Dr. Benny J Panakkal Senior Resident Dept. of Cardiology
Medical College, Kozhikode PHARMACOLOGICAL STRESS
ECHOCARDIOGRAPHY
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Understanding Basic Concepts
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Ischemia Cascade The answer to the Question Why Echo
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Wall Motion More Specific Requires Ischemia Perfusion Changes
More Sensitive May occur without producing Ischemia
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Low costEnvironment friendlyNo ionizing radiationEqually
accurate Why Echo in comparison to SPECT, PET etc.
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Coronary Flow Reserve WITHOUT Angina with ST-T changes WITHOUT
Wall Motion Abnormalities Microvascular Ischemia Syndrome X LV
Hypertrophy
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Stressors in Stress Testing
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Exercise Stress Testing Treadmill Most potent Bicycle Imaging
at Peak Stress and during each stage of stress Avoids problem of
early resolution of ischemia Can accurately measure the time of
onset of ischemia Prognostically important
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Drawbacks Hyperventilation Hypercontractility of Normal Walls
Excessive Tachycardia Excessive chest wall movement Unable to
exercise at all or maximally Circumvented by Pharmacological
Stressers Exercise as a Stressor Prototype of Demand driven
ischemic stress
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Situations where Pharmacological Stress is preferred to
Exercise Stress
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Dipyridamol Less myocardial dysfunction More blood flow
heterogeneity Sometimes even without wall motion abnormalities
Still supply is sufficient for the demand More myocardial
dysfunction Less blood flow heterogeneity Dobutamine
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Adverse Effects and Complications
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Protocols
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Exercise Stress Test Protocol
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Dipyridamol Stress Echo Protocol
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Ergonovine Stress Protocol for Coronary Vasospasm
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Imaging Equipment and Acquisition
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Quad screen Format Normal response to Exercise, Dobutamine or
Pacing Stress Echo
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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 2- chamber view
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Contrast Echo in Stress Echo LV Opacification by micro bubbles
Improved Wall motion detection Simultaneous perfusion analysis
Targetted approach to assess wall motion 3D Imaging Decreased
Acquisition periods Technically easier Contrast Echo and 3D
Imaging
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How Contrast Echo improves Endocardial border defintion
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Excessive Gain setting spoiling the Endocardial border
definition
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Comparing Similar looking but totally different views
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TDI or Strain Rate Imaging QRS to onset of Relaxation = 350
400ms Normally interval decreases by 34% 10% In Ischemia 12% 18%
Speckle Tracking Diastolic stunning Lasts longer than wall motion
abnormalities TDI in Stress Echo
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Applying Strain Rate Imaging in Stress Echo Resting
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Applying Strain Rate Imaging in Stress Echo Low dose
Dobutamine
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Applying Strain Rate Imaging in Stress Echo High dose
Dobutamine
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The Do(s) and Dont(s)
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CAD Diagnosis Prognosticat ion Pre Op risk assessment
Exertional dyspnoea to rule out cardiac etiology Localizing
ischemia Evaluation of valve stenosis severity Indications of
Stress Echo
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Special clinical conditions and target endpoints in Stress Echo
Discordant symptoms and severity of lesion Rise in contractile
reserve Exercise induced peak sytolic pulmonary pressures > 60mm
Hg Regurgitant lesions
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Diagnostic and Prognostic value of CFR during Vasodilator
testing Standalone diagnostic criteria: Structural limitations Only
LAD imaged LCx and RCA very difficult to image and impractical
Cannot differentiate between microvascular and macrovascular CAD
Addition of CFR Sensitivity, with modest in Specificity CFR Flow
(High Neg Pred Value) 2D Function (High Pos Pred Value) Used in
DCMP too!!
