Quality Challenges and Pitfalls in the Evaluation of Patients with Suspected Heart Disease
Joseph A. Ladapo, MD, PhD Assistant Professor of Medicine Department of Population Health NYU School of Medicine
Disclosures: K23 HL116787 Award from National Heart, Lung, and Blood Institute; Consultant for CardioDx, Inc
Overview
• Health and economic burden of coronary artery disease (CAD)
• Pitfalls in care of patients suspected of having CAD
• Approaches to improve quality of care
• Introduction to Corus CAD, a gene expression test for CAD
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1 Coronary Artery Disease (CAD) is a Major Public Health Challenge
Epidemiology
• 15.4 million adults in the US live with CAD • 6.4% of adults overall; 7.9% of men and 5.1% of women
Mortality Myocardial infarction
• Accounts for over 386,000 deaths • Nearly one million new or recurrent annually (1 in 6 of all deaths) heart attacks each year
• More than half of sudden cardiac • Early diagnosis is important deaths occur in people with no prior because treatment & preventive history of heart disease practices significantly reduce morbidity and mortality
National Health Interview Survey, 2010; Go, Circulation 20133
Healthcare Utilization and Costs Attributable to CAD are Substantial
Healthcare utilization and costs
• CAD costs $195.2 billion in direct and indirect costs annually (2009) • In 2006, Medicare spent $11.7 billion on inpatient care for CAD • By 2030, medical costs for CAD (real 2010$) projected to increase ≈100%
Ambulatory care Hospital care
• In 2009, there were over 14 million • 1.3 million hospital admissions with ambulatory care visits with CAD as the CAD listed as the first diagnosis first-listed diagnosis • 954,000 percutaneous coronary interventions (PCIs), 397,000 cardiac bypass surgeries, 1.03 million diagnostic cardiac catheterizations
National Health Interview Survey, 2010; Go, Circulation 20134
2 Cardiac Stress Testing
Source of picture: American College of Cardiology, CardioSmart website
Primary Care Physicians Routinely Manage Patients With Suspected or Diagnosed CAD
~4M Stable, Symptomatic Patients Suggestive of Coronary Disease Annually Diagnostic Tools
Clinical Factors Primary Care EKG Treadmill
Stress Echo Often Repeat Cardiology Nuclear Imaging Testing CT Angiography
Invasive Obstructive CAD is not found in Angiography ~60% patients1
~$4.5B annual expenditures2
1 Patel et al, N Engl J Med 2010;362:886-95; COMPASS study. 2 IMV Market Reports 6
3 Ambulatory Care: Cardiac Stress Tests In Patients Without CAD, From 1993 To 2010
5,000,000
4,000,000
3,000,000
2,000,000 Any cardiac stress test
No. of Tests Stress imaging 1,000,000 Avg. Avg. annual annual cost in cost in - 1993-1995 2008-2010 All cardiac $820M $2.0B stress tests
Stress $550M $1.9B imaging
7 Source: Ladapo et al, Annals of Internal Medicine 2014
Opportunities For Quality Improvement
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4 Despite Wide Array of Available Tests for Working Up CAD, Patients Routinely Encounter…
1. Diagnostic uncertainty
2. Unnecessary testing and procedures
3. Unnecessary radiation exposure
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Challenges to Clinical Care: Diagnostic Uncertainty
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5 Uncertainty About How to Interpret Diagnostic Test Results is Common
• Bayes’ theorem defines how pretest disease risk and diagnostic test performance can be used to guide interpretation of test results
Missed or Correctly misdiagnosed identified
Reverend Thomas Bayes
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Stress Test Effectiveness in Diagnosing CAD: Results From Meta-analyses
