In a multicenter cohort study, 61% of patients with suspected non–ST-segment elevation myocardial infarction had sixth-generation high-sensitivity cardiac troponin T concentrations less than 13 ng/L at presentation compared with 28% below the guideline-recommended threshold for the current fifth-generation assay.
In a prespecified secondary analysis of the Point of Care Evaluation of High-Sensitivity Troponin study, researchers evaluated 987 adults with possible non–ST-segment elevation myocardial infarction (MI) who presented to three secondary and tertiary hospitals in Scotland from November 2022 to January 2025.
The primary outcome was type 1, 4b, or 4c MI at index presentation, or subsequent type 1, 4b, or 4c MI or cardiac mortality within 30 days. Overall, 8% (n = 82) of the patients met the primary outcome. The cohort had a median age of 59 years, 62% were male, 96% were White, and chest discomfort was the primary symptom in 94% of patients.
The researchers defined the sixth-generation high-sensitivity cardiac troponin T threshold as the highest presentation concentration that achieved a negative predictive value of at least 99.5% and sensitivity of at least 99% for the primary outcome.
At presentation, 61% (n = 601/987) of the patients had sixth-generation cardiac troponin T concentrations less than 13 ng/L. That threshold had a negative predictive value of 99.9% and sensitivity of 99.4% for the primary outcome. By comparison, 28% (n = 271)of the patients were below the guideline-recommended less than 5-ng/L threshold for the fifth-generation assay, which had a negative predictive value of 99.8% and sensitivity of 99.4%.
In the High-Sensitivity Troponin in the Evaluation of Patients With Suspected Acute Coronary Syndrome early rule-out pathway, 41% (n = 376/918) of the patients would have been identified as low risk at presentation using the sixth-generation assay compared with 17% (n = 160) of the patients using the fifth-generation assay. Application of the sixth-generation pathway would have reduced the proportion of patients requiring serial troponin testing for risk stratification (23% vs 43%).
The researchers externally validated the sixth-generation threshold in 1,721 patients from the Advantageous Predictors of Acute Coronary Events study conducted across Czechia, Italy, Poland, Spain, and Switzerland. In that cohort, 45% (n = 782) of the patients had sixth-generation cardiac troponin T concentrations less than 13 ng/L at presentation compared with 7% (n = 118) of the patients below the guideline-recommended fifth-generation threshold. The sixth-generation presentation threshold analysis had a negative predictive value of 99% and sensitivity of 97.8%.
The sixth-generation assay measured higher cardiac troponin T concentrations compared with the fifth-generation assay, and the researchers highlighted that values from the two assays were highly correlated but not interchangeable. Using the sixth-generation assay, 6% (n = 55) of the patients were reclassified as not having myocardial injury, and 2 of those patients met the primary outcome.
In subgroup analyses, 72% (n = 271/376) of the female patients and 54% (n = 330/611) of the male patients had sixth-generation cardiac troponin T concentrations less than 13 ng/L at presentation. No false negatives occurred in either subgroup in the derivation cohort, but the researchers reported less precise sensitivity estimates among female patients because fewer events occurred in that subgroup. In the validation cohort, 4 female patients were incorrectly classified as low risk at presentation.
The study had several limitations. It was not powered to precisely estimate sensitivity, and care was guided by current clinical assays rather than the sixth-generation assay. The derivation cohort was predominantly White, just 38% of patients were female, and just 13% presented within 2 hours of symptom onset. The researchers said more diverse cohorts and prospective implementation studies are needed.
“Prospective studies are needed to confirm whether implementation of the sixth-generation [high-sensitivity cardiac troponin T] assay will reduce the need for serial testing and facilitate earlier discharge in low-risk patients,” wrote lead study author Alexander J. F. Thurston, MD, of the BHF Centre for Cardiovascular Science at the University of Edinburgh, and colleagues.
Full disclosures can be found in the published study.
Source: JAMA Cardiology
