Subha V. Raman, MD, MSEE, FACC, FAHA

Transcription

1 OSU Cardiovascular MR/CT Update April 27, 2018 Contemporary Approaches to Myocardial Ischemia Subha V. Raman, MD, MSEE, FACC, FAHA Professor and Medical Director, CMR/CCT Disclosures Institutional research support from Siemens Co-inventor, MR-compatible treadmill 1

2 Outline Motivation for stress testing in IHD; typical scenarios Exercise and pharmacologic stress methods Guidelines Myocardial Ischemia: inadequate oxygen supply to meet demand 2

3 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? Substernal chest discomfort Provoked by exertion Relieved with rest or nitroglycerin Ventricular arrhythmias is substrate ischemia? Infarct scar Reentry loop 3

4 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

5 Choosing between Exercise & Pharmacologic Stress for Ischemia Testing Can patient exercise? No Pharmacologic stress imaging Yes Resting ECG interpretable? Yes Exercise stress ECG No Exercise stress imaging ACC/AHA Guidelines preoperative evaluation often can t exercise Estimated Perioperative Risk Poor or unknown functional capacity Pharmacologic Stress Testing 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management 5

6 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

7 Dobutamine Stress Echo vs. CMR DSE DCMR Sensitivity 74% 86% Specificity 70% 86% PPV 81% 91% NPV 61% 78% Accuracy 73% 86% Nagel E et al. Circ Dobutamine CMR: Prognostic Value and Cost-Effective HR for MI/cardiac death: 4.1 [95% CI ] Costs Survival similar survival with ~12500 savings per life year Wallace EL et al. JACC Im Petrov G, Kelle S et al. Clin Res Cardiol

8 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 STRESS REST SPECT Breast artifact vs. anterior ischemia 8

9 SPECT vs. Vasodilator Stress CMR SPECT CMR Sensitivity 66% 86% Specificity 83% 83% PPV 71% 77% NPV 79% 91% Greenwood JP et al. Lancet Adenosine CMR: Similar Accuracy in Women and Men Males vs. Females AUC: CMR 0.89 vs (NS) SPECT 0.74 vs (p<0.001) Greenwood J et al. Circ

10 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 Lower Cost $2533 Fewer Events $842 HR of event with usual care: 3.4 (1.4 to 8.0), p = Time (Months) Miller CD et al. JACC Im 2011, JACC Im CMR-IMPACT Trial Underway Troponin up to 1.0 ng/ml Aorta/proximal PAs, T1 & T2 mapping, adenosine, LGE Intermediate/high risk chest pain patients with detectable to minimally elevated troponin Randomize Control Guideline-adherent, invasive strategy CMR-guided care CMR determines need for 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; NCT

11 Ischemic Heart Disease: Coronary Artery Disease and Beyond Epicardial Coronary Artery Plaque erosion Plaque composition Resistance Artery Vascular function; neurohumoral factors Endothelium Smooth muscle cells Vascular remodeling Capillaries Systemic inflammation Blood viscosity Vessel density modified from Gan LM et al. JCTR Perfusion CMR: Uniquely Able to Detect Coronary Microvascular Dysfunction 11

12 Late Gadolinium Enhancement (LGE-CMR): Bright is Dead LV Transmural enhancement (scar) of the lateral wall Improvement in contractility, % Transmurality of scar, % Kim RJ et al. NEJM Silent MIs in Diabetics MI by history LGE-negative, no MI history Death MI New CHF or UA Stroke Ventricular arrhythmias NS LGE, no MI history p=0.001 Kwong RY et al. Circ

13 Value Added: Other Causes of Symptoms Subendocardial Infarct Scar Midwall Enhancement of NICM Epicardial Enhancement of Myocarditis Cardiac Amyloidosis Distinct signatures to help diagnose myocardial disease Cardiac MRI in DDx of Chest Pain Cine T2 69 ms >60 ms 70-90ms LGE Ischemia Myocarditis Tako-tsubo JACC Im 2011, Circ Im

14 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, MD Jason Craft, MD Salman Bhatti, MD Matthew Tong, DO Saurabh Rajpal, MBBS Daniel Addison, MD Orlando Simonetti, PhD Rizwan Ahmad, PhD Juliet Varghese, PhD Ning Jin, PhD Andrea Cardona, MD Beth McCarthy, RT Suzanne Smart, BS Debbie Scandling, BS Aaron O Brien, MS Mohamed Elamin, MD Vidhya Kumar, PhD 14