Update on the IAC Carotid Project

Heather L. Gornik, MD, RVT, RPVIOn behalf of the IAC Carotid Diagnostic Criteria

Committee

Disclosure

Heather Gornik has the following disclosures:• Non-compensated Board member of the of

IAC – Vascular Testing division• Research support – CVR Global

The ICA Criteria Crisis

There are no universal standard criteria for ICA stenosis • IAC has historically been OK with this, as long as each lab

validates the criteria it uses Criteria for ICA stenosis vary from lab to lab

• Even within the same institution sometimes!

Methods of angiographic correlation for ultrasound criteria vary (ECST vs. NASCET)

This situation is confusing for technologists, interpreting physicians, referring doctors (who read reports), and patients• “My carotid went from 50-69% to 60-79% blocked in a few

months!”• Problem more relevant in this era of patient direct access to

EMRs and their own medical reports

Elderly Woman with Cervical Bruits

Distal CCA (PSV/EDV) = 76/15 cm/secICA/CCA PSV Ratio = 4.8

EDV Ratio = 3.9

Cleveland Clinic Vasc Lab 60-79% StenosisCleveland Clinic Neuro Lab 50-69% StenosisStrandness 50-79% StenosisSRU Consensus >70% Stenosis

2002 Society of Radiologists in Ultrasound (SRU) Consensus Conference

ICAVL did not mandate nor endorse SRU Consensus Criteria**though ICAVL board members and staff participate in the process

SRU Consensus Criteria not validated at the time of publication**though individual elements were derived from validated criteria

2010 ICAVL Survey152 Vascular Labs; >16 Diagnostic Criteria

8 810

6 3

23

3

26

15

2 31 2 1 2 2

6

31

0

5

10

15

20

25

30

35

No.

Lab

orat

orie

s

UWAUWA modifiedUWA + MonetaBluth + UWABluthBluth modifiedBluth + MonetaSRUSRU modifiedFaughtCarrollMoneta modifiedCCFSidhu and Allen StanfordWake Forest Internally developedOther

Gornik H, Hutchisson, M, et al. Presented at AHA 2011.

Other

27.0% SRU based23.0% Bluth based21.1% UWA based20.4% Unreferenced or hybrid of 3+ named criteria3.9% “home grown” criteria

2010 ICAVL SurveyUptake SRU Consensus Criteria by Year 1st

Accredited

18.8%

50.0%

0%5%

10%15%20%25%30%35%40%45%50%

% L

abs

Usin

g SR

U Ba

sed

Crite

ria

Before 2006 2006+Year of 1st Accreditation

N=152 labsP<0.001 for comparison

27% of laboratories in overall sample use SRU-based criteria

Gornik H, Hutchisson, M, et al. Presented at AHA 2011.

Q9: In your opinion, if IAC Vascular Testing (ICAVL) developed one set of standardized diagnostic criteria

that were researched and validated should laboratories be required to incorporate their use for accreditation?

68.4%

31.6%N=722

Yes

No

Gornik H, Needleman L, et al. Presented at ACC 2013.

2012 IAC-VT Carotid Survey

IAC - VT White Paper Document Released (January, 2014)

www.intersocietal.org/vascular/

From the White Paper

Acknowledgement: IAC Vascular Testing has not required, endorsed, or referenced any specific diagnostic criteria for carotid stenosis interpretation in their Standards

The variability in carotid stenosis interpretation across accredited facilities undermines the usefulness of this important diagnostic modality

Provides summary of criteria and the two IAC carotid research surveys

www.intersocietal.org/vascular/

From the White Paper

After careful review and discussion, the IAC Vascular Testing Board of Directors felt that no existing criteria for carotid stenosis interpretation has been sufficiently validated to fulfill all of the needs of facilities performing carotid interpretation.

Following an in-depth literature review… IAC Vascular Testing recommends the use of the …. SRU Consensus Conference Criteria for carotid interpretation.

Facilities which have rigorously internally validated their own criteria may continue to use these criteria at the present time.

www.intersocietal.org/vascular/

From the White Paper

Future actions:

• The IAC… plans to internally validate and make recommendations for specific ICA diagnostic criteria to be used by all facilities applying for accreditation. The future recommended diagnostic criteria may or not be identical to the SRU consensus criteria.

• A multi-disciplinary Carotid Diagnostic Criteria Committee has been formed by IAC Vascular Testing and will convene regularly to move this effort forward. Periodic status updates regarding the progress of this important initiative will be provided to IAC accredited vascular testing facilities.

