L and R posterior cerebral arteries
posterior communicating arteries of the
circle of Willis.
-
7/27/2019 Carotid Artery Disease-1
11/40
Anatomy
Branches of external carotid can anastamose
with orbital arteries supply internal
carotid artery in case of proximal occlusionCollateral between external and ophthalmic
are most important of these.
-
7/27/2019 Carotid Artery Disease-1
12/40
Anatomy
Vertebral gives off branches to muscles ofneckif proximal vertebral gets occluded,the external can supply the distal vertebral
via these branches.
If common occluded, blood can go fromvertebral to external branches to internal
Finally branches of the L and R external cananastamose freely across the face.
-
7/27/2019 Carotid Artery Disease-1
13/40
Pathophysiology
Complication of atherosclerosis (most common)
High shear stress (bifurcations)
Intimal injury
Carotid bulb plaques
Aneurysms, kinks, coiling.
FMD (thickened,beaded), Takayashu (women,
branches of aorta) arteritis, Temporal arteritis(elderly, blindness).
Trauma
-
7/27/2019 Carotid Artery Disease-1
14/40
Atherosclerosis
Locations of turbulence, like bifurcations
The common carotid is most common spot
in the cerebral circulationOccur along the outer wall of bifurcation,
and only proximal portion of external.
-
7/27/2019 Carotid Artery Disease-1
15/40
Atherosclerosis
At bifurcation you get separation of flow,
disruption of laminar flow, flow stasis,
prolonged residence time, shear stressGrossly the plaque is thickest at the
bifurcation, extending 2cm into distal
internal carotid.
-
7/27/2019 Carotid Artery Disease-1
16/40
Atherosclerosis
The plaque occupies the media and intima, sparing
the outer media and adventitia.
The plaque tapers from the media into the normal
intima.
Mature plaques are characterized by a
heterogeneous core and fibrous cap. Disruption of
the cap leads to embolization and thrombosis.Also exposes the non-endothelized intima to
platelets (ulcer).
-
7/27/2019 Carotid Artery Disease-1
17/40
Plaque Composition
Fibroblast proliferation
Lipid accumulation
CalcificationUlceration
Sub-intimal hemorrhage
Thrombosis
-
7/27/2019 Carotid Artery Disease-1
18/40
Clinical Presentation
TIA: resolves within 24h. Can present as a
transient hemispheric event or monocular
blindness (amaurosis fugax). A hemisphericattack presents with contralateral combined
sensory and motor deficit or purely motor or
purely sensory deficit.
-
7/27/2019 Carotid Artery Disease-1
19/40
Clinical Presentation
When ischemia occurs in the posterior
circulation, it causes vertebrobasilar
insufficiency presenting as vertigo, dropattacks, binocular vision loss, dysarthria,
dysphagia, incoordination.
A stroke lasts more than 24h. Most are a
result of emboli to branches of middle
cerebral artery
-
7/27/2019 Carotid Artery Disease-1
20/40
Evaluation
Physical Exam
Duplex (most accurate in >50% stenosis)
MRAAngiography (gold standard, but risks)
-
7/27/2019 Carotid Artery Disease-1
21/40
Duplex
Excellent screen for neurologic sympt.
peak sys. Velocity > 220cm/sec
end dias. Velocity > 80cm/secpost stenotic turbulence
Less reliable in anatomic variants
Operator dependant
-
7/27/2019 Carotid Artery Disease-1
22/40
Carotid Angiography
Gold Standard
Remains the most definitive tool for
decision to operateComplications ~ 1-4%
Pseudoaneurysm
StrokeDissection
-
7/27/2019 Carotid Artery Disease-1
23/40
Natural History- Symptomatic Dz
Cumulative risk for stroke at 5 years after aTIA is 30-50%.
1/3 patients die within 5y of TIA, usually ofCAD.
Risk for stroke following TIA 10-30% infirst year, 6% risk subsequent years.
After stroke, a 20-30% mortality, risk ofrecurrent is 5-40%, with 30% of these fatal.
-
7/27/2019 Carotid Artery Disease-1
24/40
Asymptomatic Disease
Only 10% of stroke patients have had a TIA
prior.
Asymptomatic bruits are present in 5% ofpopulation>50
Bruits are not diagnostic of significant
stenosis. (only 23% have >50% stenosis)
-
7/27/2019 Carotid Artery Disease-1
25/40
Asymptomatic Disease
Risk of stroke is proportional to degree of
stenosis (greatest over 80% stenosis)
For patients with 75-80% stenosis, risk ofstroke 18-46%.
