Detectable High-Sensitivity Cardiac Troponin within the Population Reference Interval Conveys High 5-Year
Martin P Than1, Sally J Aldous1, Richard W Troughton1,2
1Christchurch Hospital, Christchurch, New Zealand.
Insights
Detectable cardiac troponin levels within the normal range, even after ruling out acute coronary syndrome (ACS), are linked to increased long-term risk of major adverse cardiovascular events (MACE) and mortality. High-sensitivity cardiac troponin T (hs-cTnT) shows a stronger association with mortality risk than high-sensitivity cardiac troponin I (hs-cTnI).
Area of Science:
- Cardiology
- Clinical Chemistry
- Biomarker Research
Background:
- Elevated cardiac troponin I or T (hs-cTnI/hs-cTnT) indicates increased adverse prognosis.
- The prognostic value of detectable but putatively normal cTn concentrations remains unclear.
Purpose of the Study:
- To determine if patients with normal, detectable cTn concentrations face increased risks of major adverse cardiovascular events (MACE) or all-cause mortality.
- To compare the prognostic value of hs-cTnI and hs-cTnT in this patient group.
Main Methods:
- Prospective 5-year follow-up of 1113 emergency department patients with suspected acute coronary syndrome (ACS).
- Cardiac troponin concentrations measured using hs-cTnI and hs-cTnT assays.
- Cox regression models used to assess risks, adjusted for covariates in patients without presentation MACE.
Main Results:
- Among 836 patients without presentation MACE, 138 incurred MACE and 169 died over 5.8 years.
- Detectable hs-cTnI and hs-cTnT concentrations within the upper reference limit were associated with increased MACE and mortality risks.
- hs-cTnT concentrations showed a stronger association with 5-year mortality compared to hs-cTnI.
Conclusions:
- Many patients with ACS ruled out and normal detectable hs-cTnI have long-term risks similar to those with presentation MACE.
- Detectable hs-cTnT is more strongly associated with 5-year mortality than hs-cTnI.
- Normal but detectable troponin levels warrant careful risk assessment and management.
Background:
Increased cardiac troponin I or T detected by high-sensitivity assays (hs-cTnI or hs-cTnT) confers an increased risk of adverse prognosis. We determined whether patients presenting with putatively normal, detectable cTn concentrations [> limit of detection and < upper reference limit (URL)] have increased risk of major adverse cardiovascular events (MACE) or all-cause mortality.
Methods:
A prospective 5-year follow-up of patients recruited in the emergency department with possible acute coronary syndrome (ACS) and cTn concentrations measured with hs-cTnI (Abbott) and hs-cTnT (Roche) assays. Cox regression models were generated with adjustment for covariates in those without MACE on presentation. Hazard ratios (HRs) for hs-cTn were calculated relative to the HRs at the median concentration.
Results:
Of 1113 patients, 836 were without presentation MACE. Of these, 138 incurred a MACE and 169 died during a median 5.8-year follow-up. HRs for MACE at the URLs were 2.3 (95% CI, 1.7-3.2) for hs-cTnI and 1.8 (95% CI, 1.3-2.4) for hs-cTnT. Corresponding HRs for mortality were 1.7 (95% CI, 1.2-2.2) for hs-cTnI and 2.3 (95 % CI, 1.7-3.1) for hs-cTnT. The HR for MACE increased with increasing hs-cTn concentration similarly for both assays, but the HR for mortality increased at approximately twice the rate for hs-cTnT than hs-cTnI. Patients with hs-cTnI ≥10 ng/L or hs-cTnT ≥16 ng/L had the same percentage of MACE at 5-year follow-up (33%) as patients with presentation MACE.
Conclusions:
Many patients with ACS ruled out and putatively normal but detectable hs-cTnI concentrations are at similar long-term risk as those with MACE. hs-cTnT concentrations are more strongly associated with 5-year mortality than hs-cTnI.
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