EDITORIALS Editorials represent the opinions
of the authors and JAMA and not those of
the American Medical Association.
Noninvasive Coronary Angiography
Hype or New Paradigm?
Mario J. Garcia, MD and only a few have reported the performance characteris-
tics of MSCT using each patient as the unit of analysis.5,9,10
In this issue of JAMA, Hoffmann and colleagues12 evalu-
W
HEN SONES INADVERTENTLY PERFORMED THE
first coronary angiogram in 1958,1 he could ated the diagnostic accuracy of MSCT for the detection of
not anticipate the profound future implica- obstructive CAD. Their study includes a large series of non-
tions of that event. Four years later, when he selected patients in whom very few (6.4%) coronary seg-
reported his experience with more than 1000 procedures,2 ments larger than 1.5 mm in diameter were excluded from
the technique was still considered experimental and was dis- analysis due to limited image quality. The majority (68%)
missed by many leading authorities in cardiovascular medi- of these excluded segments were considered nonevaluable
cine. Yet, the introduction of coronary angiography started due to imaging artifacts related to cardiac motion, most of-
a new era, leading to the rapid development of coronary ar- ten in patients with resting heart rates greater than 80/min.
tery bypass graft surgery and percutaneous revasculariza- Motion artifacts still represent an important limitation of
tion for the routine management of ischemic heart disease. current MSCT technology, even though most investigators
Four decades later, more than 2 million angiographic pro- now routinely administer -blockers to reduce resting heart
cedures are performed annually in the United States alone.3 rate. Extensive vessel calcifications also limit the interpre-
Although invasive coronary angiography clearly has led to tation of luminal stenosis by MSCT, often leading to over-
improved outcomes, it also has contributed to greater ex- estimation of severity. These accounted for many of the false-
penses in health care cost,3 limiting its potential to become positive results observed by Hoffmann et al.12 Despite these
more widely available. This has led to a growing interest in limitations, their reported per-segment sensitivity (95%) and
the scientific community in the development of less expen- specificity (98%) are noteworthy, particularly when these
sive, noninvasive alternative methods for evaluating coro- performance characteristics are compared with those of other
nary anatomy. indirect methods used for the detection of obstructive CAD,
Multislice computed tomography (MSCT) has recently such as nuclear scintigraphy or echocardiographic stress tests.
emerged above other competing technologies, such as elec- The authors also report diagnostic characteristics accord-
tron-beam computed tomography and magnetic resonance ing to a per-patient–based analysis. This is critically impor-
imaging, as a practical alternative to invasive coronary angi- tant, since the implications of detecting or missing the pres-
ography. Modern MSCT systems can provide electrocar- ence or absence of any significant coronary obstruction are
diogram-gated acquisition with adequate temporal resolu- more clinically relevant from the perspective of the indi-
tion (100-220 ms) and with the submillimeter spatial vidual patient. Even after accounting for nonevaluable seg-
resolution needed to visualize with sufficient detail the lumen ments, the high positive (90%) and negative (95%) predic-
of the coronary arteries. Several studies have investigated tive values strongly support the conclusion that, in this
the accuracy of MSCT in patients with known or suspected patient population, MSCT is a robust test for establishing
coronary artery disease (CAD).4-11 In these studies, analysis the diagnosis of obstructive CAD. In addition to the con-
of MSCT has been mostly limited to coronary segments greater ventional binomial analysis, the authors performed a quan-
than or equal to 1.5 or 2 mm in diameter, and up to 5% to titative comparison of percentage luminal stenosis as de-
20% of all analyzable segments have been deemed non- termined by MSCT and invasive angiography. Receiver
evaluable due to motion artifacts, severe calcified plaques, operating characteristic curves were constructed to esti-
and other technical imaging problems. The sensitivity and mate discriminative power for identifying patients who might
specificity of MSCT for detecting a 50% or greater diameter be candidates for revascularization. The area under the curve
reduction in coronary segments has ranged between 72% was 0.97 (95% confidence interval, 0.91-1.00) for detect-
and 95% and between 85% and 100%, respectively. Many ing greater than 50% left main artery disease, greater than
of the published series have enrolled nonconsecutive patients,
Author Affiliations: Cardiovascular Imaging Section, Departments of Cardiology
and Radiology, Cleveland Clinic Foundation, Cleveland, Ohio.
