Time from symptom onset influences high-sensitivity troponin T diagnostic accuracy for the diagnosis of acute myocardial infarction

[Evaluation of rule out strategy for patients with non-ST-elevation acute coronary syndrome with single measurement of high-sensitivity cardiac troponin I from one sample tested beetween 3 and 6 hours after chest pain onset]

BACKGROUND

Guidelines recommend to consider excluding non-ST-segment elevation myocardial infarction (NSTEMI) when high-sensitivity cardiac troponin is below the limit of quantification and a single blood sample is taken > 6 h after the onset of chest pain. The aim of our study was to assess such exclusion when a single blood sample was taken 3-6 h after the onset of permanent chest pain.

METHODS

This observational study included consecutive patients admitted into the emergency room of our hospital with chest pain and suspected NSTEMI, with non-contributive electrocardiograms and a single high-sensitivity cardiac troponin I (hs-cTnI) blood sample taken 3-6 h after the onset of chest pain and hs-cTnI < 4 ng/l (Abbott Diagnostic). Clinical follow-up was undertaken 1 month after admission.

RESULTS

The mean age of the 432 patients was 48.5 ± 5.6 years and 51% were male. Based on a clinical algorithm, the pre-test probability of NSTEMI was low in 70%, and intermediate in 21% of patients. Among 419 patients with available 1-month follow-up data, there were no myocardial infarctions or deaths. Thirty-eight patients (9%) were admitted into hospital but none for cardiac reasons.

CONCLUSIONS

Our results suggest that exclusion of NSTEMI in patients with a non-contributive electrocardiogram and a single "negative" troponin test in a blood sample taken 3-6 h after the onset of symptoms is valid.

EMS blood collection from patients with acute chest pain reduces emergency department length of stay

BACKGROUND

Expediting the measurement of serum troponin by leveraging EMS blood collection could reduce the diagnostic time for patients with acute chest pain and help address Emergency Department (ED) overcrowding. However, this practice has not been examined among an ED chest pain patient population in the United States.

METHODS

A prospective observational cohort study of adults with non-traumatic chest pain without ST-segment elevation myocardial infarction was conducted in three EMS agencies between 12/2016-4/2018. During transport, paramedics obtained a patient blood sample that was sent directly to the hospital core lab for troponin measurement. On ED arrival HEART Pathway assessments were completed by ED providers as part of standard care. ED providers were blinded to troponin results from EMS blood samples. To evaluate the potential impact on length of stay (LOS), the time difference between EMS blood draw and first clinical ED draw was calculated. To determine the safety of using troponin measures from EMS blood samples, the diagnostic performance of the HEART Pathway for 30-day major adverse cardiac events (MACE: composite of cardiac death, myocardial infarction (MI), coronary revascularization) was determined using EMS troponin plus arrival ED troponin and EMS troponin plus a serial 3-h ED troponin.

RESULTS

The use of EMS blood samples for troponin measures among 401 patients presenting with acute chest pain resulted in a mean potential reduction in LOS of 72.5 ± SD 35.7 min. MACE at 30 days occurred in 21.0% (84/401), with 1 cardiac death, 78 MIs, and 5 revascularizations without MI. Use of the HEART Pathway with EMS and ED arrival troponin measures yielded a NPV of 98.0% (95% CI: 89.6-100). NPV improved to 100% (95% CI: 92.9-100) when using the EMS and 3-h ED troponin measures.

CONCLUSIONS

EMS blood collection used for core lab ED troponin measures could significantly reduce ED LOS and appears safe when integrated into the HEART Pathway.

High-sensitivity troponin assays for early rule-out of acute myocardial infarction in people with acute chest pain: a systematic review and economic evaluation

BACKGROUND

Early diagnosis of acute myocardial infarction is important, but only 20% of emergency admissions for chest pain will actually have an acute myocardial infarction. High-sensitivity cardiac troponin assays may allow rapid rule out of myocardial infarction and avoid unnecessary hospital admissions.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of high-sensitivity cardiac troponin assays for the management of adults presenting with acute chest pain, in particular for the early rule-out of acute myocardial infarction.

METHODS

Sixteen databases were searched up to September 2019. Review methods followed published guidelines. Studies were assessed for quality using appropriate risk-of-bias tools. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies; otherwise, random-effects logistic regression was used. The health economic analysis considered the long-term costs and quality-adjusted life-years associated with different troponin testing methods. The de novo model consisted of a decision tree and a state-transition cohort model. A lifetime time horizon (of 60 years) was used.

