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Stresstesting housestaffdidactic_10092014[1]
- 1. Stress Testing UTSWHouse Staff Didactic Series Anand Rohatgi, MD, MSCS, FACC, FAHA Assistant Professor Division of Cardiology
- 2. Stress Tests Stressmodality “Detection” modality Treadmill exercise* Vasodilator Adenosine Regadenson Dobutamine EKG (ETT) Myocardial perfusion Echo (stress echo)
- 3. Probability Gibons atal, Progr Cardiol 1983;12:67 Positive Predictive Value Probability of a subject with a positive test, actually having disease Depends upon Sensitivity Specificity Population prevalence or pretest likelihood
- 4. Pretest Probability AgeGender Typical Angina Atypical Angina Nonanginal CP Asymptoma tic 30-39 Men Intermediate Intermediate Low Very Low 40-49 High Intermediate Intermediate Low 50-59 High Intermediate Intermediate Low 60-69 High Intermediate Intermediate Low 30-39 Women Intermediate Very Low Very Low Very Low 40-49 Intermediate Low Very Low Very Low 50-59 Intermediate Intermediate Low Very Low 60-69 High Intermediate Intermediate Low Diamond et al, NEJM 1979;300:1350
- 5. ACC/AHA 2002 ETTIndication Class I (Indicated) • Intermediate prob CAD • including RBBB, <1mm resting ST depression Class III (Not indicated) • Pre-excitation • V-paced • >1mm resting ST dep • LBBB • Diagnosis for pt w/ established CAD MI or death 1 per 2500
- 6. Contraindications to ETT • Acute myocardial infarction (<2 days) • Unstable angina with recent rest pain • Untreated life-threatening cardiac arrhythmias • Advanced atrioventricular block • Acute myocarditis or pericarditis • Critical aortic stenosis or severe IHSS • Uncontrolled hypertension • Acute systemic illness (PE, dissection, anemia, thyroid, fever, etc.)
- 7. Exercise Treadmill Testing-Protocols Standard Bruce Protocol Stage Min MPH Grade METS I 03:00 1.7 10% 5 II 03:00 2.5 12% 7 III 03:00 3.4 14% 10 IV 03:00 4.2 16% 13.5 V 03:00 5.0 18% 16+ *3 minute stages Variations Modified Bruce Protocol 2 warm-up stages Naughton Protocol fixed speed Submaximal ETT Not to exceed 5 METS Not to exceed 70% MPHR
- 8. Diagnosis of Ischemia Positive test – 1mm horizontal or down sloping ST segment depression 0.06-0.08msec after the j-point (5% w/ CAD meet criteria in recovery alone) – Lateral leads (V4-V6) Up sloping Horizontal Down sloping Adequate stress: 85% max predicted HR (220-age)
- 9. Decreased Specificity •LVH with repolarization abnormalities – Decreased specificity with no change in sensitivity • Resting ST depression > 1mm • LBBB • RBBB (diagnostic accuracy preserved in V5, V6, II, AVF • Digoxin – ST depression in 25-40% of healthy subjects – 2 weeks required washout
- 10. Non-coronary Causes ofST segment depression • Severe aortic stenosis • Severe hypertension • Cardiomyopathy • Anemia • Hypokalemia • Severe hypoxia • Digitalis use • Sudden excessive exercise • Glucose load • Left ventricular hypertrophy • Hyperventilation • Mitral valve prolapse • Intraventricular conduction defect • Preexcitation syndrome • Severe volume overload • Supraventricular tachyarrhythmias
- 12. Thompson CA, etal. JACC 2000; 36:2140-5. Lauer MS, et al. Circulation 1996;93:1520-6
- 13. Prognostic Markers •Maximal exercise capacity • Chronotropic incompetence • HR recovery • Risk scores
- 14. Exercise Capacity MET=02 uptake of 70kg man at rest for 1 min =3.5ml O2/kg/min Exercise capacity is one of the strongest prognostic markers Encompasses many different factors Each 1 MET increase = 12% increased survival Stanford database of 6000 men >13 >11 Ref <10 <8 Myers et al, NEJM 2002;346:793
- 15. ETT in asymptomaticpts Class I • None. Class IIa • Evaluation of asymptomatic persons with diabetes mellitus who plan to start vigorous exercise (see page 39). (Level of Evidence: C) Class IIb • Evaluation of persons with multiple risk factors as a guide to risk-reduction therapy.* • Evaluation of asymptomatic men older than 45 years and women older than 55 years: – Who plan to start vigorous exercise (especially if sedentary) or – Who are involved in occupations in which impairment might impact public safety or – Who are at high risk for CAD due to other diseases (e.g., peripheral vascular disease and chronic renal failure) Class III • Routine screening of asymptomatic men or women.
