dissection identification and classification using ivus...ivus angiography 46 8 post-adjunctive pta...

Dissection Identification and Classification using IVUS:

The iDissection Grading System

Nicolas W Shammas, MD, MS, FACCFounder and Research Director,

Midwest Cardiovascular Research FoundationDavenport, IA

Disclosure

Speaker name: Nicolas W Shammas, MD, MS

.................................................................................

I have the following potential conflicts of interest to report:

Consulting: Intact Vascular, Bard, Boston Scientific

Research and Educational Grants: Intact Vascular, Bard,

Boston Scientific, Phillips

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Imaging Predictors of Restenosis

• Media and external elastic lamina injury

• Circumference of injury

• Small vessel diameter

• Longer lesion length

• Presence and severity of calcium

• Lesion severity underappreciated outside the treated segment

• High residual narrowing underappreciated in treated segment

• Intra-medial route of wire passage in CTO

• Stent under-expansion and asymmetry of expansion

Dissection

Dissection

• Dissection and, to a much lesser extent, plaque compression is what creates the lumen post-PTA

• “intentional dissection” optimizes lumen during vessel prep for subsequent planned therapy

Dissection leaves an unpredictable and unreliable surface

Angiography Has Limitations

• Severity of calcium1,2

• Presence of intraluminal thrombus3

• Plaque morphology4

• Vessel diameter5

• Residual narrowing post-intervention6,7

• Number and severity of dissections including medial and adventitial injury5

1Mintz, Circulation 19952Kashyap, J Endovasc Ther 2008

3Shammas, J Endovasc Ther 20084Arthurs J Vasc Surg 2010

5Korogi, Cardiovasc Interv Radiol 19966Katzen, Circulation 1991

7Cavaye, Interv Angiol 1993

Identifying:

NHLBI Dissection Classification

AMinor radiolucent

areas

BLinear dissection

CContrast outside the

lumen

DSpiral dissection

EPersistent filling

defects

FTotal occlusion w/o

distal antegrade flow

Images adjudicated by core laboratory

NHLBI Dissection ClassificationLimitations:• Formulated in 1985 when current imaging and

therapy techniques were not available

• Considers only the single worst dissection, regardless of how many are present

• Length, depth, extent of dissection not considered

• No consensus on “severe” dissection in the periphery

– Variance in DCB and RCTs and registries

What Is Needed

• Imaging-based dissection classification that is:

– Easily reproducible

– Quickly performed during the procedure

• And captures:

– Presence of injury

– Depth of injury

– Extent of injury


Shammas, J Invasive Cardiol 2018

• Depth of dissection:

– A: Intima

– B: Media

– C: Adventitia



• Extent (circumference) of dissection:– 1: arc of injury < 180°

– 2: arc of injury ≥ 180°

Six iDissection Grades


A1 B1 C1

A2 B2 C2

Prospective, single arm, single center/operator

Population 15 patients with de novo or stenotic (non-stented) lesions in the femoropopliteal arteries

Treatment Atherectomy + adjunctive PTA• Atherectomy: JetStream XC or B-laser• PTA: POBA, DCB or lithoplasty

Imaging Angiography and IVUS (Eagle Eye ST, Philips) at:• Baseline• Post-atherectomy• Post-PTA

Core Lab Angiography (using NHLBI)• MCRF QVL

IVUS (using iDissection)• MCRF QVL• St. John Providence

iDissection Study Design

Patient and Lesion Characteristics


Subjects N=15

Age (y) 70.6 ± 8.0

BMI (kg/m2) 30.4 ± 7.5

Gender (male) 93.3 %

Hx of CAD 80 %

Chronic renal insufficiency 6.7 %

Hypertension 100 %

Hyperlipidemia 93.3 %

Smoking 60 %

Current ulcer 26.7 %

Prior target vessel treatment 73.3 %

Rutherford ≥ 3 73.3 %

Lesion Baseline

Lesion length (mm)

