Accepted Manuscript When is it right to be wrong? Michael P. Thomas, MD Hitinder S. Gurm, MD Brahmajee K. Nallamothu, MD, MPH PII:
S0735-1097(13)05731-8
DOI:
10.1016/j.jacc.2013.10.010
Reference:
JAC 19527
To appear in:
Journal of the American College of Cardiology
Received Date: 23 September 2013 Accepted Date: 1 October 2013
Please cite this article as: Thomas MP, Gurm HS, Nallamothu BK, When is it right to be wrong?, Journal of the American College of Cardiology (2013), doi: 10.1016/j.jacc.2013.10.010. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
When is it right to be wrong? Running Title: When is it right to be wrong?
RI PT
Michael P. Thomas, MD,* Hitinder S. Gurm, MD,* Brahmajee K. Nallamothu, MD, MPH* *Division of Cardiovascular Medicine, University of Michigan; VA Ann Arbor Healthcare System and Center for Clinical Management Research
SC
Word Count: 1761
EP
TE D
Corresponding Author: Michael P. Thomas, MD University of Michigan Cardiovascular Medicine Cardiovascular Center 1500 E. Medical Center Dr., SPC 5869 Ann Arbor, MI 48109-5869 [email protected] Phone: (734) 615-3878 Fax: (734) 764-4142
M AN U
Dr. Gurm reports receiving research funding from the National Institutes of Health, Agency for Healthcare Research and Quality, and Blue Cross Blue Shield of Michigan. Dr. Gurm acts as a consultant for Osprey Medical and has served as a peer reviewer of PCI quality and appropriateness in Michigan. All other authors do not have any relationships relevant to the contents of this paper to disclose.
AC C
Key Words: coronary angiography, patient selection, institutional variability, quality improvement
1
ACCEPTED MANUSCRIPT
Coronary angiography is a critical diagnostic tool for defining anatomy and guiding therapy in coronary artery disease. Not surprisingly, it has gained widespread use since Mason Sones first
RI PT
described it over 50 years ago with an estimated 2 million procedures performed each year in the US alone.(1) However, there are well-known, significant costs associated with coronary
angiography – both to the patient, given its procedural risks, and to the healthcare system as a
SC
whole. In 2010, a highly-publicized article by Patel et al. in the New England Journal of
Medicine raised concerns about the potential, indiscriminate use of coronary angiography given
M AN U
its “low diagnostic yield”.(2) Utilizing data on nearly 400,000 patients without known coronary artery disease who had been referred for elective procedures in the CathPCI Registry, just 38% were found to have obstructive disease while 39% had little or no disease – i.e., “normal” coronary arteries. Adding to these troubling findings were the observations that a large number
improve diagnostic yield.
TE D
of patients were asymptomatic (~30%) and noninvasive testing before the procedure did not
Ko and colleagues further explored these issues in an intriguing report published earlier
EP
this year in JAMA that used cross-national comparison data between New York State and Ontario.(3) In this study, the authors compared 18 114 patients in New York and 54 933 patients
AC C
in Ontario (which utilizes a government-funded, single-payer system) who were undergoing elective coronary angiography from 2008 to 2011. The overall rate of obstructive disease in New York was just 30% compared with 45% in Ontario – a finding primarily driven by a higher rate of referral of low-risk patients in New York. Using a risk model based on clinical factors and noninvasive testing, less than 1 in 5 patients in New York had a greater than 50% likelihood of obstructive CAD compared with more than 2 in 5 patients in Ontario. Importantly, no underdetection of patients with surgical coronary artery disease (left main disease or 3-vessel coronary 2
ACCEPTED MANUSCRIPT
artery disease) was noted despite a historically 50% lower use of coronary angiography per capita in Ontario. Thus, a more restricted approach to patient selection for coronary angiography in Ontario did not appear to miss those with critical disease.
