Cardiac iron concentration in relation to systemic iron status and disease severity in non-ischaemic heart failure with reduced ejection fraction.

AIMS: Low cardiac iron levels promote heart failure in experimental models. While cardiac iron concentration (CI) is decreased in patients with advanced heart failure with reduced ejection fraction (HFrEF), CI has never been measured in non-advanced HFrEF. We measured CI in left ventricular (LV) endomyocardial biopsies (EMB) from patients with non-advanced HFrEF and explored CI association with systemic iron status and disease severity. METHODS AND RESULTS: We enrolled 80 consecutive patients with non-ischaemic HFrEF with New York Heart Association class II or III symptoms and a median (interquartile range) LV ejection fraction of 25 (18-33)%. CI was 304 (262-373) µg/g dry tissue. CI was not related to immunohistological findings or the presence of cardiotropic viral genomes in EMBs and was not related to biomarkers of systemic iron status or anaemia. Patients with CI in the lowest quartile (CIQ1 ) had lower body mass indices and more often presented with heart failure histories longer than 6 months than patients in the upper three quartiles (CIQ2-4 ). CIQ1 patients had higher serum N-terminal pro-B-type natriuretic peptide levels than CIQ2-4 patients [3566 (1513-6412) vs. 1542 (526-2811) ng/L; P = 0.005]. CIQ1 patients also had greater LV end-diastolic (P = 0.001) and end-systolic diameter indices (P = 0.003) and higher LV end-diastolic pressures (P = 0.046) than CIQ2-4 patients. CONCLUSION: Low CI is associated with greater disease severity in patients with non-advanced non-ischaemic HFrEF. CI is unrelated to systemic iron homeostasis. The prognostic and therapeutic implications of CI measurements in EMBs should be further explored.

Diagnostic and prognostic value of sex- and age-specific cutpoints for high-sensitivity Troponin T in non-ST-elevation acute coronary syndrome.

INTRODUCTION: Sex- and age-specific high-sensitivity Troponin T (hs-cTnT) cutpoints for the diagnosis and prognosis in acute coronary syndromes are not well established. We evaluated the use of such dichotomous thresholds for calculation of the GRACE score. METHODS: We analyzed a retrospective cohort study of 1146 patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). Sex-dependent hs-cTnT cutpoints comprised 15.5 ng/L for men and 9.0 ng/L for women, while the sex-/age-specific cutpoints comprised 17 ng/L for 50-64-year-old men and ≥65-year-old women, 31 ng/L for ≥65-year-old men and 14 ng/L for the remainder of patients. RESULTS: For the diagnosis of NSTEMI using sex-specific hs-cTnT cutpoints, in women, the positive likelihood ratio (LR+) was 2.04 (1.68-2.47) while in men, the negative likelihood ratio (LR-) was 0.05 (0.04-0.07). Using sex-/age-specific hs-cTnT cutpoints, in ≥65-year-old women the LR- was 0.09 (0.06-0.15), in 50 to 64-year-old men the LR- was 0.08 (0.04-0.13) while in ≥65-year-old men the LR- was 0.32 (0.28-0.37). Sex-specific hs-cTnT cutpoints achieved an NRI of -0.020 (95% CI, -0.101-0.118) for women and 0.030 (95% CI, -0.013-0.079) for men, and the sex-/age-specific hs-cTnT cutpoints achieved an NRI of 0.061 (95% CI, -0.019-0.132) for women and 0.021 (95% CI, -0.062-0.108) for men, while net benefit and clinical utility were highest for women using the sex-/age-specific hs-cTnT cutpoints. CONCLUSIONS: Sex-dependent hs-cTNT cutpoints imply increasing diagnostic sensitivity for women at the cost of specificity. Considering age for hs-cTNT cutoffs slightly improves risk reclassification, although the overall gain in terms of the clinical management appears negligible.

Growth-differentiation factor 15 for long-term prognostication in patients with non-ST-elevation acute coronary syndrome: an Invasive versus Conservative Treatment in Unstable coronary Syndromes (ICTUS) substudy.

