Douleur thoracique aux urgences : utilisation adéquate des scores diagnostiques

La douleur thoracique est un motif très fréquent de consultation aux urgences. Le diagnostic différentiel est large et regroupe diverses étiologies parmi lesquelles les syndromes coronariens aigus (SCA) qui sont à l’avantplan. L’exclusion d’un SCA demeure une priorité absolue pour l’urgentiste au vu de la morbidité et de la mortalité qui lui sont associées. Afin d’aider le praticien dans sa démarche diagnostique, plusieurs algorithmes ont été élaborés pour exclure et diagnostiquer efficacement un SCA. Ceux-ci intègrent des données cliniques, électrocardiographiques et le dosage de la troponine. Leur utilisation est relativement simple et a été validée dans plusieurs essais cliniques. Ils permettent d’écarter le diagnostic de SCA chez une proportion significative de patients, avec une marge d’erreur très faible. Le score HEART se montre supérieur aux autres scores existants, et son application en salle d’urgences permet d’orienter de manière adéquate la démarche diagnostique, afin de réduire les investigations complémentaires et d’accélérer la prise en charge. Afin d’exclure un SCA sans recourir au dosage de la troponine, la règle CARE a été proposée récemment avec des résultats prometteurs. Issue directement du score HEART, elle permet d’écarter très rapidement le diagnostic de SCA puisqu’elle se passe de dosage biologique tout en gardant un profil de sécurité semblable.

Is high-sensitivity troponin, alone or in combination with copeptin, sensitive enough for ruling out NSTEMI in very early presenters at admission? A post hoc analysis performed in emergency departments

OBJECTIVES

Copeptin and high-sensitivity cardiac troponin (HS-cTn) assays improve the early detection of non-ST-segment elevation myocardial infarction (NSTEMI). Their sensitivities may, however, be reduced in very early presenters.

SETTING

We performed a post hoc analysis of three prospective studies that included patients who presented to the emergency department for chest pain onset (CPO) of less than 6 hours.

PARTICIPANTS

449 patients were included, in whom 12% had NSTEMI. CPO occurred <2 hours from ED presentation in 160, between 2 and 4 hours in 143 and >4 hours in 146 patients. The prevalence of NSTEMI was similar in all groups (9%, 13% and 12%, respectively, p=0.281).

MEASURES

Diagnostic performances of HS-cTn and copeptin at presentation were examined according to CPO. The discharge diagnosis was adjudicated by two experts, including cardiac troponin I (cTnI). HS-cTn and copeptin were blindly measured.

RESULTS

Diagnostic accuracies of cTnI, cTnI +copeptin and HS-cardiac troponin T (HS-cTnT) (but not HS-cTnT +copeptin) lower through CPO categories. For patients with CPO <2 hours, the choice of a threshold value of 14 ng/L for HS-cTnT resulted in three false negative (Sensitivity 80%(95% CI 51% to 95%); specificity 85% (95% CI 78% to 90%); 79% of correctly ruled out patients) and that of 5 ng/L in two false negative (sensitivity 87% (95% CI 59% to 98%); specificity 58% (95% CI 50% to 66%); 52% of correctly ruled out patients). The addition of copeptin to HS-cTnT induced a decrease of misclassified patients to 1 in patients with CPO <2 hours (sensitivity 93% (95% CI 66% to 100%); specificity 41% (95% CI 33% to 50%)).

CONCLUSION

A single measurement of HS-cTn, alone or in combination with copeptin at admission, seems not safe enough for ruling out NSTEMI in very early presenters (with CPO <2 hours).

TRIAL REGISTRATION NUMBER

DC-2009-1052.