RI PT
In this issue of JACC, Bradley and colleagues add to this discussion with a report from the Veterans Affair (VA) Healthcare System’s Cardiovascular Assessment, Reporting and Tracking for Cath Labs (CART-CL) program.(4) This study is important since the VA
SC
Healthcare System represents a large, integrated healthcare delivery system in the US where financial incentives for performing coronary angiography and medico-legal concerns may be less
M AN U
than in the private sector and care coordination more extensive. The authors utilized data from 76 VA cardiac catheterization labs between 2007 and 2010. Of the 22 538 patients who underwent elective coronary angiography during this time period, 4 829 had normal coronary arteries (21%) and 11 622 (52%) had obstructive disease. Patients with normal coronary arteries
TE D
were more likely to have low Framingham risk scores and a noninvasive test. In order to assess hospital-level variation, hospitals were divided into quartiles based upon the percentage of cases with normal coronary arteries with Quartile 1 having a rate of normal coronary arteries of 11%
EP
and Quartile 4 having a rate of 30%. Patients in Quartile 1 were more likely to undergo noninvasive testing, but no consistent trends were noted across quartiles in patient demographics,
AC C
cardiovascular risk factors, Framingham scores, or hospital characteristics. This work by Bradley and colleagues is important for several reasons. First, it suggests a higher referral threshold for coronary angiography within the VA. Given the possibility of less direct financial incentives for testing in an integrated healthcare delivery system, this finding may have implications for Accountable Care Organizations (ACOs) that will gain traction in the coming years. Second, their observation of 10-fold variation in hospital rates of normal coronary
3
ACCEPTED MANUSCRIPT
arteries is important. Despite finding an overall rate of normal coronary arteries that was almost half what was reported from the CathPCI Registry, this inconsistency implies an ongoing need to improve patient selection across institutions and reminds us that factors beyond financial
RI PT
incentives are playing a role. Third, this report raises a real concern regarding studies that
compare rates of normal coronary arteries across healthcare systems that many VA cardiologists will immediately recognize. Given a higher burden of baseline disease in the VA population, a
SC
poor decision to perform coronary angiography in a Veteran (e.g., asymptomatic and low-risk stress test) may be statistically more likely to yield obstructive disease than an appropriate
M AN U
decision in other settings. As even 10% of patients with an acute coronary syndrome might have non-obstructive disease,(5) we may be right but for the wrong reasons or wrong for the right reasons.
Thus, it remains unclear as to what we as a clinical community are to do collectively with
TE D
these studies of rates of normal coronary arteries (and the others that may potentially follow) or if and how should they influence our use of coronary angiography. However, the questions that they raise are potentially enormous: to what extent do high rates of coronary arteries indicate
EP
poor quality or suggest that we are performing too many procedures? Do we need to become more adept at risk stratification or do we need more or better noninvasive testing? How are
AC C
financial incentives driving these decisions and what other factors – such as medico-legal concerns – are playing a role in patient selection? And finally, what is a reasonable rate of normal coronary arteries that should be expected for cardiologists, realizing that 0% is neither possible nor desirable?
Of course, many of these questions deal with the overall quality of current clinical assessments and noninvasive testing. These issues were highlighted over 3 decades ago in the
4
ACCEPTED MANUSCRIPT
seminal work of Diamond and Forrester with their application of Bayes’ theorem to coronary angiography. Results of any clinical finding or diagnostic test must be placed into the context of a patient as their interpretation inherently depends upon the pre-test probability of disease. (6)
RI PT
Diamond and Forrester demonstrated that the probability of coronary artery disease may be obtained in large part through assessment of the patient’s age, sex, and symptoms. Despite significant advancements in noninvasive tests since that time, it is disappointing that these tests
SC
only marginally improve the diagnostic yield of coronary angiography over these clinical factors, perhaps as a result of their more widespread use in contemporary practice and verification bias.
M AN U
(7)
Despite the clear need to improve our decision-making process for coronary angiography, it also is important to acknowledge that some elective procedures undoubtedly will result in the finding of normal coronary arteries. So when is it right for us to be wrong? Is the rate of normal
TE D
coronary arteries found in the CathPCI Registry of 39% too high or perhaps the rate of 21% in the VA population too low? Too high a rate suggests waste and the danger of unnecessary procedures while too low a rate implies we may be causing harm by missing patients
EP
appropriately referred for this diagnostic test. Although the study by Ko et al. suggests this latter concern may be minimized, it is clear even from that study that we must be able to accept a few
AC C
false-positive tests as part of the process. In some circumstances, there may be great value to a negative study that identifies normal coronary arteries given the concerns many patients have with the possibility of cardiac conditions as a cause of their symptoms. In fact, the value of any diagnostic test lies not only in its ability to “rule-in” disease, but how it helps clinicians to “ruleout” disease as well since that also strongly influences subsequent management.