See also p 2471. Corresponding Author: Mario J. Garcia, MD, Cleveland Clinic Foundation, 9500
Euclid Ave, Desk F-15, Cleveland, OH 44139 (garciam@ccf.org).
©2005 American Medical Association. All rights reserved. (Reprinted) JAMA, May 25, 2005—Vol 293, No. 20 2531
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EDITORIALS
70% stenosis in any other epicardial vessel, or both, also con- ported by the findings of Hoffmann et al, MSCT should be
firming excellent diagnostic accuracy. avoided in patients for whom resting heart rate exceeds 80
The study by Hoffmann et al provides evidence support- beats per minute after judicious administration of negative
ing the concept that among patients with suspected CAD chronotropic agents.
who are referred for diagnostic coronary angiography, MSCT And fifth, image resolution may be compromised in mor-
could alternatively provide similar diagnostic information. bidly obese patients due to x-ray attenuation. In the study
In their study population, the vast majority of patients (98%) by Hoffmann et al, the average body mass index was 26.5.
had intermediate or high probability of disease. If MSCT It remains to be determined whether MSCT coronary an-
would have been used as an initial diagnostic test, more than giography could be obtained with similar diagnostic qual-
40% of the patients in this group could have avoided un- ity in patients with higher body mass index, who unfortu-
necessary invasive angiography, and only 2 patients (2%) nately represent an increasingly prevalent segment of the
having significant disease would have been missed. Un- US population.
doubtedly, if these results could be replicated in clinical prac- Despite these existing limitations, there is an important
tice, the clinical and economic implications could be sub- segment of the population at risk for heart disease in whom
stantial. MSCT angiography could provide coronary anatomic in-
Despite these promising results, several important limi- formation with sufficient diagnostic quality. Indeed, MSCT
tations of MSCT must be considered. First, MSCT requires may offer another advantage over conventional angiogra-
ionizing radiation. In the study by Hoffmann et al, the av- phy, which is the potential ability to detect and quantify ath-
erage dose used was 8.1 mSv for a 75-kg patient. This dose erosclerotic plaques in the coronary vessel walls.16-19 Nev-
is equivalent to 2 to 3 times the dose typically adminis- ertheless, in the absence of outcome and cost analysis studies,
tered during a diagnostic invasive angiogram.13 Although it is not yet clear how MSCT coronary angiography should
the long-term risks associated with this level of radiation be integrated in the clinical practice. Should it be used as a
exposure are relatively low, it raises a concern about repeti- first test for the evaluation of chest pain or as a complemen-
tive use or use in younger individuals and women of child- tary test in patients with equivocal stress test results? In either
bearing age. On the other hand, this level of radiation ex- case, adequate patient selection will be critically impor-
posure is equivalent to that received during nuclear tant. The results of the study by Hoffmann et al cannot be
scintigraphic stress testing.14 extrapolated from their intermediate- to high-risk patients
Second, the extent and severity of coronary calcifica- to a low-risk population, which will be tempting. It is well
tions in the population studied by Hoffmann et al is not documented that diagnostic tests will not perform as well
known definitively. The mean age of the study group was when extended to populations with low disease preva-
61 years. Since the prevalence and severity of calcifications lence; inevitably, higher rates of false-positive results will
increases with age, it is likely that the diagnostic accuracy occur. Moreover, the risks of ionizing radiation probably ex-
of MSCT would decrease with advancing age. In clinical prac- ceed the potential benefits in this group.
tice, performing a low-radiation noncontrast calcium scan Should MSCT coronary angiography be used as a screen-
prior to MSCT angiography may identify patients with ex- ing test in asymptomatic patients at risk? It is clearly estab-
tensive calcification, in whom the procedure may not be all lished that the prognostic information derived from lipid
that helpful. analysis, electrocardiography, nuclear perfusion studies, or
Third, in-stent visualization with MSCT angiography is stress echocardiography is independent of angiographic re-
either not feasible or is inaccurate in most cases. Even though sults. Thus, MSCT probably will not entirely eliminate the
other segments can still be analyzed, the potential clinical need for these tests. Nevertheless, the potential value of ath-
usefulness of MSCT angiography is clearly limited if reste- erosclerotic plaque assessment by MSCT could prove to be
nosis cannot be ruled out. In patients with previous coro- useful in guiding preventive and therapeutic strategies.
nary artery bypass graft surgery, MSCT has demonstrated Future outcome studies will likely address these ques-
good accuracy in detecting graft patency, but it is often dif- tions and help to define the role of MSCT coronary angi-
ficult to evaluate the distal anastomosis and native ves- ography in the clinical practice. Meanwhile, the growing en-
sels.15 Therefore, at the present time, there is limited evi- thusiasm for MSCT in the community must be matched with
dence to suggest that MSCT angiography could be useful adequate training, proper credentialing and, above all, ap-
in these settings. propriate utilization.
