Association of High-Sensitivity Cardiac Troponin I Concentration With Cardiac Outcomes in Patients With Suspected...

Area of Science:

• Cardiology
• Biomarkers
• Diagnostic Accuracy

Background:

• High-sensitivity cardiac troponin I (hs-cTnI) is crucial for diagnosing acute coronary syndrome (ACS).
• A hs-cTnI concentration <5 ng/L is often used to identify low-risk patients, but its optimal threshold for risk stratification remains uncertain.

Purpose of the Study:

• To evaluate the performance of a hs-cTnI threshold of 5 ng/L for risk stratification in patients with suspected ACS.
• To determine the accuracy of this threshold in predicting myocardial infarction or cardiac death.

Main Methods:

• Systematic literature search of major databases (MEDLINE, EMBASE, Cochrane, Web of Science) from 2006 to 2017.
• Meta-analysis of 19 prospective cohorts including 22,457 patients, with individual patient-level data from 17 cohorts.
• Evaluation of hs-cTnI concentrations across a range of 2-16 ng/L to assess risk stratification performance.

Main Results:

• A hs-cTnI concentration <5 ng/L was observed in 49% of patients (11,012/22,457).
• This low hs-cTnI group had a 99.5% negative predictive value (95% CI, 99.3%-99.6%) for the primary outcome (myocardial infarction or cardiac death within 30 days).
• No cardiac deaths occurred within 30 days in this low-risk group, with a 99.9% negative predictive value for cardiac death at 1 year.

Conclusions:

• A hs-cTnI concentration <5 ng/L reliably identifies patients with suspected ACS who are at low risk of 30-day myocardial infarction or cardiac death.
• Further research is recommended to explore the clinical utility and cost-effectiveness of this risk stratification strategy.
• The findings support the use of a 5 ng/L hs-cTnI threshold for ruling out ACS in select patient populations.