A Single High-Sensitivity Cardiac Troponin T Strategy for Ruling Out Myocardial Infarction

Area of Science:

• Cardiology
• Emergency Medicine
• Biomarker Research

Background:

• Ruling out acute myocardial infarction (AMI) in the emergency department (ED) presents diagnostic challenges.
• Current guidelines suggest using high-sensitivity cardiac troponin T (hs-cTnT) levels below 5 ng/L or 6 ng/L at presentation to exclude AMI.
• The need for more efficient and accurate diagnostic thresholds for AMI in the ED is recognized.

Purpose of the Study:

• To determine if a higher hs-cTnT threshold can be safely employed for ruling out AMI in the ED.
• To evaluate the negative predictive value (NPV) of elevated hs-cTnT concentrations for AMI and all-cause death.
• To compare the effectiveness of a higher hs-cTnT threshold against existing thresholds.

Main Methods:

• A derivation cohort of 24,973 ED patients with chest pain was analyzed.
• The highest 0-hour hs-cTnT concentration achieving an NPV of ≥99.5% for AMI/30-day all-cause death was identified.
• Validation was performed in two independent cohorts totaling 132,021 and 1167 ED chest pain patients.

Main Results:

• A 0-hour hs-cTnT threshold of <9 ng/L demonstrated an NPV of 99.6% for the primary endpoint.
• This <9 ng/L cutoff identified 59.7% of patients as low risk, significantly higher than the <5 ng/L (35.8%) and <6 ng/L (43.9%) cutoffs.
• Similar performance was observed in validation cohorts, with improved efficacy in specific subgroups like those with later hs-cTnT measurement or non-high-risk profiles.

Conclusions:

• A 0-hour hs-cTnT cutoff of <9 ng/L safely rules out AMI and 30-day death in a majority of chest pain patients.
• This higher threshold represents a more effective strategy for identifying low-risk patients compared to current <5 ng/L and <6 ng/L cutoffs.
• The study provides evidence for optimizing AMI rule-out protocols in the emergency department.