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

## TL;DR

This study finds that a higher threshold for a blood test can safely rule out heart attacks in most chest pain patients arriving at the emergency department.

## Contribution

The study identifies a higher high-sensitivity cardiac troponin T threshold (<9 ng/L) that safely rules out AMI with high negative predictive value.

## Key findings

- A 0 h hs-cTnT threshold of <9 ng/L achieved a 99.6% negative predictive value for AMI/death within 30 days.
- This cutoff identified 59.7% of patients as low risk, compared to lower thresholds.
- The results were validated in two large cohorts and showed improved performance in specific patient subgroups.

## Abstract

Ruling out acute myocardial infarction (AMI) in the emergency department (ED) is challenging. Studies have shown that a high-sensitivity cardiac troponin T (hs-cTnT) <5 ng/L or <6 ng/L at presentation (0 h) can be used to rule out AMI. The objective of this study was to identify whether an even higher hs-cTnT threshold can be used for a safe rule out of AMI in the ED.

The derivation cohort consisted of 24,973 ED patients with a primary complaint of chest pain. In this cohort, we identified the highest concentration of 0 h hs-cTnT that corresponded to a negative predictive value (NPV) of ≥99.5% for the primary endpoint of AMI/all-cause death within 30 days and the secondary endpoint of all-cause death within one year. The results were validated in two cohorts consisting of 132,021 and 1167 ED chest pain patients.

The 0 h hs-cTnT threshold corresponding to a NPV of ≥99.5% for the primary endpoint was <9 ng/L (NPV: 99.6% and 95% CI: 99.5–99.7). This cutoff provided a sensitivity of 96.2% (95% CI: 95.2–97.1) and identified 59.7% of the patients as low risk compared to 35.8% and 43.9% with a 0 h hs-cTnT <5 ng/L and <6 ng/L, respectively. The results were similar in the validation cohorts and seemed to perform even better in patients where the 0 h hs-cTnT was measured >3 h after symptom onset and in those with a nonischemic ECG and nonhigh risk history.

A 0 h hs-cTnT cutoff of <9 ng/L safely rules out AMI/death within 30 days in a majority of chest pain patients and is a more effective strategy than the currently recommended <5 ng/L and <6 ng/L cutoffs. This trial is registered with NCT03421873.