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Exercise Treadmill Testing

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Title: Exercise Treadmill Testing


1
Exercise Treadmill Testing
  • Prognostication in Coronary Artery Disease
  • Dr. Peter Krampl
  • 11 October 2001

2
Introduction
  • 300,000 ER visits per year acute non traumatic
    chest pain
  • Only apx. 25 have clear positive,
  • Unstable coronary disease
  • Angiography
  • Image studies
  • Acute myocardial infarction
  • or negative diagnosis of coronary syndromes

3
Introduction
  • Current ED Modalities
  • Reviewed in EM Clinics February 2001
  • History / Physical
  • Mair. Chest. 1995.
  • 110 patients non traumatic chest pain
  • Using NPV as most used indicator for admission
  • PPV 53 NPV 75 for acute cardiac ischemia

4
Introduction
  • Current ED Modalities
  • ECG
  • Rovan, American Journal Cardiology. 1989.
  • Multicentre Chest Pain Trial
  • Sensitivity 61 Specificity 90 for ischemia
  • Current ST, Q, LBBB criteria
  • Variable Specific
  • Addition of T wave abnormality
  • Sensitivity increases to 95
  • Specificity may decreases to 23
  • Current computer algorithms tend to higher
    sensitivity

5
Introduction
  • Current ED Modalities
  • Cardiac Markers
  • Hedges et al. Acad EM. (CK-MB)
  • 1042 patients CK-MB at presentation and serial
    investigated
  • Sensitivity 19-31 Specificity 95-96
  • Hamm et al. NEJM. 1997 (TnT)
  • 776 patients
  • Prospective study looking at prognosis of TnT and
    TnI and 30 day cardiac event rate
  • Negative values of T and I gave annual event
    rates of 1.1 and 0.3 respectively
  • Sensitivity 31 Specificity 98

6
Introduction
  • Are We Satisfied With Those Numbers?
  • How Do We Further Risk Stratify Coronary
    Patients?
  • Treadmill Testing
  • Observation Units / Time
  • Radionuclear Imaging /- Exercise
  • Echocardiography /- Exercise
  • Angiography

7
Introduction
  • In ED, old chart or patient notes
  • I was on treadmill for 8 minutes.
  • A negative treadmill.
  • I did not have pain on the treadmill.
  • What do those mean?
  • Can we use those simple guides to further
    stratify these patients?

8
  • What Use Has The Exercise Stress Test?

9
Outline
  • Introduction
  • Treadmill Testing
  • Review of Current Literature
  • Introduction
  • Indications
  • Procedures
  • Results
  • Notable Studies
  • Exercise Modalities
  • Conclusions
  • Questions

10
Treadmill Testing Introduction
  • Froelicher. Hdbk of Exercise Testing. 1996
  • Goals
  • Diagnosis CAD
  • Prognosis CAD
  • Evaluation of Medical Therapy
  • Evaluation of Exercise Capacity

11
Treadmill Testing Indications
  • When to use.
  • AHA / CPSA guidelines advise to use only up to
    intermediate pre test probability cases
  • Kuntz et al. Ann Int Med. 1999.
  • Exercise stress test or rest echo most cost
    effective (mild-mod)
  • Life expectancy
  • Cost
  • Incremental Cost Effectiveness over other
    modalities
  • For high risk, immediate coronary angio most cost
    beneficial.
  • Other stress modalities supplement to Exercise
    Treadmill

12
Treadmill Testing Indications
  • Braunwald et al. High / Intermediate / Low Risk /
    Pretest Probability Guidelines published by AHA
    1995. Reviewed by Primary Care Clinics. 2001
  • Example Low Risk
  • Chest pain by history classified as probable not
    or definitely not angina
  • normal ECG
  • New onset angina 2 months
  • No change in previous 2 months
  • T wave flattening or inversion lt1 mm in leads
    with dominant R waves
  • One risk factor other than diabetes

13
Treadmill Testing Indications
  • Majority of tests done on referral basis
  • Advent of chest pain units in United States
  • Studies by
  • Zalenski. Ann EM. 1997. Low and Intermediate
    Risk.
  • Safety at 4-12 hours
  • Mikhail. Ann EM. 1997. Intermediate risk.
  • Safety at 12 to 24 hours
  • Lewis. Am J Card. 1994. Low risk.
  • Safety at 1-2 hours
  • Kirk. Ann EM. 1998. Low risk.
  • Safety at 1-2 hours
  • CP Observation Units have adopted 6 hours as
    Industry standard for exercise port work up and
    stabilization

14
Treadmill Testing Indications
  • Indications
  • Froelicher / Annals of EM
  • Clear (Class 1)
  • Evaluation of male patients with atypical
    symptoms
  • Functional capacity testing
  • Evaluation of exercise related dizziness,
    syncope, palpitations
  • Evaluation of Recurrent exercise induced
    Arrhythmias

