Sensitive cardiac troponin in the diagnosis and risk stratification of acute heart failure

BACKGROUND

The aim of our study was to investigate the diagnostic and prognostic value of a sensitive cardiac troponin I (s-cTnI) assay in patients with acute heart failure (AHF).

METHODS

Sensitive cardiac troponin I was measured in 667 consecutive patients at presentation to the emergency department with acute dyspnoea. Three s-cTnI strata were predefined: below the limit of detection (<0.01 μg L(-1) , undetectable), detectable but still within the normal range (0.01-0.027 μg L(-1) ) and increased (≥0.028 μg L(-1) , ≥99th percentile). The final diagnosis was adjudicated by two independent cardiologists blinded to the s-cTnI levels. Median follow-up in patients with AHF was 371 days.

RESULTS

Levels of s-cTnI were higher in patients with AHF (n = 377, 57%) compared to patients with noncardiac causes of acute dyspnoea (median 0.02 vs. <0.01 μg L(-1) , P < 0.001). In patients with AHF, in-hospital mortality increased with increasing s-cTnI in the three strata (2%, 5% and 14%, P < 0.001). One-year mortality also increased with increasing s-cTnI (21%, 33% and 47%, P < 0.001). s-cTnI remained an independent predictor of 1-year mortality [adjusted odds ratio 1.03 for each increase of 0.1 μg L(-1) , 95% confidence interval (CI) 1.02-1.05, P < 0.001] after adjustment for other risk factors including B-type natriuretic peptide. The net reclassification improvement was 68% (P < 0.001), and absolute integrated discrimination improvement was 0.18 (P < 0.001). The diagnostic accuracy of s-cTnI for the diagnosis of AHF as quantified by the area under the receiver operating characteristic curve was 0.78 (95% CI, 0.75-0.82).

CONCLUSIONS

Sensitive cardiac troponin I is a strong predictor of short- and long-term prognosis in AHF that helps to reclassify patients in terms of mortality risk. Detectable levels of s-cTnI, even within the normal range, are independently associated with mortality.

Interleukin family member ST2 and mortality in acute dyspnoea

OBJECTIVES

The study objective was to investigate the prognostic utility and patient-specific characteristics of ST2 (suppression of tumorigenicity 2), assessed with a novel sensitive assay.

BACKGROUND

Suppression of tumorigenicity 2 signalling has been shown to be associated with death in cardiac and pulmonary diseases.

DESIGN/SUBJECTS

In an international multicentre cohort design, we prospectively enrolled 1091 patients presenting with acute dyspnoea to the emergency department (ED). ST2 was measured in a blinded fashion using a novel assay and compared to B-type natriuretic peptide (BNP) and NT-proBNP. The primary end-point was mortality within 30 days and 1 year. The prognostic value of ST2 was evaluated in comparison and in addition to BNP and NT-proBNP.

RESULTS

Suppression of tumorigenicity 2 concentrations was higher amongst decedents than among survivors (median 85 vs. 43 U mL⁻¹, P < 0.001) and also higher in patients with impaired left ventricular ejection fraction (LVEF) when compared with preserved LVEF (P < 0.001). In receiver operator characteristics analysis, the area under the curve (AUC) for ST2, BNP and NT-proBNP to predict 30-day and 1-year mortality were 0.76, 0.63 and 0.71, and 0.72, 0.71 and 0.73, respectively. The combinations of ST2 with BNP or NT-proBNP improved prediction of mortality provided by BNP or NT-proBNP alone. After multivariable adjustment, ST2 values above the median (50 U mL⁻¹) significantly predicted 1-year mortality (HR 2.3, P < 0.001).

CONCLUSION

In patients presenting to the ED with acute dyspnoea, ST2 is a strong and independent predictor of 30-day and 1-year mortality and might improve risk stratification already provided by BNP or NT-proBNP.

SIMS investigation of CrN sputtercoatings

Chromium nitride layers produced by reactive sputtering with different process parameters were characterized with EPMA, SIMS depth profiling, and three-dimensional SIMS imaging. EPMA results are used to quantify the major components of the films while SIMS is used to gather information about the distribution of the elements chromium, silicon, nitrogen, and oxygen. For all measurements a Cs+ primary ion beam was applied to sputter the sample. Positive MCs+ (M represents the element to be analyzed) secondary ions were detected. SIMS depth profiling shows an even distribution of all major elements except oxygen, which shows significant differences in concentration and distribution depending on the process parameters. CrN layers produced at low sputter power have much higher concentration of oxygen than layers produced with high sputter power. Heating the silicon substrate during the process results in an enrichment of oxygen at the interface.