Journal of Cardiovascular Computed Tomography (2011) 5, 110–112

Editorial

Cheaper, better, or good enough: Evidentiary standards forcoronary CTA

Despite an emphasis on evidence-based therapies, newdiagnostic imaging techniques have not traditionally beenheld to the same standards as new pharmaceuticals ortherapeutic procedures. For imaging modalities, as long asthe pictures have been compelling to patients, practitioners,and payers, evaluation before adoption has rarely gonebeyond technical function, safety, diagnostic accuracy, andprognostic power. In the hierarchy of levels of evidence fordiagnostic testing described by Fryback and Thornbury,1

higher standards would include evaluation of the effectsof a given test on diagnostic decision making, treatment se-lection, and, ultimately, outcomes from both the patientperspective (clinical effectiveness) and societal perspective(cost effectiveness) relative to other strategies of care (com-parative effectiveness). In the past, these evidentiary stan-dards have rarely been achieved, in part because of theindirect nature of the link between testing and outcomes.

In the United States, explosive growth in medicalimaging utilization has moved efforts to justify and controlspending on imaging to the forefront of current health carediscussions.2 Although growth in imaging use has leveledoff since 2004–2005, the push for lower costs continues,alongside the demand for higher levels of evidence forcare strategies relying on new (and often expensive) imag-ing modalities.3,4

For better or worse, the adoption of cardiac computedtomography angiography (CCTA) has been profoundlyinfluenced by these two trends. Advances in CCTA sys-tems, including improved gating and multiple detectorarrays of increasing size, made effective noninvasive cor-onary angiography possible and drove an initial phase ofrapid CCTA adoption.3 Even as use increased, however,skepticism about the adequacy of data supporting the useof CCTA mounted.5,6 These issues came to a head in late2007, with the proposed, although ultimately rejected, se-verely restrictive national coverage decision (NCD) forCCTA by the Centers for Medicare and Medicaid Services(CMS) that would have limited payment for CCTA to veryselect patients enrolled in a handful of narrowly focusedclinical trials.7

1934-5925/$ - see front matter � 2011 Society of Cardiovascular Computed

doi:10.1016/j.jcct.2011.03.003

In the wake of the draft NCD reversal, a patchwork ofreimbursement schemes by payer and geographic arearemains, with various acceptable indications and require-ments for preauthorization, and adoption has slowed. Thereare also outstanding questions about the costs, downstreamradiation effects, and proper role of CCTA-based diagnosticstrategies in clinical care.

In this issue of the Journal, Cheezum et al8 specificallyaddress the first of these questions: downstream resourceutilization and costs after CCTA compared with myocardialperfusion stress (MPS) testing. They report the results of aretrospective, single-center study of non–emergency de-partment, low-to-intermediate pretest likelihood, sympto-matic patients without known coronary artery disease(CAD) referred for noninvasive testing at an army medicalcenter; 252 patients were evaluated with CCTA and 241with MPS testing. After a mean follow-up of 30 months,there were similar composite rates of posttest clinical re-source utilization (emergency department visits, cardiologyclinic visits, hospitalizations for further evaluation of symp-toms, or cardiac testing), although fewer patients in CCTAgroup underwent invasive coronary angiography (3.3%vs 8.1%; P 5 0.02). Overall median direct costs weresignificantly lower in the CCTA group than in the MPS test-ing group; importantly, the cost differences were driven al-most completely by differences in the prices of the baselinetests.

This study is notable in its assessment of downstreamresource utilization in a closely followed cohort (helped byenrollment in the military medical system) for a moderatelength of follow-up. Comparison with a currently acceptedstandard of care, an MPS testing–based strategy, in anappropriate population makes their results clinically rele-vant. The finding of cost savings with CCTA-based strat-egies is consistent with previously published work,including retrospective studies and decision analyticmodels of patients with stable chest pain,9–12 patientswith chest pain in an emergency department setting,9,13,14

and asymptomatic patients with positive stress tests other-wise referred to invasive angiography,15 which have shown

Tomography. All rights reserved.

Mudrick and Douglas Evidentiary standards for coronary CTA 111

lower costs or improved outcomes or both with CCTA-based strategies. The reporting by Cheezum et al8 ofincidental findings and downstream evaluation of suchaddresses an important difference between the two testingstrategies which has not always been considered.

