Background: High-sensitivity troponin assays promise earlier discrimination of myocardial infarction. Yet, the benefits and harms of this improved discriminatory performance when incorporated within rapid testing protocols, with respect to subsequent testing and clinical events, has not been evaluated in an in-practice patient-level randomized study. This multicenter study evaluated the noninferiority of a 0/1-hour high-sensitivity cardiac troponin T (hs-cTnT) protocol in comparison with a 0/3-hour masked hs-cTnT protocol in patients with suspected acute coronary syndrome presenting to the emergency department (ED). Methods: Patients were randomly assigned to either a 0/1-hour hs-cTnT protocol (reported to the limit of detection [<5 ng/L]) or masked hs-cTnT reported to ≤29 ng/L evaluated at 0/3-hours (standard arm). The 30-day primary end point was all-cause death and myocardial infarction. Noninferiority was defined as an absolute margin of 0.5% determined by Poisson regression. Results: In total, 3378 participants with an emergency presentation were randomly assigned between August 2015 and April 2019. Ninety participants were deemed ineligible or withdrew consent. The remaining participants received care guided either by the 0/1-hour hs-cTnT protocol (n=1646) or the 0/3-hour standard masked hs-cTnT protocol (n=1642) and were followed for 30 days. Median age was 59 (49–70) years, and 47% were female. Participants in the 0/1-hour arm were more likely to be discharged from the ED (0/1-hour arm: 45.1% versus standard arm: 32.3%, P <0.001) and median ED length of stay was shorter (0/1-hour arm: 4.6 [interquartile range, 3.4–6.4] hours versus standard arm: 5.6 (interquartile range, 4.0–7.1) hours, P <0.001). Those randomly assigned to the 0/1-hour protocol were less likely to undergo functional cardiac testing (0/1-hour arm: 7.5% versus standard arm: 11.0%, P <0.001). The 0/1-hour hs-cTnT protocol was not inferior to standard care (0/1-hour arm: 18/1646 [1.1%] versus 16/1642 [1.0%]; incidence rate ratio, 1.06 [ 0.53–2.11], noninferiority P value=0.001, superiority P value=0.744), although an increase in myocardial injury was observed. Among patients discharged from ED, the 0/1-hour protocol had a negative predictive value of 99.6% (95% CI, 99.0–99.9%) for 30-day death or myocardial infarction. Conclusions: This in-practice evaluation of a 0/1-hour hs-cTnT protocol embedded in ED care enabled more rapid discharge of patients with suspected acute coronary syndrome. Improving short-term outcomes among patients with newly recognized troponin T elevation will require an evolution in management strategies for these patients. Clinical Trial Registration: URL: https://www.anzctr.org.au . Unique identifier: ACTRN12615001379505.

Chew , The appropriateness of coronary investigation in myocardial injury and Type 2 myocardial infarction (ACT-2): A randomized trial design. Ymhj (2018),

IMPORTANCEAlthough international guidelines recommend use of the Global Registries of Acute Coronary Events (GRACE) risk score (GRS) to guide acute coronary syndrome (ACS) treatment decisions, the prospective utility of the GRS in improving care and outcomes is unproven.OBJECTIVE To assess the effect of routine GRS implementation on guideline-indicated treatments and clinical outcomes of hospitalized patients with ACS. DESIGN, SETTING, AND PARTICIPANTS Prospective cluster (hospital-level) randomized open-label blinded end point (PROBE) clinical trial using a multicenter ACS registry of acute care cardiology services. Fixed sampling of the first 10 patients within calendar month, with either ST-segment elevation or non-ST-segment elevation ACS. The study enrolled patients from June 2014 to March 2018, and data were analyzed between February 2020 and April 2020.INTERVENTIONS Implementation of routine risk stratification using the GRS and guideline recommendations. MAIN OUTCOMES AND MEASURESThe primary outcome was a performance score based on receipt of early invasive treatment, discharge prescription of 4 of 5 guideline-recommended pharmacotherapies, and cardiac rehabilitation referral. Clinical outcomes included a composite of all-cause death and/or myocardial infarction (MI) within 1 year. RESULTSThis study enrolled 2318 patients from 24 hospitals and was stopped prematurely owing to futility. Of the patients enrolled, median age was 65 years (interquartile range, 56-74 years), 29.5% were women (n = 684), and 62.9% were considered high risk (n = 1433). Provision of all 3 measures among high-risk patients did not differ between the randomized arms (GRS: 424 of 717 [59.9%] vs control: 376 of 681 [55.2%]; odds ratio [OR], 1.04; 95% CI, 0.63-1.71; P = .88). The provision of early invasive treatment was increased compared with the control arm (GRS: 1042 of 1135 [91.8%] vs control: 989 of 1183 [83.6%]; OR, 2.26; 95% CI, 1.30-3.96; P = .004). Prescription of 4 of 5 guideline-recommended pharmacotherapies (GRS: 864 of 1135 [76.7%] vs control: 893 of 1183 [77.5%]; OR, 0.97; 95% CI, 0.68-1.38) and cardiac rehabilitation (GRS: 855 of 1135 [75.1%] vs control: 861 of 1183 [72.8%]; OR, 0.68; 95% CI, 0.32-1.44) were not different. By 12 months, GRS intervention was not associated with a significant reduction in death or MI compared with the control group (GRS: 96 of 1044 [9.2%] vs control: 146 of 1087 [13.4%]; OR, 0.66; 95% CI, 0.38-1.14).CONCLUSIONS AND RELEVANCE Routine GRS implementation in cardiology services with high levels of clinical care was associated with an increase in early invasive treatment but not other aspects of care. Low event rates and premature study discontinuation indicates the need for further, larger scale randomized studies.