Stress MPI Stress ECHO
Sens Spec # studies Sens Spec # studies
Garber et 88% 77% 10 76% 88% 6 al
Fleischma 87% 64% 27 85% 77% 24 nn et al
Mowatt et 76% 65% 10 --- al*
Mowatt et 92% 74% 4 --- al**
*includes or **excludes patients with prior myocardial infarction
Garber, Annals 1999; Fleischmann, JAMA 1998; Mowatt, HTA 2004 12
6 Physicians Interpret Test Results in a Bayesian Manner
Stress MPI example
• Most frequently performed imaging stress test • Sensitivity = 87%, Specificity = 64%
Normal test result Abnormal test result
• With a pretest probability of 20%, • With a pretest probability of 20%, post-test probability of CAD is 5% post-test probability of CAD is after a normal test result 38% after an abnormal test result
• With a pretest probability of 60%, • With a pretest probability of 60%, post-test probability of CAD is 23% post-test probability of CAD is after a normal test result 78% after an abnormal test result
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Referral Bias also Influences Diagnostic Accuracy and Test Interpretation
Referral bias Biases clinical • Sometimes called “verification bias” or “workup bias” decision-making • Occurs because higher-risk patients are preferentially referred to cardiac catheterization • Bayesian methods needed to adjust • Because it biases test diagnostic test performance for referral performance, it may also bias clinical decision-making
• Studies of stress test performance do not adjust Most studies do for this phenomenon so not account for estimates of sensitivity and referral specificity biased
Begg, Biometrics 1983 14
7 Presentation Title Goes HereLadapo et al, JAHA 2013 15
Cardiac Catheterization Referral Rates After Normal Exercise ECHO or MPI Results
Referral rates are low after a normal study • Range of ~1% to 5% generally
Homogenous • Geographic location and patient characteristics vary but little variation in referral rates
Ladapo et al, JAHA 2013 16
8 Cardiac Catheterization Referral Rates After Abnormal Exercise ECHO or MPI Results
Referral rates higher after an abnormal test • Range of ~20% to 50% generally
Heterogeneity • Significant variation in referral rates
Ladapo et al, JAHA 2013 17
Observed vs. True Diagnostic Performance of Exercise ECHO
99% 100% 91% 81% 80%
60% 40% 40%
20%
0% Sensitivity Specificity Observed performance True performance
True performance = observed performance after adjustment for referral18
9 Observed vs. True Diagnostic Performance of Exercise MPI
97% 100% 91%
80% 67% 60% 44% 40%
20%
0% Sensitivity Specificity Observed performance True performance
True performance = observed performance after adjustment for referral19
Challenges to Clinical Care: Unnecessary Testing and Procedures
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10 Unnecessary Testing is Common
Our Threshold for Testing Patients is Falling
• 39,515 patients undergoing stress MPI between 1991- 2009 at Cedars Sinai
• Incidence of abnormal scans fell from 41%→9%
• Incidence of ischemic scans fell from 30%→5%
• Only 3% of patients who did not have typical angina and could exercise had an abnormal scan
Rozanski, JACC 2013 21
Unnecessary Procedures are Common
Cardiac Catheterization Frequently Performed Needlessly
• 398,978 patients in American College of Cardiology (ACC) National Cardiovascular Data Registry (NCDR)
• Noninvasive cardiac testing performed in 84% of patients prior to catheterization
• Only 1 in 3 patients were found to have obstructive coronary disease
• No coronary artery disease was reported in 39% of patients
Patel, NEJM 2010 22
11 Inappropriate Imaging is Common
What is appropriate imaging?
