Prognostic Significance of High-Sensitivity Cardiac Troponin T Concentrations between the Limit of Blank and Limit of Detection in Community-Dwelling Adults: A Metaanalysis.

BACKGROUND: There is controversy regarding whether to report concentrations of high-sensitivity cardiac troponin T (hs-cTnT) to the limit of blank (LOB) (3 ng/L) or the limit of detection (LOD) (5 ng/L) of the assay in community-based cohorts. We hypothesized that hs-cTnT concentrations between the LOB and LOD would be associated with poorer cardiovascular outcomes compared to concentrations below the LOB. METHODS: hs-cTnT was analyzed in a total of 10 723 participants from the Cardiovascular Health Study (CHS), Atherosclerosis Risk in Communities (ARIC) study, and Dallas Heart Study (DHS). Participants were divided into 2 groups, those with hs-cTnT concentrations below the limit of blank (LOB) (<3 ng/L) and those with hs-cTnT between the LOB and limit of detection (LOD) (3-4.99 ng/L). Cross-sectional associations with traditional cardiovascular risk factors and cardiac structural measurements, and longitudinal associations with long-term cardiovascular outcomes of incident heart failure and cardiovascular death, were determined. RESULTS: Participants with hs-cTnT between the LOB and LOD for all 3 cohorts were older, more likely to be male, and have a higher burden of cardiovascular risk factors and structural pathology. A metaanalysis of the 3 cohorts showed participants with hs-cTnT between the LOB and LOD were at increased risk of new-onset heart failure (hazard ratio, 1.18; 95% CI, 1.02-1.38) and cardiovascular mortality (hazard ratio, 1.29; 95% CI, 1.06-1.57). CONCLUSIONS: hs-cTnT concentrations between the LOB and LOD (3-4.99 ng/L) are associated with a higher prevalence of traditional risk factors, more cardiac pathology, and worse outcomes than concentrations below the LOB (<3 ng/L).

Soluble ST2 for Prediction of Heart Failure and Cardiovascular Death in an Elderly, Community-Dwelling Population.

BACKGROUND: Soluble ST2 (sST2), a marker of myocyte stretch and fibrosis, has prognostic value in many cardiovascular diseases. We hypothesized that sST2 levels are associated with incident heart failure (HF), including subtypes of preserved (HFpEF) and reduced (HFrEF) ejection fraction, and cardiovascular death. METHODS AND RESULTS: Baseline serum sST2 was measured in 3915 older, community-dwelling subjects from the Cardiovascular Health Study without prevalent HF. sST2 levels were associated with older age, male sex, black race, traditional cardiovascular risk factors, other biomarkers of inflammation, cardiac stretch, myocardial injury, and fibrosis, and abnormal echocardiographic parameters. In longitudinal analysis, greater sST2 was associated with a higher risk of incident HF and cardiovascular death; however, in multivariate models adjusting for other cardiac risk factors and the cardiac-specific biomarker, N-terminal pro-type B natriuretic peptide, these associations were attenuated. In these models, an sST2 level above the US Food and Drug Administration-approved cut-off value (>35 ng/mL) was significantly associated with incident HF (hazard ratio [HR], 1.20; 95% CI, 1.02-1.43) and cardiovascular death (HR, 1.21; 95% CI, 1.02-1.44), and greater sST2 was continuously associated with cardiovascular death (per 1-ln increment: HR, 1.24; 95% CI, 1.02-1.50). sST2 was not associated with the HF subtypes of HFpEF and HFrEF in adjusted analysis. Addition of sST2 to existing risk models of HF and cardiovascular death modestly improved discrimination and reclassification into a higher risk. CONCLUSIONS: The predictive value of sST2 for HF of all subtypes and cardiovascular death is modest in an elderly population despite strong cross-sectional associations with risk factors and underlying cardiac pathology.

Use and interpretation of high sensitivity cardiac troponins in patients with chronic kidney disease with and without acute myocardial infarction.

It is well known that the population with chronic kidney disease (CKD) is at greater risk for cardiovascular disease and death than the general population. The use and interpretation of high sensitivity cardiac troponin (hs-cTn) assays have been particularly challenging in these patients with the majority having elevated levels at baseline. The diagnostic accuracy of acute myocardial infarction (AMI) may be decreased in patients with CKD when using these newer troponins. In order to improve the sensitivity and specificity for the diagnosis of AMI, one must look at the change in cTn and consider using higher cut-off values. In asymptomatic patients with CKD, research has shown increased prevalence of cardiovascular risk factors and underlying structural heart disease with increasing cTn levels. Prognostically, elevated cTn has been associated with adverse outcomes including incident heart failure and cardiovascular mortality. The purpose of the review is to evaluate hs-cTn in patients with CKD for the diagnosis of AMI and for the prognostic significance of elevated levels in CKD patients without AMI. Although the underlying etiology of persistently elevated cTn in the CKD population remains unclear, the review will also evaluate studies attempting to explain whether the source of cTn is from increased cardiac production versus decreased renal clearance. Further longitudinal studies are required in order to bridge the gap between the prognostic importance of elevated cTn and clinical management to prevent symptomatic cardiac disease.