15
Treadmill Testing Indications
  • Indications
  • Probable Benefit (Class 2)
  • Evaluation of Women with atypical symptoms
  • Evaluation of Variant Angina
  • All those in Class one with baseline ECG changes
    other than LBBB
  • Evaluation of patients on digitalis or RBBB

16
Treadmill Testing Indications
  • Indications
  • Not Indicated (Class 3)
  • Assymptomatic young men / women with no risk
    factors and high suspicion non cardiac chest
    discomfort
  • Evaluation of patients with LBBB
  • Evaluation of Patients with Pre-excitation
    Syndromes

17
Treadmill Testing Indications
  • Contraindications
  • AHA Guidelines
  • Absolute
  • AMI within 3-5 days
  • Unstable angina not stabilized by medical therapy
  • Aortic dissection
  • Endo, Myo, or pericarditis
  • PE
  • Lower Extremity Thrombosis
  • Uncontrolled symptomatic cardiac arrhythmias
  • Severe aortic stenosis
  • Symptomatic severe and terminal heart failure

18
Treadmill Testing Indications
  • Contraindications
  • Relative
  • High degree AV block
  • Moderate stenotic valvular disease
  • DBP gt200 or DBP gt 110
  • Bradyarrythmias
  • Known left main coronary stenosis
  • Mental / physical incapacity

19
Treadmill Testing Indications
  • Complications
  • Brady / Tachyarrythmias
  • AMI / Sudden Death
  • CHF / Shock
  • MSK Trauma / Fatigue / Malaise

20
Treadmill Testing Procedures
  • Important Concepts
  • VO2 max maximum oxygen uptake
  • Amt of O2 transported for cellular metabolism
  • Useful to express in multiples of METS
  • CO X (arteriovenous oxygen difference)
  • METS used to standardize protocols
  • MO2 myocardial O2 uptake
  • wall tension, thickness, contractility and HR
  • Estimated by double product (HR X BP)
  • Angina usually occurs at the same double product

21
Treadmill Testing Procedures
  • Physiology
  • Exercise creates increase CO
  • Four to six fold increase from rest at peak
  • CO increase by increase HR and PB and decreased
    vagal tone
  • HR affected by
  • Age, sex, motivation, habitus, blood volume,
    health
  • SBP increases with exercise
  • DBP stays same or slightly decreases
  • Hypotension ominous sign
  • Outflow obstruction, ventricular dysfunction or
    ischemia

22
Treadmill Testing Procedures
  • Equipment
  • Treadmill or cycle ergometer
  • Cycle has major pitfall of rapid fatigue of
    quadriceps in older patients
  • Most studies use treadmill
  • Handrails, Rest Area
  • Assistant, Supervisor
  • Resuscitation Equipment

23
Treadmill Testing Procedures
  • Preparation
  • Fast 3 hours prior / dress appropriately
    footwear
  • Medications reviewed by physician prior
  • History and physical prior regarding change in
    disease
  • CHF valvular disease onset of unstable angina
    bronchospasm
  • Consent
  • Baseline supine and upright ECG

24
Treadmill Testing Procedures
  • Protocols
  • Most diagnostic and prognostic studies based on
    Bruce protocol
  • Seven phases
  • Change in grade and speed every 3 minutes
  • Correlation with METS
  • Large incremental stages
  • Not correlated for height / weight / stride
  • Ideal protocol lasts 6-12 minutes and adjusts for
    patients ability
  • Others include Naughton, McHenry, USAF, Blake

25
Treadmill TestingProcedures
  • Borg Scale
  • Borg. Sports and Exercise. 1982.
  • Correlation of scale to actual fatigue
  • 6-20 grade scale for exertion
  • 10 grade scale for exertion now adopted
  • 0 nothing
  • 9 very strong
  • 10 very, very strong
  • Continues to be a clinical assessment of fatigue
    by technician (skilled) and supervisor
  • Mainly used as repetitive assessment tool in rehab

26
Treadmill Testing Procedures
  • Measurements
  • ST depression / elevation (60-80 ms J point
    changes)
  • ST slope (downsloping worse than horizontal)
  • Duration of changes into recovery
  • Exercise induced arrhythmias
  • Peak HR / BP
  • Total Duration
  • Exertional hypotension
  • Angina
  • Other exercise induced symptoms

27
Treadmill Testing Procedures
  • Termination
  • Absolute
  • Drop of SPB gt 10
  • Anginal Pain (other than non-limiting / known
    pain)
  • CNS symptoms
  • Signs of poor perfusion
  • Serious Arrhythmias (runs of VT gt 3 multiform)
  • Technical Difficulties in monitoring
  • Subject Request

