Preoperative cardiac troponin below the 99th-percentile upper reference limit and 30-day mortality after noncardiac...

Area of Science:

• Cardiology
• Perioperative Medicine
• Clinical Biochemistry

Background:

• Preoperative high-sensitivity cardiac troponin (hs-cTn) above the 99th-percentile upper reference limit (URL) is a known mortality predictor.
• The prognostic significance of hs-cTn levels below the 99th-percentile URL but above the limit of detection (LOD) remains less understood.

Purpose of the Study:

• To investigate whether preoperative hs-cTn concentrations, mildly elevated but below the 99th-percentile URL, can predict 30-day mortality after noncardiac surgery.
• To determine the hs-cTn threshold associated with increased mortality risk.

Main Methods:

• Retrospective analysis of 12,415 noncardiac surgical patients with preoperative hs-cTn I below the 99th-percentile URL.
• Patients categorized into two groups: hs-cTn I below LOD (≤6 ng/L) and mildly elevated hs-cTn I (above LOD but <40 ng/L).
• Multivariate and propensity score matched analyses to assess 30-day mortality.

Main Results:

• The mild elevation group (35.9%) had significantly higher 30-day mortality compared to the LOD group (64.1%) (4.0% vs. 2.1%, HR 1.73).
• Propensity score matching confirmed this association (4.2% vs. 2.6%, HR 1.61).
• The mortality risk threshold was identified at a preoperative hs-cTn I level of ≥12 ng/L.

Conclusions:

• Preoperative hs-cTn I levels above the LOD but below the 99th-percentile URL are associated with increased 30-day mortality after noncardiac surgery.
• Mildly elevated hs-cTn I concentrations provide valuable prognostic information for perioperative risk stratification.
• A preoperative hs-cTn I threshold of 12 ng/L indicates an elevated mortality risk.