STRESS TESTING Indications, modalities and patient selection Miguel A. Leal, M.D. Fellow, Cardiovascular Medicine University of Wisconsin February

Disclosures None whatsoever!

Stress Testing When? – Indications What type? – Modalities Who? – Patient selection How often? – Frequency How much? – Cost

Diagnostic Testing Testing threshold Diagnostic uncertainty Treating threshold

The 2 x 2 (or 4 x 4) table Test Disease PositiveNegative PresentACSe A/(A+C) AbsentBDSp D/(B+D) PPV A/(A+B) NPV D/(C+D) Acc (A+D)/total

How “normal” is the normal curve?

The norm isn’t always the norm…

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

Statistics can be tricky… 1 P 40% CAD32060 No CAD P 5% CAD4095 No CAD Accuracy 86% vs. 89.5%

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

Stress Testing: Who? Adults with intermediate (10-90%) pre-test probability of CAD AgeSexTypicalAtypicalNon-anginalAsymp MaleIntermediate LowVery low FemaleIntermediateVery LowVery low MaleHighIntermediate Low FemaleIntermediateLowVery low MaleHighIntermediate Low FemaleIntermediate LowVery low MaleHighIntermediate Low FemaleHighIntermediate Low

Angina Precordial (retrosternal) chest pain that… Is triggered by physical or emotional stress Is relieved by rest or SL NTG Lasts for minutes each episode

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

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

Importance of typicality Jones et al. Prognostic importance of presenting symptoms in patients undergoing exercise testing for evaluation of known or suspected coronary disease. Am J Med patients presenting for exercise tolerance testing (treadmill) Prospective follow-up over 5.8 years

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

Stress Testing: Who? Post-MI –Prognostic assessment –Activity prescription –Evaluation of medical therapy –Before beginning cardiac rehabilitation

Stress Testing: Who? Special Groups –Women Lower sensitivity, similar specificity –Elderly (>75 years of age) Other evaluated endpoints include chronotropic response, exercise-induced arrhythmias, and assessment of exercise capacity

Chronotropic response

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

Stress Testing: Absolutely Who Not! Acute MI High risk unstable angina Uncontrolled arrhythmias with symptoms Symptomatic, severe aortic stenosis* Uncontrolled, symptomatic heart failure Acute PE Acute myocarditis or pericarditis Acute aortic dissection

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

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

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

Stress Testing: When? Before and after revascularization* –Demonstration of ischemia –Evaluation of post-procedure chest pain –Evaluation of territory at risk –Evaluation of restenosis –Post-bypass surgery – useful later not early

Stress Testing: How Often? Change in clinical symptom pattern Prognostication: –There is no absolute guarantee Progression of testing modality to higher sensitivity and specificity Depends on risk factors, their degree of control and intensity of modification

Stress Testing: What Type? Exercise modality –Treadmill Bruce, Modified Bruce, Branching, Naughton… –Bicycle (recumbent) –Chemical/Pharmacologic Dipyridamole (Persantine®) Adenosine (Adenoscan®) Dobutamine

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

Protocol description StageTime (min)km/hrSlope % % % % % % % % % %

Stress Testing: What Type? Non-imaging versus imaging –Consideration of imaging Resting ST depression (<1 mm) Digoxin LVH Women

Stress Testing: What Type? Non-imaging vs. Imaging –Require imaging Intermediate risk non-imaging exercise test Pre-excitation Paced rhythm LBBB or QRS > 120 ms > 1 mm resting ST depression Vessel localization Improved prognostic information

Stress Testing: What Type? “T o nuke or not to nuke?” Modality Sensitivity Specificity Exercise test68%77% Nuclear Imaging 87-92%80-85% Stress Echo 80-85%88-95%

Normal Myocardial Perfusion

Myocardial Ischemia

Myocardial Infarction

Stress Testing: What Type? Choice of imaging modality is multi-factorial –Body habitus – attenuation, COPD, etc. –Local expertise –Claustrophobia –Understanding of sensitivity and specificity –Coincident information: Ejection fraction Valvular structure Exercise capacity

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

Last but not least… cost TESTCOST ETT$ 140 ETT + IMAGING$ 906 (Nuclear) $ 886 (Echo) CORONARY ANGIOGRAPHY $ 5200 Marine et al. COST-EFFECTIVENESS OF STRESS-ECHOCARDIOGRAPHY. Cardiology Clinics, Volume 17, Comprehensive and well-obtained History & Physical Exam: priceless

Stress Testing Additional information & references: –JACC, October 16,2002 –Circulation, October 1, 2002 – –

Thank you!