p.21 抽出テキスト

algorithm (second-best option) (Figure 6). These algorithms have been derived and validated in large multicentre diagnostic studies using central adjudication of the final diagnosis for all currently available hs-cTn assays.27–39,62,70,73,82,89–93 Optimal thresholds for rule-out were selected to allow a sensitivity and NPV of at least 99%. Optimal thresholds for rule-in were selected to allow a positive predictive value (PPV) of at least 70%. These algorithms were developed from large derivation cohorts and then validated in large independent validation cohorts. The previous ESC 0 h/3 h algorithm was considered as an alternative,40,56 but three recent large diagnostic studies suggested that the ESC 0 h/ 3 h algorithm appears to balance efficacy and safety less well than more rapid protocols using lower rule-out concentrations, including the ESC 0 h/1 h algorithm.41–43 The very high safety and high efficacy of applying the ESC 0 h/1 h algorithm was recently confirmed in three real-life implementation studies, including one randomized controlled trial (RCT).44,94,95 Therefore, the ESC 0 h/3 h algorithm is an alternative for cases where the ESC 0 h/1 h or 0 h/2 h algorithms are not available. Of note, patients assigned to the ‘rule-out’ pathway using the ESC 0 h/ 1 h or 0 h/2 h algorithms have a very low rate of clinical events through to 30 days.95,96

3.3.4.1 European Society of Cardiology 0 h/1 h and 0 h/2 h

algorithms The ESC 0 h/1 h and 0 h/2 h algorithms are based on two underlying concepts: firstly, hs-cTn is a continuous variable and the probability of MI increases with increasing hs-cTn values.28,30,31,34,35,73,82 Secondly, early absolute changes in the levels within 1 h or 2 h can be used as surrogates for absolute changes over 3 h or 6 h and provide incremental diagnostic value to the single cTn assessment at presentation.27,28,30,31,34,35,73,82,97 The cut-off concentrations within the 0 h/ 1 h and 0 h/2 h algorithms are assay specific (Supplementary data online, Table S4).27,28,30,31,34,35,73,82

3.3.4.1.1 Rule-out. The NPV for MI in patients assigned to the

‘rule-out’ pathway has exceeded 99% in several large validation cohorts.28–30,34,35,73 Assignment to the rule-out pathway does not always equal outpatient management. However, when used in conjunction with clinical and ECG findings, the 0 h/1 h and 0 h/2 h algorithms will enable the identification of appropriate candidates for early discharge and outpatient management. Even after the ruling out of MI, elective non-invasive or invasive imaging may be appropriate according to clinical and risk assessment, and an alternative diagnosis to MI should be identified.

3.3.4.1.2 Rule-in. The PPV for MI in patients meeting the ‘rule-in’

pathway criteria in several studies has been ∼70–75%. Most of the ‘rule-in’ pathway patients with diagnoses other than MI still have conditions that require specialist cardiology input and either coronary angiography or non-invasive imaging in order to establish an accurate final diagnosis.28,30,31,34,35,73,82 Therefore, the vast majority of patients triaged towards the ‘rule-in’ pathway by these algorithms will require hospital admission and invasive coronary angiography (ICA).

3.3.4.1.3 Observe. Patients who do not qualify for the ‘rule-out’ or

‘rule-in’ pathways are assigned to the ‘observe’ pathway. These patients represent a heterogeneous group and have been shown to have a mortality rate that is comparable to rule-in patients.98 Therefore, an individual assessment based on the particular risk profile of the patient (i.e. risk scores) is of paramount importance for patients in this group. Additionally, a third measurement of cTn at 3 h (± echocardiography) is recommended as the next step in order to guide further management.45,46 Most patients in the observe zone with a high degree of clinical suspicion of ACS (e.g. relevant increase in cTn from presentation to 3 h) are candidates for ICA. Conversely, most patients with a low to intermediate likelihood for ACS according to clinical judgment are candidates for non-invasive imaging after transfer from the ED to the ward. Computed tomography (CT) angiography can be used to aid diagnosis and, in particular, to identify patients with non-obstructed coronary arteries who can be discharged if other relevant diseases have been excluded. CT angiography can also identify patients with obstructive coronary disease in whom revascularization may be considered. In the appropriate clinical context, if alternative conditions have been identified that explain the cTn values (i.e. rapid ventricular rate response to atrial fibrillation [AF], marked anaemia, or a hypertensive emergency), further diagnostic testing (i.e. ICA) may not be required. The same concepts apply to the 0 h/2 h algorithm. Cut-off levels for both the 0 h/1 h and 0 h/2 h algorithms are also assay specific, and these cut-off levels are shown in Supplementary data online, Table S4.99 The ESC 0 h/1 h and 0 h/2 h algorithms should always be integrated with a detailed clinical assessment and a 12-lead ECG. Repeat blood sampling is mandatory in cases where there is ongoing or recurrent chest pain. Recently, artificial intelligence models that include serial hs-cTn measurements in conjunction with individual risk profiles have been proposed to be useful to facilitate a personalized diagnostic evaluation of patients with suspected MI. Similarly, risk-assessment models combining hs-cTn values at presentation and after early or late resampling have been developed to predict MI events during the first 30 days. These models may facilitate alternative hs-cTn cut-offs based on the balance between NPV and PPV best suited to individual clinical sites.27 A diagnostic approach to the use of the ESC 0 h/1 h and 0 h/2 h algorithms is shown in Figure 6. Downloaded from academic.oup.com/eurheartj/article/44/38/3720/7243210 by guest on 07 October 2026