5
ACCEPTED MANUSCRIPT
We believe many forces will push this debate even further in coming years. Rates of normal coronary angiographies have been discussed as a performance measure for over a decade now, but there has been little pursuit of it. (8) However, the emerging data highlighted by Patel
RI PT
et al., Ko et al., and Bradley et al. suggest that a greater interest will and should be placed on risk stratification and patient selection in coming years. This is further supported by the recent
publication of appropriate use criteria (AUC) for coronary angiography. Using rates of normal
SC
coronary arteries may supplement AUC to fully inform us on how well an entire system is doing in this regard and ensure validity in quality comparisons across hospitals. Bradley and
M AN U
colleagues raise these points eloquently in their paper but also warn us about potential limitations with its use in isolation. For example, before rates of normal coronary arteries become a performance measure we clearly need more empirical work as ranking of hospitals in the VA Healthcare System was highly sensitive to how “normal” was defined. In Figure 3 of the paper
TE D
by Bradley et al., the top hospital ranked by its rate of normal coronary arteries was approximately 50th by its rate of non-obstructive CAD. Although the extent to which the use of rankings and performance measurement of rates
EP
of normal coronary arteries may influence clinicians is unclear, it may be consequential. A prominent example of the real-world implications of these decisions was recently illustrated. In
AC C
a $4 million settlement by a physician and healthcare system for allegedly performing unnecessary coronary angiography, it was purported that 75% of patients had “no significant heart blockages”. (9) This case is obviously complex and raised multiple issues, including the improper reading of nuclear stress tests prior to coronary angiography. Yet it is telling that this case is fundamentally different from prior reports of inappropriate coronary stenting or cardiac surgery since it involves the claim that a diagnostic test – not a therapeutic procedure – was
6
ACCEPTED MANUSCRIPT
overused. And it raises the natural question as to whether this logic may be extended to other diagnostic tests, such as measures of normal rates of echocardiograms, CT scans, ultrasounds and even some expensive laboratory tests?
RI PT
Improving our understanding of all these issues around rates of normal coronary arteries will be fundamental as we move forward in an era of AUC, quality improvement initiatives, performance measures, and escalating costs. It must be done carefully with recognition that
SC
large differences will exist across the populations that we serve and that this should influence how these data are collected, interpreted and reported. As clinicians, we certainly need to
M AN U
become better at how we utilize expensive and sometimes risky tests like coronary angiography. This desire for improvement, however, must be balanced with the knowledge that there remains an important role for judgment in such decisions. That is, we need to hold on to the right to be
AC C
EP
TE D
wrong.
7
ACCEPTED MANUSCRIPT
References 1.
Ryan TJ. The coronary angiogram and its seminal contributions to cardiovascular
2.
RI PT
medicine over five decades. Circulation 2002;106:752-6. Patel MR, Peterson ED, Dai D et al. Low diagnostic yield of elective coronary angiography. N Engl J Med 2010;362:886-95.
Ko DT, Tu JV, Austin PC et al. Prevalence and extent of obstructive coronary artery
SC
3.
disease among patients undergoing elective coronary catheterization in New York State
4.
M AN U
and Ontario. JAMA 2013;310:163-9.
Bradley SM, Maddox TM, Stanislawski MA et al. Normal coronary rates for elective coronary angiography in the VA Health Care System: Insights from the VA CART Program. J Am Coll Cardiolo, 2013 (In Press).
5.
Maddox TM, Ho PM, Roe M, Dai D, Tsai TT, Rumsfeld JS. Utilization of secondary
TE D
prevention therapies in patients with nonobstructive coronary artery disease identified during cardiac catheterization: insights from the National Cardiovascular Data Registry
6.
EP
Cath-PCI Registry. Circ Cardiovasc Qual Outcomes 2010;3:632-41. Diamond GA, Forrester JS. Analysis of probability as an aid in the clinical diagnosis of
7.
AC C
coronary-artery disease. N Engl J Med 1979;300:1350-8. Diamond GA, Kaul S. Low diagnostic yield of elective coronary angiography. N Engl J Med 2010;363:92-95. (letter) 8.
Bashore TM, Bates ER, Berger PB et al. American College of Cardiology/Society for Cardiac Angiography and Interventions Clinical Expert Consensus Document on cardiac catheterization laboratory standards. A report of the American College of Cardiology
8
ACCEPTED MANUSCRIPT
Task Force on Clinical Expert Consensus Documents. J Am Coll Cardiol 2001;37:2170214. Baldas T. Cardiology practice, Jackson hospital to pay $4M in lawsuit alleging medically
RI PT
inappropriate heart procedures. Detroit Free Press, July 2013. Available at:
http://www.freep.com/article/20130710/NEWS05/307100126/cardiology-settlement-
EP
TE D
M AN U
SC
jackson-hospital-medically-inappropriate. Accessed September 17, 2013.
