CARDIAC STRESS TESTING how to understand it.ppt

for further reading

1. STRESS TESTINGSTRESS TESTING
Indications, modalities Indications, modalities
and patient selection and patient selection
Dr. Kalyana SundaramDr. Kalyana Sundaram

2. Stress TestingStress Testing
When? – IndicationsWhen? – Indications
What type? – ModalitiesWhat type? – Modalities
Who? – Patient selection Who? – Patient selection
How often? – Frequency How often? – Frequency
How much? – Cost How much? – Cost

3. Diagnostic TestingDiagnostic Testing

Testing thresholdTesting threshold

Diagnostic uncertaintyDiagnostic uncertainty

Treating thresholdTreating threshold

4. The 2 x 2 (or 4 x 4) tableThe 2 x 2 (or 4 x 4) table

TestTest
DiseaseDisease
PositivePositiveNegativeNegative
PresentPresent AA CC SeSe
A/(A+C)A/(A+C)
AbsentAbsent BB DD SpSp
D/(B+D)D/(B+D)
PPVPPV
A/(A+B)A/(A+B)
NPVNPV
D/(C+D)D/(C+D)
AccAcc
(A+D)/(A+D)/
totaltotal

5. How “normal” is the normal curve?How “normal” is the normal curve?

6. The norm isn’t always the norm…The norm isn’t always the norm…

7. Which test is more accurate?Which test is more accurate?

An exercise treadmill test (Se 80%, Sp An exercise treadmill test (Se 80%, Sp
90%) in a population of post-CABG 90%) in a population of post-CABG
patients with worsening angina?patients with worsening angina?
oror

The same test (Se 80%, Sp 90%) in a The same test (Se 80%, Sp 90%) in a
population of young, healthy women population of young, healthy women
without family history of CAD?without family history of CAD?

8. Statistics can be tricky…Statistics can be tricky…
1
P 40%
1000
+ -
CAD 320 60
No
CAD
80 540
2
P 5%
1000
+ -
CAD 40 95
No
CAD
10 855
Accuracy 86% vs. 89.5%

9. If there is one thing If there is one thing
you should think about you should think about
before ordering ANY test…before ordering ANY test…
LIKELIHOOD RATIOLIKELIHOOD RATIO

12. Stress Testing: Who?Stress Testing: Who?
Adults with intermediate (10-90%) Adults with intermediate (10-90%)
pre-test probability of CADpre-test probability of CAD
Age Sex Typical Atypical Non-anginalAsymp
30-39
Male IntermediateIntermediateLow Very low
FemaleIntermediateVery Low Very low Very low
40-49
Male High IntermediateIntermediateLow
FemaleIntermediateLow Very low Very low
50-59
Male High IntermediateIntermediateLow
FemaleIntermediateIntermediateLow Very low
60-69
Male High IntermediateIntermediateLow
FemaleHigh IntermediateIntermediateLow

13. AnginaAngina
Precordial (retro-sternal) chest pain Precordial (retro-sternal) chest pain
that…that…

Is triggered by physical or emotional Is triggered by physical or emotional
stressstress

Is relieved by rest or SL NTGIs relieved by rest or SL NTG

Lasts for 15-20 minutes each episodeLasts for 15-20 minutes each episode

14. For those of you who like history…For those of you who like history…
First described in 1772 by the English First described in 1772 by the English
physician William Heberden in 20 patients physician William Heberden in 20 patients
who suffered from "a painful and most who suffered from "a painful and most
disagreeable sensation in the breast, which disagreeable sensation in the breast, which
seems as if it would extinguish life, if it were seems as if it would extinguish life, if it were
to increase or to continue." Such patients, he to increase or to continue." Such patients, he
wrote, "are seized while they are walking wrote, "are seized while they are walking
(more especially if it be uphill, and soon after (more especially if it be uphill, and soon after
eating). But the moment they stand still, all eating). But the moment they stand still, all
this uneasiness vanishes." this uneasiness vanishes."
Sir William Heberden, 1710-1801

15. Back to contemporary times…Back to contemporary times…
Classic anginal features:Classic anginal features:

Is triggered by physical or emotional Is triggered by physical or emotional
stressstress

Is relieved by rest or SL NTGIs relieved by rest or SL NTG

Lasts for 15-20 minutes each episodeLasts for 15-20 minutes each episode
2-3/3: typical angina
1/3: atypical angina
0/3: likely non-cardiac chest pain

