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Smith LM, Ashburn NP, Snavely AC, et al. Identification of very low-risk acute chest pain patients without troponin testing. Emerg Med J. 2020 Aug 4. pii: emermed-2020-209698. doi: 10.1136/emermed-2020-209698. (Original study)

BACKGROUND: The HEART Pathway combines a History ECG Age Risk factor (HEAR) score and serial troponins to risk stratify patients with acute chest pain. However, it is unclear whether patients with HEAR scores of <1 require troponin testing. The objective of this study is to measure the major adverse cardiac event (MACE) rate among patients with <1 HEAR scores and determine whether serial troponin testing is needed to achieve a miss rate <1%.

METHODS: A secondary analysis of the HEART Pathway Implementation Study was conducted. HEART Pathway risk assessments (HEAR scores and serial troponin testing at 0 and 3 hours) were completed by the providers on adult patients with chest pain from three US sites between November 2014 and January 2016. MACE (composite of death, myocardial infarction (MI) and coronary revascularisation) at 30 days was determined. The proportion of patients with HEAR scores of <1 diagnosed with MACE within 30 days was calculated. The impact of troponin testing on patients with HEAR scores of <1 was determined using Net Reclassification Improvement Index (NRI).

RESULTS: Providers completed HEAR assessments on 4979 patients and HEAR scores<1 occurred in 9.0% (447/4979) of patients. Among these patients, MACE at 30 days occurred in 0.9% (4/447; 95% CI 0.2% to 2.3%) with two deaths, two MIs and 0 revascularisations. The sensitivity and negative predictive value for MACE in the HEAR <1 was 97.8% (95%CI 94.5% to 99.4%) and 99.1% (95% CI 97.7% to 99.8%), respectively, and were not improved by troponin testing. Troponin testing in patients with HEAR <1 correctly reclassified two patients diagnosed with MACE, and was elevated among seven patients without MACE yielding an NRI of 0.9% (95%CI -0.7 to 2.4%).

CONCLUSION: These data suggest that patients with HEAR scores of 0 and 1 represent a very low-risk group that may not require troponin testing to achieve a missed MACE rate <1%.Trial registration numberNCT02056964.

Discipline Area Score
Emergency Medicine 7 / 7
Internal Medicine 7 / 7
Cardiology 5 / 7
Comments from MORE raters

Emergency Medicine rater

Thesea are very interesting data on the value of HEAR vs HEART in low-risk patients. As an ER doc for the past 29+ years, I find it very reassuring but, practically, I am not convinced I can throw myself in front of the bus of protocol orders for CC: CP in my large-volume ED.

Internal Medicine rater

I am not a fan of the net reclassification index (NRI), a metric playing a central role in this study, for the reasons stated here: https://pubmed.ncbi.nlm.nih.gov/31651317/ https://pubmed.ncbi.nlm.nih.gov/26504496/
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