- Email: [email protected]
Nuclear cardiology in hospital-based practice
Nuclear cardiology in hospital-based
practice
Raymond Gibbons, MD Managed care has drastically changed the environment in which we practice hospital-based nuclear cardiology. As of 1995, traditional fee for service comprises only 8% of all reimbursement in the United States. Nuclear cardiology is now a cost center, not a revenue center, for the hospital. In Minnesota, many physicians and hospitals work together toward common goals in various “integrated health service networks.” There are several ways in which nuclear cardiology can help a health care network reduce costs. Results of myocardial perfusion, for example, can be used to help reduce unnecessary coronary angiography and revascularization procedures. On the other hand, nuclear cardiology is generally not cost-effective in patients with a low likelihood of benefitting from the test and should usually be avoided in such patients. (J Nucl Cardiol 1997;4:S179-83.) Key Words: managed care - cost-effectiveness healthcare reform l
We practice nuclear cardiology in a drastically different environment from that of just 3 or 4 years ago. Table 1 summarizes the major changes we now encounter as a result of the increasing impact of managed care. The degree to which individual physicians feel the pain of this transition in our health care system depends on where they live. In a 1993 survey, adult cardiologists in the mid-Atlantic region obtained 18% of their practice revenue from health maintenance organizations, compared with 43% in the Pacific region.’ However, the trend indicates that some form of a managed care system will reach every region of the country in the near future. According to a recent review,’ traditional fee for service now comprises only 8% of all reimbursement in the United States; newer payment systems, such as health maintenance organizations and preferred provider organizations, now handle more than 50% of health care costs in the United States. Any hospital-based physicians who believe that the concept of managed care has not yet affected their geographic area should consider the impact of diagnosisrelated groups on medicare reimbursement. At most institutions, about 50% of all cardiology inpatients are medicare patients. Because medicare reimbursement is fixed for cardiovascular diagnosis-related groups, most hospital administrators see nuclear cardiology as a cost center for at least 50% of the patients we evaluate. Medicare reimbursement of the technical component (part A) of a nuclear cardiology test comprises about From the Department of Cardiology, Mayo Clinic, Rochester, Minn. Presented at the Forty-fourth Annual Scientific Sessions of the American College of Cardiology, Orlando, Fla., March 23, 1996. Reprint requests: Raymond Gibbons, MD, Department of Cardiology, Mayo Clinic, 200 First St. SW., Rochester, MN 55905. Copyright 0 1997 by American Society of Nuclear Cardiology. 1071-3581/97/$5.00 + 0 43/O/79772
75% to 85% of the charge for the procedure, and the professional fee component (part B) comprises about 15% to 25% of the charge.3 This situation creates an interesting paradox between the physician and institution, because the professional fee is viewed as a revenue center for physicians and a cost center for hospitals. We can approach this conflict between a physician’s and a hospital’s vested interest in one of three ways: 1. Ignore or deny it. This “isolationist” approach may work for a couple of years. I recommend this approach only for physicians about to retire. 2. Accept it and hope for the best. This “peaceful coexistence” approach may in the short-term preserve your budget for equipment and supplies, but it does not fully address the importance of the cost aspect of nuclear cardiology. 3. Forge a new partnership. This “integrated health service network” approach puts the physician and hospital on the same team. In Minnesota the new buzzwords in medicine are “integrated health service network,” in which every component (i.e., hospital administrators and nuclear cardiologists) is part of the same corporate system. At the Mayo Clinic, our parent foundation includes many different hospitals, physician groups, and outpatient facilities. Physicians care about hospital interests, and the hospital cares about physician interests, because we all want to keep our entire medical system financially healthy.
How Nuclear Cardiology Hospital’s
Bottom
Can Benefit the
Line
What potential economic benefits can nuclear cardiology offer the hospital? We might potentially help to s179
Gibbons Nuclearcardiologyin hospital-based practice
SlSO
Table 1. Differences before
in nuclear and after managed cilre
cardiology
practice
Before
After
Acceptable to spend
Pressure to spend less money
more money Fee-for-service system More procedures encouraged, to generate more revenue from
reimbursements Nuclear cardiology was a revenue center Hospital administrators
supported revenue
Fixed costs, capitation, etc.
Journalof NuclearCardiology March/April1997,Part2 distinguish between patients who will and will not benefit from those procedures. In other words, we can have our most important impact on health care costs by reducing the number of patients referred for cardiac catheterization and revascularization; we must serve as a “gatekeeper” with respect to these more expensive procedures.