16. Importance of typicalityImportance of typicality
Jones et al. Prognostic importance of presenting symptoms in patients undergoing exercise Jones et al. Prognostic importance of presenting symptoms in patients undergoing exercise
testing for evaluation of known or suspected coronary disease. testing for evaluation of known or suspected coronary disease. Am J Med Am J Med 2004.2004.
560 patients presenting for exercise tolerance testing (treadmill)
Prospective follow-up over 5.8 years
0
1
2
3
4
5
6
7
Typical Atypical Non-
cardiac
Mortality

17. Stress Testing: Who?Stress Testing: Who?

Patients with symptoms or prior history of Patients with symptoms or prior history of
CADCAD
•Initial evaluation with suspected or Initial evaluation with suspected or
known CADknown CAD
•Known CAD with change in status Known CAD with change in status
(crescendo)(crescendo)
•Low risk, unstable angina 8-12 hours Low risk, unstable angina 8-12 hours
after presentation free of symptoms after presentation free of symptoms
(“rule out time”)(“rule out time”)
•Intermediate risk, unstable angina, 2-3 Intermediate risk, unstable angina, 2-3
days free of active ischemiadays free of active ischemia

18. Stress Testing: Who?Stress Testing: Who?

Post-MIPost-MI
•Prognostic assessmentPrognostic assessment
•Activity prescriptionActivity prescription
•Evaluation of medical therapyEvaluation of medical therapy
•Before beginning cardiac rehabilitationBefore beginning cardiac rehabilitation

19. Stress Testing: Who?Stress Testing: Who?

Special GroupsSpecial Groups
•WomenWomen

Lower sensitivity, similar specificityLower sensitivity, similar specificity
•Elderly (>75 years of age)Elderly (>75 years of age)

Other evaluated endpoints include Other evaluated endpoints include
chronotropic response, exercise-induced chronotropic response, exercise-induced
arrhythmias, and assessment of exercise arrhythmias, and assessment of exercise
capacitycapacity

20. Chronotropic responseChronotropic response

21. Stress Testing: Who?Stress Testing: Who?

Asymptomatic patientsAsymptomatic patients
•Diabetics planning to start exerciseDiabetics planning to start exercise
•Guide to risk reduction therapy in a Guide to risk reduction therapy in a
patient with multiple risk factors*patient with multiple risk factors*
•Men > 45 and women > 55Men > 45 and women > 55

Starting exerciseStarting exercise

Impact public safetyImpact public safety

High risk due to concomitant disease (PVD, High risk due to concomitant disease (PVD,
CRF)CRF)

22. Stress Testing: Stress Testing:
Absolutely Who Not!Absolutely Who Not!

Acute MIAcute MI

High risk unstable anginaHigh risk unstable angina

Uncontrolled arrhythmias with symptomsUncontrolled arrhythmias with symptoms

Symptomatic, severe aortic stenosis*Symptomatic, severe aortic stenosis*

Uncontrolled, symptomatic heart failureUncontrolled, symptomatic heart failure

Acute PEAcute PE

Acute myocarditis or pericarditisAcute myocarditis or pericarditis

Acute aortic dissectionAcute aortic dissection

23. Stress Testing: Stress Testing:
Maybe Who Not?*Maybe Who Not?*

Left main coronary stenosisLeft main coronary stenosis

Moderate stenotic valvular heart diseaseModerate stenotic valvular heart disease

Electrolyte abnormalitiesElectrolyte abnormalities

Severe hypertension (SBP > 200, DBP > Severe hypertension (SBP > 200, DBP >
110)110)

Tachy or bradyarrhythmiasTachy or bradyarrhythmias

Outflow tract obstruction (HCM)Outflow tract obstruction (HCM)

Mental or physical impairment (unsafe)Mental or physical impairment (unsafe)

High-degree AV blockHigh-degree AV block

24. Stress Testing: When?Stress Testing: When?

Patients with chest painPatients with chest pain
•Change in clinical statusChange in clinical status

Acute coronary syndromesAcute coronary syndromes
•Low, intermediate, high risk (H&P, ECG, Low, intermediate, high risk (H&P, ECG,
markers – TIMI risk score)markers – TIMI risk score)
•Low: 8-12 h symptom-freeLow: 8-12 h symptom-free
•Intermediate: 2-3 days symptom-free*Intermediate: 2-3 days symptom-free*
•High: consider chemical imaging study High: consider chemical imaging study
versusversus coronary angiography* coronary angiography*

25. Stress Testing: When?Stress Testing: When?

Post-MIPost-MI
• Pre-discharge*Pre-discharge*

Submaximal (<70% MPHR)Submaximal (<70% MPHR)
•Early after discharge* (14-21 days)Early after discharge* (14-21 days)

Symptom limited (85% MPHR)Symptom limited (85% MPHR)
•Late after discharge* (3-6 weeks if early Late after discharge* (3-6 weeks if early
test was submaximal)test was submaximal)

