Using IVUS to optimize PCI outcome is it really necessary

 Identify specific disease - left main stem, ostial lesions  Detect angiographically silent disease - transplant vasculopathy  Identify plaque morphology  Examine vessel when angi

Dr Jack Tan

Senior Consultant Interventional Cardiologist

National Heart Centre Singapore MBBS, MRCP(UK), FAMS(Cardiology), FAsCC

Using IVUS to optimize PCI

outcome: is it really necessary?

14th Vietnam National Congress of

Cardiology

Mechanical Transducer – 40 MHz Atlantis Pro (BosSci)

Solid-State Transducer – 25 MHz EagleEye (Volcano)

 Identify specific disease

- left main stem, ostial lesions

 Detect angiographically silent disease

- transplant vasculopathy

 Identify plaque morphology

 Examine vessel when angiography is

inconclusive

-hazy lesions, presence or absence of thrombus or dissection

 Measure plaque load

 Measure true vessel size

Lumen Area

Vessel Area

Atheroma Area

IVUS Determination of Atheroma Area

Precise Planimetry of EEM and Lumen Borders

with Calculation of Atheroma Cross-sectional Area

Vessel Diameter

Lumen Diameter

Visualisation of inner wall structures and

morphology Continuous image Precise measurements

 Pre-intervention

 During the intervention

 Post-intervention

Pre-intervention

 estimate hemodynamic significance

 precise anatomic analysis (type of

bifurcation, plaque burden in ostial side

branches or left main bifurcation)

 reference diameters define normal to normal segments

 Type of lesion preparation required e.g

atherectomy

During Intervention

 CTO intervention to guide wires or reentry

 Assessment of side branch ostium after

predilatation

 Adequacy of debulking post atherectomy

 Decision making for LM, bifurcation stenting

Post Intervention

 Stent expansion, stent apposition

 Diagnosis of complications (dissection,

geographic mismatch, thrombus formation ,plaque protrusion inside the stent

 MLA <4 mm 2 correlated well with ischemia on SPECT

Nishioka JACC ’99

correlated moderately well with an FFR <0.75 with

sensitivity 92% and specificity 56% Brigouri AJC 2001

intermediate lesions in whom intervention was deferred

FFR <0.80, but poor specificity limits its value for

identify ischemia-inducible intermediate stenoses Kang SJ Circ Card Interv 2011

Patient Referred for ISR of a 2.5 mm stent in the pLAD

RAO cranial IVUS

4 mm

2.5 mm

Insights

From IVUS

• IVUS can assist in the differentiation of

restenosis related predominantly to intimal hyperplasia versus mechanical complications, such as stent fracture or stent

underexpansion

• An IVUS-guided high-pressure angioplasty

with a noncompliant balloon can be the sole treatment when stent underexpansion is the major mechanism for restenosis

371 prox lads

<3 3.0-3.5 3.5-4.0 4.0-4.5 4.5-5.0 5.0-5.5 5.5-6.0 >6.0 0

10

20

30

<3 3.0-3.5 3.5-4.0 4.0-4.5 4.5-5.0 5.0-5.5 5.5-6.0

Vessel size: Angiography vs IVUS

IVUS

Moussa et al AJC 1999;83:1012-1017

IVUS

SIRIUS IVUS sub study 72 SES and 50 BMS

Sonoda, et al JACC 2004;43: 1959-63

 975 elective BMS or DES for unprotected LMCA stenosis

discretion

MAIN COMPARE REGISTRY

• Trend toward lower 3-year mortality with an IVUS-guided strategy vs angiography alone (6.0% vs 13.6%, p =0.063)

• Interestingly, in the 145 matched-patient

subgroup receiving DES, the 3-year incidence

of mortality was significantly lower in the

IVUS-guided group (4.7% vs 16.0%, p 0.048)

• Driven by reduced rates of sudden cardiac

death from late stent thrombosis

Integrated use of FFR and IVUS in left main stenting

Park S et al J Am Heart Assoc 2012;1:e004556

© 2012 Park S et al

7484 PCI’s with IVUS: 27 SAT (0.36%)

Inadequate Stent Expansion 18 (78%) Stent malappostition 2 (5%)

Dissection 4 (17%) Tissue protrusion 1 (4%)

Thrombus post PCI 1 (4%)

IVUS Cheneau et al Circulation 2003;108:43

• Pre-intervention assessment of plaque morphology and distribution at the side branch ostium

