Intravascular imaging and vulnerable plaque detection Ron Waksman MD, FACC, FSCAI Professor of Medicine (Cardiology), Georgetown University Associate Chief of Cardiology Washington Hospital Center Washington DC
Intravascular imaging and vulnerable plaque detection
Ron Waksman MD, FACC, FSCAIProfessor of Medicine (Cardiology), Georgetown
University Associate Chief of Cardiology Washington Hospital Center
Washington DC
Need for intervention in original non-culprit lesion correlates to underlying extent of coronary artery disease
0%
2%
4%
6%
8%
10%
0 60 120 180 240 300 360
Days from study entry
New
Les
ion
PCI
Single Vessel (n=1479) Double Vessel (n=1091) Triple Vessel (n=777)
Glaser et al Circulation 2006
Female sex
Minimal lumen irregularities
Prior coronary intervention
NO REPEAT PCI
REPEAT PCI0.1 1.0 10.0
New lesion PCI in subgroups
OR=0.77
Double vessel disease
Triple vessel disease (vs. single)
Age ≥65 years
Hx hypertension
Diabetes mellitus
OR=1.70
OR=3.61
OR=0.66
OR=1.47
OR=1.01
OR=1.41
OR=2.03
Glaser R et al Circulation 2005.111:143
Glaser R et al Circulation 2005.111:143
Glaser R et al Circulation 2005.111:143
Braunwald, J Am Coll Cardiol 2006;47:C101
Proposed algorithm for the detection of plaques likely to result in acute coronary syndromes
Invasive approaches to vulnerable plaque diagnosis
• Intravascular thermography• IVUS based: Palpography and
virtual histology• Near infrared spectroscopy• Optical coherence tomography-optical
analog of ultrasound imaging measuring the back-scattered light (optical echoes) returning from an arterial sample as a function of delay.
Individual temperature wall differences by in-vivo thermography
Circulation 1999;99:1965S1-S5: proximal to distal sites
IBIS study
Van Mieghem et al J Am Coll Cardiol 2006;47:1134
High strain spots on palpography• pre- 4.8 ± 4.5• post- 3.6 ± 4.4• Significant decrease inSTEMI patients
MSCT
VH
Palp
Use of VH to predict distal embolization after PCI for STEMI
Kanaguchi et al. J Am Coll Cardiol 2007;50:1641
Serruys PW et al. Circulation 2008;118:1172
IBIS 2. Darapladib reduces necrotic core area in patients with an acute coronary syndrome: Representative examples
Change in individual plaque components
Necrotic core
Dense calcium
Fibro-fatty
Fibrous
Darapladib Placebo
Serial assessment of bioabsorbable stent with IVUS and VH
Serruys PW et al Lancet 2009;373:897
Before stenting After stenting 6 months 2 years
Use of NIR spectroscopy to distinguish cholesterol from collagen
1100 1200 1300 1400 1500 1600 1700 1800 1900
wavelength
1.0
0.8
0.6
0.4
0.2
Abs
orba
nce
Chemogram of a RCA in a DM/HC pig that died of sudden cardiac death 3 months later.
Acute sudden cardiac death in a DM/HC pig.
Additional information from intra-coronary NIR
Spectroscopy
RCA
Ring oflipid core plaque
No stenosis, however, a lipid core plaque
Mild narrowing but no LCP
Courtesy of Dr. Simon DixonBeaumont Hospital, Royal Oak, MI
Dilation of the lipid core plaque
No flow in artery after angioplasty
Complete Heart Block,BP 30 mm Hg
Balloon angioplasty
Plaque contents passed downstream
Courtesy of Dr. Simon DixonBeaumont Hospital, Royal Oak, MI
Stenosis
Chemogramof RCA withring LCP at stenosisin 62 yo male
Distalembolizationfollowing dilationleading to MIand CPR
Similar chemogramwith ring LCPfrom autopsyspecimen of48 yo male
Suddencoronary death
Massive LCPand remnantof fatalthrombus Thrombus
remnant
Assessment of AMI culprit lesion morphology with OCT, angioscopy, IVUS
Kubo et al J Am Coll Cardiol 2007;50:933
Assessment of AMI culprit lesion morphology with OCT, IVUS, angioscopy
Kubo et al J Am Coll Cardiol 2007;50:933
Measurement of fibrouscap thickness
Serruys PW et al Lancet 2009;373:897
Serial assessment of stent struts with optical coherence tomography
Plaque ErosionPlaque Erosion
Plaque rupturePlaque rupture
Plaque erosionPlaque erosion
(Kubo et al. J Am Coll Cardiol 2007;50:933(Kubo et al. J Am Coll Cardiol 2007;50:933--9)9)(Kubo et al. J Am Coll Cardiol 2007;50:933(Kubo et al. J Am Coll Cardiol 2007;50:933--9)9)
Incidence=73%Incidence=73% Incidence=47%Incidence=47% Incidence=40%Incidence=40%
Incidence=23%Incidence=23% Incidence=3%Incidence=3% Incidence=0%Incidence=0%
RTRT
1m1mmmIncidence=Incidence=
100%100%RTRTIncidence=100%Incidence=100%
Incidence=33%Incidence=33%
WTWT
RTRT
Incidence=100%Incidence=100%
Incidence=100%Incidence=100%
Thro
mbu
s Fo
rmat
ion
Thro
mbu
s Fo
rmat
ion
Proximal Distal
s
Lipid fraction index (LFI):
High Intermediate Low Void
D
P
•• 48 year old female with stable angina
• Previous revascularization
• Risk factors: hypertension, hyperlipidemia and family history
• Three vessel disease
• Proximal LAD, 20% stenosis
Intravascular magnetic resonance imaging
LFI Distribution in 99 patients sorted by max LFIEach column represents a single patient
0102030405060708090
100
0 10 20 30 40 50 60 70 80 90 100
Patients
LFI
66% of patients had > 1 lipid-rich measurement19% of patients had > 2 lipid-rich measurements33% of patients had no lipid-rich measurements
66% of patients had > 1 lipid-rich measurement19% of patients had > 2 lipid-rich measurements33% of patients had no lipid-rich measurements
TOPIMAGE – LFI Results
LFI ≥35 = lipid rich
Summary• New non-invasive techniques are being
developed which may show the presence of lesions with an increased propensity to instability.
• However, invasive approaches, may be necessary to demonstrate those specific lesions at increased risk of causing clinical instability.
• No one device demonstrates all the information needed to assess vulnerable plaques and so a combination may be necessary.