Symptom limited (85% MPHR)Symptom limited (85% MPHR)

26. Stress Testing: When?Stress Testing: When?

Before and after revascularization*Before and after revascularization*
•Demonstration of ischemiaDemonstration of ischemia
•Evaluation of post-procedure chest painEvaluation of post-procedure chest pain
•Evaluation of territory at riskEvaluation of territory at risk
•Evaluation of restenosisEvaluation of restenosis
•Post-bypass surgery – useful later not Post-bypass surgery – useful later not
earlyearly

27. Stress Testing: How Often?Stress Testing: How Often?

Change in clinical symptom patternChange in clinical symptom pattern

Prognostication:Prognostication:
•There is no absolute guaranteeThere is no absolute guarantee

Progression of testing modality to Progression of testing modality to
higher sensitivity and specificityhigher sensitivity and specificity

Depends on risk factors, their degree Depends on risk factors, their degree
of control and intensity of of control and intensity of
modificationmodification

28. Two ComponentsTwo Components

Each cardiac imaging modality has Each cardiac imaging modality has
two components:two components:
•Stressing agent: treadmill, dobutamine, Stressing agent: treadmill, dobutamine,
or adenosineor adenosine
•Imaging agent: EKG, echo, or Imaging agent: EKG, echo, or
radionuclide tracer (thallium or radionuclide tracer (thallium or
technetium)technetium)

29. Stress Testing: What Type?Stress Testing: What Type?

Exercise modalityExercise modality
•TreadmillTreadmill

Bruce, Modified Bruce, Branching, Bruce, Modified Bruce, Branching,
Naughton…Naughton…
•Bicycle (recumbent)Bicycle (recumbent)
•Chemical/PharmacologicChemical/Pharmacologic

Dipyridamole (Persantine®)Dipyridamole (Persantine®)

Adenosine (Adenoscan®)Adenosine (Adenoscan®)

DobutamineDobutamine

30. The Bruce protocolThe Bruce protocol

Developed in 1949 by Developed in 1949 by
Robert A. Bruce, Robert A. Bruce,
considered the “father considered the “father
of exercise physiology”.of exercise physiology”.

Published as a Published as a
standardized protocol standardized protocol
in 1963.in 1963.

Remains the gold-Remains the gold-
standard for detection standard for detection
of myocardial ischemia of myocardial ischemia
when risk stratification when risk stratification
is necessary.is necessary.

31. Protocol descriptionProtocol description
Stage Time (min) km/hr Slope
1 0 2.74 10%
2 3 4.02 12%
3 6 5.47 14%
4 9 6.76 16%
5 12 8.05 18%
6 15 8.85 20%
7 18 9.65 22%
8 21 10.46 24%
9 24 11.26 26%
10 27 12.07 28%

32. Stress Testing: What Type?Stress Testing: What Type?

Non-imaging Non-imaging versusversus imaging imaging
•Consideration of imagingConsideration of imaging

Resting ST depression (<1 mm)Resting ST depression (<1 mm)

DigoxinDigoxin

LVHLVH

WomenWomen

33. Stress Testing: What Type?Stress Testing: What Type?

Non-imaging vs. ImagingNon-imaging vs. Imaging
•Require imagingRequire imaging

Intermediate risk non-imaging exercise testIntermediate risk non-imaging exercise test

Pre-excitationPre-excitation

Paced rhythmPaced rhythm

LBBB or QRS > 120 msLBBB or QRS > 120 ms

> > 1 mm resting ST depression1 mm resting ST depression

Vessel localizationVessel localization

Improved prognostic informationImproved prognostic information

34. Sensitivity and SpecificitySensitivity and Specificity
SensitivitySensitivity SpecificitySpecificity
Exercise EKGExercise EKG68%68% 77%77%
Stress EchoStress Echo 76%76% 88%88%
Nuclear Nuclear
ImagingImaging
79-92%79-92% 73-88%73-88%

35. Normal Myocardial Perfusion

36. Myocardial Ischemia

37. Myocardial Infarction

38. Stress Testing: What Type?Stress Testing: What Type?

Choice of imaging modality is multi-factorialChoice of imaging modality is multi-factorial
•Body habitus – attenuation, COPD, etc.Body habitus – attenuation, COPD, etc.
•Local expertiseLocal expertise
•ClaustrophobiaClaustrophobia
•Understanding of sensitivity and specificityUnderstanding of sensitivity and specificity
•Coincident information:Coincident information:

Ejection fractionEjection fraction

Valvular structureValvular structure

Exercise capacityExercise capacity

39. Stressing AgentsStressing Agents
Stressor Pro Con
Treadmill Physiologic, simple,
less expensive,
good for patient
who can walk
Dobutamine No exercise
needed
Caution in patients with
arrhythmias
Adenosine or
dipyridamole (used with
nuclear)
No exercise
needed;
uncomfortable
sensation of “heart
stoppage”
Adenosine may induce
bronchospasm – caution in
COPD and asthma!

