Detection and Assessment of MI: Use of Imaging Methods Robert O. Bonow, M.D.
Detection and Assessment of MI: Use of Imaging Methods Robert O. Bonow, M.D. No Relationships to Disclose
Expert Consensus Document
Expert Consensus Document Third Universal Definition of Myocardial Infarction Chairpersons: Kristian Thygesen (DENMARK) Joseph S. Alpert (USA) Harvey D. White (NEW ZEALAND) Imaging Group: Richard Underwood (UK) Jeroen J. Bax (THE NETHERLANDS) Robert O. Bonow (USA) Raymond J. Gibbons (USA) Fauso Pinto (PORTUGAL)
Cardiac Imaging in MI Imaging parameters: Myocardial perfusion Myocyte viability Myocardial thickness and thickening Myocardial wall motion Effects of fibrosis on radiolabelled, paramagnetic, and iodinated contrast agents
Cardiac Imaging in MI Echocardiography Nuclear cardiology Cardiac magnetic resonance Cardiac computed tomography
Cardiac Imaging in MI Echocardiography Versatile Portable and available Relatively inexpensive Stress protocols established and straightforward Advances in contrast, TDI, 3D imaging
Cardiac Imaging in MI Echocardiography Strengths: Assessment of thickness, thickening, and wall motion Increasing use of 3D imaging Contrast agents for endocardial definition, perfusion, and microvascular obstruction Tissue Doppler and strain imaging for assessment of regional function
Cardiac Imaging in MI Echocardiography Strengths: Assessment of thickness, thickening, and wall motion Increasing use of 3D imaging Contrast agents for endocardial definition, perfusion, and microvascular obstruction Tissue Doppler and strain imaging for assessment of regional function Portability, availability
Cardiac Imaging in MI Nuclear cardiology Readily available Relatively inexpensive Stress protocols established and straightforward Extensive data base regarding diagnosis, prognosis, risk stratification
Cardiac Imaging in MI Nuclear cardiology Strengths Direct imaging of myocardial viability Common SPECT tracers assess infarction and inducible perfusion abnormalities Evolving techniques to assess sympathetic innervation (MIBG), MMP activation in LV remodeling, and assessment of metabolism
Cardiac Imaging in MI Nuclear cardiology Strengths Direct imaging of myocardial viability Common SPECT tracers assess infarction and inducible perfusion abnormalities Evolving techniques to assess sympathetic innervation (MIBG), MMP activation in LV remodeling, and assessment of metabolism Limitation Low resolution, may not detect small MI s
Cardiac Imaging in MI Cardiac magnetic resonance Strengths Assessment of global function and regional thickness, thickening and motion Myocardial perfusion, microvasc obstruction Detection of necrotic / fibrotic myocardium High spatial resolution for small MI s
Cardiac Imaging in MI Cardiac magnetic resonance Strengths Assessment of global function and regional thickness, thickening and motion Myocardial perfusion, microvasc obstruction Detection of necrotic / fibrotic myocardium High spatial resolution for small MI s Limitations Cost / availability Not practical for acute imaging
Copyright, 1994, by the Massachusetts Medical Society Volume 343 NOVEMBER 16, 2000 Number 20 LAD LCX RCA
Transmural infarction Subendocardial infarction SPECT CMR Histology Wagner et al. Lancet 2003;361:374-379
Magnetic Resonance Imaging Infarct Detection Wagner et al. Lancet 2003;361:374-379
Magnetic Resonance Imaging Infarct Detection Wagner et al. Lancet 2003;361:374-379
Cardiac Imaging in MI Cardiac computed tomography Strengths Noninvasive coronary angiography Assessment of global function and regional thickness, thickening and motion Myocardial perfusion Detection of necrotic / fibrotic myocardium Available in acute settings
Cardiac Imaging in MI Cardiac computed tomography Strengths Noninvasive coronary angiography Assessment of global function and regional thickness, thickening and motion Myocardial perfusion Detection of necrotic / fibrotic myocardium Available in acute settings Limitations Validation of infarct detection
Cardiac Imaging in MI Cardiac computed tomography The CT-STAT Trial CCTA definitively established the presence or absence of significant CAD in 86% of patients with suspected ACS Time-to-diagnosis decreased by half, due to more rapid facilitation in testing Cost-to-diagnosis decreased by one-third, primarily due to expedited time-to-diagnosis and reduced length of stay Raff et al. Circulation 2009;120:2160
Contrast Hyperenhancement CMR CT A B C Mahnken et al, J Am Coll Cardiol 2005;45:2042-2047
Cardiac Imaging in MI Applications in acute phase of MI Imaging is useful in diagnosis of MI by detection of wall motion abnormalities or loss of viability in presence of elevated biomarkers If biomarkers not measured or have normalized, new loss of viability meets criteria for MI Normal function and viability have very high negative predictive value to exclude acute MI
Cardiac Imaging in MI Applications in acute phase of MI Imaging is useful in diagnosis of MI by detection of wall motion abnormalities or loss of viability in presence of elevated biomarkers If biomarkers not measured or have normalized, new loss of viability meets criteria for MI Normal function and viability have very high negative predictive value to exclude acute MI However, if biomarkers have been measured at appropriate times and are normal, they take precedence over imaging criteria
Cardiac Imaging in MI Applications in subacute phase of MI Measurement of infarct size is helpful in predicting subsequent adverse LV remodeling and prognosis
6-Month Mortality (%) 6 Myocardial Salvage 5 4 3 2 1 0 87 <12 12-19 88 20-35 89 36-50 90 >50 Infarct Size(% LV)
Wu et al, Lancet 2001;357:21-28
Late LV Ejection Fraction (percent) Late LVEDV (ml/m 2 ) Infarct Size and LV Remodeling 70 60 50 40 30 20 10 n=71 r = 0.76 p<0.001 140 120 100 80 60 40 20 r = 0.72 p<0.001 0 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Initial Infarct Size (%LV) Initial Infarct Size (%LV) Wu et al. Heart 2008;94:730-736
LV Remodeling Post-MI 4 days Wu et al. Heart 2008;94:730-736
LV Remodeling Post-MI 4 days 6 months Wu et al. Heart 2008;94:730-736
Survival (percent) Infarct Size and Survival 100 80 60 40 20 Infarct size <20% Infarct size 20% p<0.01 0 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 Time (years) Wu et al. Heart 2008;94:730-736
Infarct Size (%) Myocardial Salvage (%) 20 18 16 14 12 10 8 6 4 2 0 Infarct Size p=0.005 <90 90-150 150-360 >360 87 88 89 90 Time Time to to Reperfusion (min) (min) 10 8 6 4 2 0 Myocardial Salvage p=0.003 <90 90-150 150-360 >360 87 Time to 88 Reperfusion 89(min) 90 Francone, J Am Coll Cardiol 2009;54:2145-2153
LV Volume (ml) 180 160 140 120 End-Diastolic Volume 180 160 140 120 End-Systolic Volume Initial 6 Months 100 100 80 80 60 60 40 40 20 20 0 <90 90-150 150-360 >360 87 88 89 90 Time to to Reperfusion (min) 0 <90 90-150 150-360 >360 87 88 89 90 Time to Reperfusion (min) Francone, J Am Coll Cardiol 2009;54:2145-2153
Cardiac Imaging in MI Applications in healing or healed phase of MI Regional wall motion abnormalities, wall thinning or scar, in the absence of nonischemic causes, provides evidence of previous MI High resolution and specificity of late contrast enhancement on CMR makes this a valuable technique
Cardiac Imaging in MI Echocardiography Nuclear cardiology Cardiac magnetic resonance Cardiac computed tomography