Rapid rule-out of suspected acute coronary syndrome in the Emergency Department by high-sensitivity cardiac troponin T levels at presentation

The reliability of initial high-sensitivity cardiac troponin T (hs-cTnT) under limit-of-detection in ruling-out short- and long-term acute coronary events in subjects for suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is not definitely settled. In a retrospective chart review analysis, 1001 subjects with hs-cTnT ≤ 14 ng/L out of 4053 subjects with hs-cTnT measured at Emergency Department (ED) presentation were recruited. The main outcome measure is fatal or non-fatal myocardial infarction (MI) within 30 days; secondary outcomes are MI or major acute coronary events (MACE) as a combination of MI or re-hospitalization for unstable angina within 1 year. In subjects with hs-cTnT < 5 ng/L [32.6% of cases, mean age 63 years (interquartile range 23)], no cases (0%, NPV 100%) had MI within 30 days, 2 cases (0.6%, NPV 99.4%) MI at 1-year, and 11 cases (3.4%, NPV 96.6%) MACE at 1-year. Patients with hs-cTnT < 5 ng/L would have benefited from a shortened decision (9.30 h and 53% overnight ED stay saved). Hs-cTnT < 5 ng/L is confirmed as safe for patients and comfortable for physicians in ruling out MI or MACE both at short and long term, suggesting that a sizable number of patients can be rapidly discharged without unnecessary diagnostic tests and ED observation.

Multi-centre evaluation of recent troponin assays for the diagnosis of NSTEMI

Objectives

We aimed to compare the use of nine different cardiac troponin (cTn) assays (2 cTnT and 7 cTnI) for the diagnosis of NSTEMI in a single multi-centre population.

Design and methods

One hundred and fifty-eight patients were included (mean age 60 years, SD 17 years), including 23 patients (14%) with NSTEMI.

Results

The analytical comparison highlighted a large heterogeneity of cTn assays, as reflected by percentages of patients with detectable cTn, correlation coefficients, Passing-Bablok comparisons and concordance coefficients. Correlations within cTnI assays were good and correlation within cTnT assays was excellent. Diagnostic performances demonstrated that each cTn assay has specific threshold values. Furthermore, some assays (HS-cTnI and T, cTnI-Pathfast and cTnI-Centaur) indicated high sensitivity and negative predictive value using the limit of detection (LoD) diagnostic strategy. For the latter assays, a significant increase in specificity was found when using the 99th percentile or the H0-H3 strategies, in comparison to the LoD strategy. When applying the European Society of Cardiology H0-H3 algorithm, comparable diagnostic performances were obtained.

Conclusion

All 9 cTn assays indicated overall good diagnostic performances for the diagnosis of NSTEMI in emergency departments when the recommended algorithm based on the variation of cTn value between two measurements at admission and 3 h later was used.

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We compare nine troponin assays for the diagnosis of NSTEMI.

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Each cTn assay owns specific thresholds for the ESC H0-H3 algorithm.

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All assays present high specificity for NSTEMI diagnosis using H0-H3 algorithm.

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Assay-specific threshold and delta change values for each cTn assays are mandatory.

A single value of high-sensitive troponin T below the limit of detection is not enough for ruling out non ST elevation myocardial infarction in the emergency department

BACKGROUND

Recent 2015 ESC recommendations for the management of patients with suspected acute myocardial infarction (AMI) support that a single value of high-sensitivity cardiac troponin (HS-cTn) measured at presentation could rule out AMI if below the limit of blank (LoB) or detection (LoD).

OBJECTIVES

We aimed to evaluate whether an undetectable HS-cTnT at presentation safely rules out NSTEMI in unselected patients with chest pain.

PATIENTS AND METHODS

This is a post hoc analysis of two prospective cohorts with similar design that included patients suspected of AMI at three French university hospitals. Patients were followed-up during one month, before the adjudication of a final diagnosis.

RESULTS

413 patients (mean age 58±17years) were analyzed; 45 (11%) had a final diagnosis of NSTEMI, and 26 (6%) had STEMI. The sensitivity of HS-cTnT value at 3ng/L (LoB) for NSTEMI was 97.8% [95% CI: 86.8-99.9], yielding a negative predictive value (NPV) of 99.3% [95% CI: 95.4-100.0]. Proportion of patients ruled out for NSTEMI was 32% when applying the LoB. The sensitivity of HS-cTnT value at 5ng/L (LoD) was 97.8% [95% CI: 86.8-99.9] yielding a NPV of 99.5% [95% CI: 96.5-100.0]. Proportion of patients ruled out for NSTEMI was 43% when applying the LoD. One patient (delay between onset of chest pain and presentation <3h) had NSTEMI and HS-cTnT <LoB at presentation.

CONCLUSION

The NPV of a single measurement of HS-cTnT below the LoD is high in unselected patients, but not enough to rule out safely NSTEMI for very early presenters.