Outcome at 30 days for low-risk chest pain patients assessed using an accelerated diagnostic pathway in the emergency department

Potential length of stay reductions from emergency department use of a point-of-care high-sensitivity cardiac troponin assay: Pilot findings from Australia's first cardiac emergency department

OBJECTIVE

To compare actual ED length of stay (LOS) using laboratory-based high-sensitivity cardiac troponin I (hs-cTnI) testing with the potential LOS that could result from using point-of-care (POC) hs-cTnI tests.

METHODS

Baseline hs-cTnI tests were performed on the same blood sample in the laboratory (Access hsTnI assay) and in the ED (Atellica VTLi POC assay). Actual and potential LOS were compared for patients who were discharged after having a baseline laboratory hs-cTnI test only. Total LOS incorporated time from arrival to blood sample collection, blood sampling to result availability and result availability to discharge. For potential LOS, the blood sampling to result availability time with POC use was fixed at 10 min (2-min preparation and 8-min test-processing). The laboratory blood sampling to result availability time was from blood sample collection to result uploading on the pathology computer system. For the study, it was assumed that this was the only LOS component that would differ with POC use. Invalid POC result rates were monitored.

RESULTS

For 152 patients discharged after having a single baseline laboratory hs-cTnI test, the median actual LOS was 195 (interquartile range [IQR]: 152-319) min, which included a median laboratory blood-sampling-to-result-availability time of 48 (IQR: 41-59) min. The potential LOS from POC use was 157 (IQR: 103-282) min, which included the fixed 10-min blood-sampling-to-result-availability time. The mean actual-potential LOS difference was 43 (95% confidence interval [CI]: 40-46) min. The POC invalid result rate was 11%.

CONCLUSION

The Atellica VTLi could deliver a mean ED LOS reduction of 43-min per patient for those discharged after a single baseline hs-cTnI test. Use in actual practice and the invalid result rate require further evaluation.

Implementation and evaluation of a rural general practice assessment pathway for possible cardiac chest pain using point-of-care troponin testing: a pilot study

OBJECTIVES

To assess the feasibility and acceptability, and additionally to preliminarily evaluate, the effectiveness and safety of an accelerated diagnostic chest pain pathway in rural general practice using point-of-care troponin to identify patients at low risk of acute myocardial infarction, avoiding unnecessary patient transfer to hospital and enabling early discharge home.

DESIGN

A prospective observational pilot evaluation.

SETTING

Twelve rural general (family) practices in the Midlands region of New Zealand.

PARTICIPANTS

Patients aged ≥18 years who presented acutely to rural general practice with suspected ischaemic chest pain for whom the doctor intended transfer to hospital for serial troponin measurement.

OUTCOME MEASURES

The proportion of patients managed using the low-risk pathway without transfer to hospital and without 30-day major adverse cardiac event (MACE); pathway adherence; rate of 30-day MACE; patient satisfaction with care; and agreement between point-of-care and laboratory measured troponin concentrations.

RESULTS

A total of 180 patients were assessed by the pathway. The pathway classified 111 patients (61.7%) as low-risk and all were managed in rural general practice with no 30-day MACE (0%, 95% CI 0.0% to 3.3%). Adherence to the low-risk pathway was 95.5% (106 out of 111). Of the 56 patients classified as non-low-risk and referred to hospital, 9 (16.1%) had a 30-day MACE. A further 13 non-low-risk patients were not transferred to hospital, with no events. The sensitivity of the pathway for 30-day MACE was 100.0% (95% CI 70.1% to 100%). Of low-risk patients, 94% reported good to excellent satisfaction with care. Good concordance was observed between point-of-care and duplicate laboratory measured troponin concentrations.

CONCLUSIONS

The use of an accelerated diagnostic chest pain pathway incorporating point-of-care troponin in a rural general practice setting was feasible and acceptable, with preliminary results suggesting that it may safely and effectively reduce the urgent transfer of low-risk patients to hospital.

Potential impact of a novel pathway for suspected myocardial infarction utilising a new high-sensitivity cardiac troponin I assay

BACKGROUND

High-sensitivity cardiac troponin I (hs-cTnI) assays promise high diagnostic accuracy for myocardial infarction (MI). In an ED where conventional cTnI was in use, we evaluated an assessment pathway using the new Access hsTnI assay.