Fewer procedures encouraged, fewer costs
to generate
Nuclear cardiology is a cost center
Hospital administers may not support cost centers
centers
increase reimbursement from surgical or interventional procedures when nuclear cardiology tests demonstrate that certain patients need revascularization. However, as indicated below, radionuclide myocardial perfusion scans are even more useful in identifying other patients who can avoid unnecessary revascularization. It is unlikely, therefore, that total revascularizations and revenue would increase significantly as a result of nuclear cardiology studies. We can provide a more substantial economic benefit to the hospital in another area by helping to decrease patient length of stay. Hospital administrators are interested in any technique that shows which patients can be discharged earlier. Each day a patient spends in the hospital increases the amount of resources, diagnostic tests, and treatment procedures consumed by that patient. Finally, and most important, we can serve as a “gatekeeper” for invasive diagnostic tests, interventional cardiology, and surgical procedures. When nuclear test results show which patients are unlikely to benefit from these expensive procedures, we can help hospitals avoid those costs without compromising patient care. For many patients with ischemic heart disease, the following sequence of events describes a typical assessment and treatment: clinical examination, exercise treadmill electrocardiography, stress myocardial perfusion imaging (scintigraphy or echocardiography), and coronary angiography. After angiography, many patients undergo revascularization by percutaneous transluminal coronary angioplasty or coronary bypass grafting. For nuclear cardiology to decrease the use of subsequent tests and treatments, scintigraphic results need to
Reducing
the Use of Angiography
Coronary angiography is now coming under increasing scrutiny because its use varies enormously among states, regions, and even countries without discernible differences in patient outcome. According to recent data,4 medicare patients in Texas who have a myocardial infarction are much more likely to undergo coronary angiography than patients in New York, with no measurable difference in outcome. Nuclear cardiology techniques can potentially reduce the need for angiography by demonstrating normal (or near-normal) myocardial perfusion at stress in the following situations: l
l l l
l
l
Clinical findings that indicate intermediate to high likelihood of coronary artery disease (CAD) Left bundle branch block Abnormal left ventricular function of unknown cause Treadmill electrocardiogram results that indicate intermediate to high risk for CAD Preoperative cardiac risk assessment before noncardisc surgery Predischarge evaluation after acute myocardial infarction without reperfusion therapy
Multiple studies have shown that patients with normal or near-normal stress perfusion images are at low risk for subsequent cardiac events, even if they have underlying CAD. The extensive literature on this subject is summarized in the excellent review article by Brown.5 Recently Berman et a1.6 demonstrated that patients with an intermediate to high likelihood of CAD, who had normal or near-normal perfusion images, had a low subsequent event rate, thus reducing the need for angiography. Patients with left bundle branch block are known to have an increased prevalence of CAD. Patients with normal or near-normal perfusion images are unlikely to have CAD, thus reducing the need for angiography. With both dipyridamole and exercise stress, the absence of a large, severe perfusion defect in patients with abnormal left ventricular function of unknown cause makes the presence of underlying CAD unlikely.7,8 Thus coronary angiography is not required to
Journal Volume
of Nuclear 4, Number
Cardiology 2;S179-83
Nuclear
establish the cause of left ventricular dysfunction in such patients. Even in the presence of a positive exercise electrocardiogram, suggesting intermediate to high risk for CAD, normal or near-normal perfusion images suggest an excellent outcome.6 The potential value of normal or near-normal perfusion images is highlighted in two specific clinical scenarios-preoperative cardiac risk assessment before noncardiac surgery and the predischarge evaluation of patients after myocardial infarction who have not received reperfusion therapy-in two recently published Clinical Practice Guidelines from the American College of Cardiology-American Heart Association Task Force on Practice Guidelines.9Jo Reducing the Use of Revascularization There are two plausible situations in which myocardial perfusion studies can show that the patient would not benefit from revascularization: . Patients with known CAD and normal (or nearnormal) myocardial perfusion Patients with abnormal results of myocardial perfusion studies that show ischemia in a region that is not amenable to revascularization l
When Nuclear Carcliology
is Not Cost-Effective
To maintain credibility as we promote the costeffectiveness of nuclear cardiology, we must acknowledge situations when these techniques are not costeffective. Studies indicate that the costs of myocardial perfusion imaging outweigh the benefits in patients without symptoms with l
l
Low likelihood of CAD based on clinical signs, symptoms, and history Normal resting electrocardiograms
Berman et al6 published a study of 99”Tc-labeled sestamibi imaging in patients with low clinical likelihood of CAD. The rate of cardiac death or myocardial infarction during the 20-month follow-up was 0% in patients with normal results of sestamibi studies compared with 2.8% in patients with abnormal results of sestamibi studies, a statistically significant difference. At first glance it may appear that we should be evaluating these patients with myocardial perfusion studies. However, the actual number of events predicted by sestamibi imaging in 548 patients was only three. The cost of nuclear cardiology testing alone per possible event, prevented in this patient group, exceeded $100,000. Therefore, the
