Carotid Artery Stenting Where do we stand in 2013?

Carotid Artery StentingWhere do we stand in 2013?

Chong Tze Tec MBBS FACSConsultant Vascular and Endovascular Surgeon

Singapore General HospitalAdjunct Assistant Professor of Surgery

Duke NUS Medical School

Stroke

• 3rd leading cause of death in US

• 750 000 people will have a stroke this year

• 160 000 will die from it

• 15-30% become permanently disabled

• 20-30% caused by extracranial carotid disease

• Carotid endarterectomy

• Carotid artery stenting

• Unresolved issues

Carotid Endarterectomy Procedures

CEA: Large-Scale Randomized Trials

• ECST (1991)

• NASCET (1991)

• VA Asymptomatic Study (1993)

• ACAS (1995)

• ACST (2004)

Barnett HJM et al NEJM 1998;339:1415-1425

26% vs 9% rate at 2 years

NASCET

ACAS Investigators JAMA 1995;273:1421

11% vs 5.1% rate at 5 years; p=.004

ACAS

Curves cross at 3 years

Curves cross at 1.5 years

ACST

Results

Carotid Artery Stenting

Carotid Stenting- Indications

• Carotid restenosis• Anatomically difficult lesion (e.g. above C2)• Radiation-induced disease• “High-risk” patients

- Consensus Conference, Montefiore Vascular Symposium 2001

“High Risk” criteria for CEA ?Anatomic/technical

• Inaccessible

lesion

• Hostile neck

• Radiation

disease

• Restenotic

lesion

Comorbidities

• Age>80

• CHF

• Recent coronary

event or procedure

• COPD

• Contralateral

occlusion

• Renal failure

CEA vs CAS: Major RCTs

• CAVATAS (Lancet 2001)• SAPPHIRE (NEJM 2004)• SPACE (Lancet 2006)• EVA-3S (NEJM 2006)• CREST (2010)• ICSS (2009)

SAPPHIRE

SAPPHIRE Primary endpoints

1. Death/stroke/MI within 30 days2. Death/ipsilateral stroke between 31 days

and 1 year

747 patients were enrolled in the study and 334 patients underwent randomization. Of those not randomized, 406 entered into a stent registry and 7 entered a surgical registry

SAPPHIRE results

SAPPHIRE Discussion

• CAS is not inferior to CEA in high risk patients based on 1 year data

• Trial was terminated early due to the establishment of nonrandomized stent registries

SPACEStent-Supported Percutaneous Angioplasty of the Carotid

Artery versus Endarterectomy

SPACE Hypothesis

• CAS is not inferior to CEA for the treatment of severe symptomatic carotid stenosis

SPACE results

SPACE Discussion

• SPACE failed to prove the non-inferiority of CAS compared to CEA

• 30d stroke/death rate was 6.84% for CAS versus 6.34% for CEA

• CEA 30d event rates are similar to NASCET (6.5%)

SPACE – Follow up

SPACE – Follow up results

SPACE – Follow up results

• Recurrent restenosis >70% was higher in the CAS group compared to the CEA group at 2 years– 10.7% vs 4.6%, p=0.0009

EVA-3S

EVA-3S: Results at 30 days

EVA-3S – Follow up

EVA-3S – Follow up results

• Cumulative probability of periprocedural stroke or death and non-procedural ipsilateral stroke at 4 years

CAS vs CEA trials

• Failed to show benefit so far

• Perhaps there are subtleties involved which are underappreciated

– Lesion characteristics

– Technical aspects to CAS

– Operator experience

Confounding issues

• Arch anatomy• Stents design• Embolic protection devices• Plaque evaluation

Open cell vs Closed cell stents

Open cell stents are more conformable therefore offer better wall apposition and are more flexible and trackable

Cerebral embolization, as detected by TCD and DW-MRI, occurs with similar frequency After CAS with open-cell and closed-cell stents… does not support the superiority of any stent design with respect to cerebral embolization

Cerebral Protection Devices

Difficult Anatomies for Distal Protection

MOMA device

Gore Flow Reversal System

Embolic protection

• Asymptomatic lesions (n=36)• Diffusion weighted MRI at 24h post

procedure• Average number of hits 6.1 vs 6.2 • Filter group did not show reduction in

microemboli

?

Transcranial Doppler (TCD)

• Allow precise assessment of number embolic (air, contrast, particles) events during procedure.

Procedure CEA CAS

Number of hits

52±64 202±119

Crawley F, Clifton A, Buckenham T, et al. Comparison of hemodynamic cerebral ischemia and microembolic signals detected during CEA and CAS. Stroke 1997

ICSS MRI study

Compared to patients undergoing CEA, patients treated with CAS had higher numbers of periprocedural ischemic brain lesions, and lesions were smaller and more likely to occur in cortical areas and subajacent white matter. These findings may reflect differences in underlying mechanisms of cerebral ischemia

Cerebral embolizationAre EPDs needed ?

J Vasc Surg 2012;56:1579-84.

Plaque evaluation – GSM (Gray Scale Median)

Carotid plaque echolucency increases the risk of stroke? (GSM <25)

GSM

CREST trial

•

Long term follow up?

No difference

Cochrane Review 2012

• Endovascular treatment is associated with an increased risk of peri-procedural stroke or death compared with endarterectomy. However, this excess risk appears to be limited to older patients… Further trials are needed to determine the optimal treatment for asymptomatic carotid stenosis

Guidelines ?

… the disagreement in the five most recent guidelines, and the likelihood of ongoing and future improvements in CAS make it possible that the 2011 carotid guidelines may turn out to be misleading or incorrect…

Advances in CEA

Perioperative stroke and death rate - Symptomatic

Perioperative stroke and death rate - Asymptomatic

CAS is also evolving

Why do we treat carotid disease?

• To prevent strokes

Options for treatment

• Carotid endarterectomy

• Carotid artery stenting

• Medical management

The End