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

Abstract

Objectives: To examine differences in care and inhospital course of patients with possible acute coronary syndrome (ACS) in Australia and New Zealand based on whether a highly sensitive (hs) troponin assay was used at the hospital to which they presented. Design, setting and patients: A snapshot study of consecutive patients presenting to hospitals in Australia and New Zealand from 14 to 27 May 2012 with possible ACS. Main outcome measures: Rates of major adverse cardiac events (inhospital death, new or recurrent myocardial infarction, stroke, cardiac arrest or worsening heart failure); association between assay type and outcome (via propensity score matching and a generalised estimating equation [GEE]; averages of the predicted outcomes among patients who were treated with and without the availability of an hs assay (via inverse probability‐weighting [IPW] with regression‐adjusted estimators). Results: 4371 patients with possible ACS were admitted to 283 hospitals. Over half of the hospitals (156 [55%]) reported using the hs assay and most patients (2624 [60%]) had hs tests (P = 0.004). Use of the hs assay was independent of hospital coronary revascularisation capability. Patients tested with the hs assay had more non‐invasive investigations (exercise tests, stress echocardiography, stress nuclear scans, and computed tomography coronary angiography) than those tested with the sensitive assay. However, there were no differences between the groups in rates of angiography or revascularisation. All adjusted analyses showed a consistently lower rate of inhospital events, including recurrent heart failure in patients for whom the hs assay was used (GEE odds ratio, 0.75; 95% CI, 0.60–0.94; P = 0.014); IPW analysis showed a 2.3% absolute reduction in these events with the use of the hs assay (P = 0.018). Conclusion: Use of hs troponin testing of patients hospitalised with possible ACS was associated with an increased rate of non‐invasive cardiac investigations and fewer inhospital adverse events.

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

“…The death rate was highest among patients with STEMI (16.2%) and NSTEMI (16.3%), reflecting both the substantial residual risk associated with these conditions and their comparable natural histories 20 , 21 . The lower mortality observed in the unstable angina population contrasts with older data, 22 but probably reflects the lower risk status of this population in the era of sensitive troponin assays 23 …”

Interpretation of Positive Troponin Results Among Patients with and Without Myocardial Infarction

“…Similarly, the median times between the fi rst and second test following the initial elevation, as well as the second and third test following the initial elevation, did not diff er ( P = 0.95 and 0.37, respectively). Th e median number of troponin tests performed per patient until the fi rst elevation occurred was 1 for both AMI and non-AMI patients; however, the median total number of tests performed for AMI patients was 4 [3,5], compared to 3 [2,4] for non-AMI patients ( P = 0.01). Of the 124 patients who had at least one elevated troponin, 114 (91.9%) had at least one subsequent test performed.…”

“…H igh-sensitivity troponin I testing has been shown to improve the early diagnosis of acute myocardial infarction (AMI) and aid with risk stratifi cation ( 1 -3 ). Investigators using a registry in Australia and New Zealand determined that high-sensitivity troponin I testing was associated with fewer in-hospital adverse events for patients hospitalized with possible acute coronary syndrome ( 4 ). Th ere are multiple non-AMI clinical scenarios, however, where troponin may exceed the 99th percentile, including renal failure, stroke, heart failure, pulmonary embolism, sepsis, and hypertension ( 5 ).…”

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

“…The vastness of Australia's geography and the nation's cultural diversity are both possible contributors to ACS practice variation and to patient outcomes. Mortality and complication rates due to MI are higher in rural and regional areas than in metropolitan areas; 1 , 13 lack of access to clinical expertise and to timely invasive management for non‐ST‐segment‐elevation ACS may contribute to variation in these areas of care 14 . Variation in prescription of secondary prevention medications and lifestyle modifications, and in the engagement of patients to adhere to them, are likely to be particularly challenging gaps to address in the diverse demographic profile of modern Australia, yet they are important targets for well‐designed interventions.…”