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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.

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THANK YOU