METHODS

This retrospective analysis recruited ED patients with suspected MI between June and September 2019. All patients received routine care with a conventional cTnI assay (AccuTnI +3: limit of detection (LoD) 10 ng/L, 99th centile upper reference limit (URL) 40 ng/L, abnormal elevation cut-point 80 ng/L). Arrival, then 90-minute or 360-minute cTnI levels for low and non-low risk patients, respectively (ED Assessment of Chest pain score) guided diagnosis and disposition which was at treating physician discretion. The same patients had arrival and 90-minute or 180-minute samples drawn for hs-cTnI levels (Access hsTnI: LoD 2 ng/L, 99th centile URL 10 ng/L (females) and 20 ng/L (males); abnormal elevation above the URL and delta >30%). Treating physicians were blinded to the hs-cTnI results. Using the hs-cTnI values, investigators retrospectively assigned likely diagnosis, disposition and likelihood of a 30-day major adverse cardiac event (MACE). Admission was recommended for significantly rising hs-cTnI elevations. The primary objective was to demonstrate an acceptable unexpected 30-day post-discharge MACE rate of <1%. cTnI elevation rates, diagnostic outcomes and ED disposition were also compared between pathways.

RESULTS

For the 935 patients, unexpected 30-day post-discharge MACE rates were 0/935 (0%, 95% CI 0% to 0.4%) with the conventional or novel pathway. For the high-sensitivity and conventional assays, respectively, abnormal elevation rates were 29% (95% CI 26% to 32%) and 19% (95% CI 17% to 22%), for MI were 9% (95% CI 8% to 11%) and 8% (95% CI 6% to 10%), and for hospital admission were 42% (95% CI 39% to 45%) and 43% (95% CI 40% to 47%).

CONCLUSION

The novel pathway using the Access hsTnI assay has an acceptably low 30-day MACE rate.

Study protocol for an observational study to evaluate an accelerated chest pain pathway using point-of-care troponin in New Zealand rural and primary care populations

INTRODUCTION Accelerated diagnostic chest pain pathways are used widely in urban New Zealand hospitals. These pathways use laboratory-based troponin assays with good analytical precision. Widespread implementation has not occurred in many of New Zealand's rural hospitals and general practices as they are reliant on point-of-care troponin assays, which are less sensitive and precise. An accelerated chest pain pathway using point-of-care troponin has been adapted for use in rural settings. A pilot study in a low-risk rural population showed no major adverse cardiac events at 30 days. A larger study is required to be confident that the pathway is safe. AIMS To assess the safety and effectiveness of an accelerated chest pain pathway adapted for rural settings and general practice using point-of-care troponin to identify low-risk patients and allow early discharge. METHODS This is a prospective observational study of an accelerated chest pain pathway using point-of-care troponin in rural hospitals and general practices in New Zealand. A total of 1000 patients, of whom we estimate 400 will be low risk, will be enrolled in the study. OUTCOME MEASURES The primary outcome is the proportion of patients identified by the pathway as low risk for a 30-day major adverse cardiac event. Secondary outcomes include the proportion of low-risk patients who were discharged directly from general practice or rural hospitals, the proportion of patients reclassified as having acute myocardial infarction by the pathway and the proportion of patients with low and intermediate risk safely managed in the rural hospital.

Received care compared to ADP-guided care of patients admitted to hospital with chest pain of possible cardiac origin

Purpose

To assess the extent to which accelerated diagnostic protocols (ADPs), compared to traditional care, identify patients presenting to emergency departments (EDs) with chest pain who are at low cardiac risk and eligible for early ED discharge.

Patients and methods

Retrospective study of 290 patients admitted to hospital for further evaluation of chest pain following negative ED workup (no acute ischemic electrocardiogram [ECG] changes or elevation of initial serum troponin assay). Demographic data, serial ECG and troponin results, Thrombolysis in Myocardial Infarction (TIMI) score, cardiac investigations, and outcomes (confirmed acute coronary syndrome [ACS] at discharge and major adverse cardiac events [MACEs]) over 6 months of follow-up were analyzed. A validated ADP (ADAPT-ADP) was retrospectively applied to the cohort, and processes and outcomes of ADP-guided care were compared with those of care actually received.

Results

Patients had mean (±SD) TIMI score of 1.8 (±1.7); six (2.0%) patients were diagnosed with ACS at discharge. At 6 months, one patient (0.3%) re-presented with ACS and two (0.6%) died of non-coronary causes. The ADAPT-ADP defined 97 (33.4%) patients as being at low risk and eligible for early ED discharge, but who instead incurred mean hospital stay of 1.5 days, with 40.2% in telemetry beds, and 21.6% subject to non-invasive testing with only one positive result for coronary artery disease. None had a discharge diagnosis of ACS or developed MACE at 6 months.

Conclusion

Compared to traditional care, application of the ADAPT-ADP would have allowed one-third of chest pain patients with initially negative investigations in ED to have been safely discharged from ED.