cardiology
in hospital-based
Gibbons practice
S181
investigators concluded that myocardial perfusion imaging is not cost-effective in this setting. Our laboratory has published several studies that have examined the incremental value of both equilibrium radionuclide angiography”x12 and single-photon emission computed tomographic myocardial perfusion imaging l3 for the detection of severe CAD and the assessment of prognosis in patients with normal resting electrocardiograms. Patients with normal resting electrocardiograms are highly likely to have normal left ventricular function.14 As a result, the major determinant of subsequent outcome is the severity of underlying CAD. Christian et a1.13 showed that the incremental value of single-photon emission computed tomographic perfusion imaging for the detection of severe CAD in such patients was modest compared with the exercise electrocardiogram. Perfusion imaging did not appear to be costeffective for this purpose, because the incremental cost for the detection of each additional patient with threevessel or left main CAD was $20,000. Furthermore, the prognosis of patients with normal resting electrocardiograms was generally favorable, and myocardial perfusion imaging did not demonstrate any incremental prognostic value in this setting. Christian et al. therefore concluded that the routine use of myocardial perfusion imaging in such patients was not justified. Example of Cost-Effective Making
Diagnostic
Decision
A typical scenario might involve a medicare inpatient with stable chest pain and an intermediate to high likelihood of CAD, based on clinical variables. The hospital reimbursement is fixed based on the medicare diagnosis-related group for chest pain. Let us assume that the patient has a resting electrocardiogram with some ST segment changes, raising a concern about possibly abnormal left ventricular function and possible previous infarction. Consider these two potential noninvasive strategies for further evaluation: (1) exercise treadmill electrocardiography and rest echocardiography, followed by stress echocardiography if the treadmill electrocardiographic results are abnormal or (2) a nuclear cardiology imaging approach, such as a stress myocardial perfusion study with 99mTc-labeled sestamibi (Cardiolite) and a rest ejection fraction (first-pass or gated study). In the first strategy, if the treadmill electrocardiogram is negative, the total cost is the sum of the costs for the treadmill electrocardiogram and rest echocardiogram (about 14.91 relative value units [RVUs] according to 1996 Medicare rules). For such patients, this strategy would have lower immediate costs than the nuclear cardiology approach (about 17.45 RVUs according to
S182
Gibbons Nuclear
cardiology
in hospital-based
1996 Medicare rules without the isotope charge). However, most patients with an abnormal ST segment on their resting electrocardiogram will not have a normal treadmill. In patients without CAD but with resting ST segment changes, treadmill electrocardiography gives false-positive results at a rate close to 50%.15 Patients with positive treadmill electrocardiograms would undergo all three tests in strategy 1. The cost of these three tests combined (19.56 RWs according to 1996 Medicare) is comparable to the cost of obtaining simultaneous myocardial perfusion and ejection fraction with a 99mT~labeled sestamibi study. Even if this patient were one of the minority of cases with an abnormal ST segment on rest electrocardiogram and a normal exercise test, it is still possible that the patient has CAD and would have a subsequent cardiac event. Although the first (echocardiography) strategy may result in short-term savings, any hidden CAD that goes untreated may cost more in the long term. Berman et a1.6 found that the event rate in patients with normal treadmill electrocardiograms and abnormal results on 99mTc-labeled sestamibi imaging had a substantial (4.0%) future event rate. The second (nuclear cardiology) strategy, therefore, can help reduce costs by identifying such patients earlier, before they require emergency treatment for a subsequent cardiac event. Once you view the whole picture from the standpoint of a health care network, you recognize the importance of decreasing the costs of subsequent care, beyond the initial hospitalization, because the network is going to bear those long-term costs. Let us look at cost and outcome if this hypothetical patient had a positive treadmill and negative stress echocardiogram. According to four reports in the literature,16-19 negative stress echocardiographic results are less reliable than radionuclide myocardial perfusion studies for predicting outcome. The future annual cardiac event rates are significantly higher in patients with normal stress echocardiograms than in patients with normal stress perfusion studies (about 3% vs about 1%). The initial cost of each noninvasive diagnostic testing strategy is comparable, but results are more accurate with nuclear studies than with echocardiography. The long-term costs will therefore hopefully be lower with strategy 2. Discussion
Journal of Nuclear Cardiology March/April 1997, Part 2
practice
and Conclusion
Today a hospital-based nuclear cardiology practice is a cost center, not a revenue center. To succeed in the era of managed care, we must clearly demonstrate the cost-effectiveness-both short and long term-of nuclear cardiology studies. In addition, we need to understand when our tests are not cost-effective so we can
avoid using them in those situations. Finally, as I have discussed in detail elsewhere,*O we need to pursue research to gather evidence that will better establish the cost-effectiveness of myocardial perfusion imaging in patient situations in which the published data are scant (such as patients whose Duke treadmill electrocardiographic scores indicate an intermediate to high risk for subsequent cardiac events).
