Title: Exercise Treadmill Testing
1Exercise Treadmill Testing
- Prognostication in Coronary Artery Disease
- Dr. Peter Krampl
- 11 October 2001
2Introduction
- 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
3Introduction
- 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
4Introduction
- 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
5Introduction
- 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
6Introduction
- 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
7Introduction
- 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?
9Outline
- Introduction
- Treadmill Testing
- Review of Current Literature
- Introduction
- Indications
- Procedures
- Results
- Notable Studies
- Exercise Modalities
- Conclusions
- Questions
10Treadmill Testing Introduction
- Froelicher. Hdbk of Exercise Testing. 1996
- Goals
- Diagnosis CAD
- Prognosis CAD
- Evaluation of Medical Therapy
- Evaluation of Exercise Capacity
11Treadmill 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
12Treadmill 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
13Treadmill 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
14Treadmill 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
15Treadmill 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
16Treadmill 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
17Treadmill 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
18Treadmill 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
19Treadmill Testing Indications
- Complications
- Brady / Tachyarrythmias
- AMI / Sudden Death
- CHF / Shock
- MSK Trauma / Fatigue / Malaise
20Treadmill 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
21Treadmill 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
22Treadmill 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
23Treadmill 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
24Treadmill 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
25Treadmill 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
26Treadmill 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
27Treadmill 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
28Treadmill 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
29Treadmill 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
30Treadmill 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
31Treadmill 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
32Treadmill 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
33Treadmill 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
-
34Treadmill 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
35Treadmill 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
36Treadmill 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
37Treadmill 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
38Treadmill 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
39Treadmill 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
40Treadmill 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
41Notable 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
42Notable 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
43Notable 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
44Notable 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.
45Notable 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
46Notable 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
47Exercise 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
48Exercise 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
49Exercise 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.
50Exercise 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
51Conclusions
- 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
52Resources
- 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.