Low-risk acute chest pain, then stable symptoms — case discussion

Presentation

Practice case (not a real patient). A 46-year-old woman with no known coronary artery disease presents to the emergency department with new-onset acute central chest tightness that began 5 hours before arrival while she was at rest and has now settled. She is haemodynamically stable and her examination is normal. The emergency physician suspects acute coronary syndrome; her ECG shows no ST-segment elevation, NSTEMI is suspected and there is no indication for immediate invasive angiography. Her time-zero (0 h) high-sensitivity troponin sample is drawn on arrival.^[1][2]

Step 1 — The first ECG and the first troponin

Discussion:

• AHA/ACC 2021: in all patients who present with acute chest pain regardless of the setting, an ECG should be acquired and reviewed for STEMI within 10 minutes of arrival (COR 1, LOE C-LD).^[1]
• Her ECG is normal. AHA/ACC 2021 states that an initial normal ECG does not exclude ACS, and a repeat ECG is needed if symptoms are ongoing, until other diagnostic testing rules out ACS.^[1]
• AHA/ACC 2021: in women presenting with chest pain, it is recommended to obtain a history that emphasises accompanying symptoms more common in women with ACS (COR 1, LOE B-NR).^[1]
• Her time-zero high-sensitivity troponin is below the assay limit of detection, which in this scenario is also below the ESC "very low" cut-off for that assay; ESC 2023 cut-offs are assay specific.^[2]

Step 2 — Is one troponin enough?

Discussion:

• AHA/ACC 2021: for patients with acute chest pain, a normal ECG, and symptoms suggestive of ACS that began at least 3 hours before ED arrival, a single hs-cTn below the limit of detection on initial measurement (time zero) is reasonable to exclude myocardial injury (COR 2a, LOE B-NR). She meets each of these conditions.^[1]
• ESC 2023 Figure 6 assigns a very low initial hs-cTn to the rule-out pathway only if chest pain onset was more than 3 h before the 0 h measurement; her 0 h sample was drawn on arrival, 5 hours after onset, so the condition is met.^[2]
• ESC 2023 still advises that, to maximise the safety and feasibility of the 0 h/1 h algorithm, blood samples for hs-cTn at 0 h and 1 h be obtained irrespective of other clinical details and pending results.^[2]

Step 3 — Risk category and disposition

Discussion:

• AHA/ACC 2021 Table 8 gives two hs-cTn-based definitions of low risk (below 1% 30-day risk of death or MACE): a time-zero value below the assay limit of detection or "very low" threshold if symptoms have been present for at least 3 h, which she meets, or a time-zero value and 1- or 2-h delta both below the assay "low" thresholds.^[1]
• The AHA/ACC 2021 synopsis for low-risk patients adds that every method also involves an appropriate history and physical examination and an ECG that is normal, nonischaemic or unchanged from the previous ECG; she has the history, examination and a normal ECG.^[1]
• In patients with acute chest pain and suspected ACS who are deemed low risk (below 1% 30-day risk of death or MACE), it is reasonable to discharge home without admission or urgent cardiac testing (COR 2a, LOE B-R).^[1]
• If her low-risk designation comes from the institution's CDP, AHA/ACC 2021 applies its row for patients with acute chest pain and suspected ACS who are deemed low risk by a CDP: patient decision aids are beneficial to improve understanding and effectively facilitate risk communication (COR 1, LOE B-R).^[1]
• Many low-risk patients have baseline cardiac risk factors that need to be managed, so pathways to facilitate outpatient follow-up for further evaluation and guideline-directed management of cardiac risk factors should be considered (AHA/ACC 2021).^[1]

Step 4 — Months later: recurring symptoms

Practice case continued. Four months later she returns to clinic. For the past 3 months she has had brief constricting retrosternal chest discomfort brought on by exertion and by emotional stress and relieved by rest within 5 minutes, unchanged in pattern, intensity and duration. There is no rest pain; acute coronary syndrome is not suspected, and chronic coronary syndrome is suspected. She has hypertension, dyslipidaemia and diabetes and is a current smoker.^[1][3]

Discussion:

• AHA/ACC 2021 considers chest pain stable when symptoms are chronic and associated with consistent precipitants such as exertion or emotional stress; her recurring discomfort with exertion and emotional stress, unchanged over 3 months, is assessed on that pathway.^[1]
• ESC 2024, suspected CCS: it recommends a resting 12-lead ECG in all individuals reporting chest pain (unless an obvious non-cardiac cause is identified), particularly during, or immediately after, an episode suggestive of myocardial ischaemia (Class I, Level C).^[3]
• ESC 2024, suspected CCS: it recommends estimating the pre-test likelihood of obstructive epicardial CAD using the Risk Factor-weighted Clinical Likelihood model (Class I, Level B).^[3]

Step 5 — Choosing a test

Practice case continued. Her RF-CL estimate is 12% (women aged 40–49, symptom score 3, 4–5 risk factors), and the clinical data give no reason to adjust it. She still has no known coronary artery disease.^[3]

Discussion:

• A likelihood of 12% is in the ESC 2024 low band (more than 5% to 15%).^[3]
• ESC 2024, suspected CCS: in individuals with a low (more than 5% to 15%) pre-test likelihood of obstructive CAD, the coronary artery calcium score (CACS) should be considered to reclassify subjects and to identify more individuals with very low (5% or less) CACS-weighted clinical likelihood (Class IIa, Level B).^[3]
• ESC 2024, suspected CCS: in symptomatic patients whose pre-test likelihood of obstructive CAD by clinical assessment is above 5%, CCTA or non-invasive functional imaging for myocardial ischaemia is recommended as the initial diagnostic test (Class I, Level B), and to rule out obstructive CAD in individuals with low or moderate (more than 5% to 50%) pre-test likelihood, CCTA is recommended as the preferred diagnostic modality (Class I, Level B).^[3]
• ESC 2024 adds that with low likelihood the benefit of diagnostic testing is uncertain but it may be performed if symptoms are limiting and require clarification.^[3]