References 1. DeMaria AN, Engle MA, Harrison DC, Judge RD, Kouchoukos NT, Lee TH, et al. Managed care involvement by cardiovascular specialists: prevalence, attitudes and influence on practice. J Am Co11 Cardiol 1994;23: 1245-53. 2. Michnich ME, Mills PS, Seidman JJ. The effect of managed care on nuclear cardiology. J Nucl Cardiol 1996;3:65-71. 3. American College of Cardiology. 1996 Medicare fee schedule. 4. Guadagnoli E, Hauptman PJ, Ayanian JZ, Pashos CL, McNeil BJ, Cleary PD. Variation in the use of cardiac procedures after acute myocardial infarction. N Engl J Med 1995;333:573-8. 5. Brown KA. Prognostic value of thallium-201 myocardial perfusion imaging: a diagnostic tool comes of age. Circulation 1991;83:36381. 6. Berman DS, Hachamovitch R, Kiat H, Cohen S, Cabico JA, Wang FP, et al. Incremental value of prognostic testing in patients with known or suspected ischemic heart disease: a basis for optimal utilization of exercise technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography. J Am Co11 Cardiol 1995;26:639-47. 7. Eichhom EJ, Kosinski EJ, Lewis SM, Hill TC, Emond LH, Leland OS. Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy. Am J Cardiol 1988;62:945-51. 8. Tauberg SG, Orie JE, Bartlett BE, Cottington EM, Flores AR. Usefulness of thallium-201 for distinction of ischemic from idiopathic dilated cardiomyopathy. Am J Cardiol 1993;71:67480. 9. ACC/AHA Task Force Report. Guidelines for perioperative cardiovascular evaluation for noncardiac surgery. J Am Co11 Cardiol 1996;27:910-48. 10. ACC/AHA Task Force Report. ACC/AHA guidelines for the management of patients with acute myocardial infarction. J Am Co11 Cardiol 1996;28:1328-1428. 11. Gibbons RJ, Zinsmeister AR, Miller TD, Clements IP. Supine exercise electrocardiography compared with exercise radionuclide angiography in noninvasive identification of severe coronary artery disease. Ann Intern Med 1990;112:743-9. 12. Simari RD, Miller TD, Zinsmeister AR, Gibbons RJ. Capabilities of supine electrocardiography versus exercise radionuclide angiography in predicting coronary events. Am J Cardiol 1991;67:573-7. 13. Christian TF, Miller TD, Bailey KR, Gibbons RJ. Exercise tomographic thallium-201 imaging in patients with severe coronary artery disease and normal electrocardiograms. Ann Intern Med 1994;121:825-32. 14. O’Keefe JH Jr, Zinsmeister AR, Gibbons RJ. Value of electrocardiographic findings in predicting rest left ventricular function in patients with chest pain and suspected coronary artery disease. Am J Med 1989;86:658-62.
Journal Volume
of Nuclear 4, Number
Cardiology 2;S179-83
15. Weiner DA, Ryan TJ, McCabe CH, Kennedy JM, Schloss M, Tristani F, et al. Exercise stress testing: correlations among history of angina, ST-segment response and prevalence of coronary artery disease in the Coronary Artery Surgery Study (CASS). N Engl J Med 1979;301:230-5. 16. Mazeika PK, Nadazdin A, Oakley CM. Prognostic value of dobutamine echocardiography in patients with high pretest likelihood of coronary artery disease. Am J Cardiol 1993;71:33-9. 17. Krivokapich J, Child JS, Gerber RS, Lem V, Moser D. Prognostic usefulness of positive or negative exercise stress echocardiography for predicting coronary events in ensuing twelve months. Am J Cardiol 1993;71:646-51.