- 16. Myocardial Perfusion Imaging Stress modality “Detection” modality Treadmill exercise* Vasodilator Adenosine Regadenson Dobutamine Myocardial perfusion (Nuclear)
- 17. Myocardial Perfusion Imaging Schinkel AF, Bax JJ, Geleijnse ML, et al. Eur Heart J 2003;24:789-800.
- 18. Myocardial Perfusion Testing Maximal coronary vasodilitation Rest No coronary flow reserve Stress Heterogeneous Perfusion
- 19. Vasodilators • Dipyridamole – Increases adenosine levels – 50% with side effects, last 15-25 minutes • Adenosine – Coronary vasodilation via A2A receptor – 140mcg/kg/min x 6min – 80% with side effects: flushing 40%, AV block (7.6%), hypotension (5%), <10sec ½ life – CP non-specific – 1mmST depression 5-7%>CAD • Regadenoson – A2A agonist with lower affinity for receptors > side effects – Side effets of SOB, headache, flushing, last 15- 30 min – Single 5ml injection Contra-indications • AV block (2nd or 3rd) •Bronchospasm •Methyl xanthines •ACS
- 20. Myocardial Perfusion Testing (Nuclear: SPECT) Protocol (Dual Isotope) • Resting images after Thallium-201 injection • Stress, with Technetium-99 injected at peak exercise (Cardiolite/Myoview) • Post-stress images (with gated SPECT)
- 21. → Revasc better Hachamovitch R, Hayes SW, Friedman JD, Cohen I, Berman DS. Circulation 2003;107:2900-6
- 22. Stress Tests Stressmodality “Imaging” modality Treadmill exercise* Vasodilator Adenosine Regadenson Dobutamine Echo (stress echo)
- 23. Stress Echo SchinkelAF, Bax JJ, Geleijnse ML, et al. Eur Heart J 2003;24:789-800. Abnormal flow reserve Ischemia
- 24. Stress Echocardiography •Stress echo is used to assess ischemia • Wall motion abnormalities are the earliest response to ischemia Post-balloon inflation 19 30 39 0 50 Chest Pain EKG change Wall Motion Seconds Hauser et al. JACC 1985;5:193
- 25. Dobutamine Echo Mechanismsof Action – β1 agonist– inotropy and chronotropy (some vasodilatation) – induces ischemia at lower RPP than ETT, (RPP approximately 16-20K) – Begin at 10mcg/kg/min, increasing to 40 mcg/kgmin Side Effects – 3:1000 serious side effects • MI • Ventricular fibrillation – Atrial / Ventricular arrhythmia – Hypertension – Hypotension (cavity obliteration) – Headache / Tremor
- 26. Comparing SECHO andMPI Advantages Disadvantages MPI (Nuclear) Detects abnl flow reserve Peak-exercise images acquired Most studies complete Quantified LVEF and volumes Longer time than secho Radiation Lower spatial resolution Inferior wall diff to eval Balanced ischemia missed SECHO Safe No radiation Portable, faster Structural information Peak-exercise images difficult to acquire False-neg w/ rapid recovery Ischemic response needed 15% cannot assess entire myocardium Afib, LBBB
- 27. ETT EKG not interpretable Stress Echo Poor echo arrhythmia Stress MPI Asthma COPD AV Block Dobutamine Echo LBBB V-paced arrhythmia Poor echo Adenosine MPI Unable to walk Poor echo Dobutamine MPI