108.5 ± 43.1

Treated length (mm)

162.1 ± 100.8

Lesion diameter (mm)

5.7 ± 1.1

% diameter stenosis

71.4 ± 23.4

PACCS grade0134

13.3 %26. 7 %

20 %40 %

Procedural Methods


Atherectomy

JetStream XC (Boston Scientific) 86.7 %

Blade down mode x 2 100 %

Blade up mode x 2 100 %

B-Laser (Eximo Medical) 13.3 %

Lasing time (sec) 90 ± 50.9

Energy used (J/kg) 50 ± 0

Angioplasty

Shockwave (Shockwave Medical) 33.3 %

Drug coated balloon 100 %

Balloon diameter (mm) 6.1 ± 0.7

Balloon pressure (atm) 10.3 ± 3.1

Balloon inflation time (sec) 310.0 ± 127.9

Procedural Results


Finding

Procedure Success (n = 14)* 100 %

Device Success (n = 14)** 86.7%

Procedural Complications 0 %

stenting 53. 3 %

Baseline Post-Atherectomy Final: Post-PTA

% diameter stenosis 71.4 ± 23.4 38.1 ± 13.2 19.7 ± 8.8

* < 30% residual narrowing at end of procedure

** < 50% residual narrowing post atherectomy only

Dissection Analysis

The number and severity of dissections seen were compared between angiography and IVUS

– All images adjudicated by core laboratory

– No lesion to lesion comparison available

Finding

Post-atherectomy intramural hematoma 13.3 %

Post-PTA intramural hematoma 13.3 %

Dissections < 6mm 35.3 %

Dissections cumulative < 36mm 97.6 %


Number of Dissections

Post-Atherectomy

IVUS Angiography

46 8

Post-Adjunctive PTA

IVUS Angiography

39 11

Ratio: 5.75/1 Ratio: 3.55/1

4 to 6 times more dissections are identified with IVUS over

angiography post-intervention


Severity of Dissections

Post-Atherectomy

IVUS Angiography

A1 – C1 A2 – C2 A – C D – F

40 6 (13%) 7 1 (12%)

Post-Adjunctive PTA

IVUS Angiography

A1 – C1 A2 – C2 A – C D – F

27 12 (31%) 10 1 (12%)

Wider dissections are frequently present post-atherectomy. The total number of dissections appear less after adjunctive PTA, wider

dissections are more frequent at least numerically


Case StudyNHLBI Dissections

• None

IVUS Dissections

• 5

iDissection Grade

• A1: 2

• B1: 1

• C1: 2

No dissections

1 dissection involved the media

2 involved the intima

2 involved the Adventitia


A1

Case StudyPost-atherectomy IVUS

A1 C1 C1 B1

Post-angioplasty IVUS

A1 A1 B2 A1 A1Shammas, J Invasive Cardiol 2018

Summary

• Number of dissections:– 46/8 ~6:1

• Depth of dissections:– 39.1% of dissections involved the media

and/or adventitia

• Circumference of dissections:– <180°

• A1: 56.5%• B1: 21.7%• C1: 8.7%

– ≥180°• A2: 4.3%• B2: 6.5%• C2: 2.2%


Dissections on IVUS vs. Angiography

Conclusions

• Dissections are more statistically significant on IVUS:– Number– Depth– Circumference

• Longer lesions correlated with more dissections• Lack of correlation with dissections on IVUS:

– Balloon pressure/inflation time– Limb ischemia– Calcium burden– Adjunctive lithoplasty

• No apparent predictive variable for dissections ≥180°


Dissection Identification and Classification using IVUS:

The iDissection Grading SystemNicolas W Shammas, MD, MS, FACC, FSCAI, FSVM

Adjunct Clinical Associate Professor of Medicine, University of IowaFounder and Research Director,

Midwest Cardiovascular Research FoundationDavenport, IA

dissection identification and classification using ivus...ivus angiography 46 8 post-adjunctive pta...

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