Columbia University Medical Center

The Cardiovascular Research Foundation

Double filtration during carotid artery stenting:

Reducing the risk of stroke

William A. Gray MD

Associate Professor of Medicine

Disclosures

• Contego

Consultant (equity options)

Although CAS results are improving…

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Symptomatic Asymptomatic ≥80 years < 80 years

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Contralateral

Ipsilateral

CAPTURE 3500:

Stroke by Symptoms, Age, and Location

...stroke remains the achilles heal of CAS

20%

70%

10% 0

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Access Procedure Post-Procedure

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When do strokes occur during CAS?

J Am Coll Cardiol. 2004 Nov 16;44(10):1966-9

Effect of two different neuroprotection systems on microembolization

during carotid artery stenting.

Schmidt A, Diederich KW, Scheinert S, Braunlich S, Olenburger T, Biamino G, Schuler G, Scheinert D.

Division of Clinical and Interventional Angiology, Department of Cardiology, University of Leipzig-Heart Center,

Leipzig, Germany. Andrej.Schmidt@gmx.de

OBJECTIVES: This study sought to compare the efficacy of two different cerebral protection systems for the

prevention of embolization during carotid artery stenting (CAS) using a transcranial Doppler (TCD) monitoring

with the detection of microembolic signals (MES). BACKGROUND: Despite the introduction of cerebral

protection systems, neurologic complications during CAS cannot completely be prevented. Transcranial Doppler

and detection of MES may aid in assessing the efficacy of different neuroprotection systems. METHODS: A total

of 42 patients with internal carotid artery stenoses were treated by CAS using either a filter (E.P.I. FilterWire,

Boston Scientific Corp., Santa Clara, California) (n = 21) or a proximal endovascular clamping device (MO.MA

system, Invatec s.r.l., Roncadelle, Italy) (n = 21). Microembolic signal counts were compared during five phases:

placement of the protection device, passage of the stenosis, stent deployment, balloon dilation, and retrieval of

the protection device. RESULTS: There were no significant differences in clinical or angiographic outcomes

between the two groups. Compared to the filter device, the MO.MA system significantly reduced MES counts

during the procedural phases of wire passage of the stenosis, stent deployment, balloon dilation, and in total

(MES counts for the filter device were 25 +/- 22, 73 +/- 49, 70 +/- 31, and 196 +/- 84 during the three phases and

in total, MES counts for the MO.MA system were 1.8 +/- 3.2, 11 +/- 19, 12 +/- 21, and 57 +/- 41, respectively; p <

0.0001). CONCLUSIONS: In comparison to a filter device the MO.MA system led to significantly lower MES

counts during CAS. The detection of MES by TCD may facilitate the evaluation and comparison of different

neuroprotection systems.

Microembolic Signal Counts

Wiring of lesion: 25

Pre-dilation: 73

Stenting: 70

Post-dilation: 196

Risk of embolization is highest at post-dilation

J Vasc Surg. 2005 Jun;41(6):950-5

The capture of visible debris by distal cerebral protection filters during

carotid artery stenting: Is it predictable?

Sprouse LR 2nd, Peeters P, Bosiers M.

Division of Vascular Surgery, Eastern Virginia Medical School, Norfolk, VA, USA. lrsii@msn.com

OBJECTIVES: Neurologic complications during carotid artery stenting (CAS) are most clearly associated with

embolization of visible debris. Distal filter devices may provide cerebral protection by capturing clinically

significant debris. However, they increase procedural time and expense and have their own set of

complications. The current study was undertaken to identify the clinical factors predictive for the presence or

absence of visible debris captured by distal filter devices during CAS. METHODS: Patients undergoing CAS

with use of a distal filter device (n = 279) were prospectively entered into an investigational carotid registry.

