Detection and Assessment of MI: Use of Imaging Methods. Robert O. Bonow, M.D.

Transcription

1 Detection and Assessment of MI: Use of Imaging Methods Robert O. Bonow, M.D.

2 Detection and Assessment of MI: Use of Imaging Methods Robert O. Bonow, M.D. No Relationships to Disclose

3 Expert Consensus Document

4 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)

5 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

6 Cardiac Imaging in MI Echocardiography Nuclear cardiology Cardiac magnetic resonance Cardiac computed tomography

7 Cardiac Imaging in MI Echocardiography Versatile Portable and available Relatively inexpensive Stress protocols established and straightforward Advances in contrast, TDI, 3D imaging

8 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

9 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

10 Cardiac Imaging in MI Nuclear cardiology Readily available Relatively inexpensive Stress protocols established and straightforward Extensive data base regarding diagnosis, prognosis, risk stratification

11 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

12 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

13 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

14 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

15 Copyright, 1994, by the Massachusetts Medical Society Volume 343 NOVEMBER 16, 2000 Number 20 LAD LCX RCA

16 Transmural infarction Subendocardial infarction SPECT CMR Histology Wagner et al. Lancet 2003;361:

17 Magnetic Resonance Imaging Infarct Detection Wagner et al. Lancet 2003;361:

18 Magnetic Resonance Imaging Infarct Detection Wagner et al. Lancet 2003;361:

19 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

20 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

21 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

22 Contrast Hyperenhancement CMR CT A B C Mahnken et al, J Am Coll Cardiol 2005;45:

23 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

24 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

25 Cardiac Imaging in MI Applications in subacute phase of MI Measurement of infarct size is helpful in predicting subsequent adverse LV remodeling and prognosis

26 6-Month Mortality (%) 6 Myocardial Salvage < >50 Infarct Size(% LV)

27 Wu et al, Lancet 2001;357:21-28

28 Late LV Ejection Fraction (percent) Late LVEDV (ml/m 2 ) Infarct Size and LV Remodeling n=71 r = 0.76 p< r = 0.72 p< Initial Infarct Size (%LV) Initial Infarct Size (%LV) Wu et al. Heart 2008;94:

29 LV Remodeling Post-MI 4 days Wu et al. Heart 2008;94:

30 LV Remodeling Post-MI 4 days 6 months Wu et al. Heart 2008;94:

31 Survival (percent) Infarct Size and Survival Infarct size <20% Infarct size 20% p< Time (years) Wu et al. Heart 2008;94:

32

33 Infarct Size (%) Myocardial Salvage (%) Infarct Size p=0.005 < > Time Time to to Reperfusion (min) (min) Myocardial Salvage p=0.003 < > Time to 88 Reperfusion 89(min) 90 Francone, J Am Coll Cardiol 2009;54:

34 LV Volume (ml) End-Diastolic Volume End-Systolic Volume Initial 6 Months < > Time to to Reperfusion (min) 0 < > Time to Reperfusion (min) Francone, J Am Coll Cardiol 2009;54:

35 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

36 Cardiac Imaging in MI Echocardiography Nuclear cardiology Cardiac magnetic resonance Cardiac computed tomography

37