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Stress echo.pptx
- 1. Stress Echocardiography By Dr. Gunjan Shah DMResident, UNMICRC
- 2. Definition To detectthe presence and extent of coronary artery disease by provoking regional ischemia with resulting wall motion abnormalities. “stress induced regional wall motion abnormalities” addition of exercise doppler permits evaluation of exercise- induced changes in valvular function eg, severity of mitral regurgitation/mitral stenosis gradient, pulmonary artery systolic pressure, left ventricular outflow tract gradient, and global left ventricular systolic and diastolic function.
- 3. Pathophysiol ogy Stress induceddemand-supply mismatch causing perfusion defects wall motion abnormality on echo ECG changes Angina
- 4. Indications Evaluation ofpatients with known or suspected coronary artery disease (particularly in patient with preexiting ST-T changes that precludes interpretations of electrocardiogram TMT) Assessment of myocardial viability. Evaluation of dyspnea of possible cardiac origin. Evaluation for pulmonary artery hypertension (pulmonary artery systolic pressure can be estimated at rest and post- exercise)
- 5. Indications Evaluation ofmitral valve disease, including MS gradient and MR. Evaluation of aortic stenosis (assess severity of low gradientAS) Evaluation of LVOT gradients, MR, and pulmonary hypertension in patients with HCM.
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- 7. Stress techniques Exercise stress Pharmacological stress Pacing Handgrip exercise
- 8. Pharmacologic al Stress Echo patients who are unable to perform exercise testing may be preferable to exercise testing for preoperative risk and myocardial viability assessment
- 9. Agents for pharmacologic al stress Dobutamine (with atropine as needed to achieve HR) Adenosine Dipyridamole Regadenoson ASE recommend dobutamine as preferable to vasodilators. (there is greater experience using dobutamine for SE in ) dobutamine and vasodilators are equally potent ischemic stressors for inducing wall abnormalities in the presence of a critical CAD. dipyridamole is a popular pharmacologic regimen for SE in Europe.
- 10. DSE (Assessment of obstructive CAD) Gradeddobutamine infusion in five three-minute stages starting at 5 mcg/kg/minute, followed by 10, 20, 30, and 40 mcg/kg/minute Atropine in divided doses of 0.5 mg each to a total of 2 mg, as needed. Atropine increases the Sn of SE in patients receiving beta- blockers and in single-vessel disease. Use of a sustained isometric hand grip or a low-level dynamic foot exercise (with or without atropine) in the late stages of the dobutamine protocol as a supplemental maneuver to achieve peak heart rate also described.
- 12. DSE (Viability assessment) Dobutaminedosing for viability assessment starts at a lower initial dose than for assessment of cad. Continuous dobutamine infusion initiated at 2.5 mcg/kg/minute, and increasing at five-minute intervals in 2.5 mcg/kg/minute increments until a contractile response is noted, up to a maximum dose of 10 mcg/kg/minute.
- 13. End points for DSE Exceeding target heart rate of 85% age-predicted maximum Development of significant angina Recognition of a new wall motion abnormality A decrease in systolic blood pressure >20 mm Hg from baseline Arrhythmias such as atrial fibrillation or nonsustained ventricular tachycardia Limiting side effects or symptoms
- 14. Effects of Beta blockers Use of beta-blockers may attenuate HR response and evidence of myocardial ischemia during DSE. The effect of beta-blockers on HR response to dobutamine can be overcome by the administration of atropine. Moreover, performing the SE while the patient stays on all medications, including beta-blockers, may be useful for assessment of treatment efficacy.
- 15. Vasodilator stress echocardiography Dipyridamole(dose): up to 0.84 mg/kg in two separate infusions: 0.56 mg/kg over 4 minutes ("standard dose"), followed by four minutes of no dose, then an additional 0.28 mg/kg is given over two minutes if no HR achieved. If no endpoint is reached following total of 0.84 mg/kg, then atropine (doses of 0.25 mg, up to a maximum of 1 mg). Adenosine (dose): max dose of 140 mcg/kg/minute over six minutes Imaging is performed prior to and after starting adenosine infusion.
- 16. Adenosine isa shorter-acting agent employed for MPI and, to a lesser extent, to detect stress-induced changes in wall motion, but this method has not been in wide clinical use. Vasodilator stress is better suited for perfusion than wall motion analysis. (as they redistribute coronary blood flow– steal phenomena) Both these C/I in reactive airway obstruction and significant conduction defects Dobutamine Inducible ischemia &myocardial viability Adenosine, dipyridamole myocardial perfusion imaging
- 17. Pacing In selectedpatients with a PPM, increasing the pacing rate to facilitate achievement of target heart rate may be used Can also be done via trans esophageal pacing wire combined with dobutamine infusion, starting with dobu infusion following the usual protocol and then holding the infusion at 20 mcg. At this dose of dobutamine, we start a stepwise increase of the HR by increase pacing rate until achievement of the THR. During recovery the pacing rate is progressively reduced at one-minute intervals.
