Ideal high sensitivity troponin baseline cutoff for patients with renal dysfunction

Area of Science:

• Cardiology
• Clinical Chemistry

Background:

• High-sensitivity cardiac troponin (hs-cTn) assays are crucial for diagnosing myocardial infarction (MI).
• Lower specificity of hs-cTn assays for non-ST Elevation MI (NSTEMI) is observed in patients with renal disease.
• Optimizing diagnostic thresholds is necessary to improve accuracy in specific patient populations.

Purpose of the Study:

• To determine an optimized hs-cTn rule-in cutoff for diagnosing NSTEMI in patients with renal disease.
• To enhance the specificity of hs-cTn assays in individuals with impaired kidney function.
• To evaluate the impact of adjusted cutoffs on diagnostic accuracy and patient management.

Main Methods:

• Secondary analysis of a prospective FDA study involving adults with suspected MI.
• Data collection included hs-cTn levels and estimated glomerular filtration rate (eGFR) at multiple time points.
• NSTEMI adjudication was performed by physicians blinded to hs-cTn results; an adjusted hs-cTn rule-in cutoff was generated.

Main Results:

• A cohort of 2341 subjects (after exclusions) was analyzed, with 20.8% having an eGFR <60 mL/min/1.73 m².
• In patients with eGFR <15 mL/min/1.73 m², increasing the hs-cTn rule-in cutoff from 120 ng/L to 600 ng/L significantly improved specificity (85.0% to 93.3%) and Positive Predictive Value (62.5% to 78.9%).
• The higher cutoff improved specificity and PPV across all eGFR subgroups, with a minimal increase in patients requiring further observation.

Conclusions:

• An estimated glomerular filtration rate (eGFR)-adjusted rule-in threshold for the Siemens Atellica hs-cTnI assay enhances specificity while maintaining sensitivity.
• This optimized threshold can improve the accuracy of NSTEMI diagnosis in patients with renal disease.
• Further prospective studies in populations with higher incidences of renal disease are recommended to validate these findings.