Nuclear
cardiology
in hospital-based
Gibbons practice
S183
18. Poldermans D, Fioretti PM, Boersma E, Come1 JH, Borst F, Vermeulen EGJ, et al. Dobutamine-atropine stress echocardiography and clinical data for predicting late cardiac events in patients with suspected coronary artery disease. Am J Med 1994;97: 119-25. 19. Kamaran M, Teague SM, Finkelhor RS, Dawson N, Bahler RC. Prognostic value of dobutamine stress echocardiography in patients referred because of suspected coronary artery disease. Am J Cardiol 1995;76:887-91. 20. Gibbons RJ. The ASNC project on myocardial perfusion imaging: measuring outcomes in response to emerging guidelines. J Nucl Cardiol 1996;3:436-42.
practice
Raymond Gibbons, MD Managed care has drastically changed the environment in which we practice hospital-based nuclear cardiology. As of 1995, traditional fee for service comprises only 8% of all reimbursement in the United States. Nuclear cardiology is now a cost center, not a revenue center, for the hospital. In Minnesota, many physicians and hospitals work together toward common goals in various “integrated health service networks.” There are several ways in which nuclear cardiology can help a health care network reduce costs. Results of myocardial perfusion, for example, can be used to help reduce unnecessary coronary angiography and revascularization procedures. On the other hand, nuclear cardiology is generally not cost-effective in patients with a low likelihood of benefitting from the test and should usually be avoided in such patients. (J Nucl Cardiol 1997;4:S179-83.) Key Words: managed care - cost-effectiveness healthcare reform l
We practice nuclear cardiology in a drastically different environment from that of just 3 or 4 years ago. Table 1 summarizes the major changes we now encounter as a result of the increasing impact of managed care. The degree to which individual physicians feel the pain of this transition in our health care system depends on where they live. In a 1993 survey, adult cardiologists in the mid-Atlantic region obtained 18% of their practice revenue from health maintenance organizations, compared with 43% in the Pacific region.’ However, the trend indicates that some form of a managed care system will reach every region of the country in the near future. According to a recent review,’ traditional fee for service now comprises only 8% of all reimbursement in the United States; newer payment systems, such as health maintenance organizations and preferred provider organizations, now handle more than 50% of health care costs in the United States. Any hospital-based physicians who believe that the concept of managed care has not yet affected their geographic area should consider the impact of diagnosisrelated groups on medicare reimbursement. At most institutions, about 50% of all cardiology inpatients are medicare patients. Because medicare reimbursement is fixed for cardiovascular diagnosis-related groups, most hospital administrators see nuclear cardiology as a cost center for at least 50% of the patients we evaluate. Medicare reimbursement of the technical component (part A) of a nuclear cardiology test comprises about From the Department of Cardiology, Mayo Clinic, Rochester, Minn. Presented at the Forty-fourth Annual Scientific Sessions of the American College of Cardiology, Orlando, Fla., March 23, 1996. Reprint requests: Raymond Gibbons, MD, Department of Cardiology, Mayo Clinic, 200 First St. SW., Rochester, MN 55905. Copyright 0 1997 by American Society of Nuclear Cardiology. 1071-3581/97/$5.00 + 0 43/O/79772
75% to 85% of the charge for the procedure, and the professional fee component (part B) comprises about 15% to 25% of the charge.3 This situation creates an interesting paradox between the physician and institution, because the professional fee is viewed as a revenue center for physicians and a cost center for hospitals. We can approach this conflict between a physician’s and a hospital’s vested interest in one of three ways: 1. Ignore or deny it. This “isolationist” approach may work for a couple of years. I recommend this approach only for physicians about to retire. 2. Accept it and hope for the best. This “peaceful coexistence” approach may in the short-term preserve your budget for equipment and supplies, but it does not fully address the importance of the cost aspect of nuclear cardiology. 3. Forge a new partnership. This “integrated health service network” approach puts the physician and hospital on the same team. In Minnesota the new buzzwords in medicine are “integrated health service network,” in which every component (i.e., hospital administrators and nuclear cardiologists) is part of the same corporate system. At the Mayo Clinic, our parent foundation includes many different hospitals, physician groups, and outpatient facilities. Physicians care about hospital interests, and the hospital cares about physician interests, because we all want to keep our entire medical system financially healthy.
How Nuclear Cardiology Hospital’s
Bottom
Can Benefit the
Line
What potential economic benefits can nuclear cardiology offer the hospital? We might potentially help to s179
Gibbons Nuclearcardiologyin hospital-based practice
SlSO
Table 1. Differences before
in nuclear and after managed cilre
cardiology
practice
Before
After
Acceptable to spend
Pressure to spend less money
more money Fee-for-service system More procedures encouraged, to generate more revenue from
reimbursements Nuclear cardiology was a revenue center Hospital administrators
supported revenue
Fixed costs, capitation, etc.
Journalof NuclearCardiology March/April1997,Part2 distinguish between patients who will and will not benefit from those procedures. In other words, we can have our most important impact on health care costs by reducing the number of patients referred for cardiac catheterization and revascularization; we must serve as a “gatekeeper” with respect to these more expensive procedures.
