Current and Future Imaging Trends in Risk Stratification for CAD Brian P. Griffin, MD FACC Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic Disclosures: None
Introduction CVD remains leading cause of death New imaging technologies are they effective in CAD risk stratification? What do recent studies say about the utility of imaging techniques in CAD risk assessment?
Anybody wonder why CAD is such an epidemic?
Low Grade Stenoses Cause Most Infarctions
Different Noninvasive Imaging Modalities Echocardiography Stress echo, Db Myocardial perfusion scintigraphy SPECT, PET Cardiac magnetic resonance Cardiac computed tomography Calcium score, CTA Inexpensive, safe, prognostic Radiation, expensive, prognostic Expensive, time consuming, structure New data
Sensitivity Comparison of Different Testing Modalities 100 90 80 70 60 50 40 30 20 10 0 1 vessel 2 vessel 3 vessel All CAD Stress ECG Stress ECHO Nuclear
Specificity of Different Stress Testing Modalities 100 90 80 70 60 50 40 30 20 10 0 Stress ECG Stress ECHO Nuclear NUCLEAR TECHNIQUES MORE SENSITIVE BUT LEAST SPECIFIC
Exercise echocardiography
Event-free Survival (%) Stress Echo and Prognosis 100 90 80 P<0.001 70 60 Females, exwmsi<1.25 Males, exwmsi<1.25 Females, exwmsi 1.25 Males, exwmsi 1.25 50 0 1 2 3 4 5 Years Category No at risk F<1.25 1929 1808 1348 890 518 299 M<1.25 1945 1783 1376 920 568 321 F 1.25 538 457 327 210 120 63 M 1.25 1372 1104 846 551 345 199 Arruda-Olsen et al JACC 2002
Adenosine MRI Adenosine stress MRI: Sensitivity 100% Specificity 93% Arai JACC 2006
Survival Probability 0.5 0.6 0.7 0.8 0.9 1.0 Event-Free Survival after Vasodilator Stress CMR As a Function of the Number of CMR Components Abnormal* None One or Two * All Three 0 250 500 750 1000 1250 1500 Time (days) *LV Function, DE, Stress perfusion N=908; 2.6 year FU Cardiac death, MI, late CABG/PCI Bingham and Hachamovitch, 2010
CTA is gold standard for assessment of Coronary Anomalies
Case 52 year old male presents with atypical left shoulder pain
Role of imaging in an asymptomatic individual without known CAD? Calcium scoring Low Cost Low radiation
MESA study: CAC and prognosis
Proportion free of CHD Proportion free of CVD 1.00 Reclassification by coronary calcium: Comparison with CRP 1.00 0.95 0.90 0.85 0.80 0.90 0.80 0.70 0.75 CAC 0 CAC 1-100 CAC >100 0.60 0.00 0.00 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 Time (Years) Time (Years) 950 subjects from MESA study with LDL < 130 mg/dl and CRP > 2 mg/l (JUPITER Criteria) followed for 5.8 years Blaha M et al. Lancet 2011
Sensitivity Sensitivity CAC, novel risk factors and intermediate risk Specificity 1.0 0.8 0.6 0.4 0.2 0.0 1.0 0.8 0.6 0.4 0.2 Incident Coronary Heart Disease 0.0 0.0 0.2 0.4 0.6 0.8 1.0 1-Specificity Specificity 1.0 0.8 0.6 0.4 0.2 0.0 1.0 0.8 0.6 0.4 0.2 Incident Cardiovascular Disease 0.0 0.0 0.2 0.4 0.6 0.8 1.0 1-Specificity Framingham Risk Score (FRS) alone (reference) FRS + coronary artery calcium FRS + carotid intima media thickness FRS + brachial flow-mediated dilation FRS + C-reactive protein FRS + plus family history FRS + plus ankle-brachial index 1330 were intermediate risk, without DM II, as part of MESA study CAC improved AUC from 0.623 vs 0.784 JAMA. 2012;308(8):788-795
Asymptomatic individuals without known CAD 2013 ACC/AHA Guidelines Calcium scoring: Class IIb If, after quantitative risk assessment, a risk-based treatment decision is uncertain J Am Coll Cardiol 2014
Experiencing Event, % Experiencing Event, % FACTOR-64 Randomized Clinical Trial 14 12 Primary Intention-to-treat Analysis of MACE Cox P value=0.38 14 12 As-treated Analysis of MACE Cox P value=0.16 10 8 No CCTA 10 8 No CCTA 6 4 CCTA 6 4 CCTA 2 2 0 0 1 2 3 4 5 6 Years of Follow-up 0 0 1 2 3 4 5 6 Years of Follow-up 900 patients with DM I or II and no documented CAD randomized to CCTA vs. standard Rx No role of screening CCTA Muhlestein et al. JAMA. 2014;312(21):2234-2243
