Studies have suggested that acute coronary syndrome (ACS) may be excluded by a single undetectable high-sensitivity troponin (hs-TnT) taken at least three hours after the onset of symptoms in patients with non-pleuritic chest pain whose electrocardiogram (ECG) is non-ischaemic.
During a six-month period between April and September 2015, we identified 147 consecutive patients with non-pleuritic chest pain and non-ischaemic ECG whose first hs-TnT was less than 5 ng/L at least three hours after the onset of symptoms. We used the Elecsys hs-TnT assay, which has a lower limit of detection of 5 ng/L and a 99th centile of <14 ng/L.
Sixty-seven of 147 (46%) patients were male. The average age of our cohort was 52 years, range 19–83 years. Coronary heart disease (CHD) was known to have been present in 24 (16%) before the index admission. Median length of hospital stay was 15.4 hours (mean 22.5 hours) with 86 (59%) patients spending more than 12 hours in hospital. We referred 60 (41%) patients to cardiology for further assessment, either during or after admission, in order to rule out unstable angina. No patient was readmitted with hs‑TnT positive ACS, one patient underwent elective revascularisation and no patient died during one year of follow-up. Only one patient was lost to follow-up.
In conclusion, patients with non-pleuritic chest pain, non-ischaemic ECG and undetectable hs-TnT at least three hours after the onset of symptoms have a low risk of hs-TnT positive ACS, revascularisation and death during one year of follow-up. Most such patients could safely be discharged from hospital after a few hours of observation, without the need for a second hs-TnT.