Fourth, since MSCT angiography requires electrocardio-
Financial Disclosures: Dr Garcia receives institutional research funding from Phil-
gram-gated acquisition and reconstruction from several car- ips Medical Systems.
diac cycles, it is presently limited to patients with stable, regu-
lar heart rates. The existing limitations in temporal resolution REFERENCES
are determined by the rotational speed of the MSCT gantry
1. Sones FM Jr. Stormy petrel of cardiology. In: Hurst JW, Conti CR, Fye WB, eds.
(375-420 ms/revolution). It is likely that this will rapidly Profiles in Cardiology. Mahwah, NJ: Foundation for Advances in Medicine and
improve with technological advances. Meanwhile, as is sup- Science; 2003:411-413.
2532 JAMA, May 25, 2005—Vol 293, No. 20 (Reprinted) ©2005 American Medical Association. All rights reserved.
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2. Sones FM Jr, Shirey EK. Cine coronary arteriography. Mod Concepts Cardio- 11. Martuscelli E, Romagnoli A, D’Eliseo A, et al. Accuracy of thin-slice com-
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International Adoption, Behavior,
and Mental Health
Laurie C. Miller, MD able social and mental health services and are therefore likely
to be overrepresented among populations receiving such as-
A
DOPTION HAS BEEN A PART OF HUMAN CULTURE SINCE sistance.
earliest recorded times: Moses is perhaps the most Another limitation in many studies of mental health and
famous adopted person in history.1,2 Fascination behavioral outcomes of adopted children is a focus on a single
with adoption pervades literature (from fairy tales time point. Results of such cross-sectional studies may be
and myths to modern novels), psychology, and medicine. misleading: evidence suggests that adopted children im-
Researchers have long studied adoption in attempts to iso- prove their behavior as adolescence progresses, especially
late the effects of “nature” and “nurture” on behavioral out- if they have received earlier supportive or therapeutic ser-
comes and mental health.3 Genetic factors, separation from vices.9 Indeed, adoptees are underrepresented in juvenile
birth parents, environmental exposures (both prenatal and court and adult mental health populations.10
postnatal), and aspects of the adoptive home environment Other research investigations do not differentiate be-
have all been cited as possible contributors to adverse be- tween various types of adoption (private vs social services,
havioral and mental health outcomes among adoptees.4 international vs domestic), the age of the child at adoptive
Although numerous articles have been published under placement, the reasons for placement, and adoptive family
the search headings of “adoption and mental health” or characteristics. Criteria used to match children and par-
“adoption and behavior,” the use of disparate patient popu- ents are rarely examined critically.11 For children placed af-
lations, diverse research questions, and varied methods make ter infancy, few investigations differentiate between prob-
the results bewilderingly difficult to synthesize. Positive adop- lems noted at placement and those that manifest later. Studies
tion outcomes are undoubtedly underreported.5 Further- of biological predictors of behavioral or mental health out-
more, reports of increased prevalence of mental health prob- comes of adoptees are hampered by outdated or unreliable
lems among adoptees may be due in part to their adoptive information about the birth parents. Moreover, few out-
family characteristics.6-8 Adoptive families are usually eco-
nomically advantaged, well-educated, and familiar with avail- Author Affiliation: Department of Pediatrics, Tufts-New England Medical Center,
Boston, Mass.
Corresponding Author: Laurie C. Miller, MD, Department of Pediatrics, Tufts-
See also p 2501. New England Medical Center, Box 286, 750 Washington St, Boston, MA 02111
(lmiller1@tufts-nemc.org).
©2005 American Medical Association. All rights reserved. (Reprinted) JAMA, May 25, 2005—Vol 293, No. 20 2533
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