RESULTS

Thirty-seven studies (123 publications) were included in the review. The high-sensitivity cardiac troponin test strategies evaluated are defined by the combination of four factors (i.e. assay, number and timing of tests, and threshold concentration), resulting in a large number of possible combinations. Clinical opinion indicated a minimum clinically acceptable sensitivity of 97%. When considering single test strategies, only those using a threshold at or near to the limit of detection for the assay, in a sample taken at presentation, met the minimum clinically acceptable sensitivity criterion. The majority of the multiple test strategies that met this criterion comprised an initial rule-out step, based on high-sensitivity cardiac troponin levels in a sample taken on presentation and a minimum symptom duration, and a second stage for patients not meeting the initial rule-out criteria, based on presentation levels of high-sensitivity cardiac troponin and absolute change after 1, 2 or 3 hours. Two large cluster randomised controlled trials found that implementation of an early rule-out pathway for myocardial infarction reduced length of stay and rate of hospital admission without increasing cardiac events. In the base-case analysis, standard troponin testing was both the most effective and the most costly. Other testing strategies with a sensitivity of 100% (subject to uncertainty) were almost equally effective, resulting in the same life-year and quality-adjusted life-year gain at up to four decimal places. Comparisons based on the next best alternative showed that for willingness-to-pay values below £8455 per quality-adjusted life-year, the Access High Sensitivity Troponin I (Beckman Coulter, Brea, CA, USA) [(symptoms > 3 hours AND < 4 ng/l at 0 hours) OR (< 5 ng/l AND Δ < 5 ng/l at 0 to 2 hours)] would be cost-effective. For thresholds between £8455 and £20,190 per quality-adjusted life-year, the Elecsys® Troponin-T high sensitive (Roche, Basel, Switzerland) (< 12 ng/l at 0 hours AND Δ < 3 ng/l at 0 to 1 hours) would be cost-effective. For a threshold > £20,190 per quality-adjusted life-year, the Dimension Vista® High-Sensitivity Troponin I (Siemens Healthcare, Erlangen, Germany) (< 5 ng/l at 0 hours AND Δ < 2 ng/l at 0 to 1 hours) would be cost-effective.

CONCLUSIONS

High-sensitivity cardiac troponin testing may be cost-effective compared with standard troponin testing.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154716.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 33. See the NIHR Journals Library website for further project information.

Prehospital use of a modified HEART Pathway and point-of-care troponin to predict cardiovascular events

The HEART Pathway is a validated risk stratification protocol for Emergency Department patients with chest pain that has yet to be tested in the prehospital setting. This study seeks to test the performance of a prehospital modified HEART Pathway (PMHP). A prospective cohort study of adults with chest pain without ST-segment elevation myocardial infarction was conducted at three EMS agencies between 12/2016-1/2018. To complete a PMHP assessment, paramedics drew blood, measured point-of-care (POC) troponin (i-STAT; Abbott Point of Care) and calculated a HEAR score. Patients were stratified into three groups: high-risk based on an elevated troponin, low-risk based on a HEAR score <4 with a negative troponin, or moderate risk for a HEAR score ≥4 with a negative troponin. Sensitivity, specificity, negative and positive predictive values of the PMHP for detection of major adverse cardiac events (MACE: cardiac death, MI, or coronary revascularization) at 30-days were calculated. A total of 506 patients were accrued, with PMHP completed in 78.1% (395/506). MACE at 30-days occurred in 18.7% (74/395). Among these patients, 7.1% (28/395) were high risk yielding a specificity and PPV for 30-day MACE of 96.6% (95%CI: 94.0–98.3%) and 60.7% (95%CI: 40.6–78.6%) respectively. Low-risk assessments occurred in 31.4% (124/395), which were 90.5% (95%CI: 81.5–96.1%) sensitive for 30-day MACE with a NPV of 94.4% (95%CI: 88.7–97.7%). Moderate-risk assessments occurred in 61.5% (243/395), of which 20.6% had 30-day MACE. The PMHP is able to identify high-risk and low-risk groups with high specificity and negative predictive value for 30-day MACE.

Improving the diagnostic accuracy of acute myocardial infarction with the use of high-sensitive cardiac troponin T in different chronic kidney disease stages

High-sensitive cardiac troponin T (hs-TnT) is a critical biomarker in diagnosis of acute myocardial infarction (AMI). However, CKD individuals usually have elevated hs-TnT even in the absence of AMI. Our study aimed to explore the optimal cutoff-value of hs-TnT and further to improve diagnostic accuracy of AMI in CKD patients. Clinical data of 489 patients were collected from the maintained database between September 2010 and June 2014. CKD patients with AMI were assigned to CKD+AMI group and CKD patients without AMI were assigned to CKD group. Receiver operating characteristic curves were utilized to derive the optimal cutoff-value. In CKD+STEMI and CKD group, hs-TnT was increased with descending eGFR. In CKD+NSTEMI group, hs-TnT showed an upward trend with increasing SYNTAX Score. In patients with CKD+STEMI, hs-TnT was significantly correlated with SYNTAX Score in CKD stage 2, stage 4 and in total. In CKD patients, the optimal cutoff-value of hs-TnT for diagnosis of AMI was 129.45 ng/l with 75.2% sensitivity and 83.2% specificity. The cutoff-value appeared to be hs-TnT level of 99.55ng/l in CKD stage 3, 129.45 ng/l in CKD stage 4, 105.50 ng/l in CKD stage 5 and 149.35 ng/l in dialysis patients, respectively. In different stages of CKD, eGFR-range-specific optimal cutoff-values should be considered.