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Circulation. 2021;144:e368–e454. DOI: 10.1161/CIR.0000000000001029 November 30, 2021 e393 CLINICAL STATEMENTS AND GUIDELINES ≤1%.17 This estimate is based on clinical information that is readily available during the course of evaluation, typically occurring in the ED. There are several methods to determine that a patient is low risk (Table 8) but, invariably, all involve taking an appropriate history and physical examination, demonstration that the ECG is normal, nonischemic, or unchanged from the previous ECG, and cTn measurement at a single point in time (if presentation is >3 hours from symptom onset and using a high-sensitivity assay) or serially1-11 (with incorporation of a chest pain risk score into the CDP if using a conventional cTn assay). Importantly, there is no evidence to support routine admission or cardiac testing for chest pain patients who are low risk, although outpatient CAC scanning can provide additional information for longer-term risk stratification. Recommendation-Specific Supportive Text 1. A large proportion of patients presenting to the ED with chest pain are low risk based on a combination of features, including clinical stability, medical history, nonischemic ECG, and absence of acute myocardial injury on cTn measurement. Such individuals have a <1% frequency of ACS or MACE at 30 days.1-11 Although achieving this with conventional cTn assays requires incorporation of risk scores into a CPD, hscTn results can be used on their own. This approach has been validated based on 15 studies including a total of >9 600 patients, with a demonstrated negative predictive value for MI or death at 30 days of 99.8%.11 These findings reflect studies involving both hs-cTnI and hs-cTnT using serial measurement algorithms or a single hs-cTn, provided the final measurement is performed ≥3 hours after the onset of symptoms, without incorporation of risk scores. 2. For this low-risk subset of ED patients who have chest pain, there is no evidence that stress testing or cardiac imaging within 30 days of the index ED visit improves their outcomes.18 This represents a change from previous guidelines where stress testing within 72 hours was broadly recommended for patients with acute chest pain.19 However, many of these patients have baseline cardiac risk factors that need to be managed. Pathways to facilitate outpatient follow-up for further evaluation and guideline-directed management of cardiac risk factors should be considered. Among patients presenting to the ED with chest pain, there is a separate group that is at such low risk of having atherosclerotic plaque or 30-day MACE that they do not even need CDP-based risk stratification. 4.1.1.1. Cost-Value Considerations in the Evaluation of Low-Risk Patients The costs associated with the acute evaluation of chest pain have been examined within systematic reviews, health technology appraisals, and data collected in the observational or randomized clinical trial setting.1-10 The decision analytic models suggest that the use of hs-Tn can be cost effective as a rule-out for ACS, primarily attributable to prompt discharge of patients without hs-Tn elevations.2,8,11,12 Moreover, hs-Tn–guided diagnostic strategies also reduced the use of stress testing by nearly one-third.13 From a large multicenter registry, the reduced time to discharge and use of noninvasive testing contributed to a cost savings of 20%.13 Nonadherence to management recommendations impact the potential for cost savings.5 From a randomized trial applying the HEART Pathway, a modest 30-day cost savings of $216 per patient (P=0.04) was observed.6 However, the overall reductions in hospital admission and length of stay impacted population estimates for cost savings from 1 ED registry of 30 769 patients presenting before and 23 699 patients presenting after implementation of an accelerated diagnostic pathway and resulted in a total cost reduction of $13.5 million (Australian).7 Thus, improved process efficiency and discharge of low-risk patients largely results in overall cost reductions. 4.1.2 Intermediate-Risk Patients With Acute Chest Pain Recommendations for Intermediate-Risk Patients With Acute Chest Pain Referenced studies that support the recommendations are summarized in Online Data Supplements 12 and 13. COR LOE Recommendations 1 C-EO 1. For intermediate-risk patients with acute chest pain, TTE is recommended as a rapid, bedside test to establish baseline ventricular and valvular function, evaluate for wall motion abnormalities, and to assess for pericardial effusion. 2a A 2. For intermediate-risk patients with acute chest pain, management in an observation unit is reasonable to shorten length of stay and lower cost relative to an inpatient admission.1-7 Synopsis Patients in the ED without high-risk features and not classified as low risk by a CDP fall into an intermediate-risk group. Intermediate-risk patients do not have evidence of acute myocardial injury by troponin but remain candidates for additional cardiac testing. Some may have chronic or minor troponin elevations. This testing often requires more time than is appropriate for an ED visit. These patients may be placed in an inpatient bed or managed in a dedicated observation unit using a chest pain protocol. Recommendation-Specific Supportive Text 1. Prompt use of TTE allows for an evaluation of cardiac cause for symptoms and evaluation of alternative pathologies for acute chest pain.8-13 Rapid echocardiographic assessment may facilitate imaging of patients while they are symptomatic. Point-of-care echocardiograms performed at the Downloaded from http://ahajournals.org by on October 7, 2026