Availability of highly sensitive troponin assays and acute coronary syndrome care: insights from the SNAPSHOT registry

Implementation of more sensitive cardiac troponin T assay in a state-wide health service

AIMS

Explore the impact of deploying high-sensitivity (hs) cardiac troponin T (cTnT) assay across a state-wide health service.

METHODS AND RESULTS

Presentations to emergency departments of six tertiary hospitals between January 2008 and August 2019 were included; standard cTnT assay was superseded by hs-cTnT in June 2011 without changing the reference range (≥30 ng/L reported as elevated), despite cTnT level of 30 ng/L being equivalent to ∼44 ng/L with hs-cTnT. Clinical outcomes were captured using state-wide linked health records. Interrupted time series analyses were used adjusted for seasonality and multiple co-morbidities using propensity score matching allowing for correlation within hospitals. In total, 614,847 presentations had ≥1 troponin measurement. Clinical ordering of troponin decreased throughout the study with no increase in elevated measurements amongst those tested with hs-cTnT. Small but statistically significant changes in index myocardial infarction (MI) diagnosis (-0.36%/year, 95%CI [confidence interval]:-0.48, -0.24,p < 0.001) and invasive coronary angiography (0.12%/year,95%CI:0, 0.24,p = 0.02) were seen, with no impact on death/MI at 30 days or 3-year survival in episodes of care (EOCs) with elevated cTnT after hs-cTnT implementation. Length of stay (LOS) was shorter among those with an elevated hs-cTnT (-4.44 h/year, 95%CI:-5.27, -3.60, p < 0.001). Non-elevated cTnT EOCs demonstrated shorter total LOS and improved 3-year survival (adjusted hazard ratio:0.90, 95%CI:0.83, 0.97,p = 0.008) although death/MI at 30 days was unchanged using hs-cTnT.

CONCLUSION

Widespread implementation of hs-cTnT without altering clinical thresholds reported to clinicians provided significantly shorter LOS without a clinically significant impact on clinical outcomes. A safer cohort with non-elevated cTnT was identified by hs-cTnT compared to the standard cTnT assay.

Elevated Plasma Soluble Triggering Receptor Expressed on Myeloid Cells-1 Level in Patients with Acute Coronary Syndrome (ACS): A Biomarker of Disease Severity and Outcome

Background and Aims

Plasma levels of soluble triggering receptor expressed on myeloid cells (sTREM-1) reflect innate immune cell activation. We sought to evaluate sTREM-1 levels in patients with acute coronary syndrome (ACS) and their predictive value for disease severity and outcome.

Methods

Plasma sTREM-1 levels were prospectively measured by ELISA in 121 consecutive patients with new-onset (≤24 h) chest pain at arrival to the emergency department (ED) and 73 healthy controls. Secondary endpoints were the association of plasma levels of sTREM-1 with day 30 and month 6 major adverse cardiovascular events (MACE) defined as death, ACS, stroke, and need for coronary revascularization, as well as with CAD severity. The primary endpoint of the study was the association of plasma sTREM-1 level at the time of admission to the ED with a diagnosis of ACS at day 30.

Results

Fifty-nine patients (48.7%) were diagnosed with ACS and 62 (51.3%) with nonspecific chest pain (NSCP). Median plasma sTREM-1 level at admission was significantly higher in the ACS group than the NSCP group and the control group (539.4 ± 330.3 pg/ml vs. 432.5 ± 196.4 pg/ml vs. 230.1 ± 85.5 pg/ml, respectively; P < 0.001) and positively correlated with the number of stenosed/occluded coronary arteries on angiography (P < 0.001). On logistic regression analysis, higher sTREM-1 levels predicted definite ACS vs. NSCP determined on day 30 (OR 1.29, 95% CI 1.07-1.54, P = 0.01) as well as with recurrent ACS (P = 0.04) and stroke (P = 0.02) at 6 months.

Conclusions

Plasma sTREM-1 levels are significantly elevated in patients with ACS and might serve as a biomarker differentiating ACS from NSCP in the ED as well as an inflammatory biomarker for coronary artery disease severity and outcome.

Sex-specific effects of implementing a high-sensitivity troponin I assay in patients with suspected acute coronary syndrome: results from SWEDEHEART registry

Using high-sensitivity cardiac troponin (hs-cTn) assays with sex-specific 99th percentiles may improve management of patients with suspected acute myocardial infarction (AMI). We investigated the impact of transitioning from a conventional troponin I assay to a high-sensitivity assay with sex-specific thresholds, in patients with suspected acute coronary syndrome admitted to Swedish coronary care units. Based on data from SWEDEHEART registry (females, n = 4,819/males, n = 7,670), we compared periods before and after implementation of hs-cTnI assay (Abbott) using sex-specific 99th percentiles. We investigated differences on discharge diagnosis, in-hospital examinations, treatments, and clinical outcome. Upon implementation of the hs-cTnI assay, proportion of patients with troponin levels above diagnostic AMI threshold increased in women and men by 24.3% versus 14.8%, respectively. Similarly, incidence of AMI increased by 11.5% and 9.8%. Diagnostic interventions and treatments increased regardless of sex. However, these associations did not persist following multivariable adjustment, probably due to the effect of temporal management trends during the observation period. Overall, no risk reduction on major adverse cardiovascular events was observed (HR: 0.91 [95% CI 0.80-1.03], P = 0.126). The implementation of hs-cTnI assay together with sex-specific 99th percentiles was associated with an increase in incidence of AMI regardless of sex, but had no major impact on clinical management and prognosis.

