Cost Efficacy of Cardiac PET

In cardiology, imaging options are extensive and often redundant. Because financial resources in health care are increasingly limited, the question of cost-effectiveness is crucial. The value of PET as a research tool and as a gold standard for other diagnostic imaging techniques is not in question, but reimbursement and general clinical application of the technique is under more scrutiny because a PET procedure is more expensive than other non-invasive procedures. Looking only at the costs of a single test is a short-sighted, incomplete approach. Estimation of the total cost of diagnostic tests for CAD requires consideration of indirect and induced costs of management algorithms based on the test. False positives may result in unnecessary subsequent diagnostic or therapeutic procedures, which carry additional costs and risks. A missed diagnosis due to a false-negative test, on the other hand, may result in preventable adverse events that could impair life duration and quality. A comprehensive analysis of utility has to account for the impact of medical care on quality as well as quantity of life.

Dr. Patterson⁷, Emory University, used a mathematical model to compare cost-effectiveness of exercise electrocardiography, SPECT, PET, and invasive angiography to diagnose CAD. Their model accounted for costs per effect or cost per utility unit (including cost of diagnostic and therapeutic measures, which included those that yield false-positive results, as well as, those that yield false-negative results). They observed that PET, despite the high cost of a single test, shows the lowest cost per effect in patients with a pre-test likelihood of CAD below 70%. This was attributed to its superior diagnostic accuracy and avoidance of false-positive and false-negative studies. Only when the pre-test likelihood was above 70% was direct angiography the most cost-effective approach. Dr. Gould, University of Texas, using a somewhat less complex model, had earlier come to similar conclusions, but both studies were published more than 13 years ago.

Dr. Merhige⁴, Heart Center of Niagara, more recently compared the frequency of diagnostic arteriography, revascularization, costs, and 1-year clinical outcomes in 2,159 patients studied with PET with an internal and an external SPECT control group. They showed reduced use of downstream invasive procedures when using perfusion PET versus SPECT, which resulted in lower costs with comparable outcomes. Similar issues need to be considered for PET imaging of myocardial viability. The costs of a single test are high, but the costs and risk of avoidable surgical or interventional treatment may be even higher. Avoidance of an unnecessary bypass operation, or even of an unnecessary cardiac transplantation, may justify conducting numerous non-invasive tests if they are appropriate for guidance of clinical decision-making. It has clearly been shown that PET assessment of viability influences decision-making, and if PET recommendations are followed, outcomes will improve.

Reimbursement

Approval of PET radiotracers for clinical cardiac application by the U.S. Food and Drug Administration (FDA) in 1989 and 2000, followed by reimbursement of their use for myocardialperfusion (1995) and viability (2001) imaging by the Centers for Medicare and Medicaid Services (CMS) (see below), were important first steps toward clinical success. In recent years, continuous improvement of scanner systems, commercial marketing of the tracers fluorodeoxyglucose (FDG) and rubidium-82(82Rb), and increasing availability of the technique, mostly due to its tremendous success in oncology, have all contributed to a rapid growth of PET for clinical cardiac imaging. Today, many leading nuclear cardiology institutions run high-through put PET programs and create further evidence for its clinical usefulness. Large sample-size studies and randomized trials are underway or have been published.

Current Medicare Policy

“Effective for services performed on or after March 14, 1995, PET scans performed at rest or with pharmacological stress used for non-invasive imaging of the perfusion of the heart for the diagnosis and management of patients with known or suspected coronary artery disease using the FDA‐approved radiopharmaceutical Rubidium 82 (Rb-82) are covered, provided the requirements below are met:

// The PET scan, whether at rest alone, or rest with stress, is performed in place of, but not in addition to, a single photon emission computed tomography (SPECT); or
// The PET scan, whether at rest alone or rest with stress, is used following a SPECT that was found to be inconclusive. In these cases, the PET scan must have been considered necessary in order to determine what medical or surgical intervention is required to treat the patient. (For purposes of this requirement, an inconclusive test is a test(s) whose results are equivocal, technically uninterpretable, or discordant with a patient’s other clinical data and must be documented in the beneficiary’s file.)

Any PET scan for which Medicare payment is claimed for dates of services prior to July 1, 2001, the claimant must submit additional specified information on the claim form (including proper codes and/or modifiers), to indicate the results of the PET scan. The claimant must also include information on whether the PET scan was performed after an inconclusive non-invasive cardiac test. The information submitted with respect to the previous non-invasive cardiac test must specify the type of test performed prior to the PET scan and whether it was inconclusive or unsatisfactory. These explanations are in the form of special G codes used for billing PET scans using Rb 82. Beginning July 1, 2001, claims should be submitted with the appropriate codes.”

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References

1.  Bateman TM. PET Myocardial Perfusion Imaging: Making the Transition to a Clinical Routine. Appl Imaging: Applications NuclCardiol. 2002; 3(1): 1-6
2.  Bateman, TM, Heller, GV, McGhie, IA, et. al. Diagnostic accuracy of rest/stress ECG-gated Rb-82 myocardial perfusion PET: comparison with ECG-gated Tc-99m Sestamibi SPECT. Journal of Nuclear Cardiology. 2006;13:24-33.
3.  Nandalur, KR, Dwamena, BA, Choudhri, AF, et al. Diagnostic performance of positron emission tomography in the detection of coronary artery disease: a meta-analysis. Academic Radiology. 2008; 15:444-451
4.  Merhige ME, Breen WJ, Shelton V, et al. Impact of myocardial perfusion imaging with PET and (82)Rb on downstream invasive procedure utilization, costs, and outcomes in coronary disease management. J Nucl Med.2007;48:1069-1076.
5.  Bateman, TM. Cardiac positron emission tomography and the role of adenosine pharmacologic stress. American Journal of Cardiology.2004; 94:19-24. 5. Gould, KL. Reversal of coronary atherosclerosis: clinical promise as the basis for non-invasive management of coronary artery disease. Circulation. 1994;90:1558-1571.
6.  Nuclear Medicine Self-Study Program III: Nuclear Medicine Cardiology. Botvinik, EH, Ed. 1998: Society of Nuclear Medicine,Reston, VA.
7.  Comparison of cost-effectiveness and utility of exercise ECG, single photon emission computed tomography, positron emission tomography, and coronary angiography for diagnosis of coronary artery disease. Patterson RE, Eisner RL, Horowitz SF. Carlyle Fraser Heart Center, Emory, Atlanta, GA. Circulation. 1995 Jan 1;91(1):54-65.

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