• Carotid angioplasty ,indications ,techniques And controversies. dr gopi krishna.

IMPORTANCE IMPORTANCE OFOF

CAROTID ARTERY CAROTID ARTERY DISEASE DISEASE

TREATMENTTREATMENT

Stroke:• 3rd cause of death in US• 500,000 cases/year• 2 milion/year handicaped people

HIGH SOCIAL / ECONOMIC COST

Mellière et al. J Mal Vasc, 1993

• 20 - 30% of CVE are related to carotid occlusive disease.• Increased incidence with age .

(33% < 45 yrs and 80% >50 yrs)

De Bakey et al. J Endovasc Surg, 1996

• Stenoses > 75%risk of stroke in 1st yr = 2-5%

Roederer et al. Stroke, 1984

Hennereci et al. Brain, 1987

• Ulceration = Iminent stroke risk of stroke = 7,5%

Autret et al. Lancet, 1987

• Carotid stenosis + TIA • Risk of stroke in 1st yr = 12-13%

5th yr = 30-37% Sundt et al., 1987

Dennis et al. Stroke, 1990

• CVA - risk in 1st yr = 59% 5th yr = 25-45%

Sacco et al. Stroke, 1982

Meissner et al. Stroke, 1988

• Heterogeneous and ulcerated lesions = Risk 2-4 x

Langsfeld et al. J Vasc Surg, 1989 Sterpetti et al. Stroke, 1988

SURGICALTREATMENT

ENDARTERECTOMY (1953)

– risk of stroke

–TIA = 1-2% / Yr

–CVA = 2-3% / Yr

Carotid Stent

AHA Quality StandardsSurgical Treatment

CVA / Death• Symptomatic Patients < 6%• Asymptomatic Patients < 3%

Carotid Stent

NASCET (North American Syntomatic Carotid Trial)

Cranial Nerve Lesion : 7,6%Hematoma : 5,5%

Extensive list of exclusion criteria !Extensive list of exclusion criteria !

N Engl J Med 1991;325:445

Tools & Techniques

• The benchmark for perioperative stroke or death for carotid revascularisation is the limit of 6% for symptomatic pts.

and • 3% for asymptomatic patients.

How to achieve good outcomes…

• 1. A “tailored-approach”- The application of endovascular

technologies and techniques to a specific-patient with a specific lesion and vascular anatomy.

• 2. The choice of stent, embolic protection device (EPD), guidingcatheter and sheath is strongly dependant on an in-depth knowledge of neuro-assessment, carotid plaque characteristics,vascular anatomy and technical features of a vast array of endovascular materials.

• 3. Experience with a wide range of devices allows the operator the flexibility to choose the most appropriate tools and techniques for the safe application of CAS.

Carotid plaque and vascular anatomyevaluations

• Length/bulk of disease and the morphologic features that predict lesion complexity such as degree of calcification and embolisation-potential (“vulnerable plaque”).

• “soft-lesions”on B-mode ultrasound with GSM <25.

(A) Angiographic aspect of an ulcerated carotidplaque (circle); (B) ulcerated portion in detail;

ultrasonographic appearance of a “soft” plaque

The assessment of vascular profile• 1. Configuration of the aortic arch .• 2. Arch embologenic-risk in terms of burden of

irregular, ulcerated and calcified atheroma .• 3. Angulations and tortuosity, coiling and kinking

of supra- aortic trunks .• 4. Level of carotid bifurcation and its anatomy

regarding angle of take-off of the internal carotid artery (ICA), tortuosity at lesion-site and vessel dimensions .

• 5.Intracranial segment of the ICA and ipsilateral/contralateral cerebral circulation to determine collateral flow including circle of Willis and identify abnormal flow patterns.

Aortic arch anatomyType I (A), Type II (B) and Type III (C) arches

Example of an aortic arch with high emboligenic-risk.

extense, irregular and calcified plaque in the aortic wall

Challenging anatomies of the supra-aortic trunks.A bovine aortic arch configuration is where the LCC originates from the brachiocephalic trunk

Challenging anatomies of the supra-aortic trunks

(A) accentuated tortuosity of the RCCA; (B) tortuosity of both common carotid arteries;

(C) proximal kinking followed by distal tortuosity of the LCCA, (D) Kinking of the brachiocephalic trunk followed by angulated common carotid arteries in a bovine aortic arch.

Intracranial ICA and ipsilateral/contralateralcerebral circulation

A) Right AP intracranial angiogram .

B) Right lateral intracranial angiogram.

