The new high-sensitivity cardiac troponin T assay improves risk assessment in acute coronary syndromes

Background

Cardiac troponins are currently the markers of choice for diagnosis of acute myocardial infarction and risk assessment in acute coronary syndrome (ACS). With the introduction of the new high-sensitivity cardiac troponin T (hs-cTnT) assay, it has become possible to measure cTnT even in healthy subjects. However, how the hs-cTnT assay compares with the old cTnT assay for risk assessment in ACS is still unknown.

Methods

Cardiac troponin T levels were measured with the new hs-cTnT assay and the old third-generation cTnT assay in serum samples collected 48 hours after randomization in 1,452 randomly selected ACS patients enrolled in the GUSTO-IV trial. During 30 days of follow-up, deaths and myocardial infarctions were recorded. At 12 months, only all-cause mortality was collected.

Results

The 16% of the patients that had levels higher than the 99th percentile cutoff for hs-cTnT but less than for cTnT had a similar 1-year mortality as the 60% that were positive for both assays (9.2% vs 10.7%, P = .52) and a higher 1-year mortality compared with the 24% that were negative for both assays (9.2% vs 2.6%, P = .001). For death or acute myocardial infarction at 30 days, the group that was positive only for hs-cTnT had an intermediate risk compared with the groups negative or positive for both assays (2.4%, 5.2%, and 8.7%; P < .001).

Conclusion

The new hs-cTnT assay, compared with the old cTnT assay, identified more patients with myocardial damage and who were at an increased risk for new cardiac events.