- 18. Handgrip exercise Handgrip maybe used as an adjunct to exercise or DSE. During the last stage of exercise or dobutamine infusion and 30 seconds before acquiring the peak exercise images, patients are asked to exert a sustained grip on a tennis ball. The hand grip response reliably raises BP at least 10 mmHg and usually also increases HR; superimposed on the maximum achieved levels, this augmentation results in a "bonus" increment in rate pressure product. increasing sensitivity of method
- 19. Complications and risks ofSE Risk of complications is very low In the largest survey to date, the overall rate of life- threatening events was 1 per 1000 examinations (0.015% for exercise and 0.18% for dobutamine) MC minor complications include PVCs and atrial arrhythmias Most frequent major complications were acute MI or ventricular tachycardia or fibrillation.
- 20. Safety of DSE No absolute contraindications to DSE. Unstable patients as in with ADHF or unstable angina, should rarely be subjected to stress testing of any kind. Can be been safely performed in patients with recent MI, extensive left ventricular dysfunction, abdominal aortic aneurysm, syncope, aortic stenosis, hypertrophic cardiomyopathy, history of ventricular tachycardia, and aborted sudden death. But to be performed according to risk benefit ratio. Unlike dipyridamole/adenosine, dobutamine is safer in bronchospastic lung disease.
- 21. Echo assessment for CAD WhenSE is performed to evaluate CAD, the main goal is to side-by-side comparison of images for assessment of global and regional LV systolic function at rest and immediately after stress. Images are also compared with pre-peak and peak stress, during pharmacologic stress. With stress, the normal LV becomes hypercontractile, cavity size is reduced, and EF increases. Function in each segment is graded (normal, hyperdynamic, hypokinetic, akinetic, dyskinetic, or aneurysmal) at rest and with stress. Imp to detect RWMA wall thickening and endocardial excursion
- 22. Interpretation The presenceof baseline RWMA that remain “fixed” (unchanged) with stress a previous infarct. The development of a new or worsening RWMA a flow- limiting stenosis in the coronary artery supplying the abnormal segment or segments. A large ischemic territory—such as left main or multivessel CAD diminished global LVEF and chamber dilation with stress (i.e., transient ischemic LV dilatation).
- 23. Rest Stress Interpretation NormalHyperkinetic Normal Normal Hypokinetic / akinetic Ischemia Akinetic Akinetic Infarction (previous) Hypokinetic Akinetic / dyskinetic Infarction and/or ischemia Hypokinetic / akinetic Normal Viable Response to stress and interpretation
- 25. Echo Assessment for Viability Low-dosedobutamine stress echocardiography enables identification of dysfunctional but viable myocardial segments. In segments that have resting dysfunction but are viable (hibernating or stunned), low-dose dobutamine infusion leads to improved contractility. As the dobutamine dose is increased, a biphasic response is detected with the segmental motion improving at low-dose and then deteriorating at a higher dose to a level of dysfunction that is worse than it was at rest. • This biphasic response is highly Sp for identifying a dysfunctional hibernating myocardium that is served by a stenotic coronary artery. • The highest Sn for viability detection is obtained by identification of improvement with low-dose dobutamine; highest Sp is achieved when a biphasic response occurs.
- 26. Interpretation of response (viability) Monophasic contractility increase at low dose and also increase at high dose viable (most sensitive) Biphasic increase at low dose and worsens at high dose viable (most specific) Non phasic no improvement at any dose non viable scarred (thinned out <5mm)
- 28. Doppler assessment Mitral valve– Changes in mitral stenosis gradient or mitral regurgitation following stress Aortic valve – Evaluation of aortic valvular gradients in suspected low-flow, low-gradient aortic stenosis Tricuspid valve – Assessment of tricuspid regurgitation velocity for estimation of pulmonary artery systolic pressure in patients with suspected pulmonary hypertension Left ventricular outflow tract (LVOT) – Evaluation for inducible or worsening LVOT gradient in suspected or known HCM
- 29. SE after MI Particularly helpful in case of multivessel disease (post revascularization of IRA) if stenosis in other vessels is significant or not (to identify need of revasc) identify ischemia at distance new onset RWMA compare to previous one.
- 30. Choosing b/w stress modalities Clinical situationtreadmill bicycle dobutamine Chest pain evaluation ++ ++ + Postmyocardial infarction risk ++ ++ ++ Viability -- -- ++ Evaluation of dyspnea/fatigue* + ++ + Preoperative risk assessment + + ++ Severity of valve disease* -- ++ -- Pulmonary hypertension* -- ++ -- *Inclusion of Doppler parameters is recommended
- 31. Prognostic value of SE Higher WMSI = worse prognosis Extent of ischemia more segments involved = worse prognosis Magnitude of hypokinesia in involved segments more severe = bad Low stress EF = bad Ischemic dilatation of LV
- 32. Comparison with stress nuclear imaging Theaccuracy of SE (stress echocardiography) is similar to that of stress radionuclide perfusion imaging. From meta-analyses, as well as from comparisons of the accuracy of SE and nuclear imaging in the same patient population, Sn 88% and Sp 83% for significant CAD (generally defined as >50% coronary artery stenosis by angiography). The specificity of SE appears to be higher than that of nuclear imaging for left main and triple-vessel CAD. Time and cost efficient compare to nuclear.
- 34. Limitations of SE Potentialfor rapid resolution of ischemia prior to image acquisition post exercise Hypertensive response to stress greater likelihood for false +ve test Suboptimal image quality (can be tackled by contrast) May be exacerbated by respiratory motion d/t heavy breathing post exercise
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