High-sensitivity assays offer better MACE prediction in patients with ACS symptoms

High-sensitivity troponin T (hsTnT) is a good prognostic factor for long-term major adverse cardiovascular events (MACEs) in people presenting to emergency departments with symptoms suggestive of acute coronary syndrome (ACS), according to a recent Singapore study.

In particular, this predictive effect of hsTnT may last up to 1 year after the index visit and seems to be stronger than that of conventional TnT (cTnT).

“This study aimed to explore the relationship between cTnT and hsTnT and found that while there is good correlation for larger values of cTnT, there was poorer correlation for smaller values of cTnT,” the researchers said. “The high-sensitivity assay was able to accurately detect values of troponin below the [limit of detection] of the conventional assay.”

The study included 1,023 patients (median age 56 years, 68.1 percent men) presenting with ACS symptoms to the Singapore General Hospital. Overall, there were 2,712 hsTnT and cTnT measurements available for comparison. The utility of either marker was assessed for the prediction of 30-day and 1-year occurrence of MACE.

HsTnT consistently yielded higher c-statistics than cTnT for the estimation of 30-day and 1-year MACE occurrence. For example, using a 0-hour optimal cut-off value of ≥16 ng/L, the resulting area under the curve for hsTnT was 0.75 (95 percent confidence interval [CI], 0.67–0.82) for 30-day MACE prediction, while that for cTnT was 0.66 (95 percent CI, 0.60–0.72). [Int J Cardiol Heart Vasc 2021;34:100758]

For 1-year MACE prediction, 0-hour AUC values were 0.72 (95 percent CI, 0.65–0.78) for hsTnT and 0.61 (95 percent CI, 0.56–0.65) for cTnT. The former continued to outperform the latter when 2- and 7-hour measurements were considered, both for the prediction of 30-day and 1-year MACEs.

Of the 844 patients with delta-hsTnT measurements between 0 and 2 hours, 201 showed positive change values. Positive delta-hsTnT was strongly predictive of both 30-day (AUC, 0.83, 95 percent CI, 0.73–0.94) and 1-year (AUC, 0.80, 95 percent CI, 0.70–0.91) MACEs. On the other hand, negative change values between 0 and 2 hours had poor predictive discriminant ability for 30-day and 1-year MACE.

The researchers then proposed a MACE rule-out cut-off value of <16 ng/L for 0- and 2-hour hsTnT, and a rule-in cut-off of ≥26 ng/L, in order to allow risk-stratification of patients with ACS symptoms presenting to the emergency department.

“Of note, the values of the cut-offs that we have selected would have fallen below the limit of detection for the corresponding values of cTnT, and thus may not be possible with conventional assays,” they pointed out.

“As different communities have different ACS prevalence, it may be useful for healthcare institutions to perform follow-up studies in their own respective sites after implementing high-sensitivity troponin assays to calibrate cut-off values to rule in and rule out ACS based on prevalence of ACS and resources available,” they added.