Comparison of a 3-hour versus a 6-hour sampling-protocol using high-sensitivity cardiac troponin T for rule-out and rule-in of non-STEMI in an unselected emergency department population

Int J Cardiol. 2013 Aug 20;167(4):1134-40. doi: 10.1016/j.ijcard.2012.09.122. Epub 2012 Oct 11.

Abstract

Background: Current European guidelines recommend the use of sensitive or high-sensitivity cardiac troponin assays to reduce the minimal sampling interval from 6 to 3h.

Methods: We compared a 3-hour versus a 6-hour protocol for diagnosis of non-STEMI and used the 99th percentile for rule-out, and relative and absolute concentration changes for rule-in of non-STEMI.

Results: 459 patients with either an NSTE-ACS or elevated hs-cTnT not due to MI and hs-cTnT measurements at 0, 3 and 6h were enrolled. Among the 404 patients excluded due to an incomplete sampling protocol performance was comparable to the 459 patients with a complete sampling protocol (AUC 0.79 vs 0.80, p=ns). In the study group, non-STEMI was diagnosed in 111 cases (24.2%) and elevated hs-cTnT not due to MI was observed in 215 cases (46.8%). For rule-out of non-STEMI, NPVs were 94.9%, 98.7% and 100% on admission, at 3 and 6h with comparable performance at 3 and 6h (AUC 0.782 vs 0.790, p=ns). For rule-in a 3-hour protocol performed as well as a 6-hour protocol, with a significantly (p<0.0001) better performance of absolute (AUC 0.851 vs. 0.845, p=0.740) as compared to relative concentration changes (AUC 0.771 vs. 0.739, p=0.169).

Conclusions: Rule-in and rule-out of non-STEMI may be accomplished comparably effective at 3 or 6h. For rule-in, absolute kinetic changes perform better than relative changes at all time points. ROC-optimal absolute δ-change was 6.95 ng/L at 3h and 8.9 ng/L at 6h.

Keywords: Diagnostic performance; High-sensitivity troponin T; Non-STEMI; Serial changes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Cardiovascular Diseases / blood*
  • Cardiovascular Diseases / diagnosis*
  • Cohort Studies
  • Emergency Medical Services / standards*
  • Emergency Service, Hospital / standards*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Specimen Handling / standards*
  • Time Factors
  • Troponin T / blood*

Substances

  • Biomarkers
  • Troponin T