Fewer procedures encouraged, fewer costs
to generate
Nuclear cardiology is a cost center
Hospital administers may not support cost centers
centers
increase reimbursement from surgical or interventional procedures when nuclear cardiology tests demonstrate that certain patients need revascularization. However, as indicated below, radionuclide myocardial perfusion scans are even more useful in identifying other patients who can avoid unnecessary revascularization. It is unlikely, therefore, that total revascularizations and revenue would increase significantly as a result of nuclear cardiology studies. We can provide a more substantial economic benefit to the hospital in another area by helping to decrease patient length of stay. Hospital administrators are interested in any technique that shows which patients can be discharged earlier. Each day a patient spends in the hospital increases the amount of resources, diagnostic tests, and treatment procedures consumed by that patient. Finally, and most important, we can serve as a “gatekeeper” for invasive diagnostic tests, interventional cardiology, and surgical procedures. When nuclear test results show which patients are unlikely to benefit from these expensive procedures, we can help hospitals avoid those costs without compromising patient care. For many patients with ischemic heart disease, the following sequence of events describes a typical assessment and treatment: clinical examination, exercise treadmill electrocardiography, stress myocardial perfusion imaging (scintigraphy or echocardiography), and coronary angiography. After angiography, many patients undergo revascularization by percutaneous transluminal coronary angioplasty or coronary bypass grafting. For nuclear cardiology to decrease the use of subsequent tests and treatments, scintigraphic results need to
Reducing
the Use of Angiography
Coronary angiography is now coming under increasing scrutiny because its use varies enormously among states, regions, and even countries without discernible differences in patient outcome. According to recent data,4 medicare patients in Texas who have a myocardial infarction are much more likely to undergo coronary angiography than patients in New York, with no measurable difference in outcome. Nuclear cardiology techniques can potentially reduce the need for angiography by demonstrating normal (or near-normal) myocardial perfusion at stress in the following situations: l
l l l
l
l
Clinical findings that indicate intermediate to high likelihood of coronary artery disease (CAD) Left bundle branch block Abnormal left ventricular function of unknown cause Treadmill electrocardiogram results that indicate intermediate to high risk for CAD Preoperative cardiac risk assessment before noncardisc surgery Predischarge evaluation after acute myocardial infarction without reperfusion therapy
Multiple studies have shown that patients with normal or near-normal stress perfusion images are at low risk for subsequent cardiac events, even if they have underlying CAD. The extensive literature on this subject is summarized in the excellent review article by Brown.5 Recently Berman et a1.6 demonstrated that patients with an intermediate to high likelihood of CAD, who had normal or near-normal perfusion images, had a low subsequent event rate, thus reducing the need for angiography. Patients with left bundle branch block are known to have an increased prevalence of CAD. Patients with normal or near-normal perfusion images are unlikely to have CAD, thus reducing the need for angiography. With both dipyridamole and exercise stress, the absence of a large, severe perfusion defect in patients with abnormal left ventricular function of unknown cause makes the presence of underlying CAD unlikely.7,8 Thus coronary angiography is not required to
Journal Volume
of Nuclear 4, Number
Cardiology 2;S179-83
Nuclear
establish the cause of left ventricular dysfunction in such patients. Even in the presence of a positive exercise electrocardiogram, suggesting intermediate to high risk for CAD, normal or near-normal perfusion images suggest an excellent outcome.6 The potential value of normal or near-normal perfusion images is highlighted in two specific clinical scenarios-preoperative cardiac risk assessment before noncardiac surgery and the predischarge evaluation of patients after myocardial infarction who have not received reperfusion therapy-in two recently published Clinical Practice Guidelines from the American College of Cardiology-American Heart Association Task Force on Practice Guidelines.9Jo Reducing the Use of Revascularization There are two plausible situations in which myocardial perfusion studies can show that the patient would not benefit from revascularization: . Patients with known CAD and normal (or nearnormal) myocardial perfusion Patients with abnormal results of myocardial perfusion studies that show ischemia in a region that is not amenable to revascularization l
When Nuclear Carcliology
is Not Cost-Effective
To maintain credibility as we promote the costeffectiveness of nuclear cardiology, we must acknowledge situations when these techniques are not costeffective. Studies indicate that the costs of myocardial perfusion imaging outweigh the benefits in patients without symptoms with l
l
Low likelihood of CAD based on clinical signs, symptoms, and history Normal resting electrocardiograms
Berman et al6 published a study of 99”Tc-labeled sestamibi imaging in patients with low clinical likelihood of CAD. The rate of cardiac death or myocardial infarction during the 20-month follow-up was 0% in patients with normal results of sestamibi studies compared with 2.8% in patients with abnormal results of sestamibi studies, a statistically significant difference. At first glance it may appear that we should be evaluating these patients with myocardial perfusion studies. However, the actual number of events predicted by sestamibi imaging in 548 patients was only three. The cost of nuclear cardiology testing alone per possible event, prevented in this patient group, exceeded $100,000. Therefore, the
