High-Sensitivity Cardiac Troponin I and Clinical Outcomes of Major Acute Cardiac Events
Michelle N Steiner1, Niti B Vyas1, Juan U Rojo1
1Department of Clinical Laboratory Science, University of Texas Medical Branch, Galveston, TX, United States.
Insights
Using sex-specific reference limits with high-sensitivity troponin I assays identifies patients at higher cardiovascular risk, yet these patients show improved long-term outcomes. This approach may have clinical value and highlights the obesity paradox.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Diagnostics
Background:
- Emerging evidence supports sex-specific 99th percentile upper reference limits (URLs) with high-sensitivity cardiac troponin (hs-cTn) assays for acute coronary syndrome (ACS).
- The clinical utility of reclassifying patients using these sex-specific URLs requires further investigation.
Purpose of the Study:
- To evaluate the long-term outcomes of patients reclassified by sex-specific URLs using the Beckman Coulter Access high-sensitivity troponin I (hs-cTnI) assay.
- To compare outcomes between reclassified patients and controls.
Main Methods:
- A retrospective observational study included 1486 emergency department patients with hs-cTnI results.
- Patients exceeding sex-specific URLs but below conventional URLs were identified and compared to non-reclassified controls.
Main Results:
- Reclassification was more frequent in women (7.6%) than men (5.7%) and associated with higher rates of major adverse cardiac events (MACEs), coronary artery disease, and cerebrovascular disease.
- Reclassified patients had a significantly longer time to first post-ED MACE.
- Reclassification independently predicted a 52.5% lower hazard of MACE over time (P = 0.016). Class 1 obesity was associated with a 68.2% hazard reduction (P < 0.001).
Conclusions:
- Integrating sex-specific URLs with hs-cTnI assays identifies patients with increased cardiovascular risk who have improved long-term outcomes, suggesting clinical value.
- The findings support the obesity paradox, linking Class 1 obesity to reduced MACE risk.
Background:
The long-term benefit of sex-specific 99th percentile upper reference limits (URLs) in conjunction with high-sensitivity cardiac troponin assays for suspected acute coronary syndrome (ACS) are emerging. We evaluated the long-term outcomes of patients reclassified by this approach using the Beckman Coulter Access high-sensitivity troponin I (hs-cTnI) assay.
Methods:
A retrospective observational study evaluated 1486 emergency department (ED) patients with hs-cTnI results for 3 years and 80 days. Patients whose values exceeded the sex-specific URL but remained below the conventional URL were identified and compared with non-reclassified controls.
Results:
Reclassification occurred 30% more frequently in women (7.6%, 68/893) compared to men (5.7%, 34/593) and demonstrated higher rates of major adverse cardiac events (MACEs), coronary artery disease, and cerebrovascular disease. Among reclassified men, myocardial infarction (MI) was more often followed by death. Among women, reclassification was associated with MI or death, but rarely both. Time to first post-ED MACE was significantly longer in reclassified patients. In a Cox regression model, reclassification independently predicted a 52.5% lower hazard of MACE over time (P = 0.016). The regression model also described Class 1 obesity as protective, with a 68.2% hazard reduction vs normal weight (P < 0.001).
Conclusions:
Integration of sex-specific URLs and a hs-cTnI assay identified patients at increased cardiovascular risk, yet was associated with improved long-term outcomes, suggesting potential clinical value. Findings also reinforce the obesity paradox, with Class 1 obesity linked to reduced MACE risk.
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