Role of Dobutamine Stress Echo (DSE) in myocardial viability

assessment

Understanding Basic Concepts

Ischemia CascadeThe answer to the Question “Why Echo”

Wall Motion

More Specific

Requires Ischemia

Perfusion Changes

More Sensitive

May occur without producing Ischemia

Low cost

Environment friendly

No ionizing radiation

Equally accurate

Why Echo in comparison to SPECT, PET etc.

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

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

Situations where Pharmacological Stress is preferred to Exercise Stress

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

Adverse Effects and Complications

Protocols

Interpretation of Pharmacological and Exercise Stress Echo

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

Adjunctive Diagnostic Criteria

LV cavity dilatation

Decreased Global LV systolic function

TVD or Left Main 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 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

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, StudiesThe Comparison

Exercise Stress Echo

Dobutamine Stress Echo

VT 1.4% 4%

VF 1 2

SVT and AF are more common than VT/VF

Single Centre Analysis ( >50,000 studies ) – Mayo Clinic

Ischemic Threshold Event Rate< 60% THR 43%≥ 60% THR 9%No Ischemia 0%

Dobutamine Stress Echo in Preop Evaluation and Prognostication

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.

Safety Data

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

Safety of Pharmacological Stress Echo

Special SubsetsMyocardial Viability Assessment

Viable

Thickness ≥ 6mm

Scarred

Thinned Echodense

Hibernating Myocardium

• Viable but underperfused myocardial tissue that regains functionality after revascularization

• Rescue of hibernating myocardium via revascularization manifests as improved left ventricular function

• DSE has emerged as a noninvasive tool for detecting hibernating myocardium and thus identifying patients most like to benefit from revascularization

Gilstrap et al . Dobutamine stress echocardiography: a review and update. Research Reports in Clinical Cardiology 2014:5 69–81

Biphasic wall motion response• At low doses: hibernating myocardium will augment due to

inotropic stimulation

• At higher doses: hibernating segment may exhibit abnormal wall motion

• This biphasic response appears to be most predictive of post-revascularization viability

• ASE guidelines recommend that viability assessment includes improvement in at least 2 echocardiographic left ventricular segments

Gilstrap et al . Dobutamine stress echocardiography: a review and update. Research Reports in Clinical Cardiology 2014:5 69–81

van der Sijde JN et al. Diabetes Care. 2012 Mar;35(3):634-9

Abnormal DSE

DSE after MI

• Has a sensitivity of 82% and a specificity of 80% for detecting a residual stenosis subtending an area of hibernating myocardium

• Myocardial viability early after MI: – Single best predictor of recurrent in-hospital

ischemia and unstable angina after discharge – Associated with better left ventricular function

recovery and lower long-term mortality

Gilstrap et al . Dobutamine stress echocardiography: a review and update. Research Reports in Clinical Cardiology 2014:5 69–81

DSE in CAD and ischemic cardiomyopathy

• Helps to identify patients most likely to have improved survival

• In ischemic cardiomyopathy: Identifies patients with highest chances of survival post-procedure

• In CAD: Useful in predicting ultimate post-revascularization left ventricular recovery

Gilstrap et al . Dobutamine stress echocardiography: a review and update. Research Reports in Clinical Cardiology 2014:5 69–81

Diagnostic Accuracy comparison for Myocardial Viability AssessmentMetanalysisBax 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

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