subha v. raman, md, msee, facc, faha professorand medical ... · stress cardiac imaging tests –...
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4/27/2018
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Subha V. Raman, MD, MSEE, FACC, FAHAProfessor and Medical Director, CMR/CCT
Contemporary Approaches to Myocardial Ischemia
OSU Cardiovascular MR/CT UpdateApril 27, 2018
Disclosures
Institutional research support from Siemens
Co-inventor, MR-compatible treadmill
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Outline
Motivation for stress testing in IHD; typical scenarios
Exercise and pharmacologic stress methods
Guidelines
Myocardial Ischemia:inadequate oxygen supply to meet demand
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What Are Looking For? Appropriate Test
Detection of myocardial ischemia Stress ECG / dynamic ECG changes
Stress cardiac imaging tests – nuclear, echo, CMR
Detection of CAD Coronary artery calcium (CAC)
CT coronary angiography (CCT)
X-ray coronary angiography
Scenarios for Stress Testing:detection / diagnosis
Typical or atypical symptoms – are they due to IHD?
Ventricular arrhythmias – is substrate ischemia?
Substernal chest discomfort
Provoked by exertion
Relieved with rest or nitroglycerin
Infarct scar
Reentry loop
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Exercise Stress
Increase demand and assess supply evaluate ECG, coronary blood flow, contractility,
regional wall motion, myocardial perfusion, oxygenation, etc.
Reproduce exertional symptoms
Arrhythmias with physical activity suppression vs. augmentation of PVCs
Peak Exercise Recovery
Right ventricular outflow tract PVCs ablation
Exercise-induced ST depression = Ischemia
CAVEATS
x No LBBB, V-paced rhythm, repolarization abnormalities
x Ischemia not localized by ST
STRENGTHS
V. strong prognostic value
Correlate symptoms & results with typical exertion
ACC/AHA Guidelines 2002.
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Pharmacologic stress imagingNo
Exercise stress imagingNoResting ECG
interpretable?
Yes
Yes
Exercise stress ECG
ACC/AHA Guidelines 2002.
Can patient exercise?
Choosing between Exercise & Pharmacologic Stress for Ischemia Testing
preoperative evaluation – often can’t exercise
Estimated Perioperative Risk
Poor orunknown functional capacity
Pharmacologic Stress Testing
2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management
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Pharmacologic Stress: Dobutamine
Synthetic catecholamine
Plasma half-life ~2 min
Up to 10 g/kg/min: Inotropic effects (via 1 and 1)
High dose (20-40 g/kg/min): HR progressively ↑ (1) Blood pressure increases (though SVR↓ via 2 >> 1)
Hemodynamic changes ↑ O2 demand Territories supplied by critical stenosis WMA
Dobutamine Stress Imaging Tests
Echo Wall motion at each stage
Acoustic window may be limited by body habitus, lung disease
Cardiac MRI Wall motion + perfusion + scar
MRI contraindications
Hundley WG et al. Circ 1999.
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DSE DCMR
Sensitivity 74% 86%
Specificity 70% 86%
PPV 81% 91%
NPV 61% 78%
Accuracy 73% 86%
Nagel E et al. Circ 1999.
Dobutamine Stress Echo vs. CMR
Dobutamine CMR: Prognostic Value and Cost-Effective
Wallace EL et al. JACC Im 2009.
HR for MI/cardiac death:4.1 [95% CI 2.2 – 9.4]
similar survival with ~12500 € savings per life year
Petrov G, Kelle S et al. Clin Res Cardiol 2013.
Costs Survival
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Vasodilator ‘Stress’
REST VASODILATOR
Vasodilator Stress Imaging Tests
Inject radioisotope at rest and during vasodilator infusion
SPECT (nuclear) Extraction of isotope where there is
myocardial blood flow
Breast & gut attenuation artifacts
Cardiac MRI First-pass imaging during infusion of T1
shortening (gadolinium-based) contrast agent
Usual MRI contraindications
Breastartifactvs. anteriorischemia
ST
RE
SS
RE
ST
SPECT
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SPECT vs. Vasodilator Stress CMR
Greenwood JP et al. Lancet 2012.