cardiology
in hospital-based
Gibbons practice
S181
investigators concluded that myocardial perfusion imaging is not cost-effective in this setting. Our laboratory has published several studies that have examined the incremental value of both equilibrium radionuclide angiography”x12 and single-photon emission computed tomographic myocardial perfusion imaging l3 for the detection of severe CAD and the assessment of prognosis in patients with normal resting electrocardiograms. Patients with normal resting electrocardiograms are highly likely to have normal left ventricular function.14 As a result, the major determinant of subsequent outcome is the severity of underlying CAD. Christian et a1.13 showed that the incremental value of single-photon emission computed tomographic perfusion imaging for the detection of severe CAD in such patients was modest compared with the exercise electrocardiogram. Perfusion imaging did not appear to be costeffective for this purpose, because the incremental cost for the detection of each additional patient with threevessel or left main CAD was $20,000. Furthermore, the prognosis of patients with normal resting electrocardiograms was generally favorable, and myocardial perfusion imaging did not demonstrate any incremental prognostic value in this setting. Christian et al. therefore concluded that the routine use of myocardial perfusion imaging in such patients was not justified. Example of Cost-Effective Making
Diagnostic
Decision
A typical scenario might involve a medicare inpatient with stable chest pain and an intermediate to high likelihood of CAD, based on clinical variables. The hospital reimbursement is fixed based on the medicare diagnosis-related group for chest pain. Let us assume that the patient has a resting electrocardiogram with some ST segment changes, raising a concern about possibly abnormal left ventricular function and possible previous infarction. Consider these two potential noninvasive strategies for further evaluation: (1) exercise treadmill electrocardiography and rest echocardiography, followed by stress echocardiography if the treadmill electrocardiographic results are abnormal or (2) a nuclear cardiology imaging approach, such as a stress myocardial perfusion study with 99mTc-labeled sestamibi (Cardiolite) and a rest ejection fraction (first-pass or gated study). In the first strategy, if the treadmill electrocardiogram is negative, the total cost is the sum of the costs for the treadmill electrocardiogram and rest echocardiogram (about 14.91 relative value units [RVUs] according to 1996 Medicare rules). For such patients, this strategy would have lower immediate costs than the nuclear cardiology approach (about 17.45 RVUs according to
S182
Gibbons Nuclear
cardiology
in hospital-based
1996 Medicare rules without the isotope charge). However, most patients with an abnormal ST segment on their resting electrocardiogram will not have a normal treadmill. In patients without CAD but with resting ST segment changes, treadmill electrocardiography gives false-positive results at a rate close to 50%.15 Patients with positive treadmill electrocardiograms would undergo all three tests in strategy 1. The cost of these three tests combined (19.56 RWs according to 1996 Medicare) is comparable to the cost of obtaining simultaneous myocardial perfusion and ejection fraction with a 99mT~labeled sestamibi study. Even if this patient were one of the minority of cases with an abnormal ST segment on rest electrocardiogram and a normal exercise test, it is still possible that the patient has CAD and would have a subsequent cardiac event. Although the first (echocardiography) strategy may result in short-term savings, any hidden CAD that goes untreated may cost more in the long term. Berman et a1.6 found that the event rate in patients with normal treadmill electrocardiograms and abnormal results on 99mTc-labeled sestamibi imaging had a substantial (4.0%) future event rate. The second (nuclear cardiology) strategy, therefore, can help reduce costs by identifying such patients earlier, before they require emergency treatment for a subsequent cardiac event. Once you view the whole picture from the standpoint of a health care network, you recognize the importance of decreasing the costs of subsequent care, beyond the initial hospitalization, because the network is going to bear those long-term costs. Let us look at cost and outcome if this hypothetical patient had a positive treadmill and negative stress echocardiogram. According to four reports in the literature,16-19 negative stress echocardiographic results are less reliable than radionuclide myocardial perfusion studies for predicting outcome. The future annual cardiac event rates are significantly higher in patients with normal stress echocardiograms than in patients with normal stress perfusion studies (about 3% vs about 1%). The initial cost of each noninvasive diagnostic testing strategy is comparable, but results are more accurate with nuclear studies than with echocardiography. The long-term costs will therefore hopefully be lower with strategy 2. Discussion
Journal of Nuclear Cardiology March/April 1997, Part 2
practice
and Conclusion
Today a hospital-based nuclear cardiology practice is a cost center, not a revenue center. To succeed in the era of managed care, we must clearly demonstrate the cost-effectiveness-both short and long term-of nuclear cardiology studies. In addition, we need to understand when our tests are not cost-effective so we can
avoid using them in those situations. Finally, as I have discussed in detail elsewhere,*O we need to pursue research to gather evidence that will better establish the cost-effectiveness of myocardial perfusion imaging in patient situations in which the published data are scant (such as patients whose Duke treadmill electrocardiographic scores indicate an intermediate to high risk for subsequent cardiac events).