28
Treadmill Testing Procedures
  • Termination
  • Relative
  • Maintenance of SBP well into protocol
  • Excessive ST / QRS changes
  • Fatigue, SOB, Wheeze, Cramps, Claudication
  • SVT
  • Development of BBB
  • Observation Important !!
  • Case 77 y.o. male level one indications no
    contraindications stable angina
  • Maintenance of SBP into Phase 2

29
Treadmill Testing Results
  • Diagnostic
  • Exercise Treadmill (ST response only)
  • Sens 66 Spec 84
  • Froelicher et al. Exercise. 1993.
  • Sens 70 Spec 75
  • Gianrossi. Meta-analysis. Circulation. 1989.
  • Using Bayes rules of pretest probability, these
    numbers may only be applied to intermediate cases
    at best.
  • Original Duke University Investigators showed
    repeated studies of poor specificity and positive
    predictive value

30
Treadmill Testing Results
  • Diagnostic
  • Lehmann and Froelicher. Veterans Study Group.
    QUEXTA. Ann Int Med. 1998.
  • 814 patients
  • 400 selected for decreased work-up bias
  • Only 40 Stress test positive ST changes
    correlated to gt minimal luminal CAD
  • Overall sensitivity 45 specificity 85

31
Treadmill Testing Results
  • Prognostic
  • Giagnoni. NEJM. 1983
  • Prospective following of 135 men with ST changes
    vs. 379 controls
  • Angina, MI, sudden death endpoints
  • 5.55 percent risk increase
  • Suggested that ECG positive ST changes should be
    independent coronary risk factor

32
Treadmill Testing Results
  • Prognostic
  • Mark et al. Duke University. Ann Int Med 1987
  • Validation Mark et al. NEJM. 1991.
  • Developed score based on 613 patients (1983-85)
  • Validated on further 1420 patients
  • Simple score to prognosticate patients
  • Associated score gt 5 with annual mortality of
  • 0.25 outpatients
  • 0.6 inpatients

33
Treadmill Testing Results
  • Prognostic
  • Duke Score
  • Time in minutes
  • ST depression in mm
  • Type of pain
  • 0 - none
  • 1 typical anginal pain
  • limited by time / fatigue / other
  • 2 limiting anginal pain

34
Treadmill Testing Results
  • Duke Score
  • Time(m) 4X Angina 5X depression(mm)
  • Score 5 above low risk
  • 4 to 9 intermediate risk
  • -10 below high risk

35
Treadmill Testing Results
  • Kowk et al. JAMA. 1999.
  • Revisited Duke Score
  • 2405 patients
  • 939 had ST segment changes on stress test
  • Found 97 seven year survival based on score
    Duke gt 5
  • These studies have solidified the prognostic
    benefits of the treadmill test

36
Treadmill Testing Results
  • Duke score
  • Low Risk
  • Less than 1 per year acute coronary syndrome
  • Optimize Medical Rx reassess in one year
  • Intermediate Risk
  • 1 to 5 per year
  • Optimize Medical Rx nuclear studies non-urgent
  • High Risk
  • Greater than 5 per year
  • Urgent referral for further risk stratification

37
Treadmill Testing Results
  • Other prognostic indices
  • Morrow Froelicher. Ann IM. 1993.
  • Veterans Score
  • Exercise duration
  • ST depression
  • Rate of change of systolic BP during exercise
  • History of CHF, digoxin use
  • Low risk groups stratified with 2 annual
    mortality

38
Treadmill Testing Results
  • Exercise Capacity
  • AHA Guidelines
  • Carliner et al. Am J Card. 1985
  • Reasonable to Use exercise testing for
  • Surgical patients recovering from
  • Congenital repair
  • Valvular replacement
  • Cardiac transplant
  • CHF
  • DM
  • CRF
  • Chronic Lung Disease
  • No exercise induced symptoms

39
Treadmill Testing Results
  • Exercise Capacity and Prognostication
  • Lauer and Fletcher. Circulation. 1996.
  • 1575 men mean age 43
  • Failure to achieve 85 of age predicted maximum
    heart rate
  • associated with increase in death of 1.84
  • Extrapolation techniques used

40
Treadmill Testing Results
  • AHA Guidelines
  • Evaluation of Medical Therapy
  • Look for improvement of exercise capacity to
    previous before angina or ST depression
  • Evaluation of Valvular Disease
  • Strict guideline for evaluation of AS
  • Evaluation of Dysrrythmias
  • PVC, Sick sinus Syndrome
  • Pre-operative
  • Anesthetists 2nd largest user of stress test for
    evaluation of patient for non cardiac surgery

