Transcript PHARMACOLOGICAL STRESS ECHOCARDIOGRAPHY Dr. Benny J Panakkal Senior Resident Dept. of Cardiology Medical College, Kozhikode.

PHARMACOLOGICAL STRESS
ECHOCARDIOGRAPHY
Dr. Benny J Panakkal
Senior Resident
Dept. of Cardiology
Medical College, Kozhikode
Understanding Basic Concepts
Ischemia Cascade
The answer to the Question “Why Echo”
Wall Motion
Perfusion Changes
More Specific
More Sensitive
Requires Ischemia
May occur without
producing Ischemia
Why Echo in comparison to SPECT, PET etc.
Low cost
Environment friendly
No ionizing radiation
Equally accurate
Coronary Flow Reserve
Angina with
ST-T changes
WITHOUT
Wall Motion
Abnormalities
Microvascular
Ischemia
• Syndrome X
• LV Hypertrophy
Stressors in Stress Testing
Exercise Stress
Testing
Treadmill
Bicycle
Imaging at Peak
Stress and during
each stage of stress
Can accurately
measure the time of
onset of ischemia
Most potent
Avoids problem of
early resolution of
ischemia
Prognostically
important
Exercise as a Stressor
Prototype of Demand driven ischemic stress
Hyperventilation
Hypercontractility
of Normal Walls
Drawbacks
Excessive
Tachycardia
Excessive chest
wall movement
Unable to exercise
at all or maximally
Circumvented by
Pharmacological
Stressers
Situations where Pharmacological Stress is preferred to Exercise Stress
Less
myocardial
dysfunction
More
More
myocardial
dysfunction
blood flow
heterogeneity
Less
blood flow
heterogeneity
Dobutamine
• Sometimes even
without wall
motion
abnormalities
• Still supply is
sufficient for the
demand
Dipyridamol
Adverse Effects
and Complications
Protocols
Exercise Stress Test Protocol
Dipyridamol Stress Echo Protocol
Ergonovine Stress Protocol for Coronary Vasospasm
Imaging Equipment
and Acquisition
Quad screen Format
Normal response to Exercise, Dobutamine or Pacing Stress Echo
2D imaging
Qualitiy issues
• Failure to
image >1 seg
(30%)
• Suboptimal
visualization
(10-15%)
Harmonic
imaging
Contrast
Echo
Follow
a Road
map
• Avoid excessive
gain settings
• Same window,
Same view for
optimal
comparison
• Perfect Apical 2chamber view
Contrast Echo and 3D Imaging
Contrast Echo in
Stress Echo
LV Opacification by
micro bubbles
Improved Wall
motion detection
Simultaneous
perfusion analysis
Targetted approach to
assess wall motion
Decreased
Acquisition periods
3D Imaging
Technically easier
How Contrast Echo
improves Endocardial
border defintion
Excessive Gain setting spoiling the
Endocardial border definition
Comparing Similar looking but totally
different views
TDI in Stress Echo
Normally interval
decreases by 34% ± 10%
TDI or Strain Rate
Imaging
QRS to onset of
Relaxation = 350 – 400ms
In Ischemia – 12% ± 18%
Diastolic stunning
Speckle Tracking
Lasts longer than wall
motion abnormalities
Applying Strain Rate Imaging in Stress Echo
Resting
Applying Strain Rate Imaging in Stress Echo
Low dose Dobutamine
Applying Strain Rate Imaging in Stress Echo
High dose Dobutamine
The Do(s) and Don’t(s)
Indications of Stress Echo
CAD
• Diagnosis
• Prognosticat
ion
Special clinical conditions and target endpoints in Stress Echo
Regurgitant lesions
• Discordant symptoms
and severity of lesion
• Rise in contractile
reserve
• Exercise induced peak
sytolic pulmonary
pressures > 60mm Hg
Diagnostic and Prognostic value of CFR during Vasodilator testing
Only LAD imaged
Standalone diagnostic
criteria: Structural
limitations
LCx and RCA very difficult
to image and impractical
Addition of CFR – ↑
Sensitivity, with modest↓
in Specificity
Cannot differentiate
between microvascular and
macrovascular CAD
CFR – Flow
(High Neg Pred Value)
2D – Function
(High Pos Pred Value)
Used in DCMP too!!
