Clinical chemistry
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Laboratory tests to assess novel oral anticoagulants (NOACs) are under evaluation. Routine monitoring is unnecessary, but under special circumstances bioactivity assessment becomes crucial. We analyzed the effects of NOACs on coagulation tests and the availability of specific assays at different laboratories. ⋯ The screening tests INR and APTT are suboptimal in assessing NOACs, having high reagent dependence and low sensitivity and specificity. They may provide information, if laboratories recognize their limitations. The variation will likely increase and the sensitivity differ in clinical samples. Specific assays measure NOACs accurately; however, few laboratories applied them.
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Decreased circulating 25-hydroxy-vitamin D (25-OH-vitamin D) concentrations have been associated with mortality rates, but it is unclear whether this association is causal. We performed a Mendelian randomization study and analyzed whether 3 common single-nucleotide polymorphisms (SNPs) associated with 25-OH-vitamin D concentrations are causal for mortality rates. ⋯ Genetic variants associated with 25-OH-vitamin D concentrations do not predict mortality. This suggests that low 25-OH-vitamin D concentrations are associated with, but unlikely to be causal for, higher mortality rates.
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Comparative Study
Comparison and evaluation of cardiac biomarkers in patients with intermittent claudication: results from the CAVASIC study.
Plasma concentrations of the peptides midregional proadrenomedullin (MR-proADM), midregional proatrial natriuretic peptide (MR-proANP), and C-terminal endothelin-1 precursor fragment (CT-proET-1) are increased in various cardiovascular conditions. However, there is limited information about the association and comparative performance of these peptides in peripheral arterial disease (PAD). ⋯ This study in a male cohort of patients with IC and age- and diabetes-matched controls indicates a significant association of high MR-proADM, MR-proANP, and CT-proET-1 concentrations with PAD. MR-proADM and CT-proET-1 provide additive information in comparison to NT-proBNP. Moreover, MR-proADM and CT-proET-1 significantly predict PAD in those patients and controls free from prevalent CVD.
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The new oral anticoagulants (NOAs) dabigatran, rivaroxaban, and apixaban have proved effective and safe when used in clinical trials, without a need to adjust the dose in response to laboratory testing. This demonstrated efficacy does not necessarily mean that the laboratory, considered the mainstay for the management of the old anticoagulants, will no longer play a role in treatment with NOAs. ⋯ Measurements of the effect of NOAs are indicated in several situations: (a) patients with adverse events (i.e., thrombotic/hemorrhagic), particularly those who present with overdosage owing to excessive drug intake or decreased clearance; (b) patients undergoing surgical procedures for ensuring that no residual drug remains in the circulation; (c) patients requiring anticoagulation reversal because of life-threatening hemorrhage; (d) patients with renal insufficiency, who are likely to accumulate the drug in the circulation; (e) patients with liver failure, because NOAs are metabolized by the liver; (f) patients taking other drugs that might increase/decrease the effects of NOAs via drug-drug interactions. The choice of tests is based on such characteristics as availability, linearity of the dose-response curve, standardization, and responsiveness to increasing drug dosage. Practitioners need to be aware that NOAs can interfere with the measurement of common hemostasis parameters.