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Interpretation
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Wall motion scoring and attribution to coronary vascular
territories
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Interpretation of Pharmacological and Exercise Stress Echo
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Stress induced myocardial ischemia Hallmarks Worsening of wall
motion abnormalities Development of new wall motion abnormalities
Specific Lack of hyperdynamic motion Beta Blockers THR not attained
Non-Specific Akinetic segment becoming dyskinetic No meaning
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Adjunctive Diagnostic Criteria LV cavity dilatation Decreased
Global LV systolic function TVD or Left Main disease Differential
responses to Exercise and Dobutamine Stress Echo
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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 Non- diagnostic 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
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Dipyridamol Stress Preferred Hypertension Atrial and
Ventricular Arrhythmias Dobutamine Stress Preferred Conduction
disturbances Bronchospastic diseases On Xanthine medications
Caffeine containing drinks Tea Coffee Cola
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Contents of Stress Echo Report
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Statistics, Studies The Comparison
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Exercise Stress Echo Dobutamine Stress Echo VT1.4%4% VF12 SVT
and AF are more common than VT/VF Single Centre Analysis (
>50,000 studies ) Mayo Clinic
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SensitivitySpecificity Stress Echo85%88% Stress SPECT85%81%
Diagnostic Accuracy - Overall SVDDVDTVD Stress Echo58%86%94% Stress
SPECT61%86%94% Sensitivities in CAD subtypes 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 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
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Cardiac Event : Cardiac Death, Non-fatal MI, Coronary
Revascularization Normal Stress Echo Event Rate < 3% (0.9% per
person years of follow up) Predictors of Cardiac Event (TMT) Low
effort tolerance LVH Advancing Age Stress Echo as a Prognostic
Indicator Mayo Clinic Study comprising 1325 patients
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HR Diabetes1.9 Previous MI2.4 Increase or No change in LV
systolic size 1.6 Predictors among patients with Good Effort
Tolerance and Abnormal Stress Echo Event Rate was 2% per person
year follow up 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
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Among patients with a High Pretest Probability for CAD cardiac
event rate At 1 yrAt 3 yra Normal Stress Echo2%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
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Ischemic ThresholdEvent Rate < 60% THR43% 60% THR9% No
Ischemia0% Dobutamine Stress Echo in Preop Evaluation and
Prognostication A Mayo clinic study of 530 patients
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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.
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Dipyridamol vs Dobutamine Stress Echo
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Dipyridamol vs Exercise Stress Echo testing
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SensitivitySpecificityAccuracy SVDMVDGLOBAL
Dipyridamol6681729277 Exercise7290798280 Meta analysis of major
trials comparing Dipyridamol with Exercise Stess Testing
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3D Echo in Stess Testing
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Prognostication
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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; 49:22737 Prognostic value of normal stress echo
Normal test Annual risk of Death = 0.4% 0.9% Prognostic Value of
Inducible Myocardial Ischemia Prognostic Value of Inducible
Myocardial Ischemia
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Stress Echo Titration of a Negative Test Prognostic Value of
Inducible Myocardial Ischemia Prognostic Value of Inducible
Myocardial Ischemia
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Biphasic Response is the single most important response in
predicting improvement in LV function in patients with LV
dysfunction undergoing revascularization 72% vs
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 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
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Special Subsets Non Cardiac Surgery
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Cytokine response Catecholami ne Surge Hemodyna mic stress
Vasospasm Reduced Fibrinolytic activity Platelet activation Hyper-
coagulability Perioperative Stress Response
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High risk category Intermediate risk category with Poor
functional capacity Age < 70 yrs blocker therapy suffices Age
> 70 yrs Revasculariza tion Peripheral Vascular Disease Stress
Echo positivity does not always mean Revascularizatio n Left main
or 2 vessel disease Only indication for revasculariz ation Others
blockers and Statins When to perform Pharmacological Stress Echo in
the context of Perioperative risk stratification
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Special Subsets Emergency Department
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Randomized muticenter trial - Italy 99% Neg predictive value to
r/o ACS Still has drawbacks Patients with negative stress test had
early readmission with ACS
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Special Subsets Myocardial Viability Assessment
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Viable Thickness 6mm ScarredThinnedEchodense
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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;26:142186 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;26:142186
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Examples
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Detection of Myocardial Ischemia Apical wall thickness,
improves at low dose but deteriorates and high dose dobutamine
stress echo.