• Imaging that provides (1) accurate information, (2) influences behavior, and (3) yields benefits that outweigh risks
• In general, imaging in intermediate to high-risk patients is appropriate (diabetics, AAA, PVD, angina/ischemic equiv., ECG uninterpretable)
• Number of inappropriate cardiac imaging stress tests in patients evaluated for CAD has risen
• Primary care doctors fare worse than cardiologists
Presented at American College of Cardiology 63rd Annual Scientific Session, March 23 2014 in Washington, DC
Challenges to Clinical Care: Unnecessary Radiation
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Unnecessary Radiation Exposure is a Growing Problem
Potential harms related to radiation exposure are poorly understood
• Stress MPI accounts for 22% of cumulative effective radiation from medical sources
• One MPI ≈ 1,000 chest x-rays ≈ 10-15 mSv
• Persons at risk for repeated radiation exposure, such as healthcare workers and the nuclear industry, typically restricted to max 100 mSv every 5 years
Columbia University Medical Center Medicare population
• 1,097 consecutive patients, 8-10 years of • Between 1993-2001, 34% of enrollees follow-up underwent repeat testing • Multiple MPIs performed in 424 patients (39%) • Median cumulative effective dose from MPI US nonelderly population was 29 mSv • Median cumulative effective dose from • 952,420 adults in 5 US markets (2005-2007) medical sources was 64 mSv • Among patients undergoing cardiac imaging, mean cumulative dose 16.4 mSv (1.5-190 mSv) • MPI accounted for 74% of cumulative dose
Fazel, NEJM 2009; Einstein, JAMA 2010; Gerber, Circulation 2009; Lucas, Circulation 2006; Chen, JACC 201026
13 Improving Quality Of Care
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Improving Quality of Care: Reducing Unnecessary Testing
Appropriate use criteria
• Growing physician awareness of appropriate use criteria for diagnostic testing in patients suspected of having CAD
• ACC and United Healthcare registry reported that 34% of stress MPIs were inappropriate or of uncertain appropriateness
Insurer policies and regulation Patient/Professional education • Prior authorization by radiology benefits managers • Informed decision-making • Reductions in reimbursement
• Medicare released national coverage • Shared decision-making decision requesting more evidence for coronary CT angiography (CTCA) • Professional society scrutiny
…Impact on health is unknown and needs to be studied
Shaw, JACC: CV Imaging 2010; Gibbons, JACC 2008 28
14 Improving Quality of Care: Comparative Effectiveness Research
Comparative effectiveness research (CER)
• Because tests vary in diagnostic accuracy, initial test choices may influence outcomes, independent of regional/physician care patterns and patients’ risk factors
• Large data set analyses and clinical trials
Stress MPI vs. ECHO (unpublished data) Stress MPI vs. ECHO vs. CTCA
• 11,794 patients underwent stress testing and • 282,830 Medicare patients undergoing were followed for 12 months stress testing and followed for 6 months
• Mean age 53 yrs, 62% male • Mean age 74 yrs, 46% men
• Risk of major adverse cardiovascular events • Risk of acute MI lower after stress ECHO lower after stress ECHO (aOR 0.6, p<0.001) (aOR 0.8, p<0.03) and CTCA (aOR 0.6, compared to MPI p<0.04) compared to MPI
Ladapo et al, in development; Shreibati, JAMA 2011 29
Improving Quality of Care: Clinical Decision Analysis
Clinical decision analysis Patient preferences
• Integrates mathematical modeling, • Impact of false positive tests uncertainty, and patient preferences to identify optimal care strategies • Preferences over medical management vs. invasive management of CAD • Informs health policy and clinical practice • Radiation concerns
No models of patient care have integrated (1) patients’ preferences about false positives and (2) accurate measures of diagnostic accuracy (referral-adjusted)
Ladapo et al, JACC 2009 30
15 Improving Quality of Care: Optimizing Diagnostic Accuracy
Research on diagnostic accuracy of stress testing that accounts for referral patterns to cardiac catheterization is needed
• Wider dissemination of accurate information about diagnostic performance
Coronary CT angiography Blood-based gene-expression test for diagnosing • High-resolution visualization of obstructive CAD (Corus CAD) coronary anatomy
• Limitation: Ischemic heart disease occurs in absence of coronary stenosis
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Gene expression score (GES) Measures Expression of 23 Genes From Peripheral Blood Cells
