Imaging for chest pain in the emergency room: Finding the right gate not the right gatekeeper
Imaging for chest pain in the emergency room: Finding the right gate not the right gatekeeper
David G. Wolinsky 0
MASNC 0 1
0 Reprint requests: David G. Wolinsky, MD, FACC, MASNC , Heart and Vascular Institute, Cleveland Clinic Florida, Weston; J Nucl Cardiol 1071-3581/$34.00 Copyright 2016 American Society of Nuclear Cardiology , USA
1 Heart and Vascular Institute, Cleveland Clinic Florida , Weston , USA
It is Friday morning at 11AM. A 68-year-old female
with history of hypertension, hyperlipidemia, and
depression comes to the ER with three weeks of near
constant throbbing left arm, chest, and shoulder pain
exacerbated by arm movement. ECG is normal, CPK is
mildly elevated but troponin-T is normal. Her stress test
3 years ago was normal. The ER physician calls the
hospitalist to admit for further evaluation of possible
ischemic chest pain. A coronary CTA is ordered and is
interpreted as ‘‘severe stenosis of right coronary artery
and moderately severe stenosis of left anterior
descending and circumflex arteries’’. Cardiology is called to
assess at 5PM, Friday. What is the next step?
Cardiovascular disease remains the leading cause of
death in the United States based on data published by the
Center for Disease Control and Prevention.1 It is not
surprising, therefore, that over 7 million patients are
evaluated yearly in our Emergency Departments (ED).2
The vast majority of patients with acute myocardial
infarction or acute coronary syndrome are readily
identified based on clinical presentation,
electrocardiographic changes, and early positive biomarkers. What
remains is the challenge of identifying a small number
of clinically stable patients who are at short-term risk for
cardiac events. The cost to the American health care
system of these evaluations is becoming increasingly
The protocols by which these patients are evaluated
are far from standardized. The cost to evaluate patients
for chest pain continues to rise despite a very low yield.
Traditional workup includes either an anatomic or
functional imaging test. This is a costly process of
increasingly low value. From 1999 to 2008, despite a
44.9% reduction in ER visits resulting in a diagnosis of
acute coronary syndrome, there was a 367.6% increase
in advanced imaging in this population.1
In this issue of the Journal of Nuclear Cardiology,
Delaney et al. review the variety of tools available to
evaluate patients with acute chest pain in the Emergency
Room.3 Despite the vast amount of published data, no
clinical consensus has been reached on the management
of these patients. There are well established clinical
guidelines for management of STEMI and NSTEMI/
acute coronary syndrome and multimodality appropriate
use criterion for assessment of stable ischemic heart
disease that have been embraced universally,4–6 no such
standards have the same level of acceptance for
evaluation in the emergency room. The AHA Scientific
Statement on testing low-risk patients presenting to the
ED with chest pain fails to come to a consensus
recommendation.2 A recent American College of
Cardiology/ American College of Radiology Appropriate
Utilization document on emergency department patients
with chest pain has met with controversy and lack of
universal acceptance.7 Cost effectiveness analyses focus
on the effect of a given test on outcome. Because chest
pain populations are so heterogeneous, an algorithm
validated in one group of patients stratified by one type
of clinician may not be able to be extrapolated to another
The ER evaluation process is unique in that various
stakeholders, all of whom have different goals and
different benchmarks for success, may make the
ultimate patient triage decisions. Each stakeholder engages
a different algorithm, and may be validating their data
with different populations making comparisons difficult.
The ER physician’s goal is to avoid discharging a
patient with a potential acute coronary syndrome based
on historical data suggesting high mortality in patients in
whom the diagnosis is missed. Many emergency room
protocols rely on the TIMI score, which was meant to
assess the risk of complications in patients with
established ACS. Use of the HEART score is associated with
more effective risk stratification in the chest pain patient
without obvious ACS. A HEART score of 0-3 excludes
MACE over a six week period with over 98% accuracy.
These patients might be managed with outpatient stress
testing or even no testing with clinical follow-up. On the
other hand, HEART scores of 7-10 would merit more
Once admitted to a chest pain unit or observation
unit, clinical decision-making is often the responsibility
of hospitalists. Evaluation usually involves serial
biomarkers followed by a functional test. Chest pain
units are effective but inefficient in that too many
patients spend too many hours in the hospital for a
negative workup. Unfortunately patients admitted to
chest pain units are a heterogeneous population. Once
through the gates of admission or observation status,
they automatically undergo testing that is often
inappropriate. Cardiology consultation may later be called
for further increasing length of stay.
Requesting a cardiology consult implies that an
advanced imaging test should be done. To provide
value, cardiac testing must provide the following: (
Accurate diagnosis of presence or absence of disease,
) Risk stratification, (
) Efficiency of workup, (
) Safety, and (
) Identification of
populations in which the test is superior. To date,
studies have been unable to demonstrate a modality
capable of satisfying all criteria.