Because of its size, low event rate, and follow-upduration, this study was underpowered to identify differ-ences in clinical event rates, thus making assessment of costeffectiveness, rather than simply cost, impossible. Essen-tially the two tests are clinically ‘‘non inferior,’’ so the ratioof incremental benefit to incremental expense cannot becalculated. In the absence of the ability to assess adifference in outcomes, the lower rate of invasive angiog-raphy in the CCTA group does show differences in down-stream care patterns between the two diagnostic strategies.

Comparisons between the two groups are limited by thenonrandomized nature of the study, particularly in a settingin which selection of the initial test may be influenced byunidentified patient characteristics and downstream caremay be affected by differences in physicians’ confidence inthe results of a test with which they may be less familiar (ie,CCTA). The single-center nature of the study, specifics ofthe testing protocols (particularly the low rate of prospec-tive gating), and the unique environment of the militaryhealth care system may also limit the generalizability ofthese results.

There are numerous methodologic branch points in theevaluation of cost as an endpoint, including whose costs tomeasure, whether to include direct or indirect costs, use ofcharges or actual payments, and so forth. In the currentstudy, the investigators reasonably chose to evaluate directcosts from the payer’s perspective, using current Medicarepayment rules. More important than these methodologicchallenges, in the current health marketplace costs can bewildly variable, driven by arbitrary policy and payment de-cisions that differ from plan to plan and year to year. Theseuncertainties become highly important in interpreting theresults of Cheezum et al,8 because the difference in overallcosts in the two testing groups in this study was fully ex-plained by the cost of the initial test. In other words, payerreimbursement policy for the two initial tests overshadowedany difference in clinical utility. Were MPS cheaper orCCTA more expensive, the results could have been quitedifferent.

The current study addresses the important question, ‘‘is aCCTA strategy cheaper?’’ But the study is not designed toadequately address the larger, more pertinent question, ‘‘is aCCTA strategy better?’’ in terms of clinical comparativeeffectiveness. As payers and policy makers demand ahigher level of evidence to justify CCTA use, and as weas an imaging community seek to provide evidence-basedservices that will improve outcomes for our patients andsocieties, our goal is to figure out how to gather the data toanswer that question. Limiting adoption of a new modalityuntil definitive outcomes data are available, as suggested bythe proposed CMS NCD in 2007, is unprecedented and

could stifle the development of new, potentially beneficialtechnologies. However, unfettered expansion of unproventechnology, especially when financial incentives rewardvolume of use rather than appropriate use, may be expen-sive and potentially harmful.

A multipronged approach is necessary, including (1)provisional acceptance of new technologies by payers andregulators on the basis of reasonable evidence of safety,technical function, and diagnostic accuracy; (2) efforts bythe medical and imaging communities to define andimplement thoughtful guidelines and indications for appro-priate use; (3) continued accumulation of research along alllevels of the evidence hierarchy; and (4) investment in largerandomized controlled trials, multicenter registries, andother high-quality research to ultimately answer questionsof quality and effectiveness.

Fortunately, in the case of CCTA, all these efforts areongoing. In many locations, private and government payersreimburse for CCTA. Guidelines and appropriate use criteriahave been developed and were recently updated.16–18 Re-search on CCTA continues to accumulate, with recentmeta-analyses reviewing the diagnostic and prognostic valueof CCTA,19–22 adding to a growing body of literature thatstrengthens the position that CCTA may be an excellent op-tion for a variety of indications.

The first large scale cardiovascular imaging researchstudies are moving forward as well. Patients are currentlybeing enrolled in the National Heart, Lung, and BloodInstitute–funded PROMISE (PROspective MulticenterImaging Study for Evaluation of Chest Pain; www.clinicaltrials.gov #NCT01174550), a 10,000-patient, multi-centered, randomized trial that compares clinical outcomesafter an initial CCTA strategy with a functional stress test-ing strategy in low- to intermediate-risk patients with stablechest pain, with locally guided care. The RESCUE (Ran-domized Evaluation of Patients with Stable Angina Com-paring Utilization of Diagnostic Examinations; www.clinicaltrials.gov #NCT01262625) study has been fundedby the Agency for Healthcare Research and Quality(AHRQ) and will compare outcomes after CCTA with nu-clear stress myocardial perfusion imaging among patientswith chest pain, with paradigm-guided posttest care featur-ing initial optimized medical therapy. ROMICAT II (Multi-center Study to Rule Out Myocardial Infarction by CardiacComputed Tomography; www.clinicaltrials.gov #NCT01084239) is an ongoing randomized trial of CCTA versusstandard of care for emergency department patients withchest pain, with assessment of clinical and economic out-comes up to 2 years.