References 1. DeMaria AN, Engle MA, Harrison DC, Judge RD, Kouchoukos NT, Lee TH, et al. Managed care involvement by cardiovascular specialists: prevalence, attitudes and influence on practice. J Am Co11 Cardiol 1994;23: 1245-53. 2. Michnich ME, Mills PS, Seidman JJ. The effect of managed care on nuclear cardiology. J Nucl Cardiol 1996;3:65-71. 3. American College of Cardiology. 1996 Medicare fee schedule. 4. Guadagnoli E, Hauptman PJ, Ayanian JZ, Pashos CL, McNeil BJ, Cleary PD. Variation in the use of cardiac procedures after acute myocardial infarction. N Engl J Med 1995;333:573-8. 5. Brown KA. Prognostic value of thallium-201 myocardial perfusion imaging: a diagnostic tool comes of age. Circulation 1991;83:36381. 6. Berman DS, Hachamovitch R, Kiat H, Cohen S, Cabico JA, Wang FP, et al. Incremental value of prognostic testing in patients with known or suspected ischemic heart disease: a basis for optimal utilization of exercise technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography. J Am Co11 Cardiol 1995;26:639-47. 7. Eichhom EJ, Kosinski EJ, Lewis SM, Hill TC, Emond LH, Leland OS. Usefulness of dipyridamole-thallium-201 perfusion scanning for distinguishing ischemic from nonischemic cardiomyopathy. Am J Cardiol 1988;62:945-51. 8. Tauberg SG, Orie JE, Bartlett BE, Cottington EM, Flores AR. Usefulness of thallium-201 for distinction of ischemic from idiopathic dilated cardiomyopathy. Am J Cardiol 1993;71:67480. 9. ACC/AHA Task Force Report. Guidelines for perioperative cardiovascular evaluation for noncardiac surgery. J Am Co11 Cardiol 1996;27:910-48. 10. ACC/AHA Task Force Report. ACC/AHA guidelines for the management of patients with acute myocardial infarction. J Am Co11 Cardiol 1996;28:1328-1428. 11. Gibbons RJ, Zinsmeister AR, Miller TD, Clements IP. Supine exercise electrocardiography compared with exercise radionuclide angiography in noninvasive identification of severe coronary artery disease. Ann Intern Med 1990;112:743-9. 12. Simari RD, Miller TD, Zinsmeister AR, Gibbons RJ. Capabilities of supine electrocardiography versus exercise radionuclide angiography in predicting coronary events. Am J Cardiol 1991;67:573-7. 13. Christian TF, Miller TD, Bailey KR, Gibbons RJ. Exercise tomographic thallium-201 imaging in patients with severe coronary artery disease and normal electrocardiograms. Ann Intern Med 1994;121:825-32. 14. O’Keefe JH Jr, Zinsmeister AR, Gibbons RJ. Value of electrocardiographic findings in predicting rest left ventricular function in patients with chest pain and suspected coronary artery disease. Am J Med 1989;86:658-62.
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15. Weiner DA, Ryan TJ, McCabe CH, Kennedy JM, Schloss M, Tristani F, et al. Exercise stress testing: correlations among history of angina, ST-segment response and prevalence of coronary artery disease in the Coronary Artery Surgery Study (CASS). N Engl J Med 1979;301:230-5. 16. Mazeika PK, Nadazdin A, Oakley CM. Prognostic value of dobutamine echocardiography in patients with high pretest likelihood of coronary artery disease. Am J Cardiol 1993;71:33-9. 17. Krivokapich J, Child JS, Gerber RS, Lem V, Moser D. Prognostic usefulness of positive or negative exercise stress echocardiography for predicting coronary events in ensuing twelve months. Am J Cardiol 1993;71:646-51.
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18. Poldermans D, Fioretti PM, Boersma E, Come1 JH, Borst F, Vermeulen EGJ, et al. Dobutamine-atropine stress echocardiography and clinical data for predicting late cardiac events in patients with suspected coronary artery disease. Am J Med 1994;97: 119-25. 19. Kamaran M, Teague SM, Finkelhor RS, Dawson N, Bahler RC. Prognostic value of dobutamine stress echocardiography in patients referred because of suspected coronary artery disease. Am J Cardiol 1995;76:887-91. 20. Gibbons RJ. The ASNC project on myocardial perfusion imaging: measuring outcomes in response to emerging guidelines. J Nucl Cardiol 1996;3:436-42.