Beyond HEART: Building a Better Chest Pain Protocol

The University of Maryland Medical System built on the HEART score in order to design a unique low risk chest pain protocol, and the early results have been positive.

Patients with chest pain that is considered low-risk for acute coronary syndrome (ACS) are a disposition challenge for emergency physicians. Many factors affect the decision to admit or discharge, such as the availability of hospital beds or ED observation units, the willingness of in-house physicians to admit, the level of risk-acceptance by the emergency physician, and published practice standards from the American Heart Association [1]. A medically-sensible and defensible approach to care has been needed for quite some time.

The recommended assessment for ACS from the American College of Cardiology and American Heart Association (ACC/AHA) is to obtain serial cardiac biomarkers and electrocardiograms (ECGs), and if results are negative, the ACC/AHA Guidelines recommend provocative cardiac testing (or coronary computed tomogram angiography) prior to discharge or within 72 hours [1].

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However, resources are often just too limited to follow the above guidelines for admission and early provocative testing on large numbers of patients. A recent multicenter chart review of patients with low-risk chest pain who were admitted to the hospital after two negative serial biomarkers reported a very low incidence of adverse outcomes during hospitalization (0.06%), and of those outcomes, a few were possibly iatrogenic [2].

At the University of Maryland Medical System, we decided to develop a system-wide evidence-based guideline that would safely allow ED discharge and outpatient followup for patients with low risk ACS. To accomplish this, we utilized the system’s Emergency Medicine Risk Forum – a committee of academic and community emergency medicine physicians, risk managers and chief medical officers from 14 hospitals. The committee reports to both the Chief Medical Officer Council and to the malpractice insurer. The committee has been successful in the past in leveraging its expertise to develop an IV contrast-only CT protocol, standardized informed consent/refusal forms, and improved procedural consent forms.

To develop a chest pain guideline, the committee researched various recommendations including the ACC/AHA guidelines, selected accelerated diagnostic protocols in use in New Zealand and Australia [3-6], and the HEART score. We also considered differences among EDs within our system – community vs. academic, suburban vs. inner city, and ease of access to primary care and cardiology follow-up. We did not consider use of point-of-care troponin assays.

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The Australasian accelerated protocol studies [3-6] used hs-cTn, which is not approved for use in the United States. The HEART Score, however, provided a prospectively validated risk assessment tool [7, 8] that had been studied and validated in the United States [9,10]. This tool is safe, efficient, and uses the FDA-approved conventional cTN I.

The HEART score (details at heartscore.org) was developed using the conventional troponin assay, cTNI. It is an easily applied scoring system that can be built into an existing electronic health record template.

The external, prospective validation by Backus, et al. [4,8], demonstrated that of 2388 patients with chest pain, only 1.7% of patients with a score of 0-3 had a major adverse cardiac event within 6 weeks. This proportion was further reduced to <1% when a second troponin was added at hour 3 in the studies of Mahler, et al [9,10].

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Based on the above information, the University of Maryland Risk Forum formally recommended the use of the HEART score to assess the patient risk for low probability ACS, and to help to determine which patients are suitable for outpatient follow-up. Furthermore, in an effort to help patients understand the risks and benefits while allowing them to be active participants in their care, the Risk Forum also incorporated a shared decision-making tool that had been published by Hess, et al [11]. In that study, patients were provided their estimated risk of a major adverse cardiac event based on a validated risk prediction instrument, and the choices of disposition (admission or observation unit stay for provocative testing vs. outpatient follow-up) were presented. Hess and colleagues found that this protocol resulted in an overall decreased rate of hospitalization and decreased rate of provocative testing but no increase in a major adverse cardiac event for the next 30 days. Furthermore, patients felt more knowledgeable of their condition, communication between provider and patient increased, and patient satisfaction improved through their engagement in the decision making process.

We have modified Hess’ and colleagues’ shared decision-making document (click image below for full PDF) for use with our low-risk chest pain protocol at the University of Maryland Medical System.

The University of Maryland Low Probability ACS Protocol (at the bottom of the page) is used for patients that are, based on the initial history and physical, to be at a reasonable but low risk for ACS. Note that if the patient’s presentation is judged to be un-concerning for ACS (by clinician gestalt), then this protocol is unnecessary. A positive troponin at any time is not appropriate for this guideline.

