Getting the Most Out of Exercise Tests

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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

2
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
3
Stress Testing Asymptomatic Pts

• No definite indications
• Possible indications
• Special Occupations
• Pilots
• Police Officers
• Bus Drivers
• Patients gt 40 years of age
• 2 or more cardiac risk factors
• Sedentary patients beginning exercise

ICSI 2007 Feb 20
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Interpreting Stress ECG
Darrow, MD. Am. Fam. Phy. 59(2), 1999
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Interpreting Stress ECG
Gervino et.al. Textbook of Cardiothoracic
Anesthesiology p 212 2001
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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
7
Findings Associated with Poor Prognosis

• Low Workload
• lt 6.5 METS
• lt 6 minutes of Bruce protocol
• Low Peak Heart Rate
• HR lt 120 bpm (not on Beta blocker)
• Decrease or blunted systolic BP response
• Remains under 130 mmHg
• ST Segment Depression gt 2 mm
• Multiple Leads
• Prolonged recovery gt 6 minutes
• ST Segment Elevation non-Q wave leads
• Increase in complex ventricular ectopy
• Exercise-induced angina

ICSI 2007, Feb 20
8
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

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Prognostic Value of Duke TM Score

• Score gt 5
• Low Risk 4 yr survival 99
• Score of -10 to 4
• Intermediate Risk 4 yr survival 95
• Score gt -10
• High Risk 4 yr survival 79

ICSI 2007 Feb 20
10
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

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Assessment of Myocardium at Risk Anatomy 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

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Treadmill
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Cycle Ergometer
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Pharmacologic Stress Test
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Pacing Stress Test
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Independent Reasons for Terminating Exercise
Stress Test

• Patients request
• ST segment depression gt 3 mm
• ST segment elevation gt 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 gt 230/110 mmHg
• Development of 2nd or 3rd degree heart block
• Fatigue/exhaustion (RPE gt 17 Borg Scale)

Gibbons et al., Circulation, 106 1883-1889 2002
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Major Contraindications

• Acute MI lt 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.
401531, 2002
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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.
401532, 2002
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ETT Recommendations

• Class I
• Pts initial evaluation of suspected or known CAD
• RBBB, lt 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.
401533, 2002
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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
• gt 1 mm resting ST depression
• LBBB or IVCD with QRS gt 120 ms
• Pt with stable course with periodic monitoring to
  guide treatment

Based on Gibbons et al., J. Am. Coll. Cardiol.
401533, 2002
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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.
401533, 2002
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Terminating Stress Tests

• Patients request
• ST segment depression gt 3 mm
• ST segment elevation gt 2 mm in a non-Q wave lead
• Progressive angina (or equivalent) of gt 8/10
• Drop in SBP with increasing workloads
• Arrhythmia with hemodynamic compromise
• Palor or clamminess
• SBP/DBP response to exercise gt 230/110 mmHg
• Development of 2nd or 3rd degree AV heart block
• Fatigue/exhaustion (RPE gt 17 Borg Scale)

Rating of Perceived Exhaustion where 20 is
tops
Gibbons et al., J. Am. Coll.
Cardiol. 401531, 2002
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Reported Average Sensitivity Specificity of
Stress Tests

• Test modality Sensitivity Specificity
• Non-Imaging ETT 65 85
• Nuclear ETT
• Quantitative 87 87
• Qualitative 87 77
• Dipyridamole 90 90
• RVG 87 75
• Echo ETT 80 87

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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
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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
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Post-Test Probability of CAD Based on Pre-Test
Symptoms - Women
Diamond and Forrester. N. Engl. J. Med. 1350-7,
1979
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Post-Test Probability of CAD Based on Pre-Test
Symptoms - Men
Diamond and Forrester. N. Engl. J. Med. 1350-7,
1979
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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-E1562006
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ECG Requiring Imaging ETT

• LVH with ST-T changes and LAA

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Advantages of Imaging Studies

• 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

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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. 401531,
2002
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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
33
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 lt 15
• Severe/critical outflow obstruction
• Resting hypotension (SBP lt 100 mmHg)

Hendel et.al. J Nucl Cardiol 2006 13 E152.
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Contraindications to Dobutamine Stress Testing

• High grade tachyarrhythmia
• Resting hypertension (BP gt 190/110 mmHg)
• Critical valvular heart disease
• Unstable angina
• History of severe anxiety/panic attacks

Cheitlin et al., Circulation, 3-88 2003
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Summary for Evaluation of Myocardial Ischemic
Syndrome
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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

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Selected References

• Gibbons RJ, Antman EM, Albert JS, et al. ACC/AHA
  2002 guideline update for exercise testing. J.
  Am. Coll. Cardiol. 2002401531-1540.
• 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 20001021726-1738.
• 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