1. Cost Effective Use of Troponin to Rule Out Acute Coronary Syndrome
Saahir Khan, MD, PhD
Resident, Internal Medicine
University of California, Irvine

2. Background
Chest pain is one of the most frequent presenting complaints seen in the ED
Rule out of acute coronary syndrome is one of the most frequent reasons for admission to a medicine service

3. HEART Pathway
HEART score is a clinically validated tool to predict risk of mortality from ACS
HEART score less than 4 with non-rising troponin at 3 hours has 99% sensitivity for excluding ACS
The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge. 8, 195–203 (2015).

5. Methodology
From a retrospective cohort of 120 patients discharged from UC Irvine medicine service during a week in December 2015, 28 patients were admitted at least partially for rule out of acute coronary syndrome
HEART pathway was applied to determine cost savings from decreased utilization of troponin

6. Methodology
For patients with HEART score less than 4 and non-rising troponin at 3 hours or later, no further troponin is indicated
For patients with HEART score greater than 4 and/or rising troponin, serial troponins can be continued until downtrending

7. Study Population
28 patients admitted for rule out ACS include 16 with chest pain and 12 with other symptoms such as syncope or dyspnea
HEART score mean was 3.82, with 14 patients having HEART score less than 4
Initial troponin was mildly elevated (1 to 3x ULN) in 8 patients, and markedly elevated in 2 patients
3 patients underwent cardiac cath, with 1 patient having ACS and 2 patients having stable CAD, and 12 patients underwent echocardiogram with none having new wall motion abnormalities

8. Results
HEART pathway ruled out 13 patients after 2 troponins but excluded the 1 patient with ACS
HEART pathway would have resulted in 19 less troponins tested, at a cost savings of $494 for 1 week, or $25,688 extrapolated over 1 year
Significant outlier effect due to a case in which 13 troponins were tested (trended until normalized) for a patient with chest pain and elevated trop who had pulmonary embolism

9. Conclusion
For patients admitted to medicine service from ED for rule out ACS, application of HEART pathway can result in decreased utilization of troponin testing and potentially save over $25,000 per year, in addition to other higher costs such as length of stay and further testing.