Although the results of these and other studies areeagerly anticipated to determine the clinical effectivenessand cost of using CCTA instead of ‘‘usual care,’’ they alsoindirectly address the question of the proper evidentiarystandard for adoption of new imaging technology. The‘‘first-ever’’ imaging outcomes studies, if successful, willnot only inform clinical decision making but hopefully will

112 Journal of Cardiovascular Computed Tomography, Vol 5, No 2, March/April 2011

alter both reimbursement policy and our approach toimaging research and technology adoption.23

Daniel W. Mudrick, MD, MPHPamela S. Douglas, MD

Duke University Medical Centerand Duke Clinical Research Institute

7022 North Pavilion DUMC, PO Box 17969Durham, NC 27715, USA

E-mail address: pamela.douglas@duke.edu

Conflict of interest:Dr. Douglas is the primary investiga-tor, and Dr. Mudrick is a co-investigator for the PROMISETrial Clinical Coordinating Center.

Dr. Mudrick is supported by the National Institutes ofHealth (grant T32-HL069749). Dr. Douglas is supported bythe National Heart, Lung and Blood Institute (grant R01-HL098237).

References

1. Fryback DG, Thornbury JR: The efficacy of diagnostic imaging. Med

Decis Making. 1991;11:88–94.

2. USGovernment Accountability Office:Medicare Part B imaging services:

rapid spending growth and shift to physicians offices indicate need for

CMS to consider additional management practices. 2008. Available at:

http://www.gao.gov/products/GAO-08-452. Accessed January 29, 2011.

3. Shaw LJ, Marwick TH, Zoghbi WA, Hundley WG, Kramer CM,

Achenbach S, Dilsizian V, Kern MJ, Chandrashekhar Y, Narula J:

Why all the focus on cardiac imaging? JACC Cardiovasc Imaging.

2010;3:789–94.

4. Shaw LJ, Min JK, Hachamovitch R, Peterson ED, Hendel RC,

Woodard PK, Berman DS, Douglas PS: Cardiovascular imaging re-

search at the crossroads. JACC Cardiovasc Imaging. 2010;3:316–24.

5. BlueCross BlueShield Association Technology Evaluation Center:

Contrast-enhanced cardiac computed tomographic angiography in

the diagnosis of coronary artery stenosis or for evaluation of acute

chest pain. 2006. Available at: http://www.bcbs.com/blueresources/

tec/vols/21/21_05.html. Accessed January 29, 2011.

6. Lauer MS: CT angiography: first things first. Circ Cardiovasc Imaging.

2009;2:1–3.

7. Centers for Medicare and Medicaid Services: Decision memo for com-

puted tomographic angiography (CAG-00385N). 2008. Available at:

http://www.cms.gov/medicare-coverage-database/overview-and-quick-

search.aspx. Accessed January 29, 2011.

8. Cheezum MK, Hulten EA, Taylor AJ, Gibbs BT, Hinds SR,

Feuerstein IM, Stack AL, Villines TC: Cardiac CT angiography com-

pared with myocardial perfusion stress testing on downstream re-

source utilization. J Cardiovasc Comput Tomogr. 2010;4:101–9.

9. Institute for Clinical and Economic Review: CCTA final appraisal–full

report. 2008. Available at: http://www.icer-review.org/index.php/ccta.

html. Accessed January 29, 2011.

10. Ladapo JA, Jaffer FA, Hoffmann U, Thomson CC, Bamberg F, Dec W,

Cutler DM, Weinstein MC, Gazelle GS: Clinical outcomes and

cost-effectiveness of coronary computed tomography angiography in the

evaluation of patientswith chest pain. JAmCollCardiol. 2009;54:2409–22.

11. Min JK, Gilmore A, Budoff MJ, Berman DS, O’Day K: Cost-effec-

tiveness of coronary CT angiography versus myocardial perfusion

SPECT for evaluation of patients with chest pain and no known coro-

nary artery disease. Radiology. 2010;254:801–8.

12. Min JK, Kang N, Shaw LJ, Devereux RB, Robinson M, Lin F,

Legorreta AP, Gilmore A: Costs and clinical outcomes after coronary

multidetector CT angiography in patients without known coronary

artery disease: comparison to myocardial perfusion SPECT. Radiol-

ogy. 2008;249:62–70.

13. Goldstein JA, Gallagher MJ, O’Neill WW, Ross MA, O’Neil BJ,

Raff GL: A randomized controlled trial of multi-slice coronary com-

puted tomography for evaluation of acute chest pain. J Am Coll Car-

diol. 2007;49:863–71.