Interpretation
Wall motion scoring and attribution to coronary vascular territories
Interpretation of Pharmacological and Exercise Stress Echo
Stress induced myocardial ischemia – Hallmarks
Specific
• Worsening of wall motion abnormalities
• Development of new wall motion abnormalities
Non-Specific
• Lack of hyperdynamic motion
• Beta Blockers
• THR not attained
No meaning
• Akinetic segment becoming dyskinetic
Adjunctive
Diagnostic
Criteria
LV cavity dilatation
Decreased Global
TVD or Left Main
LV systolic function disease
Differential responses to Exercise and Dobutamine Stress Echo
Diagnostic End Points
• Max dose of
pharmacological
agent
• Achievement of THR
• Akinesis of ≥ 2 LV
segements
• Severe Chest pain
• Obvious ECG
positivity
• ≥ 2mm ST shift
Submaximal Nondiagnostic End Points
• Non tolerable
symptoms
• Limiting
Asymptomatic side
effects
• Hypertention (BP
> 220/120)
• Hypotension (BP
drop > 40mm Hg)
• Supraventricular
Arrythmias
• Complex Ventricular
Arrythmias
• VT
• Frequent
polymorphic VPC
Dipyridamol Stress Preferred
• Hypertension
• Atrial and Ventricular Arrhythmias
Dobutamine Stress Preferred
•
•
•
•
Conduction disturbances
Bronchospastic diseases
On Xanthine medications
Caffeine containing drinks
• Tea
• Coffee
• Cola
Contents of Stress Echo Report
Statistics, Studies
The Comparison
Single Centre Analysis ( >50,000 studies ) – Mayo Clinic
Exercise Stress
Echo
Dobutamine Stress
Echo
VT
1.4%
4%
VF
1
2
SVT and AF are more common than VT/VF
Diagnostic Accuracy - Overall
Sensitivity
Specificity
Stress Echo
85%
88%
Stress SPECT
85%
81%
Sensitivities in CAD subtypes
SVD
DVD
TVD
Stress Echo
58%
86%
94%
Stress SPECT
61%
86%
94%
Pellikka PA: Stress echocardiography for the diagnosis of coronary artery disease: Progress towards
quantification. Curr Opin Cardiol 20:395, 2005.
Armstrong WF, Zoghbi WA: Stress echocardiography: Current methodology and clinical applications. J Am Coll
Cardiol 45:1739, 2005
Stress Echo as a Prognostic Indicator
Cardiac Event :
Normal Stress
Echo – Event Rate
< 3%
Cardiac Death,
Non-fatal MI,
Coronary
(0.9% per person
Revascularization years of follow up)
Predictors of
Cardiac Event
(TMT)
Low effort tolerance
LVH
Advancing Age
Mayo Clinic Study comprising 1325 patients
Predictors among patients with Good Effort Tolerance and Abnormal Stress Echo –
Event Rate was 2% per person year follow up
HR
Diabetes
1.9
Previous MI
2.4
Increase or No change in
LV systolic size
1.6
Kane GC, Hepinstall MJ, Kidd GM, et al: Safety of stress echocardiography supervised by registered nurses:
Results of a 2-year audit of 15,404 patients. J Am Soc Echocardiogr 21:337, 2008
Among patients with a High Pretest Probability for CAD – cardiac event rate
At 1 yr
At 3 yra
Normal Stress Echo
2%
4%
Abnormal Stress
Echo
17%
25%
Elhendy A, Mahoney DW, Burger KN, et al: Prognostic value of exercise echocardiography in
patients with classic angina pectoris. Am J Cardiol 94:559, 2004
Dobutamine Stress Echo in Preop Evaluation and Prognostication
Ischemic Threshold
Event Rate
< 60% THR
43%
≥ 60% THR
9%
No Ischemia
0%
A Mayo clinic study of 530 patients
Accuracy of different approaches for diagnosis of CAD with Stress Echo
Hoffmann R, Lethen H, Marwick T, et al. Standardized guidelines for the interpretation of dobutamine
echocardiography reduce interinstitutional variance in interpretation. Am J Cardiol. 1998;82:1520–
1524.
