High-sensitivity cardiac troponin I at presentation in patients with suspected acute coronary syndrome: a cohort study

Abstract

SummaryBackgroundSuspected acute coronary syndrome is the commonest reason for emergency admission to hospital and is a large burden on health-care resources. Strategies to identify low-risk patients suitable for immediate discharge would have major benefits.MethodsWe did a prospective cohort study of 6304 consecutively enrolled patients with suspected acute coronary syndrome presenting to four secondary and tertiary care hospitals in Scotland. We measured plasma troponin concentrations at presentation using a high-sensitivity cardiac troponin I assay. In derivation and validation cohorts, we evaluated the negative predictive value of a range of troponin concentrations for the primary outcome of index myocardial infarction, or subsequent myocardial infarction or cardiac death at 30 days. This trial is registered with ClinicalTrials.gov (number NCT01852123).Findings782 (16%) of 4870 patients in the derivation cohort had index myocardial infarction, with a further 32 (1%) re-presenting with myocardial infarction and 75 (2%) cardiac deaths at 30 days. In patients without myocardial infarction at presentation, troponin concentrations were less than 5 ng/L in 2311 (61%) of 3799 patients, with a negative predictive value of 99·6% (95% CI 99·3–99·8) for the primary outcome. The negative predictive value was consistent across groups stratified by age, sex, risk factors, and previous cardiovascular disease. In two independent validation cohorts, troponin concentrations were less than 5 ng/L in 594 (56%) of 1061 patients, with an overall negative predictive value of 99·4% (98·8–99·9). At 1 year, these patients had a lower risk of myocardial infarction and cardiac death than did those with a troponin concentration of 5 ng/L or more (0·6% vs 3·3%; adjusted hazard ratio 0·41, 95% CI 0·21–0·80; p<0·0001).InterpretationLow plasma troponin concentrations identify two-thirds of patients at very low risk of cardiac events who could be discharged from hospital. Implementation of this approach could substantially reduce hospital admissions and have major benefits for both patients and health-care providers.FundingBritish Heart Foundation and Chief Scientist Office (Scotland).

Redesigning the diagnostic pathway for chest pain patients in emergency departments

“…Alternatives to this strategy have been proposed taking advantage of the fact that in patients with very low pre-test probability of AMI and Acute Coronary Syndrom (ACS), very low baseline cTn levels make the possibility of AMI highly unlikely [8,11,31,37]. If incorporated in the diagnostic pathway, such an early rule-out protocol could help avoid unnecessary tests and admissions for patients who do not have AMI but present with chest pain and have had cTn measured at presentation.…”

“…Clearly, many EDs are resource limited and whereas purchase of equipment or extra staffing may not be an option [5], time and resource saving interventions that utilise existing staff may clearly be beneficial. With regards to high-sensitivity troponin, these topics have also been explored in clinical trials [31]. Whilst allowing for some assessment of impact, such investigations tend to be either expensive or time consuming, and do not allow the researcher to find the optimal combination of process changes in terms of resource and time benefits.…”

“…Project results indicated significant improvements in reducing the number of hospital admissions [28]). Finally, recent studies report that some low risk patients could be safely discharged on the basis of a single negative test if they present more than three hours after the onset of worst symptoms and have very low levels of cTn [8,11,31,37]. Our study aims to support EDs to effectively manage staff workload and to reduce the number of avoidable admissions from ED into hospital.…”

Sex‐Based Differences in the Performance of the HEART Score in Patients Presenting to the Emergency Department With Acute Chest Pain

“…Sex‐based differences in the clinical presentation, pathophysiological mechanisms, and outcomes of chest pain patients are increasingly being recognized. Compared with men, women with an acute coronary syndrome (ACS) present more frequently with atypical chest pain complaints and a nondiagnostic ECG and less frequently with elevations of troponins 1, 2, 3, 4, 5, 6. Also, women are ≈10 years older and tend to have a higher risk factor burden than men when they experience their first cardiac event 3, 7.…”

Diagnostic algorithms for acute coronary syndrome—is one better than another?

“…A "common sense" algorithm, including the many protocols that have been proposed so far, can hence be developed and hopefully validated in clinical studies (Figure 2). Briefly, a HS cardiac troponin value at presentation lower than the limit of detection (LOD) of the assay in a patient with low clinical probability of MI would enable safe rule out of ACS, with risk of missing an acute ischemic event or experimenting MACEs lower than 0.1-0.3% (36). Conversely, a cardiac troponin value lower <LOD in a patient with medium/high clinical probability of MI, as well as a value comprised between the LOD and 1,000 ng/mL (whatever the clinical probability) both necessitate additional testing.…”