SPECT CMR
Sensitivity 66% 86%
Specificity 83% 83%
PPV 71% 77%
NPV 79% 91%
Adenosine CMR:Similar Accuracy in Women and Men
Males vs. Females AUC:CMR – 0.89 vs. 0.90 (NS)
SPECT – 0.74 vs. 0.67 (p<0.001)
Greenwood J et al. Circ 2014.
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Adenosine CMR in Acute Chest Pain Intermediate risk patients randomized to –
obs unit + CMR
inpatient admission, care per admitting provider
Index visit cath in 19% (inpatient) vs. 2% (obs), p=0.01
Cath within 12 months in 33% (inpatient) vs. 15% (obs), p=0.04
Miller CD et al. JACC Im 2011, JACC Im 2013.
$2533
$842
Lower Cost
Time (Months)
Fewer Events
HR of event with usual care:3.4 (1.4 to 8.0), p = 0.006
CMR-IMPACT Trial Underway
Troponin up to 1.0 ng/mL
Aorta/proximal PAs, T1 & T2 mapping, adenosine, LGE
Randomize
CMR-guided careCMR determines need for invasive strategy
ControlGuideline-adherent, invasive strategy
Aim 1: Composite of death, nonfatal MI, and cardiac readmission
Aim 2: angiography, coronary revascularization, recurrent cardiac testing, and cardiac-related ED visits
Chadwick Miller, PI; NCT01931852
Intermediate/high risk chest pain patients with detectable to minimally elevated troponin
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Ischemic Heart Disease: Coronary Artery Disease and Beyond
Epicardial Coronary ArteryPlaque erosionPlaque composition
CapillariesSystemic inflammationBlood viscosityVessel density
modified from Gan LM et al. JCTR 2013.
Resistance ArteryVascular function; neurohumoral factors
EndotheliumSmooth muscle cells
Vascular remodeling
Perfusion CMR: Uniquely Able to Detect Coronary Microvascular Dysfunction
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Late Gadolinium Enhancement (LGE-CMR): “Bright is Dead”
Kim RJ et al. NEJM 2000.Transmurality of scar, %
Impr
ovem
ent
in c
ontr
actil
ity,
%
LV
Transmural enhancement (scar) of the lateral wall
LGE-negative, no MI history
MI by history
LGE, no MI history
NS
p=0.001
Kwong RY et al. Circ 2008.
Silent MIs in Diabetics
• Death• MI• New CHF or UA• Stroke• Ventricular arrhythmias
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Epicardial Enhancement of Myocarditis
Cardiac AmyloidosisMidwall Enhancement of NICM
Subendocardial Infarct Scar
Value Added: Other Causes of Symptoms
Distinct signatures to help diagnose myocardial disease
Cardiac MRI in DDx of Chest Pain
Ischemia Myocarditis Tako-tsubo
Cine
T2
LGE
69 ms >60 ms70-90ms
JACC Im 2011, Circ Im 2012
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Concluding Thoughts
Stress tests help in evaluation & management of IHD
Exercise preferred when feasible, esp. to diagnosis IHD correlate symptoms with test results
quantify functional capacity, ischemic burden
determine ischemic substrate for ventricular arrhythmia
Pharmacologic stress when needed
Physiologic effects differ by exercise/drug protocol
CMR gives you options
Thank You
Karolina Zareba, MDJason Craft, MD
Salman Bhatti, MDMatthew Tong, DO
Saurabh Rajpal, MBBSDaniel Addison, MD
Orlando Simonetti, PhDRizwan Ahmad, PhDJuliet Varghese, PhD
Ning Jin, PhDAndrea Cardona, MD
Beth McCarthy, RTSuzanne Smart, BS
Debbie Scandling, BSAaron O’Brien, MS
Mohamed Elamin, MDVidhya Kumar, PhD
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