p.25 抽出テキスト

November 30, 2021 Circulation. 2021;144:e368–e454. DOI: 10.1161/CIR.0000000000001029 e392

CLINICAL STATEMENTS AND GUIDELINES

all generally involve single or serial cTn measurement. Because there are several different manufacturers, the CDP should be based on assay-specific performance thresholds.4,5 CDPs are more likely to be successful when they incorporate multidisciplinary teams. 2.	 There are important differences in the performance of highly sensitive and conventional cTn assays. hscTn assays may be used to guide disposition by repeat sampling at 1, 2, or 3 hours from ED arrival using the pattern of rise or fall (ie, delta) and the repeat value itself, based on assay-specific diagnostic thresholds.37-43 When using conventional cTn assays, the sampling timeframe is extended to 3 to 6 hours from ED arrival.36 3.	 CDPs that include risk scores all perform well overall, with 99% to 100% sensitivity for index-visit AMI and 30-day MACE and have been shown to decrease advanced testing to varying degrees and should be used particularly with conventional cTn.2,13,30-35 However, because sex-specific considerations are not included in all scoring systems, their effectiveness in men and women may not be equal.51

4.	 Previous test results should always be considered in the evaluation of patients with acute chest pain once ACS has been ruled out. In those with recent cardiac testing and normal findings who do not have biomarker evidence of acute myocardial injury, further testing is of limited value, provided that adequate exercise levels were achieved or pharmacologic stress was performed, imaging was of sufficient quality, and there are no changes in symptom frequency or stability at the new visit. The “warranty” intervals (Table 7) for the various cardiac testing modalities differ because of the low number of incident events among patients with a normal CCTA, although patients with normal stress testing may still have significant plaque and a higher event rate.20-22 The warranty period for a normal stress-rest SPECT is highly variable because it is primarily determined by the type of stress, the patient’s clinical characteristics, and left ventricular ejection fraction.52 5.	 To use cTn properly, an understanding of the assay used (high sensitivity or conventional) and the timing of chest pain onset relative to ED arrival is critical.17,38,39 CDPs that emphasize rapid rule-out based on single hs-cTn concentrations below the limit of detection should be limited to patients whose symptoms started at least 3 hours before ED arri val.2,5,6,11,14,16,25,40-43,53-55 Unlike high-sensitivity assays, clinical decision-making based on single measurement of conventional cTn has not been validated.36 If the clinical presentation is still suspicious for ACS or diagnostic uncertainty remains after serial cTn measurement, it may be reasonable to repeat cTn assay later (ie, beyond 3 hours for high-sensitivity and beyond 6 hours for conventional assays).23,40,41

4.1.1 Low-Risk Patients With Acute Chest Pain

Recommendations for Low-Risk Patients With Acute Chest Pain Referenced studies that support the recommendations are summarized in Online Data Supplements 10 and 11.

COR LOE Recommendations

1 B-NR 1.	 Patients with acute chest pain and a 30-day risk of death or MACE <1% should be designated as low risk.1-11

2a B-R 2.	 In patients with acute chest pain and suspected ACS who are deemed low-risk (<1% 30-day risk of death or MACE), it is reasonable to discharge home without admission or urgent cardiac testing.12-16

Synopsis Low-risk patients are those with symptoms suggestive of ACS and whose probability of MACE within 30 days is

Table 7.  Warranty Period for Prior Cardiac Testing

Test Modality Result Warranty Period Anatomic Normal coronary angiogram CCTA with no stenosis or plaque 2 y Stress testing Normal stress test (given adequate stress) 1 y Table 8 provides a definition used for low-risk chest pain patients. CCTA indicates coronary computed tomographic angiography.

Table 8.  Definition Used for Low-Risk Patients With Chest Pain

Low Risk (<1% 30-d Risk for Death or MACE)

hs-cTn Based T-0 T-0 hs-cTn below the assay limit of detection or “very low” threshold if symptoms present for at least 3 h T-0 and 1- or 2-h Delta T-0 hs-cTn and 1- or 2-h delta are both below the assay “low” thresholds (>99% NPV for 30-d MACE) Clinical Decision Pathway Based HEART Pathway20 HEART score ≤3, initial and serial cTn/hs-cTn < assay 99th percentile EDACS14 EDACS score ≤16; initial and serial cTn/hs-cTn < assay 99th percentile ADAPT21 TIMI score 0, initial and serial cTn/hs-cTn < assay 99th percentile mADAPT TIMI score 0/1, initial and serial cTn/hs-cTn < assay 99th percentile NOTR15 0 factors ADAPT indicates 2-hour Accelerated Diagnostic Protocol to Access Patients with Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarkers; cTn, cardiac troponin; EDACS, Emergency Department Acute Coronary Syndrome; HEART Pathway, History, ECG, Age, Risk Factors, Troponin; hs-cTn, high-sensitivity cardiac troponin; MACE, major adverse cardiovascular events; mADAPT, modified 2-hour Accelerated Diagnostic Protocol to Access Patients with Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarkers; NOTR, No Objective Testing Rule; NPV, negative predictive value; and TIMI, Thrombolysis in Myocardial Infarction.

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