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Getting the Most Out of Exercise Tests. Ernest V. Gervino, Sc.D., FACSM Assistant Professor of Medicine Harvard Medical School Chief, Clinical Physiology Laboratory Beth Israel Deaconess Medical Center. Utility of Stress Testing. Detection of Ischemia Sx; ST r ; BP response
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Getting the Most Out of Exercise Tests Ernest V. Gervino, Sc.D., FACSM Assistant Professor of Medicine Harvard Medical School Chief, Clinical Physiology Laboratory Beth Israel Deaconess Medical Center
Utility of Stress Testing • Detection of Ischemia • Sx; ST r; BP response • Prognosis of Coronary Disease • MET capacity; Magnitude of STr • Extent of myocardial involvement • Efficacy of Rx • Risk Stratification • Exercise Rx • Arrhythmia detection/assessment Gervino et al. Textbook of Cardiothoracic Anesthesiology ; pp 203-232; 2001
Stress Testing: Asymptomatic Pts • No definite indications • Possible indications • Special Occupations • Pilots • Police Officers • Bus Drivers • Patients > 40 years of age • 2 or more cardiac risk factors • Sedentary patients beginning exercise ICSI; 2007 Feb 20
Interpreting Stress ECG Darrow, MD. Am. Fam. Phy. 59(2), 1999
Interpreting Stress ECG Gervino et.al. Textbook of Cardiothoracic Anesthesiology p 212; 2001
Key Parameters of Test Results: ST Segments and Beyond • Exercise duration • Onset/Resolution of Sx • Onset/Resolution of ST r • Magnitude of ST r • Impaired HR response (“chronotropic incompetence”) • iSBP with h workloads • High-grade arrhythmias; e.g., prolonged VT; paroxysmal atrial fibrillation/flutter; high grade AV block ICSI, guidelines 2007
Findings Associated with Poor Prognosis • Low Workload • < 6.5 METS • < 6 minutes of Bruce protocol • Low Peak Heart Rate • HR < 120 bpm (not on Beta blocker) • Decrease or blunted systolic BP response • Remains under 130 mmHg • ST Segment Depression > 2 mm • Multiple Leads • Prolonged recovery > 6 minutes • ST Segment Elevation non-Q wave leads • Increase in complex ventricular ectopy • Exercise-induced angina ICSI 2007, Feb 20
Duke Prognostic Treadmill Score • Determining Score: Duke Score = Ex time (min) - (5 X ST dep in mm) – (4 X angina score on treadmill) • Angina Score: No angina = 0 Non-limiting angina = 1 Limiting angina = 2
Prognostic Value of Duke TM Score • Score > 5 • Low Risk: 4 yr survival 99% • Score of -10 to +4 • Intermediate Risk: 4 yr survival 95% • Score > -10 • High Risk: 4 yr survival 79% ICSI; 2007 Feb 20
Principles Regarding Stress Tests • Order only if results will likely alter your management, e.g., NOT • 25 y/o with vague sx most likely normal • 85 y/o typical angina while walking • Goal to identify patients at high risk of major cardiac morbidity or mortality • Esp. Left main, 3VD or SCD risk
Assessment of Myocardium at RiskAnatomy vs. Physiology • Presence of an anatomic lesion(s) at coronary angiography may not reflect the amount of myocardium at risk • Amount of myocardium at risk may be minimal and a physiologic study (with or without imaging) may be more useful
Independent Reasons for Terminating Exercise Stress Test • Patient’s request • ST segment depression > 3 mm • ST segment elevation > 2 mm in a non-Q wave lead • Progressive angina (or equivalent) of 8/10 • Drop in SBP with increasing workloads • VEA or AEA with hemodynamic compromise • Patient appears pale or clammy • SBP/DBP response to exercise > 230/110 mmHg • Development of 2nd or 3rd degree heart block • Fatigue/exhaustion (RPE > 17 Borg Scale) Gibbons et al., Circulation, 106: 1883-1889; 2002
Major Contraindications • Acute MI < 3 days • Unstable angina pectoris • Acute myocarditis or pericarditis • Uncontrolled ventricular or atrial arrhythmias • Symptomatic 2nd or 3rd degree AV heart block • Acute illness • Acute aortic dissection • Acute PE / pulmonary infarction • Inability to give informed consent Based on: Gibbons et al., J. Am. Coll. Cardiol. 40;1531, 2002
ACC/AHA Classifications • Class I: Evidence and/or general agreement that procedure is useful and effective • Class II: Conflicting evidence and/or divergence of opinion in usefulness/efficacy • Class IIa: Weight of evidence/opinion in favor of usefulness/efficacy • Class IIb: Usefulness/efficacy less well established by evidence/opinion • Class III: Evidence or general agreement that procedure/treatment is not useful or effective and in some cases may be harmful Based on: Gibbons et al., J. Am. Coll. Cardiol. 40;1532, 2002
ETT Recommendations • Class I: • Pts initial evaluation of suspected or known CAD • RBBB, < 1 mm ST depression at rest • Pts with suspected or known CAD with significant change in clinical status • Low risk crescendo angina • Free of active ischemic or CHF sx for 8-12 hours • Intermediate risk crescendo angina • Free of active ischemic or CHF sx for 48-72 hours Based on: Gibbons et al., J. Am. Coll. Cardiol. 40;1533, 2002