AC C
9.
9
S0735-1097(13)05731-8
DOI:
10.1016/j.jacc.2013.10.010
Reference:
JAC 19527
To appear in:
Journal of the American College of Cardiology
Received Date: 23 September 2013 Accepted Date: 1 October 2013
Please cite this article as: Thomas MP, Gurm HS, Nallamothu BK, When is it right to be wrong?, Journal of the American College of Cardiology (2013), doi: 10.1016/j.jacc.2013.10.010. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
When is it right to be wrong? Running Title: When is it right to be wrong?
RI PT
Michael P. Thomas, MD,* Hitinder S. Gurm, MD,* Brahmajee K. Nallamothu, MD, MPH* *Division of Cardiovascular Medicine, University of Michigan; VA Ann Arbor Healthcare System and Center for Clinical Management Research
SC
Word Count: 1761
EP
TE D
Corresponding Author: Michael P. Thomas, MD University of Michigan Cardiovascular Medicine Cardiovascular Center 1500 E. Medical Center Dr., SPC 5869 Ann Arbor, MI 48109-5869 [email protected] Phone: (734) 615-3878 Fax: (734) 764-4142
M AN U
Dr. Gurm reports receiving research funding from the National Institutes of Health, Agency for Healthcare Research and Quality, and Blue Cross Blue Shield of Michigan. Dr. Gurm acts as a consultant for Osprey Medical and has served as a peer reviewer of PCI quality and appropriateness in Michigan. All other authors do not have any relationships relevant to the contents of this paper to disclose.
AC C
Key Words: coronary angiography, patient selection, institutional variability, quality improvement
1
ACCEPTED MANUSCRIPT
Coronary angiography is a critical diagnostic tool for defining anatomy and guiding therapy in coronary artery disease. Not surprisingly, it has gained widespread use since Mason Sones first
RI PT
described it over 50 years ago with an estimated 2 million procedures performed each year in the US alone.(1) However, there are well-known, significant costs associated with coronary
angiography – both to the patient, given its procedural risks, and to the healthcare system as a
SC
whole. In 2010, a highly-publicized article by Patel et al. in the New England Journal of
Medicine raised concerns about the potential, indiscriminate use of coronary angiography given
M AN U
its “low diagnostic yield”.(2) Utilizing data on nearly 400,000 patients without known coronary artery disease who had been referred for elective procedures in the CathPCI Registry, just 38% were found to have obstructive disease while 39% had little or no disease – i.e., “normal” coronary arteries. Adding to these troubling findings were the observations that a large number
improve diagnostic yield.
TE D
of patients were asymptomatic (~30%) and noninvasive testing before the procedure did not
Ko and colleagues further explored these issues in an intriguing report published earlier
EP
this year in JAMA that used cross-national comparison data between New York State and Ontario.(3) In this study, the authors compared 18 114 patients in New York and 54 933 patients
AC C
in Ontario (which utilizes a government-funded, single-payer system) who were undergoing elective coronary angiography from 2008 to 2011. The overall rate of obstructive disease in New York was just 30% compared with 45% in Ontario – a finding primarily driven by a higher rate of referral of low-risk patients in New York. Using a risk model based on clinical factors and noninvasive testing, less than 1 in 5 patients in New York had a greater than 50% likelihood of obstructive CAD compared with more than 2 in 5 patients in Ontario. Importantly, no underdetection of patients with surgical coronary artery disease (left main disease or 3-vessel coronary 2
ACCEPTED MANUSCRIPT
artery disease) was noted despite a historically 50% lower use of coronary angiography per capita in Ontario. Thus, a more restricted approach to patient selection for coronary angiography in Ontario did not appear to miss those with critical disease.
