There’s been a clear shift in the emergency medicine mindset toward chest pain over the past few years, including an explosion of literature and professional guidance in support of the history, electrocardiogram, age, risk factors, and troponin (HEART) score.¹ The primary application of this and other similar rules is to support risk-stratification and the early discharge of patients with chest pain at low risk for acute coronary syndrome (ACS).

In fact, various strategies for early discharge have been enshrined in the guidelines from the American College of Cardiology since 2014.² These guidelines support the use of not only such stalwarts as the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) scores, but HEART, a modification of HEART called HEARTS3, and the Vancouver Rule. Suffice it to say, if you’re not at least risk-stratifying patients for early discharge using clinical judgement or an objective tool, you’re lagging.

However, this article isn’t about discharging patients with low-risk chest pain. This article discusses discharging the other 40–50 percent of emergency department patients with chest pain who don’t fall into such an optimal classification. For instance, a septuagenarian with non-obstructive coronary artery disease on a previous cardiac catheterization, a couple seconds of atypical chest pain, and an undetectable troponin I counts as a “moderate” risk by HEART. Or a 65-year-old male without any known risk factors and non-specific pain who falls into the “not low risk” classification of the Emergency Department Assessment of Chest Pain Score (EDACS).³ How should we manage the vast heterogeneous cohort of patients like these who aren’t in the low-risk strata?

It’s Two Questions

This question basically breaks down into two components, which people frequently stick together and address singly when evaluating the performance of these algorithmic approaches. These approaches try to pare down the cohort by defining certain discharge criteria in the emergency department, and they measure success by remaining free of major adverse cardiac events (MACE) for a certain period of time.

This approach seeks to prevent the dreaded, “Hey, remember that guy with chest pain you sent home last week?” follow-up conversation on a future shift. However, assessing safety for discharge truly breaks down into these two questions: 1) “Have I adequately ruled-out an acute coronary syndrome on today‘s visit,” and 2) “What follow-up or additional testing will prevent a future MACE?”

To answer question one, we rely upon the relevant presenting features of the chest pain, the electrocardiogram, and biomarker testing. In the vast majority of cases in which acute ischemia is not apparent or highly suspected, the limiting factor becomes biomarkers. In the past, concern over the relative lack of early sensitivity to cardiac ischemia led clinicians to routinely refer patients for admission or observation for repeat biomarker testing. However, in recent years, an explosion of new literature describes the early test characteristics of both conventional and highly-sensitive troponins, and it‘s clear the biomarker rule-out can be performed entirely within the emergency department.⁴

These accelerated diagnostic protocols may involve one-hour or two-hour repeat testing, or, if the time of onset of the more recent symptoms is adequately remote, a single troponin on arrival may prove sufficient. Protocol sensitivity typically exceeds 95 percent, with negative predictive values in excess of 99 percent, even in patients with known coronary disease or coronary risk factors.⁵

Determining the best next step fundamentally asks the purpose of admission or observation. For an admission or observation to have value, whether on a health-system level or to a patient on a deductible health insurance plan, the intervention should offer a reasonable expectation of identifying a problem potentially amenable to treatment. Unfortunately, despite our reliance on various stress tests and the increasing prevalence of CT coronary angiography, population-based and claims-based data find no clear benefit signal.^6,7 These data don’t rule out individual benefit to intelligently-selected downstream testing, but the premise that admission or observation will benefit patients with known cardiac disease remains unproven.

However, the risk score data does make clear non-low risk patients are precisely that. These patients do have elevated risk for serious outcomes, some preventable, some not. When assessing whether a non-low risk patient is safe for discharge after accelerated biomarker rule-out, the key element is follow-up. Many patients have well-established coronary anatomy and disease, and the benefit from subsequent invasive or non-invasive testing ranges may easily be zero for a patient who’s primarily medically-managed. This follow-up can occur via established primary care or a cardiologist, depending on the complexity of the subsequent decision-making process—or, better yet, prior to disposition, if a specialist familiar with the patient‘s management can be looped in contemporaneously.

The bottom line: A diagnosis of ACS can be rapidly excluded in the emergency department in most patients, and we can think of our various decision instruments for risk-stratification as tools not to determine which patients we should discharge, but tools to help us triage patients for varying follow-up intensity. Anecdotally, at my institution, with well-integrated follow-up, more than 85 percent of biomarker-negative chest-pain presentations are discharged directly from the emergency department without untoward patient safety. It might seem implausible, but it can be done!

Complete the CME activity.

References

1. 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(3):2153-2158.
2. Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: A report of the American College of Cardiology/American Heart Association task force on practice guidelines. J Am Coll Cardiol. 2014;64(24):2713-2714.
3. Than M, Flaws D, Sanders S, et al. Development and validation of the emergency department assessment of chest pain score and 2 h accelerated diagnostic protocol. Emerg Med Australas. 2014;26(1):34-44.
4. Hollander JE, Than M, Mueller C. State-of-the-art evaluation of emergency department patients presenting with potential acute coronary syndromes. Circulation. 2016;134(7):547-564.
5. Zhelev Z, Hyde C, Youngman E, et al. Diagnostic accuracy of single baseline measurement of elecsys troponin T high-sensitive assay for diagnosis of acute myocardial infarction in emergency department: Systematic review and meta-analysis. BMJ. 2015;350:h15.
6. Sandhu AT, Heidenreich PA, Bhattacharya J, et al. Cardiovascular testing and clinical outcomes in emergency department patients with chest pain. JAMA Intern Med. 2017;177(8):1175-1182.
7. Morris JR, Bellolio MF, Sangaralingham LR, et al. Comparative trends and downstream outcomes of coronary computed tomography angiography and cardiac stress testing in emergency department patients with chest pain: An administrative claims analysis. Acad Emerg Med. 2016;23(9):1022-1030.