Classification performance of clinical risk scoring in suspected acute coronary syndrome beyond a rule-out troponin profile

AIMS

High-sensitivity cardiac troponin strategies can provide risk stratification in patients with suspected acute coronary syndrome (ACS) in the emergency department (ED). This study evaluated whether clinical risk scoring improves the classification performance of a rule-out profile in suspected ACS.

METHODS AND RESULTS

Patients presenting to ED with suspected ACS as part of the RAPID-TnT trial randomized to the intervention arm were included. Results ≥5 ng/L were available for all participants in this analysis. We evaluated the Thrombolysis In Myocardial Infarction (TIMI) risk score, History ECG Age Risk factors Troponin (HEART) score, and Emergency Department Assessment of Chest pain Score (EDACS) in addition to a rule-out profile based on the 0/1-h high-sensitivity cardiac troponin T protocol (<5 ng/L or ≤12 ng/L and a change of <3 ng/L at 1-h) using test performance parameters focusing on low-risk groups to identify the primary endpoint (TIMI ≤ 1, HEART ≤ 3, EDACS < 16). Primary endpoint was a composite of type 1/2 myocardial infarction (MI) at index presentation and all-cause mortality or type 1/2 MI at 30 days. A total of 3378 participants were enrolled between August 2015 and April 2019 of which 108 were ineligible/withdrew consent (intervention arm: n = 1638). Sensitivity, specificity, negative predictive value (NPV), and area under the curve (AUC) of the rule-out profile was 94.4%, 76.8%, 99.6%, and 0.86, respectively with 72.9% identified as 'low-risk'. Adding the clinical risk scores did not improve the sensitivity, NPV, or AUC with significantly lower specificity and 'low-risk' classified participants.

CONCLUSIONS

Addition of clinical risk scores to rule-out profile did not demonstrate improved classification performance for identifying the composite of type 1/2 MI at index presentation and all-cause mortality or type 1/2 MI at 30 days.

CLINICAL TRIALS REGISTRATION

URL: https://www.anzctr.org.au. Reg. No. ACTRN12615001379505.

Late Outcomes of the RAPID-TnT Randomized Controlled Trial: 0/1-Hour High-Sensitivity Troponin T Protocol in Suspected ACS

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.

A Randomized Trial of a 1-Hour Troponin T Protocol in Suspected Acute Coronary Syndromes: The Rapid Assessment of Possible Acute Coronary Syndrome in the Emergency Department With High-Sensitivity Troponin T Study (RAPID-TnT)

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: 17/1646 [1.0%] versus 16/1642 [1.0%]; incidence rate ratio, 1.06 [ 0.53-2.11], noninferiority P value=0.006, superiority P value=0.867), 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.

Prevocational medical education at the coalface: report from the 2006 national junior medical officer and director of clinical training/registrar forums

The junior medical officer (JMO) forum and the combined director of clinical training (DCT) and registrar forum, held as part of the 11th National Prevocational Medical Education Forum in Adelaide in October 2006, discussed issues including the newly launched Australian Curriculum Framework for Junior Doctors; resourcing for JMO training; the role of international medical graduates; and the importance of JMO welfare. The JMO forum resolved that the national curriculum framework be used to ensure adequate training and educational opportunities are provided to JMOs; that accreditation should be performed for all JMO positions; and that JMO welfare should be a priority. The DCT and registrar forum discussed the use of the national curriculum framework to add value to the current training system; improve support of international medical graduates entering the workforce; and improve resources available for training JMOs.

Evidence-based risk factors for postoperative deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a common postoperative complication that is associated with significant morbidity and mortality. Thromboprophylaxis has been shown to be underused. In the absence of prophylaxis, rates as high as 50% have been reported following orthopaedic surgery, and 25% following general surgery. Many risk factors have been suggested but there is often little evidence to support these claims.

METHODS

A systematic review was performed to determine the evidence base behind each suggested risk factor, and, where sufficient data were available, a random-effects meta-analysis was performed.

RESULTS

There is evidence to support a significant association between increased age, obesity, a past history of thromboembolism, varicose veins, the oral contraceptive pill, malignancy, Factor V Leiden gene mutation, general anaesthesia and orthopaedic surgery, with higher rates of postoperative DVT, although there remain some variables within the study designs that may lead to overestimation of effect. There is no evidence to support the suggested risk factors of hormone replacement therapy, gender, ethnicity or race, chemotherapy, other thrombophilias, cardiovascular factors, smoking and blood type.

CONCLUSIONS

An accurate knowledge of evidence-based risk factors is important in predicting and preventing postoperative DVT, and can be incorporated into a decision support system for appropriate thromboprophylaxis use.