41
Notable Studies
  • Exercise Hypotension
  • Dubach et al. Circulation. 1989
  • Looking at SBP drop with exercise
  • Looked at 0, 10, 20 drop of SBP
  • Drop of 20 associated with increased PPV of at
    least 50 Left Main or Triple Vessel Disease

42
Notable Studies
  • Variables
  • Prakash et al. Am Heart J. 2001
  • 3974 men
  • Kaplan-Meier regression
  • Four variables predict mortality within 5 year
  • Rate of change of rate-pressure product
  • Age gt 65
  • Maximum MET lt5
  • LVH on ECG

43
Notable Studies
  • METS
  • Ramamurthy et al. Chest. 1999.
  • Found that sensitivity increases if MET gt7
  • Also found that METS achieved may be a stronger
    variable than rate-pressure product
  • High heart rate at low MET (lt5) level carries
    adverse prognosis

44
Notable Studies
  • Risk Factors
  • Am J Cardiol. MRFIT. 1985.
  • Multiple Risk Factor Intervention Trial
  • 12,866 participants
  • Those with ST changes on Stress Treadmill benefit
    to greater degree with risk factor modification
    than controls.

45
Notable Studies
  • Women
  • Large number of false positives
  • Mitral valve prolapse
  • Higher incidence atypical chest pain
  • Hormonal, esp. estrogen mimickery of digoxin
  • Ventilation Responses and Metabolic Alkalosis
  • Curzen. Heart. 1998.
  • 205 women
  • Compared with coronary angiography
  • 42 false positives 31 false negatives (36 of
    total)
  • Increase false positives correlated with
  • Increasing age to 52
  • Increasing coronary risks to 3

46
Notable Studies
  • Early Stress Testing
  • Polanczyk. Am J Card. 1998.
  • 276 low risk patients
  • Stress test within 48 hours
  • Similar prognostication numbers
  • 0.5 event rate
  • Additional variables over 6 months
  • 15 less ED visits
  • 30 fewer admission

47
Exercise Modalities
  • Stress Echocardiography
  • Evaluate rest / stress changes in wall motion.
  • Dobutamine given to stimulate beta-1
  • Advantages Readily available little equipment
    transportable
  • Disadvantages poor images in up to 10 user
    dependant hard in presence of previous
    abnormalities

48
Exercise Modalities
  • Thallium 201
  • Older agent Replaces potassium in cells
  • Advantages
  • Able to calculate lung heart ratios
  • Disadvantages
  • Immediate imaging
  • Poor in obese patients and large breasted women
  • Maddahi. Am J Coll Card. 1989
  • Increases sensitivity from 60-70 of treadmill
    test to 90 overall with addition of perfusion
    studies but 70 with single vessel disease

49
Exercise Modalities
  • Technetium-99m sestamibi
  • Deposited into mitochondria
  • Advantages
  • Longer half life
  • Better images
  • Improved estimates of ejection fraction
  • Disadvantage
  • Poor extraction from blood at high blood flow
  • Hachamovitch et al. Circulation. 1996.
  • 834 patients treadmill, Tc-99m and
    catheterization
  • 78 of the listed 0.6 mortality from Duke Low
    Treadmill prognostication caught as severe
    perfusion scans.

50
Exercise Modalities
  • Two schools of thought
  • EM Clinics Feb 2001
  • as useful as exercise testing is, it has the
    limitations of suboptimal sensitivity and
    specificity. Imaging is a necessity, not an
    optional component of stress testing vs.
    exercise testing alone is a useful first step.
  • Froelicher. Primary Care. 2001.
  • Quotes George Bernard Shaw the doctor does the
    test he is paid the most for to stress our need
    for continued evaluation of present modalities

51
Conclusions
  • Prognosis
  • Appropriate population in step wise work-up
  • Common Sense
  • 55 y.o male 6 minutes no angina no ST changes
    no change in systolic BP.
  • In helping to risk stratify patients after
    initial (ED) work-up, do exercise treadmills meet
    our need?
  • Set indications structure
  • Understand what the test does and doesnt tell us
  • Calgary / Rural Centres / Emergency Departments
  • Ongoing Studies

52
Resources
  • Staff, Division of Nuclear Medicine, FMC
  • Dr. Stone, C-Plus Clinic
  • Froelicher. Handbook of Exercise Testing. 1996.
  • Reviews (individual studies plus)
  • Primary Care Clinics. 2001.
  • EM Clinics. 1998, 2001.
  • Froelicher et al. Chest. 1999 (Pitfalls)
  • ACC / AHA Cardiology Guidelines. 1995.
  • Updated with review 1997.
  • CPSA Guidelines. 2000.
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