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Stress Testing : Which Test to Choose? Gary J. Balady, MD Professor of Medicine Boston University School of Medicine.

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Presentation on theme: "Stress Testing : Which Test to Choose? Gary J. Balady, MD Professor of Medicine Boston University School of Medicine."— Presentation transcript:

1 Stress Testing : Which Test to Choose? Gary J. Balady, MD Professor of Medicine Boston University School of Medicine

2 Stress Testing at Boston Medical Center Exercise ECG ( treadmill test) Exercise – Echo Exercise – Nuclear Cardiopulmonary ( Metabolic ) Dobutamine –Echo Pharmacologic (regadenoson) nuclear –SPECT –PET SCM Order Set: stress test selector

3 supplydemand

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5 supplydemand coronary arteries atherosclerosis coronary vasospasm hypoxemia anemia hypotension coronary anomalies coronary vasculitis factors HR x BP contractility wall stress

6 Supply Degree of obstruction Length of lesion Dynamic properties of lesion Dynamic properties of distal vascular bed thickness of myocardium

7 Collateral flow Supply

8 supplydemand factors HR x BP contractility

9 History Chest discomfort –Types of angina Quality of discomfort/location Provocative factors Relief Age/Gender/Risk Factors Classes of Angina

10 Physical Examination hypertension weight/body habitus vascular bruits heart size skin eye grounds

11 Resting Electrocardiogram

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15 Exercise Testing Protocols

16 Treadmill Force = body weight Distance/time= Treadmill speed Estimated VO2 (ml/kg/min) –ACSM regression equations –METs Work = force x distance Workrate = work/time VO2 is directly related to workrate Stationary Cycle Force = resistance against the flywheel Distance/time= Cycling speed Estimated VO2 (ml/min) –ACSM regression equations –Need body weight to calculate METs

17 Time  METs Ramp Stepped 10 min

18 Bruce Protocol for Treadmill Testing

19 Boston Medical Center Ramp Protocols

20 Duke Activity Status Index

21 Diagnostic level of stress: 85% maximum predicted HR where MPHR = (220-age) where MPHR = (220-age)

22 Normal Response IschemicResponse

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24 Sensitivity/Specificity/Predictive Value high prevalence population 9010 exercise ecg test: 70% sensitive/ 70% specific

25 Sensitivity/Specificity/Predictive Value low prevalence population 1090 exercise ecg test: 70% sensitive/ 70% specific

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27 x x x x * Duke Prognostic Scoring System

28 Heart Rate Recovery

29 Heart Rate Recovery: Risk of mortality at 6 years Cole, et al. NEJM 1999: 341:1351

30 Cleveland Clinic ETT Score Lauer, et al. Ann Int Med 147: ; 2007

31 Circulation 2010: 121: 2109 Hypertension During Exercise: BPs > 180 at 7 METs

32 Oxygen Uptake - Workrate relationship VO 2  Workrate  No handrailHandrail ?

33 CPX System Oxygen sensor Carbon dioxide sensor Volume measures/flow meters Breath by breath measures –BTPS –Expired air Oxygen uptake Carbon Dioxide production Ventilation

34 Indications for CPX Accurate assessment of exercise capacity –Clinical –Research Diagnosis –Dyspnea on exertion Prognosis –Heart failure –Congenital Heart Disease Disability assessment Treatment –Pacemaker settings

35 Exercise Testing additional indications Adequacy of therapy –medical –revascularization ( imaging tests) Activity counseling – MET Chart Exercise prescription Rhythm assessment Valvular Heart Disease –Aortic stenosis –Mitral stenosis –Mitral regurgitation –Hypertrophic obstructive cardiomyopathy

36 Exercise Prescription Patients with CHD Intensity –Exercise Test calculate heart rate reserve (HRR) –peak HR minus resting HR –moderate intensity: » 50% HRR plus resting HR to »70% HRR plus resting HR »keep peak peak HR 10 beats < HR at ischemia –Risk Stratify using AHA criteria

37 Stress Imaging Tests Abnormal resting ECG ST segments Left bundle branch block LVH with strain Need for increased diagnostic accuracy sensitivity 85-90% specificity 85-90% localize ischemia to specific coronary vascular territory

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39 Contrast Echo

40 Stress Echocardiogram: Apical septal wall ischemia

41 Stress Nuclear Testing tomographic imaging planes Short Axis base to apex Vertical Long Axis septal to lateral Horizontal Long Axis anterior to inferior

42 normal nuclear perfusion scan stress rest

43 lateral ischemia on nuclear perfusion scan stress rest

44 Pharmacological Stress Tests dobutamine echo Dobutamine beta agonist increases myocardial oxygen demand increases HR, BP, contractility

45 Pharmacological Stress Tests nuclear perfusion scan Adenosine or Dipyridimole direct coronary vasodilator causes shifts in flow leading to relative reduction in flow distal to coronary stenosis minimal change in HR, BP, and contractility

46 Myocardial Perfusion Imaging: Pharmacologic Positron Emission Tomography (PET) vs. Single Photon Emission Computed Tomography (SPECT) PET Energy: 511 KeV Resolution: 1.5 cm Protocol: 45 min Stress EF Myocardial flow quantification More expensive than SPECT SPECT Energy: KeV Resolution: 2.0 cm Protocol: 2-3 h ( or 2 d) Post-Stress EF Courtesy of Edward Miller, MD, PhD

47 For more information –Scientific publications Statements and guidelines –Exercise standards -2013

48 Elective in Stress Testing Second and third year residents 3 weeks – preferably continuous Fellow surrogate Certification in Exercise-ECG Testing –Supervision and interpretation Exposure to stress echo and stress nuclear

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50 Body weightExercise rate (kg · m · min -1 and watts) kgLbKpms 300 Watts Approximate METs during Stationary Cycle Testing

51 Myocardial Contractility

52 P Th R Myocardial Wall Stress Wall stress = P x R/ Th


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