British journal of haematology
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Randomized Controlled Trial Multicenter Study
Exercise capacity and haemodynamics in patients with sickle cell disease with pulmonary hypertension treated with bosentan: results of the ASSET studies.
Doppler-defined pulmonary hypertension (PH) in sickle cell disease (SCD) is associated with 40% mortality at 40 months. To assess the effect of bosentan in SCD-PH, two randomized, double-blind, placebo-controlled, 16-week studies were initiated. Safety concerns are particularly relevant in SCD due to comorbid conditions. ⋯ Standard-dose bosentan appears to be well tolerated. Further investigation is warranted. Clinicaltrials.gov registration numbers NCT00310830, NCT00313196, NCT00360087.
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The anticoagulant effect of unfractionated heparin (UFH) is monitored using the activated partial thromboplastin time (APTT). An APTT of 1.5-2.5 times the control is usually taken as the therapeutic range and assumed to reflect an anti-activated factor X (anti-Xa) level of 0.35-0.7 u/ml. However, in some cases, despite administration of sufficient heparin to achieve a therapeutic anti-Xa assay level, the APTT remains sub-therapeutic. ⋯ The relationship between heparin level, APTT and anticoagulant effect at different FVIII concentrations was determined using thrombelastography and the thrombin generation assay. Thromboelastographic and thrombin generation parameters concurred with APTT, demonstrating a genuine heparin resistance in the presence of high FVIII levels. This suggests that APTT may be a more accurate measure of anticoagulant effect in vivo than anti-Xa.