RI PT
In this issue of JACC, Bradley and colleagues add to this discussion with a report from the Veterans Affair (VA) Healthcare System’s Cardiovascular Assessment, Reporting and Tracking for Cath Labs (CART-CL) program.(4) This study is important since the VA
SC
Healthcare System represents a large, integrated healthcare delivery system in the US where financial incentives for performing coronary angiography and medico-legal concerns may be less
M AN U
than in the private sector and care coordination more extensive. The authors utilized data from 76 VA cardiac catheterization labs between 2007 and 2010. Of the 22 538 patients who underwent elective coronary angiography during this time period, 4 829 had normal coronary arteries (21%) and 11 622 (52%) had obstructive disease. Patients with normal coronary arteries
TE D
were more likely to have low Framingham risk scores and a noninvasive test. In order to assess hospital-level variation, hospitals were divided into quartiles based upon the percentage of cases with normal coronary arteries with Quartile 1 having a rate of normal coronary arteries of 11%
EP
and Quartile 4 having a rate of 30%. Patients in Quartile 1 were more likely to undergo noninvasive testing, but no consistent trends were noted across quartiles in patient demographics,
AC C
cardiovascular risk factors, Framingham scores, or hospital characteristics. This work by Bradley and colleagues is important for several reasons. First, it suggests a higher referral threshold for coronary angiography within the VA. Given the possibility of less direct financial incentives for testing in an integrated healthcare delivery system, this finding may have implications for Accountable Care Organizations (ACOs) that will gain traction in the coming years. Second, their observation of 10-fold variation in hospital rates of normal coronary
3
ACCEPTED MANUSCRIPT
arteries is important. Despite finding an overall rate of normal coronary arteries that was almost half what was reported from the CathPCI Registry, this inconsistency implies an ongoing need to improve patient selection across institutions and reminds us that factors beyond financial
RI PT
incentives are playing a role. Third, this report raises a real concern regarding studies that
compare rates of normal coronary arteries across healthcare systems that many VA cardiologists will immediately recognize. Given a higher burden of baseline disease in the VA population, a
SC
poor decision to perform coronary angiography in a Veteran (e.g., asymptomatic and low-risk stress test) may be statistically more likely to yield obstructive disease than an appropriate
M AN U
decision in other settings. As even 10% of patients with an acute coronary syndrome might have non-obstructive disease,(5) we may be right but for the wrong reasons or wrong for the right reasons.
Thus, it remains unclear as to what we as a clinical community are to do collectively with
TE D
these studies of rates of normal coronary arteries (and the others that may potentially follow) or if and how should they influence our use of coronary angiography. However, the questions that they raise are potentially enormous: to what extent do high rates of coronary arteries indicate
EP
poor quality or suggest that we are performing too many procedures? Do we need to become more adept at risk stratification or do we need more or better noninvasive testing? How are
AC C
financial incentives driving these decisions and what other factors – such as medico-legal concerns – are playing a role in patient selection? And finally, what is a reasonable rate of normal coronary arteries that should be expected for cardiologists, realizing that 0% is neither possible nor desirable?
Of course, many of these questions deal with the overall quality of current clinical assessments and noninvasive testing. These issues were highlighted over 3 decades ago in the
4
ACCEPTED MANUSCRIPT
seminal work of Diamond and Forrester with their application of Bayes’ theorem to coronary angiography. Results of any clinical finding or diagnostic test must be placed into the context of a patient as their interpretation inherently depends upon the pre-test probability of disease. (6)
RI PT
Diamond and Forrester demonstrated that the probability of coronary artery disease may be obtained in large part through assessment of the patient’s age, sex, and symptoms. Despite significant advancements in noninvasive tests since that time, it is disappointing that these tests
SC
only marginally improve the diagnostic yield of coronary angiography over these clinical factors, perhaps as a result of their more widespread use in contemporary practice and verification bias.
M AN U
(7)
Despite the clear need to improve our decision-making process for coronary angiography, it also is important to acknowledge that some elective procedures undoubtedly will result in the finding of normal coronary arteries. So when is it right for us to be wrong? Is the rate of normal
TE D
coronary arteries found in the CathPCI Registry of 39% too high or perhaps the rate of 21% in the VA population too low? Too high a rate suggests waste and the danger of unnecessary procedures while too low a rate implies we may be causing harm by missing patients
EP
appropriately referred for this diagnostic test. Although the study by Ko et al. suggests this latter concern may be minimized, it is clear even from that study that we must be able to accept a few
AC C
false-positive tests as part of the process. In some circumstances, there may be great value to a negative study that identifies normal coronary arteries given the concerns many patients have with the possibility of cardiac conditions as a cause of their symptoms. In fact, the value of any diagnostic test lies not only in its ability to “rule-in” disease, but how it helps clinicians to “ruleout” disease as well since that also strongly influences subsequent management.
