Veneuze trombo-embolie : wanneer zijn laboratoriumtesten voor trombofilie zinvol?

Laboratoriumtesten voor trombofilieonderzoek worden vaak door de kliniek aangevraagd na het optreden van veneuze trombo-embolie. Indien afwijkingen worden gevonden leidt dit niet altijd tot klinische consequenties, zoals verlenging van antistollingstherapie. In de eind 2007 vastgestelde CBO-richtlijn ‘diagnostiek, preventie en behandeling van veneuze trombo-embolie en secundaire preventie arteriële trombose’ staan wetenschappelijk onderbouwde richtlijnen beschreven voor situaties waarbij het bepalen van trombofiliefactoren zinvol is en invloed heeft op het klinisch handelen. In dit artikel wordt de consequentie van deze richtlijn voor de laboratoria beschreven. Grofweg komt het erop neer dat voor de meeste patiënten met een eerste of recidief veneuze trombo-embolie het bepalen van trombofiliefactoren anders dan antifosfolipide-antistoffen geen therapeutische consequenties heeft en daarom wordt afgeraden. Slechts in uitzonderlijke gevallen wordt het bepalen van trombofiliefactoren wel overwogen. Daarbij is het van belang dat rekening gehouden wordt met preanalytische factoren die de uitslag van trombofilietesten kunnen beïnvloeden

Clinical characteristics of women captured by extending the definition of severe postpartum haemorrhage with 'refractoriness to treatment': a cohort study

Background: The absence of a uniform and clinically relevant definition of severe postpartum haemorrhage hampers comparative studies and optimization of clinical management. The concept of persistent postpartum haemorrhage, based on refractoriness to initial first-line treatment, was proposed as an alternative to common definitions that are either based on estimations of blood loss or transfused units of packed red blood cells (RBC). We compared characteristics and outcomes of women with severe postpartum haemorrhage captured by these three types of definitions. Methods: In this large retrospective cohort study in 61 hospitals in the Netherlands we included 1391 consecutive women with postpartum haemorrhage who received either ≥4 units of RBC or a multicomponent transfusion. Clinical characteristics and outcomes of women with severe postpartum haemorrhage defined as persistent postpartum haemorrhage were compared to definitions based on estimated blood loss or transfused units of RBC within 24 h following birth. Adverse maternal outcome was a composite of maternal mortality, hysterectomy, arterial embolisation and intensive care unit admission. Results: One thousand two hundred sixty out of 1391 women (90.6%) with postpartum haemorrhage fulfilled the definition of persistent postpartum haemorrhage. The majority, 820/1260 (65.1%), fulfilled this definition within 1 h following birth, compared to 819/1391 (58.7%) applying the definition of ≥1 L blood loss and 37/845 (4.4%) applying the definition of ≥4 units of RBC. The definition persistent postpartum haemorrhage captured 430/471 adverse maternal outcomes (91.3%), compared to 471/471 (100%) for ≥1 L blood loss and 383/471 (81.3%) for ≥4 units of RBC. Persistent postpartum haemorrhage did not capture all adverse outcomes because of missing data on timing of initial, first-line treatment. Conclusion: The definition persistent postpartum haemo

Occurrence forms of key ash-forming elements in defatted microalgal biomass

This study reports occurrence forms of key ash-forming elements in a defatted microalga, and for comparison, its corresponding raw microalga. Freeze-dried powders of a marine microalga (Nannochloropsis oceanica) were sieved to a size fraction of K > P > Mg > Na > Ca. Chemical fractionation results suggest that virtually all of the Na, K, and Cl in the raw and defatted microalgae are water-soluble. While majority of P in the two fuels are water-soluble and acid-soluble, most of Mg and Ca are leached in water and NH4Ac solution. As determined via chemical fractionation analysis, lipid extraction leads to the content of water-soluble Ca in the defatted microalga being ∼69.6% higher than that in the raw microalga counterpart, which is accompanied by a reduction in the amount of Ca leached in NH4Ac solution. Similar trend is also observed for Mg, but to a lesser extent

Supplementary Material for: Empirically Reduced Dosages of Tinzaparin in Patients with Moderate-to-Severe Renal Insufficiency Lead to Inadequate Anti-Xa Levels

<strong><em>Background:</em></strong> Due to the higher molecular weight of tinzaparin, the low molecular weight heparin (LMWH) is less dependent on renal excretion than other LMWH preparations. However, several international guidelines recommend the same preemptive dosage reduction for all therapeutic dose LMWHs prescribed in renal insufficient patients, to ensure that there is no accumulation of anticoagulant activity and increased risk of bleeding. This study is aimed at assessing whether a preemptive dosage reduction of tinzaparin in all renal insufficient patients (comprising 25% reduction in patients with Modification of Diet in Renal Disease - estimated glomerular filtration rate (MDRD-eGFR) 30-60 mL/min/1.73 m² and 50% reduction in patients with MDRD-eGFR <30 mL/min/1.73 m²) leads to adequate anti-Xa levels. <b><i>Methods:</i></b> We selected the anti-Xa levels of in-hospital patients (≥18 years) with moderate-to-severe renal insufficiency (MDRD-eGFR <60 mL/min/1.73 m²), on therapeutic dosages of tinzaparin. Anti-Xa levels were measured using a chromogenic assay. <b><i>Results:</i></b> Preemptive dosage reduction resulted in a median anti-Xa activity of 0.50 IU/mL (interquartile range [IQR] 0.38-0.60). In 92.3% of patients the anti-Xa level was below the target anti-Xa level of >0.85 IU/mL for therapeutic indications. Unadjusted dosages led to a median anti-Xa activity of 0.74 IU/mL (IQR 0.56-0.92). The preemptive dosage reduction was significantly associated with anti-Xa activity below therapeutic range (<i>p</i> = 0.007). No difference in anti-Xa activity was observed between patients with moderate (0.71 IU/mL, IQR 0.61-0.95) versus severe (0.65 IU/mL, IQR 0.41-1.06) renal insufficiency in whom an unadjusted dose had been administered (<i>p</i> = 0.77). None of the anti-Xa levels were above the upper margin of the presumed therapeutic range of 2.0 IU/mL. <b><i>Conclusion:</i></b> In renal insufficient patients, the preemptive dosage reduction of tinzaparin leads to inadequate anti-Xa levels