Clinical impact of using a more sensitive troponin assay in patients with acute chest pain

Background

More sensitive troponin assays have the potential to better evaluate patients with suspected acute coronary syndrome (ACS). Meanwhile, they may result in avoidable diagnostic testing.

Hypothesis

Our aim was to determine the clinical impact of implementing a more sensitive cardiac troponin I (cTnI) assay in patients with acute non‐traumatic chest pain presenting to the emergency department (ED).

Methods

This is a pre‐post cohort study. A total of 1201 consecutive patients with acute non‐traumatic chest pain or equivalent ischemic symptoms suggestive of ACS were allocated to two groups according to the cTnI assay used. The outcomes included the ED length of stay (LOS), hospital admission rate, the use of procedures and the incidence of major adverse cardiac events (MACE) at 30 days.

Results

The introduction of the more sensitive troponin assay shortened ED LOS (odds ratio [OR] 0.39, 95% confidence interval [CI] 0.28‐0.54) regarding patients discharged home directly, increased the hospital admission rate (OR 1.43, 95% CI 1.12‐1.84), the use of echocardiography (OR 1.58, 95% CI 1.22‐2.06), coronary computed tomography angiography (OR 1.78, 95% CI 1.04‐3.06), coronary angiography (OR 1.53, 95% CI 1.10‐2.12) and percutaneous coronary intervention (OR 2.42, 95% CI 1.58‐3.70) regarding patients discharged or admitted. The incidence of MACE did not decrease significantly (OR 0.61, 95% CI 0.27‐1.37).

Conclusions

The introduction of the more sensitive troponin assay appeared to result in less time spent in the ED regarding patients discharged home directly, but prompted more hospitalizations and procedures without impacting the incidence of MACE.

High-Sensitivity Cardiac Troponin I as a Gatekeeper for Coronary Computed Tomography Angiography and Stress Testing in Patients with Acute Chest Pain

BACKGROUND

Most patients presenting to the emergency department (ED) with suspected acute coronary syndrome (ACS) undergo noninvasive cardiac testing with a low diagnostic yield. We determined whether a combination of high-sensitivity cardiac troponin I (hs-cTnI) and cardiovascular risk factors might improve selection of patients for cardiac testing.

METHODS

We included patients from the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography (ROMICAT) I and II trials who presented to the ED with acute chest pain and were referred for cardiac testing. Based on serial hs-cTnI measurements and cardiovascular risk factors, we derived and validated the criterion for no need of cardiac testing. We predicted the effect of this criterion on the effectiveness of patient management.

RESULTS

A combination of baseline hs-cTnI (<4 ng/L) and cardiovascular risk factors (<2) ruled out ACS with a negative predictive value of 100% in ROMICAT I. We validated this criterion in ROMICAT II, identifying 29% patients as not needing cardiac testing. An additional 5% of patients were identified by adding no change or a decrease between baseline and 2 h hs-cTnI as a criterion. Assuming those patients would be discharged from the ED without cardiac testing, implementation of hs-cTnI would increase ED discharge rate (24.3% to 50.2%, P < 0.001) and decrease the length of hospital stay (21.4 to 8.2 h, P < 0.001), radiation dose (10.2 to 7.7 mSv, P < 0.001), and costs of care (4066 to 3342 US$, P < 0.001).

CONCLUSIONS

We derived and validated a criterion for combined hs-cTnI and cardiovascular risk factors that identified acute chest pain patients with no need for cardiac testing and could improve effectiveness of patient management. ClinicalTrials.gov Identifiers: NCT00990262 and NCT01084239.

Clinical care standards: appropriate care everywhere - acute coronary syndromes as an example

Audit data show that despite clinical practice guidelines, some patients miss out on evidence-based care, which is not explained by individual needs or preferences. Clinical care standards are small sets of concise recommendations that focus on known gaps in evidence-based care for a particular clinical condition. They aim to ensure that all patients with the same clinical condition are offered appropriate care, regardless of their location. Clinical care standards are nationally agreed standards and are developed to maximise engagement of consumers, clinicians, health services, and state and territory health departments and agencies. They complement clinical practice guidelines and other initiatives for improving quality of health care. As an example, the Acute Coronary Syndromes (ACS) Clinical Care Standard is a significant step forward in supporting clinicians and health services to realise all of the gains promised by the ACS evidence base. The ACS Clinical Care Standard focuses on the areas of care that are known to be most associated with variation in outcome. It supports patient involvement in critical decisions that affect their care, refocuses clinicians on the priority areas of ensuring appropriate ACS care, and informs health services about the systems required to deliver evidence-based care.

