Troponin in early presenters to rule out myocardial infarction
Authors: Lowry Matthew T H , Doudesis Dimitrios , Boeddinghaus Jasper , Kimenai Dorien M , Bularga Anda , Taggart Caelan , Wereski Ryan , Ferry Amy V , Stewart Stacey D , Tuck Christopher , Koechlin Luca , Nestelberger Thomas , Lopez-Ayala Pedro , Huré Gabrielle , Lee Kuan Ken , Chapman Andrew R , Newby David E , Anand Atul , Collinson Paul O , Mueller Christian , Mills Nicholas L ,   High-STEACS Investigators, Mills Nicholas L , Strachan Fiona E , Tuck Christopher , Anand Atul , Barker Stephanie , Blades Jennifer , Boeddinghaus Jasper , Bularga Anda , Chapman Andrew R , Doudesis Dimitrios , Ferry Amy V , Fujisawa Takeshi , Georgiev Konstantin , Kimenai Dorien M , Lee Kuan Ken , Li Ziwen , Lowry Matthew T H , McKinlay Lynn , McDermott Michael , McPherson Jean , Mendusic Filip , Mills Nicholas L , Sorbie Andrew , Souter Grace , Schulberg Stacey D , Taggart Caelan , Tuck Christopher , Perez-Vicencio Daniel , Wang Yiqing , Wereski Ryan , Williams Kelly , Mills Nicholas L , Newby David E , Fox Keith A A , Berry Colin , Walker Simon , Weir Christopher J , Ford Ian , Mills Nicholas L , Newby David E , Gray Alasdair , Fox Keith A A , Berry Colin , Walker Simon , Collinson Paul O , Apple Fred S , Reid Alan , Cruikshank Anne , Findlay Iain , Amoils Shannon , McAllister David A , Maguire Donogh , Stevens Jennifer , Norrie John , Weir Christopher J , Shah Anoop S V , Anand Atul , Chapman Andrew R , Lee Kuan Ken , Andrews Jack P M , Adamson Philip D , Moss Alastair , Anwar Mohamed S , Hung John , Mills Nicholas L , Walker Simon , Malo Jonathan , Reid Alan , Cruikshank Anne , Collinson Paul O , Fischbacher Colin M , Croal Bernard L , Leslie Stephen J , Keerie Catriona , Parker Richard A , Walker Allan , Harkess Ronnie , Tuck Christopher , Wackett Tony , Weir Christopher , Armstrong Roma , Stirling Laura , MacDonald Claire , Sadat Imran , Finlay Frank , Harrison Kathy , Anand Atul , Linksted Pamela , Lavenberg Stephen 
Published: June 2023

Abstract

Aims
Whether a single cardiac troponin measurement can safely rule out myocardial infarction in patients presenting within a few hours of symptom onset is uncertain. The study aim was to assess the performance of troponin in early presenters.

Methods and results
In patients with possible myocardial infarction, the diagnostic performance of a single measurement of high-sensitivity cardiac troponin I at presentation was evaluated and externally validated in those tested ≤3, 4–12, and &gt;12 h from symptom onset. The limit-of-detection (2 ng/L), rule-out (5 ng/L), and sex-specific 99th centile (16 ng/L in women; 34 ng/L in men) thresholds were compared. In 41 103 consecutive patients [60 (17) years, 46% women], 12 595 (31%) presented within 3 h, and 3728 (9%) had myocardial infarction. In those presenting ≤3 h, a threshold of 2 ng/L had greater sensitivity and negative predictive value [99.4% (95% confidence interval 99.2%–99.5%) and 99.7% (99.6%–99.8%)] compared with 5 ng/L [96.5% (96.2%–96.8%) and 99.3% (99.1%–99.4%)]. In those presenting ≥3 h, the sensitivity and negative predictive value were similar for both thresholds. The sensitivity of the 99th centile was low in early and late presenters at 71.4% (70.6%–72.2%) and 92.5% (92.0%–93.0%), respectively. Findings were consistent in an external validation cohort of 7088 patients.

Conclusion
In early presenters, a single measurement of high-sensitivity cardiac troponin I below the limit of detection may facilitate the safe rule out of myocardial infarction. The 99th centile should not be used to rule out myocardial infarction at presentation even in those presenting later following symptom onset.