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

STRESS TESTINGSTRESS TESTING

Indications, modalities Indications, modalities and patient selection and patient selection

Dr. Kalyana SundaramDr. Kalyana Sundaram

Stress TestingStress Testing

When? – IndicationsWhen? – IndicationsWhat type? – ModalitiesWhat type? – Modalities

Who? – Patient selection Who? – Patient selection

How often? – Frequency How often? – Frequency How much? – Cost How much? – Cost

Diagnostic TestingDiagnostic Testing

Testing thresholdTesting threshold

Diagnostic uncertaintyDiagnostic uncertainty

Treating thresholdTreating threshold

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

TestTest

DiseaseDisease

PositivePositive NegativeNegative

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

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

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

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?

Statistics can be tricky…Statistics can be tricky…

1P 40%1000

+ -

CAD 320 60

NoCAD

80 540

2P 5%1000

+ -

CAD 40 95

NoCAD

10 855

Accuracy 86% vs. 89.5%

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

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-anginal Asymp

30-39Male Intermediate Intermediate Low Very low

Female Intermediate Very Low Very low Very low

40-49Male High Intermediate Intermediate Low

Female Intermediate Low Very low Very low


Female Intermediate Intermediate Low Very low


Female High Intermediate Intermediate Low

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

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

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

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


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


Post-MIPost-MI• Prognostic assessmentPrognostic assessment• Activity prescriptionActivity prescription• Evaluation of medical therapyEvaluation of medical therapy• Before beginning cardiac rehabilitationBefore beginning cardiac rehabilitation


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

Chronotropic responseChronotropic response


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)

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

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

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*

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)

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

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

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)

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

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.

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%


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


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

Sensitivity and SpecificitySensitivity and Specificity

SensitivitySensitivity SpecificitySpecificity

Exercise EKGExercise EKG 68%68% 77%77%

Stress EchoStress Echo 76%76% 88%88%

Nuclear Nuclear ImagingImaging

79-92%79-92% 73-88%73-88%

Normal Myocardial Perfusion

Myocardial Ischemia

Myocardial Infarction


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

Stressing AgentsStressing AgentsStressor 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!

Imaging AgentsImaging AgentsStressor 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 technetium Localizes ischemia and infarcted tissue.

Expensive

Sensitivity and SpecificitySensitivity and Specificity

SensitivitySensitivity SpecificitySpecificity

Exercise EKGExercise EKG 68%68% 77%77%

Stress EchoStress Echo 76%76% 88%88%

Nuclear Nuclear ImagingImaging

79-92%79-92% 73-88%73-88%

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…)

Last but not least… costLast but not least… cost

TESTTEST COST - done COST - done

HospitalHospitalCOST - doneCOST - done

OfficeOffice

ETTETT $ 637$ 637 $ 239$ 239

STRESS ECHOSTRESS ECHO $ 1600$ 1600 $657$657

NUCLEARNUCLEAR

SCANSCAN$ 3000- $ 3000- $4400$4400

$937$937

Case QuestionCase QuestionA 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 Family history does not include cardiovascular disease in any first-degree relatives. His only medication is amlodipine. any 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.

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 Adenosine nuclear perfusion stress test.test.

b.b. Coronary angiographyCoronary angiography

c.c. EchocardiographyEchocardiography

d.d. Exercise treadmillExercise treadmill

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 order, keep in mind their ability to exercise, whether any contraindications exercise, whether any contraindications are present, cost by are present, cost by LOCATIONLOCATION , body , body weight and specificity and sensitivityweight and specificity and sensitivity

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