A severe lesion (red dotted circle) at the ostium of the MCA requirestreatment before approaching the carotid bifurcation.

Neuroprotection systems•Embolisation occurs in all percutaneous cardiovascularInterventions.•It acquires more significance in the neurovascular territory.

• Carotid lesions contain friable ulcerated plaque and thrombotic material that can embolise during endovascular or open surgery.

•Embolic particles are classified as either macroemboli (>100 μm) or microemboli (<100 μm).

•Macroemboli, especially >200 μm, are usually associated withclinical events;

Distal protection devices

• Filter devices can be classified based on the relationship to the 0.014” guidewire.

“wire-mounted filters”.“bare-wire filter systems”.

• Filters are positioned in a straight portion of the ICA(“landing-zone”) in order to optimise adaptation of the frame to thevessel wal

Schematic of (A) concentric and (B) eccentric filtersillustrating the position of the wire in relation to the

basket.

LIMITATIONS OF DISTAL PROTECTION DEVICES

• 1.Unprotected crossing of the lesion in order to deploy the device,especially in tight stenoses.

• 2.Not effective in trapping microemboli, limited by pore size.

• 3. In tortuous, large or diseased distal ICA anatomies incomplete wall apposition may allow even macroemboli to bypass the system.

• 4. Debris may be dislodged during the recapture phase (“squeezing effect”) of the procedure.

• 5. Filters may be an embolic source themselves due to intimal damage at the landing zone.

Proximal protection devices

• Proximal occlusion devices interrupt or reverse blood-flow in the ICA by preventing antegrade flow from the CCA to the ICA and retrograde flow from the ECA into the ICA.

• they offer the following advantages:– 1. Crossing the lesion under protection with the

preferred guidewire.– 2. Blocking both macro- and microemboli.– 3.Navigation of the device in the distal ICA is not

required, thus reducing the risk of intimal damage, spasm or dissection.

MO.MA™ (INVATEC S.P.A., RONCADELLE, ITALY

9FR sheath with integrated baloon in CCAEXTENDED INTEGRATED BALOON IN ECA.

backpressure of >30 mmHg predicts tolerance toflow- blockage.

Following postdilatation blood is aspirated and checked for debris before deflatingthe balloons

NEUROPROTECTION SYSTEM™ (NPS) (GORE, NEWARK,DE, USA)

(A) Global view of the system. The detail shows the “balloon-sheath” and the “balloon-wire” both inflated in the CCAand ECA

B) The filter is positioned between the NPS-sheath and the venous sheath. (C) TheNPS “balloon-sheath”.

LIMITATIONS OF PROXIMAL PROTECTION DEVICES

PROXIMAL PROTECTION DURING CAS: CLINICAL OUTCOMES

• The ARMOUR study is a pivotal US trial evaluating the safety and effectiveness of the Mo.Ma system.

– 30-day major adverse cardiac and cerebrovascular events, was 2.3%. The device success rate was 98.2%.

• The DESERVE study(europe) is a Diffusion Weighted-MRI based evaluation of the effectiveness of the Mo.Ma system.

– Results awaited.

• EMPIRE is a prospective controlled single-arm multicentre trial to evaluate the performance of the NPS system.

• It enrolled 122 patients .• The primary endpoint of 30-day stroke and death rate was

1.6%.

Carotid stent selection

A) Open-cell design. B) Closed-cell design

C) Straight and tapered-stent configurations.

Carotid lesion treated by open-cell stentshowing a high flexibility and conformability that respect the original anatomy of the vessel.

Structural and functional characteristics• COBALT-ALLOY WIRE.• Advantages

– flexible delivery system, – small free-cell area with

high scaffolding and wall-coverage properties

– adaptability to the changing diameter across the bifurcation.

• disadvantaged – tendency to straighten

the vessel and foreshortening during deployment.

HYBRID STENTS

Functional characteristics of the hybrid carotid stent(CRISTALLO IDEALE)

Carotid stenting step-by-step procedure

• Peri-interventional protocol– PRE-PROCEDURE INVESTIGATIONS

• 1. Carotid duplex scan. MR or CT angiography is not mandatory,however, during the early experience it may help plan for a challenging intervention.

• 2. Independent neurological evaluation.

• PRE-MEDICATION– Dual antiplatelet therapy with aspirin and clopidogrel, ideally,initiated

five days before the procedure; and continued for at least 30 days at which time clopidogrel is usually discontinued.

GENERAL PROCEDURAL MEASURES

• 1.Head support and no sedation; • 2.standard monitoring of vital parameters

along with neuro-evaluation during procedure by simple communication and movement parameters.