ETT Recommendations (Cont.) • Class IIa: Intermediate risk of crescendo angina • Negative initial cardiac markers • Serial EKG without significant change • Negative cardiac markers 6-12 hours from onset of sx • No other evidence of ischemia during observation • Class IIb: Following EKG abnormalities • WPW • V-paced rhythm • > 1 mm resting ST depression • LBBB or IVCD with QRS > 120 ms • Pt with stable course with periodic monitoring to guide treatment Based on: Gibbons et al., J. Am. Coll. Cardiol. 40;1533, 2002
ETT Recommendations (Cont.) • Class III: • Severe comorbidity likely to limit life expectancy or candidacy for revascularization • High risk for unstable angina Based on: Gibbons et al., J. Am. Coll. Cardiol. 40;1533, 2002
Terminating Stress Tests • Patient’s request • ST segment depression > 3 mm • ST segment elevation > 2 mm in a non-Q wave lead • Progressive angina (or equivalent) of > 8/10 • Drop in SBP with increasing workloads • Arrhythmia with hemodynamic compromise • Palor or clamminess • SBP/DBP response to exercise > 230/110 mmHg • Development of 2nd or 3rd degree AV heart block • Fatigue/exhaustion (RPE* > 17 Borg Scale) *Rating of Perceived Exhaustion where 20 is tops Gibbons et al.,J. Am. Coll. Cardiol. 40;1531, 2002
Reported Average Sensitivity & Specificity of Stress Tests Test modalitySensitivitySpecificity • Non-Imaging ETT 65% 85% • Nuclear ETT • Quantitative 87% 87% • Qualitative 87% 77% • Dipyridamole 90% 90% • RVG 87% 75% • Echo ETT 80% 87%
Determining Pre-Test Probability for “Myocardial Ischemic Syndrome” vs. Obstructive CAD • Symptoms: • Angina, Atypical Angina, Non-Angina, None • Risk factors: • # HTN, # Lipids, Smoking, $ Activity, • + Fam. Hx, DM, Obesity, # Age, PVD • Activity pattern: • Bed rest, Inactive, Active, Exercise • Reason for test: • CP, known CAD, MI, Arrhythmia, Pre-Op testing Adapted from Han et al., Ann Emerg. Med . 2007
Symptoms of Non-Obstructive “Myocardial Ischemic Syndrome” • Occurs with exertion • Usually located in the anterior chest wall (but not always) • Increases in intensity with increased myocardial demand • Relieved with rest within 5 minutes • Symptom is similar on repeated bouts of exertion Gervino et.al. Textbook of Cardiothoracic Anesthesiology 203-232; 2001
Post-Test Probability of CAD Based on Pre-Test Symptoms - Women Diamond and Forrester. N. Engl. J. Med. 1350-7, 1979
Post-Test Probability of CAD Based on Pre-Test Symptoms - Men Diamond and Forrester. N. Engl. J. Med. 1350-7, 1979
Major Indications for Imaging ETT • LVH by ECG • LBBB (consider vasodilator) • Digoxin Rx • Abnormal ST-T on resting ECG • Localization of region(s) of ischemia • Increased sensitivity in selected populations Hendel et.al. J Nucl Card, 13 (6); E152-E156;2006
ECG Requiring Imaging ETT • LVH with ST-T changes and LAA
Stress Echo: hspecificity Versatility Eval cardiac anatomy & function Convenience itest duration icost Nuclear Perfusion: htechnical success rate hsensitivity for 1VD haccuracy for multiple wall motion abnormalities hpublished data Advantages of Imaging Studies
Limitations of Imaging Studies • Obesity • Breast Attenuation • Excess infra-diaphragmatic uptake • Cost (may require prior 3rd party approval!) Gibbons et al.,J. Am. Coll. Cardiol. 40;1531, 2002
Indications for Pharmacologic Stress Testing • Advanced peripheral vascular disease • Inability to ambulate • Evaluation of “stunned” or “hibernating” myocardium with dobutamine Gervino et.al. Textbook of Cardiothoracic Anesthesiology pp 203-232; 2001
Contraindications to Dipyridamole/Adenosine Stress Testing • Unprotected 2nd or 3rd degree heart block • Unstable angina • Asthma with active wheezing • Use of theophylline (last 24 hours), caffeine, xanthines, colas, chocolate (last 6-12 hours) • LVEF < 15% • Severe/critical outflow obstruction • Resting hypotension (SBP < 100 mmHg) Hendel et.al. J Nucl Cardiol 2006: 13; E152.
Contraindications to Dobutamine Stress Testing • High grade tachyarrhythmia • Resting hypertension (BP > 190/110 mmHg) • Critical valvular heart disease • Unstable angina • History of severe anxiety/panic attacks Cheitlin et al., Circulation, 3-88; 2003
Conclusion: • Study should add incremental information • Functional test preferred • Pre-test probability conditions post-test likelihood of ischemic syndrome (Bayesian analysis) • Magnitude, onset/resolution of changes (sx and/or ST segments) help determine severity of ischemia
Selected References • Gibbons RJ, Antman EM, Albert JS, et al. ACC/AHA 2002 guideline update for exercise testing. J. Am. Coll. Cardiol. 2002;40;1531-1540. • Eagle KA, Gibbons RJ, Antman EM, Gregoratos G, et al. ACC/AHA 2002 guideline update on perioperative cardiovascular evaluation for noncardiac surgery. J. Am. Coll. Cardiol. 2002; www.acc.org, 1-38. • Maslow A, Gervino EV, Lowenstein E. Textbook of Cardiothoracic Anesthesiology. Ed: DM Thys. Ch. 9: Stress testing. pp 203-232. McGraw Hill , NY, 2001. • Rodgers GP, Ayanian JZ, Balady G, Beasley JW, Brown KA, Gervino EV, et al. ACC/AHA Clinical Competence Statement on Stress Testing. Circulation 2000;102:1726-1738. • Miller T, McBride J, Basset J, Haranath S, Evenson AM. Cardiac stress test supplement. Institute for Clinical System Improvement; 2007, Feb 20. www.icsi.org