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

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

supply demand

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

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

Supply Collateral flow

supply demand factors HR x BP contractility

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

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

Resting Electrocardiogram

Exercise Testing Protocols

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

Stepped METs Ramp METs Time  10 min

Bruce Protocol for Treadmill Testing STAGE TIME SPEED (mph) GRADE (%) METS REST 00.00 0.0 1.0 1 03.00 1.7 10.0 4.6 2 2.5 12.0 7.0 3 3.4 14.0 10.1 4 4.2 16.0 12.9 5 5.0 18.0 15.1 6 5.5 20.0 16.9 7 6.8 22.0 19.2

Boston Medical Center Ramp Protocols Stage* Very Low Ramp Low Ramp Moderate Ramp High Ramp Athlete’s Ramp mph % grade METs 1 1.0 0.0 1.8 1.5 2.5 2.1 3.0 3.5 2.4 2 1.1 0.2 1.9 0.5 1.6 2.0 2.7 2.2 4.0 3.9 3 1.2 0.4 1.7 2.9 2.3 4.5 4.2 3.2 4 1.3 0.6 3.1 5.5 4.6 3.6 5 1.4 0.8 3.4 6.0 5.0 3.3 4.1 6 2.6 7.0 7 7.5 5.8 5.2 8 2.8 8.5 6.4 6.1 9 9.0 6.8 7.3 10 4.8 10.0 7.4 8.4 11 6.5 5.1 10.5 7.8 9.5 12 11.5 10.6 13 12.0 8.9 5.4 14 8.0 6.2 13.0 9.7 5.7 12.2 15 3.8 6.6 13.5 10.1 16 14.5 10.9 6.3 13.8 17 3.7 15.0 11.4 14.7 18 4.3 16.0 6.9 15.5 19 8.3 16.5 12.6 7.2 16.4 20 4.7 11.0 8.7 17.5 13.3 17.3

Duke Activity Status Index

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

Normal Response Ischemic Response

Sensitivity/Specificity/Predictive Value high prevalence population 63 3 95 27 7 21 90 10 exercise ecg test: 70% sensitive/ 70% specific

Sensitivity/Specificity/Predictive Value low prevalence population 7 27 21 3 63 95 10 90 exercise ecg test: 70% sensitive/ 70% specific

Duke Prognostic Scoring System x x * x x

Heart Rate Recovery 28

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

Cleveland Clinic ETT Score Lauer, et al. Ann Int Med 147:821-828; 2007

Hypertension During Exercise: BPs > 180 at 7 METs The risk is not immediate, but is evident in the near term – the 5-10 year period which is a focus of most preventive strategies and pharmacotherapies, and continues to increase dramatically in the long term – i.e lifetime risk – the focus of public health groups like the American Heart Association. Circulation 2010: 121: 2109

Oxygen Uptake - Workrate relationship No handrail Handrail VO2  ? Workrate 

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

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

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

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

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

Contrast Echo

Stress Echocardiogram: Apical septal wall ischemia

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

normal nuclear perfusion scan stress rest stress rest stress rest

lateral ischemia on nuclear perfusion scan stress rest stress rest stress rest

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

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

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: 80-140 KeV Resolution: 2.0 cm Protocol: 2-3 h ( or 2 d) Post-Stress EF Courtesy of Edward Miller, MD, PhD

www.americanheart.org Scientific publications For more information Statements and guidelines Exercise standards -2013 47

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

Approximate METs during Stationary Cycle Testing Body weight Exercise rate (kg · m · min-1 and watts) kg Lb Kpms 300 Watts 50 450 75 600 100 750 125 900 150 1050 175 1200 200 110 5.1 6.9 8.6 10.3 12.0 13.7 15.4 60 132 4.3 5.7 7.1 10.0 11.4 12.9 70 154 3.7 4.9 6.1 7.3 9.8 11.0 80 176 3.2 5.4 6.4 7.5 9.6 90 198 2.9 3.8 4.8 6.7 7.6 220 2.6 3.4 6.0 7.7

Myocardial Contractility

Myocardial Wall Stress P x R/ Th Th R P