2/20/2013. Why use imaging in CV prevention? Update on coronary CTA in 2013 Coronary CTA for 1 0 prevention: pros and cons Are we there yet?

Transcription

1 Evolving Role of Coronary CTA in Primary Cardiovascular Disease Prevention: Are We There Yet? Ron Blankstein, M.D., F.A.C.C. Co-Director, Cardiovascular Imaging Training Program Associate Physician, Preventive Cardiology Cardiovascular Division & Department of Radiology Brigham and Women's Hospital Assistant Professor in Medicine and Radiology Harvard Medical School February 16, 2013 Disclosures Conflicts of interest: None Board of Directors, Certification Board of Cardiovascular Computed Tomography (CBCCT) Outline Why use imaging in CV prevention? Update on coronary CTA in 2013 Coronary CTA for 1 0 prevention: pros and cons Are we there yet? 1

2 Controversies in 1 0 prevention: Treat all Treat those with risk factors Treat those with disease Identification of risk prior to a CHD event Genetics Diabetes Hypertension Dyslipidemia Inflammation Environment Risk Factors Pre-clinical atherosclerosis Overt CAD CHD Event Death MI ACS PCI / CABG Impaired MBF reserve Ischemia Outline Why use imaging in CV prevention? Update on coronary CTA in 2013 Coronary CTA for 1 0 prevention: pros and cons Are we there yet? 2

3 Cardiac CTA: How do we do it? Premedication: NTG, β blockers Patient preparation: 18g IV Contraindications: Renal insufficiency Contrast allergy Scan time: <10 seconds Scan protocol: Timing of contrast bolus individualize scanner settings Image Reconstruction Interpretation Cardiac CTA: What is new in 2013? New scanners: faster ; better resolution Lower radiation dose Emerging techniques to assess hemodynamic significance of lesions Massive expansion in literature Multi center comparative effectiveness trials: ISCHEMIA, PROMISE, RESCUE Better (but still suboptimal) insurance coverage When should CTA be performed in 2013: Symptomatic patients with a low-intermediate risk Acute chest pain (selected patients) Following equivocal results from other stress tests Suspected anomalous origin of the coronary arteries Pulmonary Artery Aorta 3

4 No plaque / stenosis Definitively exclude CAD Partially calcified plaque Non-calcified plaque 50 patients with MI by CMR CTA : 101 plaques IA: 41 plaques Plaque is better seen on CTA than on invasive angiography (Circulation, 2012) 4

5 What is the significance of non- obstructive plaque on CTA? Prognostic Value of CTA: All cause mortality CONFIRM Registry 23,854 patients ( Min et al JACC 2011) All Events 1234 patients F/U 52 months Cardiac Death MI Late Revasc 72% 31% Cardiac Death MI 88% 54% (Andreini et al, JACC CV Img, 2012) 5

6 Non-obstructive plaque is associated with higher allcause mortality than no plaque (CONFIRM registry) CONFIRM Registry: 10,418 Patients ; F/U = 27 months 5712 No Plaque: 41 (0.72%) Deaths 4706 Non-obstructive plaque: 79 (1.68%) Deaths ((Courtesy: Ben Chow MD) Plaque Higher Risk Will knowledge on presence (or absence) of plaque change patient management? Statin Rx Increases Post CTA (N=2839 individuals) Percent Taking Statin Therapy 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% No CAD Non-Obstructive CAD 50% CAD Statin pre post - intensified Statin dose change Statin post - no 29% 28% 66% 60% 54% 19% 44% 28% 15% Pre-CCTA Post-CCTA Pre-CCTA Post-CCTA Pre-CCTA Post-CCTA No (n=1147) <50% (n=1067) >50% (n=625) CAD CAD CAD (Hulten, Bittencourt et al, BWH/MGH Data, ACC 2013) 6

7 ASA Rx Increases Post CTA (N=2839 individuals) Percent taking aspirin therapy 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% No CAD Non-Obstructive CAD 50% CAD 89% 72% 46% 25% 17% 10% Pre-CCTA Post-CCTA Pre-CCTA Post-CCTA Pre-CCTA Post-CCTA Aspirin pre Aspirin post (Hulten, Bittencourt et al, BWH/MGH Data, ACC 2013) Plaque Higher Risk Will knowledge on presence (or absence) of plaque change patient management? Will treatment based on this change outcomes? Also no benefit for. - Genetic testing - Lipoprotein analysis - hscrp for high risk patients 7