Recorded variables were classified as patient-, lesion-, or procedure-related. The filter was assessed for visible

debris in each case. The odds ratio (OR) and 95% confidence interval (CI) were determined for each variable to

predict visible debris. The ability of each variable to predict the absence of visible debris was assessed by

calculating the individual negative predictive value (NPV). RESULTS: Visible debris was present in 169 filters

(60.3%). There was an increased risk of visible debris found with several variables (OR, 95% CI): hypertension

(2.9, 1.7 to 5.2), hypercholesterolemia (2.3, 1.4 to 3.9), stent diameter >9 mm (16.6, 9.0 to 30.0), and any

neurologic event (4.2, 1.5 to 9.9). The NPV failed to exceed 0.80 (80%) for any variable. The NPV of the

variables with a significantly elevated OR was as follows: hypertension (0.60), hypercholesterolemia (0.52),

stent diameter >9 mm (0.75), and any neurologic event (0.38). CONCLUSIONS: Several clinical variables are

associated with the presence of visible debris captured by distal filter devices. The current study failed to

identify any variables capable of consistently predicting the absence of visible debris. These findings support

the routine rather than the selective use of cerebral protection during CAS.

Visible debris was present in 169 filters (60.3%)

The current study failed to identify any variables capable of

consistently predicting the absence of visible debris

Prediction of embolization based on lesion angiography is unreliable

Transcranial Doppler

Middle

Cerebral

Artery

Velocity

(cm/sec)

Inflated

Maximal risk of embolization at post-dilation

Deflated

Distal Filter Wire EPD

Common Carotid Artery

External Carotid Artery

Why do strokes occur

despite EPD use?

•Overwhelming debris burden

• Pore size (100-250 microns)

•Filter malapposition

•Improper sizing

•Shape mismatch

•Patient movement

The Contego solution

• Problem:

• Risk of stroke is maximal during the post-dilation phase

• Solution:

• Increase protection during the post-dilation phase

Double filtration cases demonstrate the

need for additional protection

Double filtration pilot study: Baseline characteristics

N=191

Age 70.8

Male 78.5%

CAD 69%

DM 34%

PVD 56%

HTN 87%

Dyslipidemia 80%

NIHSS PRE 1.2

NIHSS POST 1.1

Prior CVA 24%

Age > 75 41%

Symptomatic 24%

Double filtration pilot study: Procedural and lesion data

RICA 49%

LICA 51%

Bivalirudin 100%

Mean ACT 395 seconds

Pre Stenosis 91%

Final 8%

Ulcer 31%

Mean Lesion Length 19 mm

Moderate to Severe Calcification 41%

Thrombus 1%

Ref Vessel Diameter 5.7 mm

N=191 Number of events %

Procedural Events

Myocardial Infarction 0 0%

Stroke 1 0.52%

Death 0 0%

30-Day Events

Myocardial Infarction 1 0.52%

Death 2 1.05%

Stroke 1 0.52%

Total Death/Stroke/MI 4 2.09%

Double filtration pilot study:

Procedural and 30 day results

Limitations of double filtration using two separate filters

• Cost of an extra filter

• Extra time require to deploy a second filter

• 36% of patients with insufficient landing zone for a second filter

Filter Membrane with

40-Micron Pore Size

Angioplasty

Balloon

Filter

Chassis

PALADIN®

Carotid Post-Dilation Balloon with Integrated

Embolic Protection

PALADIN®

PALADIN ®

: Key features

• Sheathless design

• 40-Micron Pore Size

• 95% capture efficiency with 100 micron particles

• Filter open time of 15-30 seconds ensures minimal risk of thrombin/fibrin deposition

• Ability to adjust size to suit patient anatomy

• Continguous treatment portion and embolic protection portion, with minimal landing zone requirements

PALADIN ®

: Short landing zone opens possiblity for

alternative vascular applications

SVG, AMI, and renal, and tibial artery

PALADIN ®

: current status

• Vigorous testing in pre-clinical porcine carotid, renal, and coronary arteries

• Successful clinical cases in Santiago, Chile and Frankfurt, Germany

• Excellent performance in all carotid, coronary, and renal areteries.

• CE Mark with commercialization early 2015

Summary

• There remains a risk of stroke during carotid artery stenting

• The majority of the risk is at the time of post-dilation

• Double filtration during post-dilation may reduce this risk of stroke

• This technology may allow an expanded role for embolic protection in all vascular beds.