5
ACCEPTED MANUSCRIPT
We believe many forces will push this debate even further in coming years. Rates of normal coronary angiographies have been discussed as a performance measure for over a decade now, but there has been little pursuit of it. (8) However, the emerging data highlighted by Patel
RI PT
et al., Ko et al., and Bradley et al. suggest that a greater interest will and should be placed on risk stratification and patient selection in coming years. This is further supported by the recent
publication of appropriate use criteria (AUC) for coronary angiography. Using rates of normal
SC
coronary arteries may supplement AUC to fully inform us on how well an entire system is doing in this regard and ensure validity in quality comparisons across hospitals. Bradley and
M AN U
colleagues raise these points eloquently in their paper but also warn us about potential limitations with its use in isolation. For example, before rates of normal coronary arteries become a performance measure we clearly need more empirical work as ranking of hospitals in the VA Healthcare System was highly sensitive to how “normal” was defined. In Figure 3 of the paper
TE D
by Bradley et al., the top hospital ranked by its rate of normal coronary arteries was approximately 50th by its rate of non-obstructive CAD. Although the extent to which the use of rankings and performance measurement of rates
EP
of normal coronary arteries may influence clinicians is unclear, it may be consequential. A prominent example of the real-world implications of these decisions was recently illustrated. In
AC C
a $4 million settlement by a physician and healthcare system for allegedly performing unnecessary coronary angiography, it was purported that 75% of patients had “no significant heart blockages”. (9) This case is obviously complex and raised multiple issues, including the improper reading of nuclear stress tests prior to coronary angiography. Yet it is telling that this case is fundamentally different from prior reports of inappropriate coronary stenting or cardiac surgery since it involves the claim that a diagnostic test – not a therapeutic procedure – was
6
ACCEPTED MANUSCRIPT
overused. And it raises the natural question as to whether this logic may be extended to other diagnostic tests, such as measures of normal rates of echocardiograms, CT scans, ultrasounds and even some expensive laboratory tests?
RI PT
Improving our understanding of all these issues around rates of normal coronary arteries will be fundamental as we move forward in an era of AUC, quality improvement initiatives, performance measures, and escalating costs. It must be done carefully with recognition that
SC
large differences will exist across the populations that we serve and that this should influence how these data are collected, interpreted and reported. As clinicians, we certainly need to
M AN U
become better at how we utilize expensive and sometimes risky tests like coronary angiography. This desire for improvement, however, must be balanced with the knowledge that there remains an important role for judgment in such decisions. That is, we need to hold on to the right to be
AC C
EP
TE D
wrong.
7
ACCEPTED MANUSCRIPT
References 1.
Ryan TJ. The coronary angiogram and its seminal contributions to cardiovascular
2.
RI PT
medicine over five decades. Circulation 2002;106:752-6. Patel MR, Peterson ED, Dai D et al. Low diagnostic yield of elective coronary angiography. N Engl J Med 2010;362:886-95.
Ko DT, Tu JV, Austin PC et al. Prevalence and extent of obstructive coronary artery
SC
3.
disease among patients undergoing elective coronary catheterization in New York State
4.
M AN U
and Ontario. JAMA 2013;310:163-9.
Bradley SM, Maddox TM, Stanislawski MA et al. Normal coronary rates for elective coronary angiography in the VA Health Care System: Insights from the VA CART Program. J Am Coll Cardiolo, 2013 (In Press).
5.
Maddox TM, Ho PM, Roe M, Dai D, Tsai TT, Rumsfeld JS. Utilization of secondary
TE D
prevention therapies in patients with nonobstructive coronary artery disease identified during cardiac catheterization: insights from the National Cardiovascular Data Registry
6.
EP
Cath-PCI Registry. Circ Cardiovasc Qual Outcomes 2010;3:632-41. Diamond GA, Forrester JS. Analysis of probability as an aid in the clinical diagnosis of
7.
AC C
coronary-artery disease. N Engl J Med 1979;300:1350-8. Diamond GA, Kaul S. Low diagnostic yield of elective coronary angiography. N Engl J Med 2010;363:92-95. (letter) 8.
Bashore TM, Bates ER, Berger PB et al. American College of Cardiology/Society for Cardiac Angiography and Interventions Clinical Expert Consensus Document on cardiac catheterization laboratory standards. A report of the American College of Cardiology
8
ACCEPTED MANUSCRIPT
Task Force on Clinical Expert Consensus Documents. J Am Coll Cardiol 2001;37:2170214. Baldas T. Cardiology practice, Jackson hospital to pay $4M in lawsuit alleging medically
RI PT
inappropriate heart procedures. Detroit Free Press, July 2013. Available at:
http://www.freep.com/article/20130710/NEWS05/307100126/cardiology-settlement-
EP
TE D
M AN U
SC
jackson-hospital-medically-inappropriate. Accessed September 17, 2013.
AC C
9.
9