14. Ladapo JA, Hoffmann U, Bamberg F, Nagurney JT, Cutler DM,

Weinstein MC, Gazelle GS: Cost-effectiveness of coronary MDCT

in the triage of patients with acute chest pain. AJR Am J Roentgenol.

2008;191:455–63.

15. Halpern EJ, Fischman D, Savage MP, Koka AR, DeCaro M,

Levin DC: Decision analytic model for evaluation of suspected coro-

nary disease with stress testing and coronary CT angiography. Acad

Radiol. 2010;17:577–86.

16. Budoff MJ, Achenbach S, Blumenthal RS, Carr JJ, Goldin JG,

Greenland P, Guerci AD, Lima JA, Rader DJ, Rubin GD, Shaw LJ,

Wiegers SE: Assessment of coronary artery disease by cardiac com-

puted tomography: a scientific statement from the American Heart As-

sociation Committee on Cardiovascular Imaging and Intervention,

Council on Cardiovascular Radiology and Intervention, and Commit-

tee on Cardiac Imaging, Council on Clinical Cardiology. Circulation.

2006;114:1761–91.

17. Hendel RC, Patel MR, Kramer CM, Poon M, Carr JC, Gerstad NA,

Gillam LD, Hodgson JM, Kim RJ, Lesser JR, Martin ET,

Messer JV, Redberg RF, Rubin GD, Rumsfeld JS, Taylor AJ,

Weigold WG, Woodard PK, Brindis RG, Douglas PS, Peterson ED,

Wolk MJ, Allen JM: ACCF/ACR/SCCT/SCMR/ASNC/NASCI/

SCAI/SIR 2006 appropriateness criteria for cardiac computed tomog-

raphy and cardiac magnetic resonance imaging: a report of the Amer-

ican College of Cardiology Foundation Quality Strategic Directions

Committee Appropriateness Criteria Working Group, American Col-

lege of Radiology, Society of Cardiovascular Computed Tomography,

Society for Cardiovascular Magnetic Resonance, American Society of

Nuclear Cardiology, North American Society for Cardiac Imaging,

Society for Cardiovascular Angiography and Interventions, and Soci-

ety of Interventional Radiology. J Am Coll Cardiol. 2006;48:1475–97.

18. Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O’Gara P,

Rubin GD, Kramer CM, Wolk MJ: ACCF/SCCT/ACR/AHA/A-

SE/ASNC/NASCI/SCAI/SCMR2010AppropriateUseCriteria forCar-

diac Computed Tomography: A Report of the American College of

Cardiology Foundation Appropriate Use Criteria Task Force, the Soci-

ety of Cardiovascular Computed Tomography, the American College

of Radiology, the American Heart Association, the American Society

of Echocardiography, the American Society of Nuclear Cardiology,

the North American Society for Cardiovascular Imaging, the Society

for Cardiovascular Angiography and Interventions, and the Society for

Cardiovascular Magnetic Resonance. Circulation. 2010;122:e525–55.

19. Hulten EA, Carbonaro S, Petrillo SP, Mitchell JD, Villines TC: Prog-

nostic value of cardiac computed tomography angiography a system-

atic review and meta-analysis [published online ahead of print

December 8, 2010]. J Am Coll Cardiol. 2011;57:1237–47.

20. Mowatt G, Cook JA, Hillis GS, Walker S, Fraser C, Jia X, Waugh N:

64-Slice computed tomography angiography in the diagnosis and as-

sessment of coronary artery disease: systematic review and meta-

analysis. Heart. 2008;94:1386–93.

21. Ollendorf DA, Kuba M, Pearson SD: The diagnostic performance of

multi-slice coronary computed tomographic angiography: a systematic

review [published online ahead of print November 10, 2010]. J Gen

Intern Med. 2011;26:307–16.

22. Schuetz GM, Zacharopoulou NM, Schlattmann P, Dewey M:

Meta-analysis: noninvasive coronary angiography using computed to-

mography versus magnetic resonance imaging. Ann Intern Med. 2010;

152:167–77.

23. Douglas PS, Taylor A, Bild D, Bonow R, Greenland P, Lauer M,

Peacock F, Udelson J: Outcomes research in cardiovascular imaging:

report of a workshop sponsored by the National Heart, Lung, and

Blood Institute. Circ Cardiovasc Imaging. 2009;2:339–48.