Screening CTA in asymptomatic patients NO INCREMENTAL VALUE IN SCREENING Cho et al. Circulation. 2012;126:304-313
Imaging in Suspected Symptomatic Ischemic Heart Disease Coronary CTA Vs. Stress testing
Is CTA accurate for stenosis? N Prev Sens Spec PPV NPV ACCURACY 230 25% 95 83 64 99 CORE 64 291 56% 85 90 91 83 Meijboom 360 68% 99 64 86 97 FLASH MODE 50 32 % 100 82 72 100 Strengths of CT are high sensitivity and high NPV Meaning, if you have disease, we will find it and more importantly, If you don t have disease, you can safely go home J Am Coll Cardiol 2008;52 J Am Coll Cardiol 2008;52:2135 44 NEJM 2008;359 J Am Coll Cardiol Img 2011;4:328 37
Survival Probability CONFIRM Registry: CTA and All 1.00 cause mortality 0.95 0.90 Normal Non-obstructive P<0.0001 1-vessel CAD P<0.0001 2-vessel CAD P<0.0001 3-vessel CAD P<0.0001 0.85 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Survival Time (Years) 24,775 patients without known CAD with 2.3 year follow-up and 404 deaths Min J et al. J Am Coll Cardiol 2011;58:849 60
PROMISE: Separating fact from fiction Symptomatic, intermediate risk population Selection of appropriate patients was EXCELLENT Wholly made in USA Low event rate, suggesting OUTDATED risk prediction models CTA associated with a lower rate of cath without obstructive CAD, i.e inappropriate caths Radiation exposure lower in CTA vs. nuclear testing Death, MI, Unstable Angina, Major Complications HR 0.94; p=0.682 CTA : Functional Hazard Ratio: 1.04 (95% CI: 0.83, 1.29) P = 0.750 Douglas P. NEJM 2015
PROMISE Economic Substudy CTA strategy improved efficiency of use of invasive cath (fewer normal caths, higher proportion of caths also getting revasc) But despite lower testing costs for CTA compared with stress echo (~$100 less) and stress nuclear (~$630 less), net effect was to drive a small (<$500), statistically non-significant increase in cost After 90 days, very little test strategy-related differences in costs out to 3 years Mark D. ACC 2015
Coronary CTA in ED 8 million patients in USA, diagnostic cost of $10 billion Again, strengths of CT are high sensitivity and high NPV Cury R et al. J Nucl Cardiol 2011;18:331 41
ACIRN trial 1370 low intermediate risk subjects (TIMI risk score 0-2): 908 in the CCTA group and 462 getting traditional care CCTA group had a higher rate of discharge from ED (49.6% vs. 22.7%), a shorter LOS (median, 18.0 hours vs. 24.8 hours; P<0.001), and a higher rate of detection of CAD (9.0% vs. 3.5%) One serious adverse event in each group Litt H et al. N Engl J Med 2012
Acute chest pain: CT-STAT trial Randomized clinical trial Low, intermediate risk patients Coronary CT vs. nuclear imaging Outcomes Time to diagnosis, h Total ED costs, $ MACE in patients with normal index test CCTA Group (n=361) MPI Group (n=338) p Value 2.9 (2.1-4.0) 6.2 (4.2-19.0) <0.0001 2,137 (1,660-3,077) 3,458 (2,900-4,297) <0.0001 2/268 (0.8%) 1/266 (0.4%) 0.29 Goldstein et al. J Am Coll Cardiol 2011;58:1414 22
Proportion of Patients Discharged (%) 100 90 80 70 60 50 40 30 20 10 0 8.6 hr CCTA 26.7 hr Standard evaluation in emergency department 0 6 12 18 24 30 36 42 48 Length of Stay (hr) 1000 patient RCT: CTA vs. standard care 30 day MACE similar in both the CCTA and standard-care groups Higher downstream costs due to revascularization in CTA group Hoffmann U et al. NEJM 2012
Summary Multiple effective ways to detect CAD in symptomatic intermediate risk group Calcium score may be indicated when therapeutic dilemma in an intermediate risk asymptomatic patient CTA useful in suspected coronary anomaly In symptomatic patients strategy of CTA vs stress did not reduce event rate or cost CTA may help triage faster in ER chest pain but larger real life studies are needed