Diagnosis of CAD S Richard Underwood

Transcription

1 Diagnosis of CAD S Richard Underwood Professor of Cardiac Imaging Royal Brompton Hospital & Imperial College Faculty of Medicine London, UK

2 The history and diagnosis 89% Non-cardiac chest pain 50% Atypical angina Typical angina 16% Diamond & Forrester NEJM 1979;300:1350 Percent coronary disease

3 Pre-test likelihood of CAD Score Probability of CAD Age line Score Angina typical 26 atypical 10 non-cardiac 0 MI history 11 Q waves 12 both 30 ECG ST/T changes Both Smoker Lipids Diabetes 7 0 No smoker or lipids Prior DB, et el. Am J Med 1983; 75:

4 Myocardial perfusion The ischaemic cascade hypoperfusion metabolic alterations diastolic dysfunction systolic dysfunction ECG-Changes angina Signs of ischaemia

5 Inducible Perfusion Abnormality Stress Rest

6 Detection of CAD Sensitivity Specificity Ex-ECG MPI Gianrossi R, et al. Circulation 1989; 80: studies, patients 2 Maddahi J. Cardiac Imaging, edition 2. WB Saunders 1996: studies, 2396 patients, qualitative and quantitative SPECT

7 Sensitivity Specificity MPS for Detection of CAD 100% 90% 80% 70% 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% % 50% 40% 30% 20% 10% 0% Miller DD, Shaw LJ. J Nucl Cardiol 2001; 8: 616-9

8 Diagnosis of CAD Metanalysis, 8964 pax ROBUST, 2652 pax 100% 80% 86% 91% 74% 87% 89% 60% 40% 20% 0% Sensitivity Specificity Normalcy

9 Detection of CAD 100% 80% % 40% 20% 0% Sensitivity Ex ECG (150 studies) Thallium SPECT (6 studies) Tetrofosmin SPECT Specificity Stress echo (14 studies) MIBI SPECT(3 studies) Adapted from Beller GA

10 Post-test probability Bayes Theorem ECG + ECG - MPI + MPI Sens Spec ECG MPS Pre-test probability

11 Special circumstances in MPS LBBB, bifascicular block, and paced rhythm adenosine chronic lung disease with pulmonary hypertension false defects with dobutamine early after percutaneous coronary intervention?false defects in first 2-6 weeks balanced three vessel disease very rare dilated cardiomyopathy reversible defects possible

12 Artefact low count attenuation diaphragm inferior breast motion reconstruction apical thinning cold inferior wall

13 low count upward creep breast motion breast diaphragm

14 Stress Rest Stress Rest Conventional, backprojection Attenuation and scatter correction, iterative reconstruction

15 Angina unlikely Presentation with chest pain Assess nature of symptom risk factors examination Angina likely Avoid unnecessary tests Manage risk For definitive exclusion of CHD, consider MPI Yes Primary Able to exercise? Normal resting ECG? Male? Secondary Investigate & treat No High risk Exercise ECG Angiography Myocardial perfusion imaging Low risk Medical therapy Investigation of stable angina. BCS & RCP Guidelines. Heart 1999; 81:

16 ACC Guidelines, stable angina Ignoring guidelines CAG MPI ECG MPI CAG MPI CAG Gibbons RJ, et al. JACC 1999; 33:

17 Southampton Chest Pain Clinic 1522 patients referred Dec 97 to Apr 2000 (630/yr) clinical management decisions by SpR with consultant supervision Male % Female % Ex-ECG MPI 8 5 Angiogram Normal angiogram Wong Y et al. Heart 2001; 85:

18 Chest pain of recent onset Assessment and investigation of recent onset chest pain or discomfort of suspected cardiac origin NICE guidance March

19 Contents Acute chest pain 215 pages 88 references 51 recommendations Stable chest pain 197 pages 60 references 42 recommendations

20 Diagnosis of angina Clinical assessment alone Clinical assessment with obstructive CAD on anatomical testing Clinical assessment with myocardial ischaemia on functional testing

21 Features of angina 1. Constricting discomfort in the chest, neck, shoulders, jaw or arms 2. Precipitated by physical exertion or psychological stress 3. Relieved by rest of GTN within 5 minutes Three features = typical angina Two features = atypical angina One feature = non-anginal chest pain

22 Presentation with stable chest pain

23 Assessing likelihood of CAD Gibbons RJ, et al. ACC/AHA guideline for chronic stable angina 2002

24 Investigation of stable chest pain

25 Low pre-test likelihood If revascularisation not considered, or If invasive angiography is not appropriate or acceptable to the person Then, appropriate functional imaging Appropriate functional imaging

26 Moderate pre-test likelihood Use: MPS secho MR perfusion MR wall motion The choice of imaging method should take account of locally available technology and expertise, and the person and their preferences, including any contraindications

27 High pre-test likelihood If revascularisation not considered, or If invasive angiography is not appropriate or acceptable to the person Then, appropriate functional imaging

28 Established CAD Use: MPS secho MR perfusion MR wall motion The choice of imaging method should take account of locally available technology and expertise, and the person and their preferences, including any contraindications

29 Unhelpful investigations Do not use MR coronary angiography for diagnosis of CAD Do not use exercise ECG as the primary diagnostic test for ischaemia in people without known CAD

30 First line diagnostic investigations Likelihood <30% Coronary calcium imaging CTA if CAC Functional imaging if CAC >400 Likelihood 30-60% Functional imaging Likelihood >60% ICA, if clinically appropriate and revasc considered Functional imaging, if ICA not appropriate

31 Total costs (CAD absent) 1600 P < Management 1400 Diagnosis P < 0.05 P < Strategy Scint Non-scint EMPIRE study. Eur Heart J 1999; 20:

32 Angiography Rates N diagnostic % Normal N patients % mgmnt angios angiograms revascularised revascularised MPS users 43 28% 18 58% Non-users 86 43% 21 43% EMPIRE study. Eur Heart J 1999; 20:

33 EMPIRE implications for Southampton Annual Ex-ECG MPI Angio So ton EMPIRE MPS user approach to investigation would save 65,000 per year for the same outcome

34 Cost effectiveness of MPS Where are the savings? patient without CAD discharged without angiography patient with CAD managed medically without angiography avoid morbidity of angiography revascularisation targeted more effectively at high risk patients with most to gain

35 Clinical Indications for Perfusion Imaging Diagnosis abnormal resting ECG unable to exercise female intermediate likelihood of CAD after ex-ecg Management confirmation of ischaemia prognosis culprit lesion viable and jeopardised myocardium hibernating myocardium