Multicentre comparison of free thyroid hormones immunoassays: the Immunocheck study.

Background: In order to evaluate whether there is still present a very large variability in measured values and analytical performance among different free thyroid (FT) hormone immunoassays, we considered the results derived from an External Quality Assessment (EQA) scheme, named Immunocheck.

Methods: The EQA Immonocheck study enrolled about 1000 participant laboratories, which measured the 54 quality control samples distributed in the three annual cycles (2007, 2008 and 2009). Participant laboratories produced a total of 30,476 results for FT3 and 31,351 for FT4, respectively.

Prognostic value of plasma renin activity in heart failure.

The prognostic role of specific biomarkers of the renin-angiotensin-aldosterone system and sympathetic activation pathways in heart failure has never been investigated in populations with current evidence-weighted treatment. To establish whether the plasma renin activity (PRA), among several neurohormonal biomarkers, is able to predict cardiac events in a population of patients with heart failure on up-to-date treatment, we selected 996 consecutive patients with systolic left ventricular dysfunction (ejection fraction <50%, mean age 65 ± 13 years), who underwent a complete clinical and humoral characterization and were then followed up (median 36 months, range 0 to 72) for cardiac death and appropriate implantable cardioverter device shock. We recorded 170 cardiac deaths and 27 shocks.

Increased plasma levels of osteopontin are associated with activation of the renin-aldosterone system and with myocardial and coronary microvascular damage in dilated cardiomyopathy.

In patients with dilated cardiomyopathy (DCM) abnormal myocardial blood flow (MBF) has been associated with coronary microvascular dysfunction. The aim of this study was to test the hypothesis that osteopontin (OPN) plasma levels could be associated with the activation of the renin-aldosterone system (RAS) in these patients and be involved in mediating myocardial and coronary damage. In 66 patients with idiopathic left ventricular dysfunction of variable severity the plasma levels of OPN were correlated with biomarkers of systemic metabolism, RAS activation, myocardial dysfunction and with clinical indexes of left ventricle (LV) function and perfusion obtained by 2D-echocardiography and PET.

Acute effects of triiodothyronine (T3) replacement therapy in patients with chronic heart failure and low-T3 syndrome: a randomized, placebo-controlled study.

Context: Low-T(3) syndrome is a predictor of poor outcome in patients with cardiac dysfunction. The study aimed to assess the short-term effects of synthetic L-T(3) replacement therapy in patients with low-T(3) syndrome and ischemic or nonischemic dilated cardiomyopathy (DC).

Design: A total of 20 clinically stable patients with ischemic (n = 12) or nonischemic (n = 8) DC were enrolled.

Increased levels of C-type natriuretic peptide in patients with idiopathic left ventricular dysfunction.

C-type natriuretic peptide (CNP) is expressed in the vascular endothelium. It is not known whether CNP is specifically increased in patients with idiopathic left ventricular systolic dysfunction (ILVDys) with or without overt heart failure, and whether in these patients it is related with indicators of myocardial and/or endothelial/microvascular impairment. We determined plasma CNP levels in 51 ILVDys and in 60 controls.

Evaluation of the analytical performance of the advanced method for cardiac troponin I for the AxSYM platform: comparison with the old method and the Access system.

Background: The determination of cardiac troponins is routinely used for rule in/out, risk stratification, and follow-up of patients with acute coronary artery syndrome. We evaluated the analytical and clinical performance of the advanced immunoassay for troponin I (cTnI) carried out on an AxSYM platform (Abbott Diagnostic Division) and compared these characteristics to those of the previous version of this assay and to cTnI on the Access 2 immunoassay system (Beckman Coulter, Inc.).

Endogenous ouabain and acute salt loading in low-renin hypertension.

Background: Endogenous ouabain (EO), which is structurally identical to the cardiac glycoside ouabain, has been isolated in human plasma. The substance EO has been implicated in states of volume expansion and in some types of arterial hypertension, especially as a factor of salt sensitivity of blood pressure. On the other hand, salt sensitivity has been described in low-renin hypertension.

Cardiac natriuretic hormones, neuro-hormones, thyroid hormones and cytokines in normal subjects and patients with heart failure.

The derangement of neuro-endocrine control of circulation influences both disease evolution and response to treatment in patients with heart failure, but little data are available about the complex relationships between the degree of neuro-hormonal activation and clinical severity. We studied the relationships between cardiac natriuretic hormones (CNHs) and several neuro-hormones and immunological markers in a prospective cohort of 105 consecutive patients with cardiomyopathy (77 men and 28 women, mean age 66.7+/-12.