The guideline was incorporated into clinical practice in the University of Maryland Emergency Medicine System in February 2015, and anecdotal feedback from the medical directors at each hospital has been that there has been a reduction in chest pain hospitalizations without known major adverse cardiac events. One of the busiest EDs reported a 22% reduction in patients placed in observation status. Informal surveys of patient satisfaction with this protocol are positive. We feel this combination of tools not only reduces the number of hospitalizations, but also helps emergency physicians determine which patients are most appropriate to discharge and provides excellent medical decision-making that can be documented within the medical record. Physicians and risk managers have been extremely happy with the potential legal protection that the protocol affords. We would encourage others to implement a similar protocol to help define a new, evidence-based and sensible approach to the management of patients with low-risk chest pain.

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THE UNIVERSITY OF MARYLAND LOW PROBABILITY ACS PROTOCOL
Determine a HEART score for patients presenting with chest pain after the first troponin value has resulted.

If the patient has a HEART Score of 0-3 and a negative initial troponin, have a discussion with the patient utilizing the Shared Medical Decision-Making document (Figure 2). Inform the patient that based on validated studies, there is a < 2 % chance of an adverse cardiac event within the next 4-6 weeks. This discussion occurs after the first troponin, not after a second troponin.

The patient chooses amongst the three options listed in the Shared Medical Decision-Making document.

• The patient can be offered, and may elect to remain for, a second troponin test and ECG obtained at hour three of the ED stay. If that troponin is negative as well, the patient can be informed that the risk of adverse cardiac event has been lowered to < 1% at 4 weeks. If the second troponin is increased by at least 20% and positive, the patient should be hospitalized for further evaluation.
• The patient may elect to be admitted to the hospital or observation unit (based on hospital availability) for observation of occurrence of a cardiac event, or for provocative testing. The patient should be given honest information about the resulting length of stay.
• The patient may elect to be discharged immediately after having the single troponin value and knowledge of the < 2% risk as described above.

If the patient chooses either the first or third option and is discharged after either one or two negative troponins, establish followup within one week and save a copy of the signed Shared Decision Making

Document in the chart. Our choice to recommend 1-week follow-up was by consensus and not based on published studies. However, we do not mandate a provocative test at that follow-up visit. The decision for further testing for risk stratification is left to the follow-up physician.

Document medical decision-making and HEART Score in the medical record.

Obtain an ECG at the time of arrival, and repeated along with each troponin, or if symptoms change. If evolving changes are noted on the repeat ECGs, the patient is judged higher risk and admitted.

REFERENCES

1. Amsterdam EA, Kirk JD, Bluemke DA, et al. Testing of low-risk patients presenting to the emergency department with chest pain. A scientific statement from the American Heart Association. Circulation 2010;122:1756-1776.
2. Weinstock MB, Weingart S, Orth F, et al. Risk for clinically relevant adverse cardiac events in patients with chest pain at hospital admission. JAMA Intern Med 2015;175:1207-1212.
3. Than M, Cullen L, Reid CM, et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet 2011;377:1077-1084.
4. Than M, Cullen L, Aldous S, et al. 2-hour accelerated diagnostic protocol to assess patients with chest pain symptoms using contemporary troponins as the only biomarker: the ADAPT trial. J Am Coll Cardiol 2012;59:2091-2098.
5. Aldous S, Pemberton C, Richards AM, et al. High-sensitivity troponin T for early rule-out of myocardial infarction in recent onset chest pain. Emerg Med J 2012;29:805-810.
6. Cullen L, Mueller C, Parsonage WA, et al. Validation of high-sensitivity troponin I in a 2-hour diagnostic strategy to assess 30-day outcomes in emergency department patients with possible acute coronary syndrome. J Am Coll Cardiol 2013;62:1242-1249.
7. Backus BE, Six AJ, Kelder JC, et al. Chest pain the emergency room. A multicenter validation of the HEART score. Crit Pathw Cadiol 2010;9:164-169.
8. Backus BE, Six AJ, Kelder JC, et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol 2013;168:2153-2158.
9. Mahler SA, Miller CD, Hollander JE, et al. Identifying patients for early discharge: Performance of decision rules among patients with acute chest pain. Int J Cardiol 2013;168:795-802.
10. Mahler SA, Riley RF, Hiestand BC, et al. The HEART pathway randomized trial. Identifying emergency department patients with acute chest pain for early discharge. Circ Cardiovasc Qual Outcomes 2015;8:195-203.
11. Hess EP, Knoedler MA, Shah ND, et al. The chest pain choice decision aid: a randomized trial. Circ Cardiovasc Qual Outcomes 2012;5:251-259.