Value of Prehospital Troponin Assessment in Suspected Non-ST-Elevation Acute Coronary Syndrome

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There is an increasing awareness that prehospital risk stratification in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) is important. The HEART score accurately identifies patients at low risk and is nowadays fully assessable outside the hospital after the development of point-of-care (POC) troponin tests. However, the added value of the troponin component to the prehospital HEART score has not yet been assessed. This is a prospective cohort study including 700 patients with suspected NSTE-ACS in which prehospital risk stratification using the HEART score was performed by paramedics. Low risk was defined as HEAR or HEART score ≦3. Troponin was measured by a POC troponin T Test device (Roche Cobas h232). Troponin <40 ng/l scored 0 point, troponin ≥40 ng/l scored 2 points. Primary end point was major adverse cardiac events (MACE) within 45 days after inclusion. Mean HEAR score was 4.5 ± 1.6, mean HEART score was 4.7 ± 1.7. Using the HEAR score, a total of 183 patients (26%) were stratified as low risk, whereas using the HEART score, 172 patients (25%) were stratified as low risk (p = 0.001). In both low-risk groups, there were no deaths within 45 days. Using HEAR, MACE occurred in 13 patients (7%) in the low-risk group, whereas using HEART, MACE occurred in 5 patients in the low-risk group (3%, p <0.001). The use of HEART (Area under the curve 0.74) obtained a higher predictive value compared to HEAR (Area under the curve 0.65, p <0.001) for MACE. In conclusion, in patients with suspected NSTE-ACS, the prehospital troponin component of the HEART score has important added predictive value.

Section snippets

Methods

This prospective observational cohort study, the second phase of the Famous Triage project,2, 3 was performed between January 2016 and July 2017. Patients from Isala and Deventer hospital were included which are tertiary and secondary care hospitals in the Netherlands. The study involved 33 emergency medical services vehicles from 2 regional ambulance services (RAV IJsselland and Witte Kruis ambulancezorg) staffed by approximately 110 paramedics. The original aim of the second phase of the

Results

From January 2016 to July 2017, a total of 823 patients were considered eligible by paramedics. A complete HEART score was not available in 120 patients (15%) due to missing troponin results (87 patients) and/or incomplete registration of HEART scores (41 patients). Main reasons for the absence of a troponin result were device error, unavailability of testing strips or inability to obtain blood. A total of 3 patients with a complete HEART score were lost to follow-up. 700 patients (83%) with a

Discussion

We demonstrated that in suspected NSTE-ACS, the prehospital troponin component within the HEART score has important value in predicting MACE within 45 days. The HEART score was designed to incorporate a systematic and integrated approach of patients with suspected non-STEMI.22 Famous triage is the first study in which the complete HEART score is investigated in a prehospital setting.2, 3,23 The first phase of this study was performed with retrospective HEART assessment and hs-TnT.2 The current,

Acknowledgment

We thank Sonja Nijhoff, Ben Nijenkamp and Gert van Putten for data collection. We thank Wouter Jansen Klomp and Esther van ‘t Riet for assistance in data analysis.

Disclosures

All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organization for the submitted work, no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years and no other relationships or activities that could appear to have influenced the submitted work. The authors declared no potential conflicts of interest with respect to the research, authorship, and/or

Ethical Approval

The study was approved by the Regional Medical Ethics Board on the 20th September 2013.

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    Funding: The study was funded by Isala Research Fund. Roche diagnostics provided POC devices and POC strips. Researchers were independent of funders and funders were not involved in writing this research or performing analyses.

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