8 APPROPRIATE USE CRITERIA Coronary CTA 2010 Indication Global CHD Risk CTA CAC Asymptomatic No known CAD Low I I Intermediate I A High U U Outline Why use imaging in CV prevention? Update on coronary CTA in 2013 Coronary CTA for 1 0 prevention: pros and cons Are we there yet? Rationale for CTA versus CAC Identify individuals with plaque who have no CAC missed disease by CAC scanning How many patients with CAC=0 have significant CAD? Study Population CAC=0 Vilines et al JACC 2012 (CONFIRM) Hulten et al SCCT 2012 N=10,037 Symptomatic N= 1145 Symptomatic Any CAD 51% 16% 3.5% 1.4% 42% 17% 1.5% 0.4% 50% 70% Prognosis 7 events in CAC=0 and stenosis, mostly late revasc 7 deaths non coronary related 8

9 Rationale for CTA versus CAC Identify individuals with plaque who have no CAC missed disease by CAC scanning Better assessment of extent and severity of CAD improved prognosis Identify if stenosis is present CTA does not offer improved prognosis over CAC in asymptomatic patients: 7,590 subjects underwent CTA and CAC Median f/u: 24 months Outcome: 2.2% : 136 deaths ; 14 non-fatal Mis CTA based algorithm no added benefit over model which had traditional risk factors and CAC. CTA does not offer improved prognosis over CAC in asymptomatic patients: Conclusion: the additional risk-predictive advantage by ccta is not clinically meaningful compared with a risk model based on CACS. application of ccta for risk assessment of individuals without CPS should not be justified. 9

10 1 0 prevention: only for asymptomatic patients? Presence of disease predicts risk more than symptoms Pre-test likelihood of stenosis Observed stenosis by CTA 14,048 pts w/ suspected CAD (Victor Cheng et al., Circulation 2011) 10

11 (Victor Cheng et al., Circulation 2011) Reasons NOT to use CTA for prevention Higher cost than CAC CAC: Lowest cost Cost (US$) $800 $600 $200 11

12 Reasons NOT to use CTA for prevention Higher cost than CAC Need for contrast Potential for unnecessary downstream testing Medicare beneficiaries who underwent CCTA were more likely to undergo subsequent invasive cardiac procedures and have higher CAD-related spending that patients who underwent stress testing Problem: Average age 74 (Shreibati et al, JAMA 2011) (Blankstein, Hoffmann, JAMA 2011) Revascularization Invasive Angiography (Hulten et al., JACC 2013 in press) 12

13 An abnormal screening CTA result was predictive of increased aspirin and statin use at 90 days and 18 months. Screening CTA was associated with increased invasive testing, without any difference in events at 18 months. Screening CTA should not be considered a justifiable test at this time. Reasons NOT to use CTA for prevention Higher cost than CAC Need for contrast Potential for unnecessary downstream testing No quantifiable score Data on risk stratification in asymptomatic patients limited Reasons NOT to use CTA for prevention Higher cost than CAC Need for contrast Potential for unnecessary downstream testing No quantifiable score Data on risk stratification in asymptomatic patients limited More susceptible to technical limitations Higher radiation ( slightly) Not supported by any guidelines / AUC 13

14 But are there sub-groups in which CTA will be better than CAC? Patients with predominantly non-calcified plaque: HIV OHT Tobacco, young age family history Diabetes Hyperlipidemia Outline Why use imaging in CV prevention? Update on coronary CTA in 2013 Coronary CTA for 1 0 prevention: pros and cons Are we there yet? When might we get there? 14

15 Will more potent therapies require better identification of higher risk patients? Will the warranty period of a normal CTA be longer than that of CAC=0? Data that treating based on CTA can improve CV outcomes? Data regarding safety of not treating high risk patients who have no plaque Will sub-groups of asymptomatic high risk patients exist in which CTA will be useful? CTA will be able to both up-classify and downclassify risk thereby resulting in significant change to patient management.and do so better than CAC and/or other biomarkers Heterozygous FH Diabetes PAD Strong family history Case: 33 year old female, strong family history, Lp(a)=180 TC 196 TG 120 HDL 57 LDL

16 Conclusion The presence of coronary plaque both by CTA and CAC testing -- is predictive of future risk of coronary events in asymptomatic individuals While CTA is considered to be an inappropriate test for screening asymptomatic individuals for 1 0 prevention, there is uncertainty whether carefully selected high risk patients may benefit from such testing. Given that CAC is cheaper and safer, further studies are needed in order to demonstrate whether sub-groups exist in which CTA provides incremental prognostic data. Thank you 16