1. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
Comparative Efficiency of Exercise Stress Testing With and Without Stress-Only Myocardial Perfusion Imaging in Patients With Low Risk Chest Pain
Jossef Amirian, MD*†, Omid Javdan, MD†, Jason Misher, MD††, Joseph Diamond, MD††, Christopher Raio MD, MBA, FACEP‡‡, Gary Rudolph, MD ‡‡, Regina S. Druz, MD, FACC, FASNC‡.
*Department of Cardiology, Icahn School of Medicine at Mount Sinai, Mount Sinai Heart at Mount Sinai Beth Israel, New York, New York. ‡Division of Cardiology, Department of Medicine, St. John’s Episcopal Hospital, Far Rockaway, New York, †Department of Medicine, ††Department of Cardiology, ‡‡Department of Emergency Medicine, North Shore University Hospital, Manhasset, New York, Long Island Jewish Medical Center, New Hyde Park, New York; Northwell Hofstra University School of Medicine, Uniondale, New York.
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2. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
BACKGROUND
Over the last decade, institutions which allocate funds for acute cardiac patients have established initiatives targeting low risk chest pain patients who can be discharged within twenty four hours from an observation unit.
Clinical decision units (CDU) are poised to increase efficiency and resource utilization, however the optimal testing strategy that would assure favorable outcomes is not defined.
The ‘2015 Appropriate Use Criteria For Cardiovascular Imaging in Emergency Department Patients with Chest Pain’ is an excellent source for physicians to establish which imaging modality to consider. However, in patients at low risk, there is a pressing need to determine outcomes of care and direct per capita cost of care for commonly used and widely available modalities such as exercise treadmill testing (ETT) and stress-only myocardial perfusion imaging (sMPI).
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3. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
METHODS
Study type: Multi-center, retrospective propensity score matched study.
Study subjects: Patients with suspected cardiac ischemia who presented to the emergency department with chest pain and were transferred to observation in the clinical decision unit based on institutional inclusion and exclusion criteria provided in Table 1 and Figure 1a, at North Shore University Hospital and Long Island Jewish Medical Center between December 2011 and September 2012.
Study variables: Patient factors pre- and post propensity score matching are illustrated in Table 2 and Table 3, respectively.
Study endpoints:
Primary end point(s): Major adverse cardiac events (MACE) including acute coronary syndrome, revascularization and cardiac death.
Secondary end point(s): Length of stay greater than twenty four hours, downstream resource use including admission for chest pain, repeat testing, angiography, and mean direct cost per patient.
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4. Table 1. Clinical Decision Unit Exclusion and Inclusion Transfer Criteria for Chest Pain Observation

5. Figure 1a. Algorithm for patient exclusion of low risk chest pain patients in the clinical decision unit. Metabolic equivalents as ascertained by the Duke Activity Status Index questionnaire.

6. Table 2. Comparability of ETT and sMPI subjects prior to propensity score matching

7. Table 3. Comparability of ETT and sMPI subjects after propensity score matching

8. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
Results: Propensity score matching yielded a total of 680 patients, 340 matches. 98% of all tests were normal. 96.6% of patients were discharged from the CDU within 24 hours but twice as many exceeded 24 hours in the sMPI group. There were no cardiac deaths. Major adverse cardiac event (MACE) rate was 1.47% at 72 hours and 1% at 1 year. Downstream resource use was 4.82% at 72 hours, and 7.69% at 1 year. Results at 72 hours and 1 year are provided by Figure 1b and Figure 1c, respectively. The sMPI group was event-free longer than the ETT group reflecting less repeat testing (Figure 2, log-rank P < ). The mean direct cost was 30% higher for sMPI ($ ) vs. ETT ($2,226.96).
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9. RESULTS Insert a key table or a key figure If figure, insert legend
Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
Figure 1b. Major adverse cardiac event rate and downstream resource utilization within 72 hours of testing. Percutaneous coronary interventions (PCI) and coronary artery bypass graft (CABG) surgery.
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Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
Figure 1c. Major adverse cardiac event rate and downstream resource utilization within 1 year of testing.
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Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
RESULTS
Figure 2. Probability of remaining event-free (admission for chest pain or symptoms suggestive of CVD, angiogram, or repeat testing) at 1 year in the CDU patient cohort censored of events within 3 days post-index stress testing. sMPI (red), ETT (blue)
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12. Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology
CONCLUSIONS
Low risk chest pain patients in the observation unit had low major adverse cardiac event rates, and when compared, stress only myocardial perfusion imaging and exercise treadmill testing were equivalent in terms of patient outcomes such as acute coronary ischemia, recidivism rates and angiography/revascularization.
The majority of exercise treadmill testing and stress only myocardial perfusion imaging tests were normal.
When compared to exercise treadmill testing, the use of stress only myocardial perfusion imaging reduced additional testing, but resulted in higher cost and prolonged length of stay.
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