new techniques for the “invasive diagnosis” of the vulnerable plaque
DESCRIPTION
New techniques for the “invasive diagnosis” of the vulnerable plaque. Antwerp, 17 March 2006. “Invasive” diagnosis. “Non-invasive” diagnosis. Biomarkers. History. Platelets. Stress/ Viability Tests. Coagulation factors. DEFINITIONS. - PowerPoint PPT PresentationTRANSCRIPT
New techniques for theNew techniques for the“invasive diagnosis” “invasive diagnosis”
of the vulnerable plaqueof the vulnerable plaque
Antwerp, 17 March 2006
“Invasive” diagnosis “Non-invasive” diagnosis Biomarkers
Coagulation factors
Platelets
History
Stress/ViabilityTests
Vulnerable plaques (or high-risk plaques or thrombosis-
prone plaques):
– Thin- cap fibro-atheroma:
65% of all vulnerable plaques,
lipid core >40% of total plaque,
fibrous cap <100 μm.
– Erosion: 30% of all vulnerable plaques,
erosion/loss of dysfunctional endothelium.
– Calcific nodule: 5% of all vulnerable plaques.
DEFINITIONS
Normal Coronary artery
Asymptomatic atherosclerosis
Vulnerable plaques
During decades can develop
Plaques that develop thrombosis
Can progress, in an unpredictable way, to
Can conduct to
Acute coronary syndromes
Stenosis progression and stable angina symptoms
Asymptomatic progression
During years can lead to
NO RELATIONSHIP
BETWEEN STENOSIS SEVERITY
AND VULNERABILITY
““Standard” techniquesStandard” techniquesCoronary angiography
““Standard” techniquesStandard” techniquesCoronary angiography
Coronary angiographyAngiographically complex plaques:
- Contrast present outside the lumen borders (ulceration)
- Irregular and undermined borders (plaque rupture)
- Intracoronary filling defect (thrombosis)
Issues:
- Visualization of the coronary lumen only
- Often these plaques are already “flow-limiting”
- Complex plaques = vulnerable plaques already at advanced stage!
““Standard” techniquesStandard” techniques
Around 70% of acute coronary
occlusions occurs in
angiographically “normal” areas
IVUS““Standard” techniquesStandard” techniques
Axial resolution: 150 μm Lateral resolution: 300 μm
Morphologic data on the plaques
Echogenicityecho-lucent plaques echo-dense plaques shadow behind calcium
Discrete sensitivity (70%) ed high specificity (90%) for calcifications
Low sensitivity (50%) e specificity (30%) for lipid “core”
No information regarding fibrous cap (low resolution!!)
IVUS““Standard” techniquesStandard” techniques
The majority of available data comes from retrospective studies in patients with known CAD.
In UA patients as compared to SA patients:– The presence of ruptured plaques is more frequent– There are plaques with larger echo-lucent areas– There is more frequently a positive “remodeling”
IVUS““Standard” techniquesStandard” techniques
Several studies have shown
the presence of multiple
plaque ruptures in the
coronary tree,
and most of them were
ASYMTOMATIC!
VIRTUAL HISTOLOGYVIRTUAL HISTOLOGY
Amplitude ee Frequencyare used
to reconstructthe image
UnstableAngina
Recent myocardial
infarction
Stable Angina
Pull-back
ELASTOGRAPHYELASTOGRAPHY
PALPOGRAPHYPALPOGRAPHY
Diffuse and severeconcentric
calcification
Other techniques…Other techniques…Optical Coherence Tomography (OCT)
Measures the intensity of reflected light, as IVUS measures ultrasounds
Quality: - high resolution (20 μm)
Defects: - Bulky devices with very large diameter - need for “removal” of blood (occlusive balloon proximal or continuos flushing with water)
Fibrous Tissue = “signal-rich” Calcium = “signal-poor” with well defined contours
Lipid Tissue = “signal-poor”with hazy contours
EndoluminalThrombosis
Other techniques…Other techniques…Thermography
- Measures the difference in temperaure between a “baseline” area and a “region of interest”
- Index of the inflammatory status of the atherosclerotic plaque
-Most clinical studies performed to date only in one center (Greece)
- “Cool-down” effect of blood
Other techniques…Other techniques…Thermography
A glimpse into the future… Absence of a reliable animal model of vulnerable
plaque
Need for prospective studies (PROSPECT, VIP)
Pan-coronary inflammation syndrome
“Push” from pharmaceutical companies and interventional cardiologists
Every technique offers data on one aspect of the vulnerable plaque more techniques togheter?
For further slides on these topics For further slides on these topics please feel free to visit the please feel free to visit the
metcardio.org website:metcardio.org website:
http://www.metcardio.org/slides.html http://www.metcardio.org/slides.html