• Currently, a single-stent strategy with provisional side

branch intervention has become the favored approach for most bifurcation lesions due to reduced cardiac events

 A propensity-matched analysis of patients undergoing PCI

of non–left main bifurcations with DES using

predominantly a single-stent strategy

 An IVUS guided PCI strategy (n=487) vs angio guided

(n=487)was associated with larger post-stent lumen

diameters in both the main vessel and side branch lower rates of death or MI (3.8% vs 7.8%, p =0.03)

 In 90 bifurcation lesions, a pre-intervention MLA of

>2.4 mm 2 in the side branch could accurately predict a nonischemic post-intervention FFR (> 0.80) in the side branch (predictive value of 98%) after main branch

stent deployment However, a MLA<2.4mm 2 could

not accurately predict side branch compromise

resulting in an ischemic FFR (predictive value of 40%)

 If the pre-intervention side branch MLA is > 2.4 mm2, provisional side branch PCI can usually be deferred

 If the side branch MLA is <2.4mm 2 , clinical judgment and/or side branch FFR should be considered to guide provisional side branch intervention

• Subintimal guide wire tracking IVUS imaging from the false lumen to guide re-entry of the wire into the true lumen

• In a small series of 31 CTO lesions (of which 22 were previous failed attempts), successful

recanalization was achieved in 100% of cases using a modified retrograde IVUS-guided

approach

Rathore S et al JACC Intervention 2010

 Oversized stents (stent to reference ratio

>1.0) result in greater rates of peri-procedural myocardial necrosis and distal embolization without reducing 9-month revascularization rates

Dense Calcium Volume 11.7 mm 3 10%

Necrotic Core Volume 28.9 mm 3 25%

Variables entered: minimal lumen area (MLA), plaque burden at the MLA, external elastic membrane at the MLA, lesion length, distance from the coronary ostium to the MLA, remodeling index, thin-cap fibroatheroma, insulin-requiring diabetes and prior percutaneous coronary intervention

Independent predictors of lesion level events

by Cox Proportional Hazards regression

 Used grayscale IVUS and RF backscatter analysis

to predict the site of future coronary events

and underwent PCI of all culprit lesions followed

by 3-vessel VH IVUS imaging

thin-cap fibroatheromas with a plaque burden

>70% and MLA<4.0 mm2 had an 18% MACE

driven largely by revascularization

Stone et al NEJM 2011

Using IVUS to optimize PCI outcome: is it really necessary?

 No, not needed

but not conclusive

procedural time, higher contrast

consumption and more complex

and need more skills than angio

guided ones

 IVUS-measured MLA is only one of many factors

affecting coronary flow hemodynamics

 Hemodynamic effects of a lesion are dependent on MLA, lesion length, eccentricity, entrance and exit angles and forces, reference vessel dimensions, and the amount of myocardium subtended by the lesion

 Although IVUS-derived MLA >2.4 mm2 may be a

useful criterion for excluding intermediate lesions with an FFR <0.80, a MLA <2.4 mm does not always equate with functional significance

 I agree with the stance to do functional tests

or FFR to decide on intervention but IVUS to optimize the end result

 Again if cost is not an issue

 Not backed by evidence but good to have if done routinely not just for complex PCI If cost is not an issue

 A must to do for CTO wire retrograde

tracking, SAT

 Good to do for LM PCI, ISR, diagnostic

uncertainty, ASA allergy

 Ultimately a diagnostic test like IVUS is

difficult to show outcome difference, very much like a Swan Ganz or thermometer

 A diagnostic tool only helps change outcome for the astute user who uses the findings to change technique or management

 If not don’t do it

 Routine IVUS guiding is not necessary in all PCI

 The selective use of IVUS may improve

clinical outcomes in the real world

Thank you

• Accurate reference lumen dimensions and lesion length assessment

• Identification of circumferential superficial calcium by

IVUS sway towards rotational atherectomy

• Post-stent IVUS assessment may detect complications of PCI and suboptimal stent deployment

 Factors associated with stent thrombosis include

smaller minimal stent area , stent under expansion,

persistent edge dissections, incomplete stent apposition and incomplete lesion coverage ,geographic miss, tissue protrusion and residual thrombus

There are known known's These are things we

know that we know There are known unknowns

That is to say, there are things that we know we

don't know But there are also unknown unknowns There are things we don't know we don't know

Donald Rumsfeld

"If you cannot convince

them, confuse them"