The use of high-sensitivity troponin T (hsTnT) assays is growing. However, the increased sensitivity of this assay has created uncertainty about the clinical relevance of positive values in a variety of clinical scenarios. This prospective cohort study aimed to elucidate the relationship between hsTnT levels and mortality and myocardial ischemia in 21,842 patients over age 45 undergoing noncardiac surgery. The authors’ aim was to detect a post-operative hsTnT threshold associated with a 3-fold increase in 30-day mortality and an absolute risk increase of 3% or more.

Patient mean age was 63.1 years and the overall 30-day mortality was 1.2%. Using a reference of hsTnT <5ng/L, peak, post-operative levels of 20-65ng/L were associated with a 30-day post-operative mortality of 3.0%, representing a 24-fold increased risk (95% CI 10.32-54.09.) Higher peak levels of hsTnT corresponded with escalating mortality rates, including a 30-day mortality rate of 9.1% with a peak hsTnT of 65-1000ng/L (HR 70.34, 95% CI 30.6-161.7) and 29.6% when ≥1000ng/L (HR 227.01, 95%CI 87.35-589.92.) Mortality remained elevated in the absence of ischemic symptoms or ECG findings if hsTnT was elevated ≥65ng/L or ≥20ng/L with an absolute change of ≥5ng/L from baseline (HR 3.2, 95% CI 2.37-4.32), but to a lesser extent than those with ischemic features (HR 5.04, 95% CI 3.56-7.12.)

Conclusions
hsTnT appears to be of prognostic significance following non-cardiac surgery even in the absence of ischemic symptoms. What remains unclear is if there are actionable measures that might abrogate the relationship between the assay results and 30-day mortality – implying that the mortality events are primarily cardiac in nature – or if the assay is simply a reflection of systemic illness severity.

Devereux et al, JAMA 2017: 317(16):1642-1651.

Kearney, Kathleen E; McCabe James M.
Division of Cardiology, University of Washington, Seattle, WA