Coronary CTA (CTA) is effective in a low-risk
population. It has a high negative predictive value and in
ROMICAT 2, was able to rescue length of stay by 7.6
hours.9 However no cost savings were achieved
compared to usual care. PROMISE evaluated CTA in a low
to intermediate risk population with chest pain and
showed no benefit of anatomic testing over functional
stress testing. CTA led to a higher incidence of
revascularization in what was a low-risk population
(3.3% suffered an endpoint over 25 months) and higher
cost.10,11 Similar findings of increased coronary
angiography and revascularization have been reported by other
authors.3 Applying CTA to a lower risk population
might further reduce downstream testing and cost.
Reducing subsequent angiography and revascularization
based on guidelines would also improve cost
CTA has technical limitations in patients with renal
insufficiency, contrast allergy, and rapid heart rate. In
addition, many hospitals do not have technical staff available
to carry out CTA around the clock. Still it appears that CTA
has a major role in evaluating low-risk patients by providing
the emergency room staff an adequate comfort level to allow
for early expeditious discharge.
Multiple studies have demonstrated the
effectiveness and safety of SPECT myocardial perfusion imaging
(MPI) in evaluating emergency room patients presenting
with chest pain.3,12–15 Patients enrolled in these studies
are more heterogeneous, have baseline higher risks, and
in fact often have known CAD. SPECT effectively
predicted which patients would need to undergo
coronary angiography. Nabi et al. reported that 38.3% of
patients with abnormal SPECT MPI subsequently
underwent revascularization, whereas only 0.9% of
patients with normal SPECT subsequently required
coronary intervention. Of patients with greater than ten
per cent ischemia by perfusion imaging, 55% underwent
Limitations of SPECT MPI are related to cost.
Patients undergoing rest-stress studies typically require
an overnight stay in the hospital. Increased length of stay
is associated with greater financial burden. False
positive scans may lead to downstream testing and treatment
if applied to a more general population. Image quality
may be limited in obese or incooperative individuals.
Some have voiced concerns over the risk of cumulative
radiation exposure with medical imaging.
Stress-only/stress-first imaging protocols, however,
address many of the concerns above. Duvall demonstrated
that low-risk patients undergoing stress with normal
perfusion scan can be safely discharged early with low
1year annual mortality (0.5%) equivalent to patients with a
normal rest- stress study.13 Similarly Lim performed
stress-only imaging after 6 hours and two sets of negative
cardiac biomarkers. Normal stress-only scans were
associated with a very low 1-year risk (0.7%)14 Also
demonstrated was the safety of allowing patients with
equivocal or low-risk stress-only scans to be discharged
and return as outpatients for completion of their studies.14
Just as CTA may have increased value if applied to
a better-defined low-risk population, so too can the value
of SPECT MPI be increased with application to a higher
risk rather than broad-based population. Cremer et al.
found the incidence of moderate to high risk MPI scans
in emergency department patients with chest pain,
negative troponins, and TIMI score less than or equal
to two was only 6.1% compared to 19.6% of patients
with TIMI scores greater than or equal to three.15 The
30-day event rate in both groups was very low
suggesting that workup need not always be carried out or
completed emergently in the absence of very-high
For patients who are not capable of exercise stress,
PET perfusion imaging may provide significant
information. Rb-82 PET has been shown to have improved
image quality and incremental prognostic value in the
obese population.16 Similarly, improved effective risk
stratification has been shown in women undergoing
Rb82 PET imaging, while reducing radiation exposure.17
One cannot ignore the ongoing mortality of risk
associated with coronary heart disease. In fact efforts to
reduce cardiovascular disease have been blunted over 3
years.18 The MACRA has mandated modification of
Medicare payment, and will therefore modify care
delivery to the Medicare population. With
implementation of Merit-Based Incentive Payment System (MIPS),
effective use of resources and quality assessment will
increasingly affect reimbursement. Therefore, all
clinicians must work together to provide optimal care.
A new model for the management of patients
presenting to the ED with chest pain emphasizing value
must be developed. This model must have input from all
groups and be accepted by all. High-risk patients with
NSTEMI or ACS can be admitted directly for further
cardiologic management. Clinical decision-making must
replace simple algorithms. Initial clinical evaluation
using effective tools other than TIMI score must assess
overall risk and decide which patients receive a
‘‘wristband’’ to go through the gate and enter a testing
algorithm. There is no one test or gatekeeper for all. The
right test must be chosen for the right patient based upon
clinical scenario and local expertise. Equally mandatory
is proper decision-making based on test results. Better
adherence to guideline-driven treatments based on the
results of cardiovascular testing must be achieved. Our
patients need us to do the right thing.
Dr. Wolinsky has received speaker honoraria and
consultant fees from Astellas Pharma and has received
consulting fees from Adenosine Therapeutics.
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