Rational use of imaging for viability evaluation

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1 EUROECHO and other imaging modalities 2011 Rational use of imaging for viability evaluation Luc A. Pierard, MD, PhD, FESC, FACC Professor of Medicine Head, Department of Cardiology, CHU Liège, Belgium

2 No disclosure

3 Dysfunctional myocardium can be viable Before CABG 1 Month after CABG 3 Months after CABG EDV: 450 ml ESV: 375 ml SV: 75 ml EF: 17 % EDV: 350 ml ESV: 255 ml SV: 95 ml EF: 27 % EDV: 207 ml ESV: 110 ml SV: 97 ml EF: 47 %

4 Definition Viable myocardium : Dysfunctional myocardium recovering or improving function after revascularisation or medical therapy

5 Abnormal myocardial states Non transmural infarction Stunned myocardium Hibernating myocardium Inducible ischaemia

6 Transmural extent of necrosis? Also clinically relevant

7 Transmural scar 2D Echo MCE LE Cardiac MR

8 Diagnostic tools for viability Myocardial Blood Flow SPECT ( 99m Tc MIBI), PET ( 13 NH 3 ) MCE, Cardiac MR Membrane Function Metabolism Contractile Reserve Scar Imaging SPECT ( 201 Tl) SPECT ( 18 F-FDG) PET ( 18 F-FDG) Dobutamine echo or cardiac MR Cardiac MR, CT, 3D-echo

9 Positive predictive value (%) Prediction of regional functional recovery MIBI PET Tl RR Tl Reinj. 70 Dob-E 60 LE-MRI Dob-MRI Negative predictive value (%)

10 Viability assessment : meta-analysis 24 studies 6 studies using Thallium-201 perfusion imaging 7 studies with dobutamine echo (low in 3, high in 4) 11 studies using FDG imaging (10 with PET, 1 with SPECT) Allman et al. JACC, 2002

11 Annual mortality (%) Allman et al. JACC 2002;39:1151 Prognostic importance of myocardial viability (56% of patients) % χ 2 =147 p< % χ 2 =1.43 p= V-RVS (n=728) V-MED (n=483) NV-RVS (n=366) NV-MED (n=579)

12 Predicted reduction in death rate with revascularization 0-25 Viable -50 Non- Viable Lef t Vent ricular EF % Allman et al. JACC, 2002

13 Limitations of cohort studies Decision for CABG may have been influenced by viability status No (or inadequate) adjustment for key baseline variables (age, comorbidities) Cohort studies performed before modern medical therapy (ß blockers, statins, antiplatelet agents, aldosterone antagonists)

14 STICH Trial Myocardial Viability and Survival in Ischemic Left Ventricular Dysfunction

15 Population 1212 patients 618 patients with viability test 594 patients without viability test 17 poor quality tests 601 patients with usable viability test 611 patients with no usable viability test Bonow et al. N Engl J Med :

16 Viability methods SPECT protocols: Thallium-201 stress-redistribution-reinjection Thallium-201 rest-redistribution Nitrate-enhanced Tc-99m perfusion imaging Dobutamine echo protocol: Staged increase in dobutamine starting at 5 μg/kg/min Bonow et al. N Engl J Med :

17 Assessment of viability 601 patients with usable viability test 471 patients with SPECT 280 patients with Dobutamine echo 487 patients with viable myocardium (80%) 114 patients with nonviable myocardium Bonow et al. N Engl J Med :

18 Overall mortality (%) Overall mortality Nonviable Viable Time (years) HR 95% CI P , Bonow et al. N Engl J Med :

19 CV mortality (%) Cardiovascular mortality HR 95% CI P , Nonviable Viable Time (years) Bonow et al. N Engl J Med :

20 Revascularization vs medical treatment 601 eligible patients 487 patients with viability 114 patients without viability 243 MED 244 CABG 60 MED 54 CABG Bonow et al. N Engl J Med :

21 Overall mortality (%) Overall mortality with viable myocardium R/ Med RVS Time (years) Bonow et al. N Engl J Med :

22 STICH Trial : Conclusions Significant association between myocardial viability and outcome, but no longer significant with multivariable analysis No significant interaction between viability and medical vs surgical treatment with respect to mortality, whether assessed according to treatment assigned (intention to treat) or to the treatment actually received. Bonow et al. N Engl J Med :

23 STICH Trial: Limitations STICH did investigate infarct size: in > 80% of the patients, viability was assessed by the size of the perfusion defect with SPECT at rest In patients tested by dobutamine echo, there was no distinction between biphasic response and sustained improvement Too small number of patients with nonviable myocardium Most patients had (perhaps too) severe LV remodeling

Overall mortality (%) Prognostic value of myocardial viability using late enhancement cmr 100 80 60 40 20 0 RVS V

24 Overall mortality (%) Prognostic value of myocardial viability using late enhancement cmr RVS V MED NV RVS NV MED V Time (months) Mantel Cox p = Gerber et al. J Am Coll Cardiol in press

25 Is viability testing clinically relevant? Case 1 55 year-old man with chest pain and ST Admitted 2 hours after the onset of symptoms ECG: acute inferior STEMI Primary PCI of the RCA No stenosis of the left coronary artery

26 12-lead ECG at admission

27 Primary PCI of the RCA

28 Is viability testing clinically relevant? Case 2 65-year old man Angina class III No clinical sign of heart failure LV ejection fraction = 35 % 3 VD, suitable for revascularization Viability testing: not clinically relevant

29 Is viability testing clinically relevant? Case 3 42-year old man Anterior MI 2 years ago Clinical signs of heart failure

30 Case 3

31 Is viability testing clinically relevant? Case 3 Thin, dyskinetic septal and anterior walls: transmural necrosis Occluded non proximal LAD artery Normal L Cx and RCA LV ejection fraction = 30% Viability testing: not clinically relevant

32 Is viability testing clinically relevant? Case 4 57-year old diabetic patient Prior anterior and inferior infarction Clinical signs of heart failure LV ejection fraction = 22%

33 Case 4

34 Is viability testing clinically relevant? Case 4 LV ejection fraction = 22% Diffuse, severe coronary atherosclerosis not suitable for revasculariztion Viability testing: to predict the EF response to ß-blockers (CHRISTMAS trial)

35 Is viability testing clinically relevant? Case 5 Symptoms of heart failure LVEF = 34 % 75% stenosis of L Cx Occluded RCA collateral circulation Viable myocardium in RCA territory?

36 Biphasic response of the inferior wall

37 Is viability testing clinically relevant? Case 6 74-year woman Severe ischemic cardiomyopathy LV ejection fraction = 28% QRS duration = 135 ms Heart failure class III under medical therapy CRT?

38 LV dyssynchrony by 2D strain

39 Suitable veins and viability

40 Scar location and extent

41 Conclusions Despite STICH, viability assessment remains clinically useful Appropriate relevant indications Extent of transmural scar: cardiac MR Contractile reserve if critical coronary stenosis Biphasic response is more predictive DSE when good images and clear response Dobutamine cardiac MR in other cases

Revascularization in Severe LV Dysfunction: The Role of Inducible Ischemia and Viability Testing

Revascularization in Severe LV Dysfunction: The Role of Inducible Ischemia and Viability Testing Evidence and Uncertainties Robert O. Bonow, MD, MS, MACC Northwestern University Feinberg School of Medicine