Background: High-sensitivity troponin assays are increasingly being adopted to expedite evaluation of patients with suspected acute coronary syndromes. Few direct comparisons have examined whether the enhanced performance of these assays at low concentrations leads to changes in care that improves longer-term outcomes. This study evaluated late outcomes of participants managed under an unmasked 0/1-hour high-sensitivity cardiac troponin T (hs-cTnT) protocol compared with a 0/3-hour masked hs-cTnT protocol. Methods: We conducted a multicenter prospective patient-level randomized comparison of care informed by unmasked 0/1-hour hs-cTnT protocol (reported to <5 ng/L) versus standard practice masked hs-cTnT testing (reported to ≤29 ng/L) assessed at 0/3 hours and followed participants for 12 months. Participants included were those presenting to metropolitan emergency departments with suspected acute coronary syndromes, without ECG evidence of coronary ischemia. The primary end point was time to all-cause death or myocardial infarction using Cox proportional hazards models adjusted for clustering within hospitals. Results: Between August 2015 and April 2019, we randomized 3378 participants, of whom 108 withdrew, resulting in 12-month follow-up for 3270 participants (masked: 1632; unmasked: 1638). Among these, 2993 (91.5%) had an initial troponin concentration of ≤29 ng/L. Deployment of the 0/1-hour hs-cTnT protocol was associated with reductions in functional testing. Over 12-month follow-up, there was no difference in invasive coronary angiography (0/1-hour unmasked: 232/1638 [14.2%]; 0/3-hour masked: 202/1632 [12.4%]; P =0.13), although an increase was seen among patients with hs-cTnT levels within the masked range (0/1-hour unmasked arm: 168/1507 [11.2%]; 0/3-hour masked arm: 124/1486 [8.3%]; P =0.010). By 12 months, all-cause death and myocardial infarction did not differ between study arms overall (0/1-hour: 82/1638 [5.0%] versus 0/3-hour: 62/1632 [3.8%]; hazard ratio, 1.32 [95% CI, 0.95–1.83]; P =0.10). Among participants with initial troponin T concentrations ≤29 ng/L, unmasked hs-cTnT reporting was associated with an increase in death or myocardial infarction (0/1-hour: 55/1507 [3.7%] versus 0/3-hour: 34/1486 [2.3%]; hazard ratio, 1.60 [95% CI, 1.05–2.46]; P =0.030). Conclusions: Unmasked hs-cTnT reporting deployed within a 0/1-hour protocol did not reduce ischemic events over 12-month follow-up. Changes in practice associated with the implementation of this protocol may be associated with an increase in death and myocardial infarction among those with newly identified troponin elevations. Registration: URL: https://www.anzctr.org.au ; Unique identifier: ACTRN12615001379505.

Demonstrating that a 0/1-hour hs-TnT protocol improves the effectiveness and efficiency of care within a robust comparative study will fill an evidence gap that currently limits the translation of more precise hs-TnT testing into better patient and health service outcomes.