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16 Blood-Based Genomic Test: A New Diagnostic Test to “Rule-out” CAD
Gene expression score (GES)
• First clinically validated gene expression test for assessing obstructive CAD (>50% stenosis in a major coronary artery) • Algorithm based on the peripheral blood gene expression of 23 genes, gender and age • Molecular basis includes genes and pathways with known involvement in atherosclerosis and its progression • GES quantifies risk of CAD
• Targeted application as a first line, rule-out test, prior to additional stress testing or cardiac catheterization • Stress testing often perceived as gatekeeper to cardiac catheterization • GES may be gatekeeper to stress testing • Nondiabetic patients only
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COMPASS Trial Overview
Purpose • Independent validation of Corus CAD in stable symptomatic patients referred for MPI (intended use population) • Also evaluated MPI performance in the real-world clinical setting
Study Design Patient Inclusion/Exclusion • Prospective, multi-center, blinded study • Symptomatic (chest pain or anginal • 19 U.S. sites, 431 patients equivalent) who have been referred for MPI • QCA Core Lab: Cardiovascular Research for the workup of suspected obstructive Foundation, NY CAD • CTA Core Lab Readers: Szilard Voros, MD, James • Non-diabetic Adams, MD • No known obstructive CAD, prior • MPI Core Lab Reader: Timothy M Bateman, MD myocardial infarction, or prior revascularization procedure • Steering committee: Greg Thomas, MD, MPH, John McPherson, MD, Alexandra Lansky, MD, Szilard Voros, MD
Thomas, Circ Genetics 2013 34
17 COMPASS Trial Design
COMPASS (Coronary Obstruction Detection by Molecular Personalized Gene Expression)
• Primary Endpoint: GES performance by ROC analysis • Steering Committee: Greg Thomas, MD, MPH, John McPherson, MD, Alexandra Lansky, MD, Szilard Voros, MD • 19 U.S. sites, 431 patients
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1 - Specificity 36
18 GES Performance in Independent Validation Studies
GES COMPASS PREDICT Performance* (N=431)** (N=526)
Sensitivity 89% 85%
NPV 96% 83%
Specificity 52% 43%
Prevalence 15% 37%
*Performance associated with a score threshold of 15 **ROC curve area (AUC) for GES was 0.79 compared to site/core-lab AUCs for MPI were 0.59 and 0.63
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IMPACT-Cardiology & -Primary Care Providers Trial Designs
IMPACT-CARD Patients Referred from Primary Care Cardiology N=83 GES-driven Decision: • Medical Management GES • Non-Invasive Test IMPACT-PCP • Cardiac Cath Patients Presenting with Angina Primary Care Related Symptoms N=251 Initial Decision: • Medical Management • Non-Invasive Test • Cardiac Cath
Primary Analysis: Change in diagnostic test utilization with vs without GES Secondary Analysis: Change in testing vs. historical controls
Herman L et al. JABFM 2014;27(2):258-267. McPherson JA et al. Crit Pathw Cardiol 2013;12(2):37-42. 38
19 Clinical Utility of GES in Evaluation of Patients with Suspected CAD
IMPACT-Cardiology (n=83): 63% of patients had GES ≤ 15 (52/83) and 37% of patients had scores > 15 (31/83) 58% of patients saw a change in diagnostic testing* following GES (p<0.001) IMPACT-PCP (n=251): 51% of patients had GES ≤ 15 (127/251) and 49% of patients had scores > 15 (124/251) 58% of patients saw a change in diagnostic testing* following GES (p<0.001)
Percentage of Percentage of Patients Percentage of Patients Patients with with No Change with Increased Decreased Testing in Testing Testing
GES ≤15 56% 44% 0% 23/52 Cardiology 29/52 0/52 GES >15 10% 39% 52% 3/31 12/31 16/31 GES ≤15 60% 38% 2% PCP 76/127 48/127 3/127 GES >15 14% 47% 39% 17/124 58/124 49/124
* E.g., myocardial perfusion imaging, CT Angiography (CTA) and/or invasive angiography
Herman L et al. JABFM 2014;27(2):258-267. McPherson JA et al. Crit Pathw Cardiol 2013;12(2):37-42. 39
Conclusions
• Despite the high prevalence and substantial economic burden of CAD, significant challenges to effectively diagnosing and treating patients exist
• Major quality issues include diagnostic inaccuracy, unnecessary testing and procedures, and radiation exposure
• Opportunities exist to improve care through multiple health policy, research, and patient-oriented dimensions
• A gene expression test for CAD, has promising diagnostic characteristics and may play a role in improving care and reducing unnecessary testing
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20 Thank you! [email protected]
646-501-2561Presentation Title Goes Here 41
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