Carotid Artery Stenosis

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UNDER CONSTRUCTION

FACTS HPI PHYSICAL EXAM IMAGING Trials Symptomatic Trials NASCET (1991)ECST CREST (2010) Symptomatic trials ACAS ACST CAVATAS (2002) CREST 2 (ongoing)

FACTS

approximately 15-30% of ischemic strokes 2/2 cervical carotid stenosis

pathophysiology of ischemic strokes:

arterial to arterial emboli
in situ thrombosis (entire vessel shuts down)
low flow-watershed infarction

HPI

Symptomatic:

deficit must be referable to same side of stenosis

Asymptomatic:

TIA:

deficit must be ≤ 24 hours

micro-embolus → causes deficit → body dissolves

History

prior neck radiation

PMHx: severe pulm disease, HF and NYHA grade, chronic renal insufficiency

PHYSICAL EXAM

universal neuro exam

focus on stroke exam (naming, speech)

IMAGING

MRI Brain without:

evaluate for strokes.

MRI neck:

evaluate for e/o lipid necrosis

carotid ultrasound

evaluate for e/o lipid necrosis

very good for evaluating circumferentially Ca2+ carotid stenosis

CTA head and neck:

best study

evaluate for associated Ca2+

evaluate relative height of bifurcation

evaluate for e/o tandem stenosis intracranially (iCAD)

Definition of stenosis (below)

String sign: entire carotid is small. Unique situation where you should probably not be operating.

A/P

Consider high-risk criteria for each modality

ㅤ	Carotid endarterectomy (CEA)	Carotid artery stenting (CAS)
ㅤ	Anatomic high risk - Tandem stenosis > 70% - bilateral carotid stenosis - contralateral carotid occlusion - recurrent carotid stenosis - high (> C2) or low (< clavicle) bifurcation Physiologic high risk - ≥ 75 years - NYHA CHV 3-4 - CAD ≥ 2 vessels - unstable angina - recent MI (within 6 weeks) - severe pulmonary disease - chronic renal insufficiency	ㅤ
Absolute c/i	- prior neck radiation (high risk venous/nerve injury)	ㅤ

TCAR: a way to bypass proximal risk and do an

tortuosity in chest and proximal calcifications in plaque is a big problem, especially in the elderly chronically calcified vessels

TCAR is CAS but allows you to directly access carotid artery

In TCAR, we implant sheath into CCA that reverses flow temporarily (pull flow backwards out of carotid).

Decision tree

ㅤ	Severe Stenosis (≥ 70%)	S
Symptomatic	ㅤ	ㅤ
Asymptomatic	ㅤ	ㅤ

Other notes
Timing matters: “hot carotid,” re-vascularize within 24-48h to capture most of the benefit (dwindles over time, less yield from surgery)

Trials

Symptomatic Trials

NASCET (1991)

Population: 649 symptomatic patients with carotid stenosis ≥ 70%

Definition of stenosis: A (stable segment of ICA distal to vessel) minus B (narrowest region in the stenosis)

best medical management: 1300 mg ASA qDaily

Conclusion:

Stroke rate in best medical treatment (26-28% in 2-5 years) vs. stroke rate in medical treatment + CEA (9-13% 2-5 years) p < 0.001.
Absolute risk reduction: 17% at 2 years, 15% at 5 years

ECST

CREST (2010)

Symptomatic 2502 patients (2000-2008)

Designed as a non-inferiority study(allows for a relatively underpowered studies)

Arms:

CEA (carotid endarterectomy)
CAS (Carotid artery stenting)

required pre-specified complication rate for eligibility (< 3% if symptomatic, < 5% if asymptomatic)

Conclusions

stenting non-inferior

Paramater and significance	CEA	CAS
peri-operative stroke risk (p = 0.01)	2.3%	4.1%
MI (p = 0.03)	2.3%	1.1%
Restenosis rates similar (HR 1.24)	ㅤ	ㅤ

Symptomatic trials

ACAS

first major randomized trial of ASYMPTOMATIC disease

Population: 1662 asymptomatic patients with ≥ 60% stenosis

Conclusion:

Stroke rate in best medical treatment (11% at 5 years) vs. stroke rate in medical treatment + CEA (5.1% at 5 years) p = 0.004.
Absolute risk reduction: 5.9% at 5 years

ACST

CAVATAS (2002)

CREST 2 (ongoing)

ongoing trial evaluating asymptomatic stenosis in a 3 arm trial

carotid angioplasty + stenting

medical management