With this action, the IAC Vascular Testing BOD hopes that the documented variances in carotid stenosis interpretation can begin to be resolved…

www.intersocietal.org/vascular/

Carotid Stenosis Diagnostic Criteria Committee

Andrei Alexandrov Jim Benenati Nirvikar Dahiya Heather Gornik Naomi Hamburg Anne Marie Kupinski Steve Leers Joann Lohr Larry Needleman

John Pellerito Ken Roll Tatjana Rundek Adnan Siddiqui Mike Lilly Marge Hutchisson (IAC) Shelly McManamon (IAC) Hannah Gardener, PhD, study

statistician

IAC Carotid Diagnostic Criteria Study Traditional ultrasound – angiogram validation study

• Gold standard catheter-based DSA (not CTA or MRA) chosen after extensive committee discussion

Study investigators: IAC-VT Board members (current and former) representing all IAC-VT specialties

De-identified materials collected from participating investigators:• Complete bilateral carotid duplex studies (performed

between 1/1/2009 – 12/31/2015)

• Digital subtraction catheter based angiograms performed within 3 months of duplex (at least 2 ICA diagnostic views)

• Limited demographic and clinical data for each case submitted

IAC Carotid Diagnostic Criteria Study: Data Collection

• Technical reviewer data abstraction: velocities for all segments, rating of technical quality of case, cursor alignment, angle of insonnation

• Ultrasound and angiogram interpretation by blinded co-investigators– Ultrasound reviewers analyzed complete ultrasound cases

and assign a diagnostic category according to SRU Consensus Criteria (2 independent reviews/case)

– Interpretive discrepancies sent to 2 additional reviewers

– Angiogram reviewers interpreted angiograms using electronic calipers and NASCET methodology

– Angiogram review panel

IAC Carotid Diagnostic Criteria Study:Initial Analysis Plan Evaluate the sensitivity, specificity, and accuracy of SRU

Consensus Criteria (SRUCC) for diagnosis of ICA stenosis compared to catheter-based angiography using cases from multiple IAC accredited facilities.

Determine optimal ultrasound velocity cut points for diagnostic parameters (PSV, EDV, ICA/CCA ratio, others) using ROC AUC analysis compared to catheter-based angiography.

Regression analysis to determine whether a single parameter or combinations of the optimal parameter values provide best predictors of % ICA stenosis

Additional analyses• Inter-reader reliability (% stenosis using SRUCC by duplex)

• Analysis of individual interpretive reader implementation of SRUCC criteria elements and diagnostic performance

Carotid Criteria Project: Participating Sites

1. Novant Health [Charlotte, NC] (K. Estes)2. Cleveland Clinic (H. Gornik, A. Grattan)3. Univ. of Southern California (S. Parese)4. Univ. of Pittsburgh (S. Leers)5. Tri-Health [Cincinatti, OH] (J. Lohr)6. Univ. of Miami (T. Rundek)7. University Hospital and Clinics [Lafayette, LA] (M.

Comeaux)8. Univ. at Buffalo (A. Siddiqui)9. Univ. of Washington (R.E. Zierler)10. Riverside Radiology [Columbus, OH] (L. Laperna)11. University of Maryland (M. Lilly)

IAC Carotid Diagnostic Criteria Study Progress

Study protocol finalized, on-line image reading and electronic database tools developed• Challenge: Development of on-line database

Site recruitment: September, 2014 – April, 2015• IRB and contract processes –13 sites attempted on boarding• Challenge: 13 separate IRB reviews and 13 contracts between

IAC and 13 medical centers (lawyers!)• Ultimately 11 sites completed the process and submitted cases

Case study collection completed as of September, 2016• Challenge: Investigators finding cases that meet all inclusion

and exclusion criteria per study protocol (many cases excluded, e.g., CEA, stent, etc.)

• Challenge: Heterogeneity of angiogram cases (views, quality)

Case study interpretation completed as of December, 2017 Challenge: Volunteer “labor” with day jobs!

IAC Carotid Diagnostic Criteria Study Progress All cases uploaded, technical review, technical data

abstraction complete N=209 cases (418 sides) meeting criteria sent for

ultrasound/angiogram interpretation ✔ All ultrasounds interpreted by 2 reviewers; discrepant

interpretations sent to additional reviewers ✔All angiograms reviewed 2.2018 Committee met in person for preliminary review of

data and to fine tune analysis plan Now finishing data clean-up and finalization Final statistical analysis and dissemination/publication of study

findings anticipated Fall, 2018 Plans for future implementation of study results to be

determined by the IAC-VT Board of Directors• Future IAC criteria may or may not look like SRUCC

To RecapThere is no such thing as a single, perfect carotid criteria

Standardization is the right thing to do for patients

2/3 of accredited vascular laboratory leaders support a standardization process

Our current situation is one of criteria chaos… this is not good for patient care

Stay tuned for data from this project in fall, 2018

Believe it or not: Many individuals out there just want to be told what to do (“give me the chart”)

Efforts continue at IAC to standardize carotid dx criteria…It’s taken longer than we (I) ever imagined, but it is moving ahead