BACKGROUND: No five-year long-term follow-up data is available regarding the prognostic value of GDF-15. Our aim is to evaluate the long-term prognostic value of admission growth-differentiation factor 15 (GDF-15) regarding death or myocardial infarction (MI) in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). METHODS: This is a subanalysis from the ICTUS (Invasive versus Conservative Treatment in Unstable coronary Syndromes) trial, including troponin positive NSTE-ACS patients. The main outcome for the current analysis was 5-year death or spontaneous MI. GDF-15 samples were available in 1151 patients. The prognostic value of GDF-15, categorized into <1200 ng/L, 1200-1800 ng/L and >1800 ng/L, was assessed in unadjusted and adjusted Cox regression models. Adjustments were made for identified univariable risk factors. The additional discriminative and reclassification value of GDF-15 beyond the independent risk factors was assessed by the category-free net reclassification improvement (1/2 NRI(>0)) and the integrated discrimination improvement (IDI) RESULTS: Compared to GDF-15<1200 ng/L, a GDF-15>1800 ng/L was associated with an increased hazard ratio for death or spontaneous MI, mainly driven by mortality. GDF-15 levels were predictive after adjustments for other identified predictors. Additional discriminative value was shown with the IDI, not with the NRI. CONCLUSION: In patients presenting with NSTE-ACS and elevated troponin T, GDF-15 provides prognostic information in addition to identified predictors for mortality and spontaneous MI and can be used to identify patients at high risk during long-term follow-up.

Incremental prognostic value of biomarkers beyond the GRACE (Global Registry of Acute Coronary Events) score and high-sensitivity cardiac troponin T in non-ST-elevation acute coronary syndrome.

BACKGROUND: Guidelines recommend the use of validated risk scores and a high-sensitivity cardiac troponin assay for risk assessment in non-ST-elevation acute coronary syndrome (NSTE-ACS). The incremental prognostic value of biomarkers in this context is unknown. METHODS: We calculated the Global Registry of Acute Coronary Events (GRACE) score and measured the circulating concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and 8 selected cardiac biomarkers on admission in 1146 patients with NSTE-ACS. We used an hs-cTnT threshold at the 99th percentile of a reference population to define increased cardiac marker in the score. The magnitude of the increase in model performance when individual biomarkers were added to GRACE was assessed by the change (Δ) in the area under the receiver-operating characteristic curve (AUC), integrated discrimination improvement (IDI), and category-free net reclassification improvement [NRI(>0)]. RESULTS: Seventy-eight patients reached the combined end point of 6-month all-cause mortality or nonfatal myocardial infarction. The GRACE score alone had an AUC of 0.749. All biomarkers were associated with the risk of the combined end point and offered statistically significant improvement in model performance when added to GRACE (likelihood ratio test P ≤ 0.015). Growth differentiation factor 15 [ΔAUC 0.039, IDI 0.049, NRI(>0) 0.554] and N-terminal pro-B-type natriuretic peptide [ΔAUC 0.024, IDI 0.027, NRI(>0) 0.438] emerged as the 2 most promising biomarkers. Improvements in model performance upon addition of a second biomarker were small in magnitude. CONCLUSIONS: Biomarkers can add prognostic information to the GRACE score even in the current era of high-sensitivity cardiac troponin assays. The incremental information offered by individual biomarkers varies considerably, however.

Growth differentiation factor 15 predicts future insulin resistance and impaired glucose control in obese nondiabetic individuals: results from the XENDOS trial.

OBJECTIVE: Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that is increased in obesity and established type 2 diabetes. We assessed whether GDF-15 can predict future insulin resistance and impaired glucose control in obese nondiabetic individuals. DESIGN AND METHODS: Plasma GDF-15 concentrations were measured with an automated electrochemiluminescent immunoassay at baseline and after 4 years in 496 obese nondiabetic individuals (52% men, median age 48 years, median body mass index (BMI) 37.6 kg/m(2)) enrolled in the XENical in the prevention of Diabetes in Obese subjects (XENDOS) trial. RESULTS: The median GDF-15 concentration at baseline was 869 ng/l (interquartile range 723-1064 ng/l). GDF-15 was related to body weight, BMI, waist-to-hip ratio, and insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR)) (all P < 0.01). Changes in GDF-15 from baseline to 4 years were related to changes in body weight, BMI, waist-to-hip ratio, and HOMA-IR (all P < 0.05). Baseline GDF-15 was associated with the risk to have prediabetes or diabetes at 4 years by univariate analysis (odds ratio (OR) FOR 1 unit increase in ln GDF-15, 3.2; 95% confidence interval (CI): 1.7-6.1; P<0.001), and after multivariate adjustment for age, gender, treatment allocation (orlistat vs placebo), BMI, waist-to-hip ratio, and glucose control at baseline (OR 2.2; 95% CI: 1.1-4.7; P=0.026). Similarly, baseline GDF-15 was independently associated with HOMA-IR at 4 years (P=0.024). CONCLUSIONS: This first longitudinal study of GDF-15 in a large cohort of obese individuals indicates that GDF-15 is related to abdominal obesity and insulin resistance and independently associated with future insulin resistance and abnormal glucose control.