40. Imaging AgentsImaging Agents
Stressor Pro Con
EKG Simple, less
expensive
Less information. May not be
able to localize the lesion. Can
not use if there are baseline
EKG abnormalities i.e. LBBB
with ST changes
Echocardiogram Good if patient has
pre-existing EKG
abnormalities. More
info than EKG.
Less expensive
than nuclear.
Operator dependent to some
extent. May have poor
windows due to body habitus.
Pre-existing wall motion
abnormalities may make
interpretation more
challenging.
Thallium or technetiumLocalizes ischemia
and infarcted
tissue.
Expensive

41. Sensitivity and SpecificitySensitivity and Specificity
SensitivitySensitivity SpecificitySpecificity
Exercise EKGExercise EKG68%68% 77%77%
Stress EchoStress Echo 76%76% 88%88%
Nuclear Nuclear
ImagingImaging
79-92%79-92% 73-88%73-88%

43. Exercise Testing: ContraindicationsExercise Testing: Contraindications

Unstable AnginaUnstable Angina

Decompensated CHFDecompensated CHF

Uncontrolled hypertension (blood Uncontrolled hypertension (blood
pressure pressure >> 200/115 mmHg) 200/115 mmHg)

Acute myocardial infarction within Acute myocardial infarction within
last 2 to 3 dayslast 2 to 3 days

Severe pulmonary hypertensionSevere pulmonary hypertension

Relative contraindications (AS, Relative contraindications (AS,
HCM…)HCM…)

44. Last but not least… costLast but not least… cost
TESTTEST COST - done COST - done
HospitalHospital
COST - doneCOST - done
OfficeOffice
ETTETT $ 637$ 637 $ 239$ 239
STRESS ECHOSTRESS ECHO $ 1600$ 1600 $657$657
NUCLEARNUCLEAR
SCANSCAN
$ 3000- $ 3000-
$4400$4400
$937$937

45. Case QuestionCase Question
A 60yo man is evaluated for chest pain of 4 months’ duration. A 60yo man is evaluated for chest pain of 4 months’ duration.
He describes the pain as sharp, located in the left chest, He describes the pain as sharp, located in the left chest,
with no radiation or associated symptoms, that occurred with no radiation or associated symptoms, that occurred
with walking one to two blocks and resolves with rest. with walking one to two blocks and resolves with rest.
Occasionally, the pain improves with continued walking or Occasionally, the pain improves with continued walking or
occurs during the evening hours. He has hypertension. occurs during the evening hours. He has hypertension.
Family history does not include cardiovascular disease in any Family history does not include cardiovascular disease in any
first-degree relatives. His only medication is amlodipine. first-degree relatives. His only medication is amlodipine.
On physical examination, he is afebrile, blood pressure is On physical examination, he is afebrile, blood pressure is
130/80mHg, pulse rate is 72/min, and respiration rate is 130/80mHg, pulse rate is 72/min, and respiration rate is
12/min. BMI is 28. No carotid bruits are present, and a 12/min. BMI is 28. No carotid bruits are present, and a
normal S1 and S2 with no murmurs are heard. Lung fields normal S1 and S2 with no murmurs are heard. Lung fields
are clear, and distal pulses are normal. EKG showed normal are clear, and distal pulses are normal. EKG showed normal
sinus rhythm.sinus rhythm.

46. Case QuestionCase Question

Which of the following is the most Which of the following is the most
appropriate diagnostic test to appropriate diagnostic test to
perform next?perform next?
a.a.Adenosine nuclear perfusion stress test.Adenosine nuclear perfusion stress test.
b.b.Coronary angiographyCoronary angiography
c.c.EchocardiographyEchocardiography
d.d.Exercise treadmillExercise treadmill

47. Take Home PointsTake Home Points

Stress testing is indicated for patients with Stress testing is indicated for patients with
intermediate pre-test probabilityintermediate pre-test probability

Each stress test has two components: an Each stress test has two components: an
imaging modality and stress modalityimaging modality and stress modality

When determining which stress test to When determining which stress test to
order, keep in mind their ability to exercise, order, keep in mind their ability to exercise,
whether any contraindications are present, whether any contraindications are present,
cost by cost by LOCATIONLOCATION , body weight and , body weight and
specificity and sensitivityspecificity and sensitivity