-
7/27/2019 Carotid Artery Disease-1
26/40
Asymptomatic Disease
Risk of stroke elevated in patients
undergoing major surgical procedures such
as CABG, vascular surgery.Stroke is not increased with unilateral
asymptomatic high grade carotid disease
during CABG, but it is in bilateral high
grade stenoses.
-
7/27/2019 Carotid Artery Disease-1
27/40
Medical Treatment
Control risk factors
No drug therapy has been shown to reduce
the risk of stroke in asymptomatic disease.
-
7/27/2019 Carotid Artery Disease-1
28/40
Medical Treatment
No study has provided definitive evidence thatsystemic anticoagulation reduces the risk of strokein patients who have had a stroke or TIA.
ASA has been shown to decrease the morbidityand mortality from symptomatic disease
In patients with TIA or stroke, ASA demonstrateda 22% risk reduction in recurrent strokes, TIA,
MI, or vascular death, compared with controls.Plavix and ASA offers no added benefit.
-
7/27/2019 Carotid Artery Disease-1
29/40
Symptomatic Disease
Degree of ICA stenosis is most importantpredictor of CVA
Severity of stenosis is proportional to Riskof Stroke
Definite benefit ofsurgery in symptomaticpts with > 70% stenosis is established in
three majorstudies (NASCET, ECST,VATCE)
-
7/27/2019 Carotid Artery Disease-1
30/40
NASCET north american symptomatic carotid endarterectomy trial
Double armed, prospective trial
Medical vs. Surgical therapy
Pt.s developing sx.s during the trial wereoperated and excluded
5 yr trial terminated at two years due to end
point
Surgery 9%, Medical 26%
-
7/27/2019 Carotid Artery Disease-1
31/40
NASCET (cont.)
Risk of major CVA was by 80% at 2yr
follow-up.
CEA was beneficial in symptomatic ptswith occlusion of contralateral carotid.
-
7/27/2019 Carotid Artery Disease-1
32/40
ECST european carotid surgery trial
Double armed prospective trial, 3y f/u
Medical vs. Surgical therapy
70-99 % stenosis778 pts with carotid distribution CVA, TIA
or retinal infarction
Surgery 12.3%, medical 22%
-
7/27/2019 Carotid Artery Disease-1
33/40
VATCE veterans affairs trial of carotid endarterectomy
Terminated early due to early endpoints in
NASCET and ECST trials.
Also showed Carotid Endarterectomy to bebeneficial in symptomatic patients.
Surgery 7%, medical 20%
-
7/27/2019 Carotid Artery Disease-1
34/40
Symptomatic Trials: Summary
0-29% CAS- medical therapy with anti-
aggregate platelet therapy
30-69% CAS- medical therapy probablydesirable in most patients*
50-69%- CAS- surgery provides modest
benefit in hemispheric ischemia 70% CAS- surgical therapy indicated
-
7/27/2019 Carotid Artery Disease-1
35/40
Asymptomatic Disease
Prevalent in the elderly population
Asymptomatic CAS >70% rare
Asymptomatic bruit 1.5% risk of CVA peryear X 5 yr.s
75% ~ 10.5%/yr.
-
7/27/2019 Carotid Artery Disease-1
36/40
CASANOVA carotid artery surgery asymptomatic narrowing :operation vs. aspirin
Asymptomatic pt.s with CAS 50-90%
Prospective double armed trial
Medical therapy (330 mg ASA QD + 75mgdypyridamole TID)
Surgical therapy- CEA
-
7/27/2019 Carotid Artery Disease-1
37/40
CASANOVA (cont)
No statistically significant difference in
medical vs. surgically treated groups.
-
7/27/2019 Carotid Artery Disease-1
38/40
ACAS asymptomatic carotid atherosclerosis study
CEA, ASA and medical risk factor mgmt in
patients < 80y/o with CAS>60%
Risk of CVA reduced over 5 yrs by 5.9%Absolute yearly reduction of 1%
Benefit negated by many factors.
-
7/27/2019 Carotid Artery Disease-1
39/40
Asymptomatic Trials: Summary
Asymptomatic patients with CAS > 80%
will benefit from surgery assuming the
surgeon has complication rate
-
7/27/2019 Carotid Artery Disease-1
40/40
Endovascular Treatment
Problem of embolization from angioplasty
Use of cerebral embolic protection devices
4 prospective randomized trials comparing endo
and surgery. 3 were in adequate risk, 1 in high riskonly. CAVATAS, Wallstent, Sapphire (only onewith protection device), the other was stopped 5/7stroked after stenting!
Long-term efficacy and durability is unknown.At present limited to high risk only
top related