Dipyridamol vs Dobutamine Stress Echo
Dipyridamol vs Exercise Stress Echo testing
Dipyridamol vs Exercise Stress Echo testing
Meta analysis of major trials comparing
Dipyridamol with Exercise Stess Testing
Sensitivity
Specificity
Accuracy
SVD
MVD
GLOBAL
Dipyridamol
66
81
72
92
77
Exercise
72
90
79
82
80
3D Echo in Stess Testing
Prognostication
Prognostic Value of Inducible
Myocardial Ischemia
Prognostic value of normal stress echo
Normal test – Annual risk of Death = 0.4% – 0.9%
Metz LD, Beattie M, Hom R, Redberg RF, Grady D, Fleischmann KE. The prognostic value of normal
exercise myocardial perfusion imaging and exercise echocardiography: a meta- analysis. J Am Coll
Cardiol 2007; 49:227–37
Prognostic Value of Inducible
Myocardial Ischemia
Stress Echo Titration of a Negative Test
Biphasic Response is the single most important response in predicting improvement
in LV function in patients with LV dysfunction undergoing revascularization
72% vs <15%
Safety Data
Safety of Pharmacological Stress
Echo
Safety of Pharmacological Stress
Echo
Physical stress with exercise is
probably safer than
pharmacological testing
Lattanzi F, Picano E, Adamo E, Varga A. Dobutamine stress echocardiography: safety in diagnosing coronary artery disease. Drug Saf 2000;
22:251–62.
Varga A, Garcia MA, Picano E. International Stress Echo Complication Registry. Safety of stress echocardiography (from the International Stress
Echo Complication Registry). Am J Cardiol 2006;98:541–3
Special Subsets
Valvular Heart Disease
Cut Offs for Diagnosis
Contractile Reserve – 20% of stroke volume
Valve area improvement to differentiate true from Pseudostenosis – 0.2%
Asymptomatic Sev AS, mean gradient rise on exercise - > 20 mmHg
Special Subsets
Non Cardiac Surgery
Perioperative Stress Response
Hemodyna
mic stress
Vasospasm
Cytokine
response
Catecholami
ne Surge
Reduced
Fibrinolytic
activity
Platelet
activation
Hypercoagulability
When to perform Pharmacological Stress Echo in the context of Perioperative
risk stratification
Left main or 2
vessel disease
High risk
category
Intermediate risk
category with
Poor functional
capacity
• Age < 70 yrs
• β blocker
therapy
suffices
• Age > 70 yrs
• Revasculariza
tion
• Only
indication
for
revasculariz
ation
Peripheral
Vascular
Disease
• Stress Echo
positivity does
not always
mean
Revascularizatio
n
Others
• β blockers
and Statins
Special Subsets
Emergency Department
Randomized muticenter
trial - Italy
99%
Still has drawbacks
Neg predictive value to
r/o ACS
Patients with negative
stress test had early
readmission with ACS
Special Subsets
Myocardial Viability Assessment
Viable
Thickness
≥ 6mm
Scarred
Thinned
Echodense
Diagnostic Accuracy comparison for Myocardial Viability Assessment
Metanalysis
Bax et al. 2001
Bax JJ, Poldermans D, Elhendy A, et al. Sensitivity, specificity, and predictive accuracies of
various noninvasive techniques for detecting hibernating myocardium.
Curr Probl Cardiol. 2001;26:142–186
Examples
Detection of Myocardial Ischemia – Apical wall thickness, improves at low dose but
deteriorates and high dose dobutamine stress echo.
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