Introduction:
A substantial minority of asymptomatic individuals will have very low but measurable levels of cardiac troponin T using a high sensitive assay (hs-cTnT). It is controversial if levels in this range provide physiologic and prognostic information. We hypothesized that hs-cTnT levels between the limit of blank (LOB) (3 ng/L) and limit of detection (LOD) (5 ng/L) are associated with increased incidence of heart failure (HF) and cardiovascular death compared to levels below the LOB (<3 ng/L).
Methods:
hs-cTnT was measured in subjects without prevalent HF from the Cardiovascular Health Study (CHS), Atherosclerosis Risk in Communities (ARIC) study, and Dallas Heart Study (DHS). Participants were divided into two groups: levels below the LOB (n=7272) and levels between the LOB and LOD (n=3451). Cross sectional and longitudinal associations with demographics, traditional cardiovascular risk factors, and cardiovascular outcomes were made. A fixed-effect meta-analysis was performed using regression coefficients and variance estimates from fully adjusted models from all three cohorts.
Results:
Participants with hs-cTnT between the LOB and LOD were older, more likely to be male, and had higher prevalence of cardiovascular risk factors and structural abnormalities such as higher coronary artery calcium score and left ventricular mass. A meta-analysis of the three cohorts showed participants with hs-cTnT between the LOB and LOD were at increased risk of new-onset HF (HR=1.18, 95% CI: 1.02, 1.38) and cardiovascular death (HR=1.29, 95% CI: 1.06, 1.57) after adjusting for demographics and traditional risk factors when compared to participants with hs-cTnT below the LOB (Figure).
Conclusions:
hs-cTnT levels between the LOB and LOD are associated with a higher prevalence of traditional risk factors, cardiac pathology, and worse outcomes compared with levels below the LOB. Therefore, in general population cohorts, hs-cTnT should be reported down to the LOB.
HIGHLY SENSITIVE CARDIAC TROPONIN-T IS AN INDEPENDENT PREDICTOR OF LONG-TERM ALL-CAUSE MORTALITY IN OUTPATIENTS WITH CHRONIC SYSTOLIC HEART FAILURE