• 3. hydrated and maintain saline infusion.• 4.Heparin intravenous or intra-arterial 70

U/Kg (ACT 200 to 300 seconds; with proximal occlusion aim for 250 to 300 seconds).

ANTI-HYPERTENSIVE MEDICATION

• Anti-hypertensive medication is omitted on the day of the procedure and during the early days postprocedure.

• Restarted once hypotension resolves to ensure no rebound hypertension.

Technique

VASCULAR ACCESSThe femoral approach is strongly recommended, but in

the presence of extreme tortuosity or occlusion of the iliac arteries the radial/brachial approach is feasible.

• BASELINE ANGIOGRAPHIC EVALUATION.• Aortic arch angiography is undertaken with a

pigtail catheter (30°to 45° left anterior oblique, LAO) to determine arch configuration and embologenic-risk, and visualise the origins of the supra-aortic vessels.

• 2. Selective bilateral extracranial angiograms.

• It is mandatory to perform an intracranial angiogram.

• Four vessel angiography, carotids and vertebrals, are indicated only where the complexity of the case recommends it as mandatory.(adequacy of the collateral circulation and the function of the circle of Willis).

COMMON CAROTID CANULATION

• safe and stable engagement of the CCA is one of the most important.

• this is a significant distinction between CAS and coronary interventions as engagement of the deep-seated supraaortic trunks is typically more difficult and requires great expertise.

• JR4 catheter is adequate.• For Type III arch or an angulated or bovine origin

of the left CCA a JB2 catheter is most commonly used.

• Sometimes in complex Type III or bovine arches a Simmons catheter is necessary.

Guiding catheter engagement

• 90-100 cm 8 Fr guiding-catheter is chosen according to the aortic arch configuration.

• For complex anatomy an angulated guide such as a Hockey-stick curve catheter is advanced into the proximal CCA.

• For simple anatomy a 40° angled soft-tip catheter is advanced to the mid-CCA over a soft-angled 0.035” standard hydrophilic wire

positioned just below the bifurcation.

• The introduction of two, or possibly three, 0.035” wires in order to advance the catheter in the presence of an unstable situation is feasible.

• Sheath placement according to need can be done after withdrawing guiding catheter over the support wire.

EPD MANAGEMENT

• Distal filters are positioned at least 30 to 40 mm distal to the target lesion.(to avoid entrapment).

• Full and adequate wall apposition of filter devices must be confirmed by angiography in two projections.

• When using distal filter devices it is critical to always visualise the position of the guiding catheter.

PREDILATATION

• Predilatation is reserved for very tight lesions, heavily calcified long fibrotic lesions.

• low profile coronary balloon.– 2.5 to 3.5 mm diameter .– 20 to 30 mm length, and inflated at nominal

pressure.9– cutting balloon for heavily calcified plaques usually

with a diameter of 3.5 to 4.0 mm and inflated at moderate pressure (8 atmospheres).

• Pre-treatment with 0.5 to 1 mg of intravenous atropine is required at this stage and/or post dilatation phase.

• A fundamental principle of balloon dilatation in CAS is the application of nominal pressure for a brief period (about five seconds).

STENT DEPLOYMENT

use stents 1 to 2 mm larger than the widest vessel diameter to be covered.

• The most commonly used stent size with reference to the proximal CCA edge is 8 to 10 mm.

and• in the case of tapered stents the most

common reference for the distal ICA edge is 6 to 8 mm.

POST DILATATION

• Sizing the balloon according to the ICA at the distal stent edge to prevent dissection and squeezing of material through the stent mesh.

• Balloons no larger than 5.5 mm should be used.

• The most common sizes required are 5.0 and 5.5 mm by a length of 20mm

• 10-30% residual stenosis is accepted.• The stent segment in the CCA does not

require post dilatation.• If plaque prolapses through the stent struts

(cheese-grater effect) no further balloon dilatations should be performed and a second stent, preferably a closed-cell stent should be implanted.

FINAL ANGIOGRAPHIC EVALUATION

• acquired in the same baseline projections.• If a distal protection device was used the

landing-zone has to checked carefully, • Ipsilateral intracranial angiography should be

routinely acquired.

Complications• Bradycardia and hypotension.• Carotid artery spasm.• Distal embolisation.• Intracranial haemorrhage.• Hyperperfusion syndrome.• Contrast encephalopathy.• Carotid dissection.• Carotid perforation.• External carotid artery occlusion.• Acute stent thrombosis.• Restenosis.