Interpretation of positive troponin results among patients with and without myocardial infarction

Measuring cardiac troponins is integral to diagnosing acute myocardial infarction (AMI); however, troponins may be elevated without AMI, and the use of multiple different assays confounds comparisons. We considered characteristics and serial troponin values in emergency department chest pain patients with and without AMI to interpret troponin excursions. We compared serial troponin in 124 AMI and non-AMI patients from the observational Performance of Triage Cardiac Markers in the Clinical Setting (PEARL) study who presented with chest pain and had at least one troponin value exceeding the 99th percentile of normal. Because 8 assays were used during data collection, we employed a method of scaling the troponin value to the corresponding assay's 99th percentile upper reference limit to standardize the results. In 81 AMI patients, 96% had elevated troponin at the first test following initial elevation, compared to 73% of the 43 non-AMI patients (P < 0.001). Scaling troponin to the 99th percentile of normal yielded a median value that was 4.8 [2.2, 14.1] times higher than the 99th percentile cutpoint among AMI patients, compared to 2.3 [1.5, 6.5] times higher among non-AMI patients (P = 0.04). The rise in serial scaled troponin values distinguished the AMI patients. Scaling to the 99th percentile was useful for comparing troponin when different assays were utilized.

Clinical impact of a high-sensitivity troponin assay introduction on patients presenting to the emergency department

OBJECTIVE

Biomarkers are a critical component in the investigation of patients with potential ischaemic heart disease. The proposed benefits of a high-sensitivity troponin (hs-Tn) assay include earlier diagnosis of myocardial infarction. However, the decreased specificity may adversely affect clinical practice. The present study aims to investigate the impact that the introduction of a hs-Tn assay had on patients presenting to the ED.

METHODS

A pre- and post-interventional analysis was performed on all patients presenting to the Royal Melbourne Hospital ED, and had a troponin, in the 12 months before and after the introduction of the hs-Tn assay. The main outcome measures were ED length of stay, admission rates, proportion of patients undergoing interventional cardiac procedures and proportion diagnosed with myocardial infarction.

RESULTS

There were 6557 patients who had a conventional assay and 7335 patients who had a hs-Tn assay. The introduction of a hs-Tn assay was associated with an increased abnormal troponin rate (23.4% vs 28.1%, P < 0.001). The median length of ED stay decreased by 9.1% (P < 0.001). The proportion admitted to hospital increased (60.9% vs 65.9%, P < 0.001); however, there was no difference in the proportion undergoing revascularisation or the proportion diagnosed with myocardial infarction.

CONCLUSIONS

Although the introduction of a hs-Tn assay led to an increase in hospital admissions, the unchanged rate of cardiac procedures or final diagnoses of acute myocardial infarction and ischaemic heart disease suggests that the hs-Tn did not improve the detection of these conditions. It remains unclear whether there was a benefit admitting the additional cohort of patients.

Survival after an acute coronary syndrome: 18-month outcomes from the Australian and New Zealand SNAPSHOT ACS study

OBJECTIVES

To assess the impact of the availability of a catheterisation laboratory and evidence-based care on the 18-month mortality rate in patients with suspected acute coronary syndromes (ACS).

DESIGN, SETTING AND PARTICIPANTS

Management and outcomes are described for patients enrolled in the 2012 Australian and New Zealand SNAPSHOT ACS audit. Patients were stratified according to their presentation to hospitals with or without cardiac catheterisation facilities. Data linkage ascertained patient vital status 18 months after admission. Descriptive and Cox proportional hazards analyses determined predictors of outcomes, and were used to estimate the numbers of deaths that could be averted by improved application of evidence-based care.

MAIN OUTCOME MEASURES

Mortality for ACS patients from admission to 18 months after admission.

RESULTS

Definite ACS patients presenting to catheterisation-capable (CC) hospitals (n = 1326) were more likely to undergo coronary angiography than those presenting to non-CC hospitals (n = 1031) (61.5% v 50.8%; P = 0.0001), receive timely reperfusion (for ST elevation myocardial infarction (STEMI) patients: 45.2% v 19.2%; P < 0.001), and be referred for cardiac rehabilitation (57% v 53%; P = 0.05). All-cause mortality over 18 months was highest for STEMI (16.2%) and non-STEMI (16.3%) patients, and lowest for those presenting with unstable angina (6.8%) and non-cardiac chest pain (4.8%; P < 0.0001 for trend). After adjustment for patient propensity to present to a CC hospital and patient risk, presentation to a CC hospital was associated with 21% (95% CI, 2%-37%) lower mortality than presentation to a non-CC hospital. This mortality difference was attenuated after adjusting for delivery of evidence-based care.

CONCLUSION

In Australia and New Zealand, the availability of a catheterisation laboratory appears to have a significant impact on long-term mortality in ACS patients, which is still substantial. This mortality may be reduced by improvements in evidence-based care in both CC and non-CC hospitals.