A pilot study of the effect of rivaroxaban in sickle cell anemia.

INTRODUCTION: The contribution of coagulation activation to the pathogenesis of sickle cell disease (SCD) remains incompletely defined. We evaluated the efficacy and safety of rivaroxaban, an oral direct factor Xa inhibitor, in subjects with sickle cell anemia. MATERIALS AND METHODS: In this pilot, single-center, randomized, double-blind, placebo-controlled, crossover study, eligible subjects with sickle cell anemia received rivaroxaban or placebo. The effect of rivaroxaban on coagulation activation, endothelial activation, inflammation, and microvascular blood flow was evaluated. RESULTS: Fourteen patients (HbSS - 14; females - 9) with mean age of 38 ± 10.6 years were randomized to receive rivaroxaban 20 mg daily or placebo for 4 weeks and, following a 2-week washout phase, were "crossed-over" to the treatment arm opposite to which they were initially assigned. Mean adherence to treatment with rivaroxaban, assessed by pill counts, was 85.6% in the first treatment period and 93.6% in the second period. Treatment with rivaroxaban resulted in a decrease from baseline of thrombin-antithrombin complex versus placebo (-34.4 ug/L [95% CI: -69.4, 0.53] vs. 0.35 ug/L [95% CI: -3.8, 4.5], p = .08), but the difference was not statistically significant. No significant differences were observed in changes from baseline of D-dimer, inflammatory, and endothelial activation markers or measures of microvascular blood flow. Rivaroxaban was well tolerated. CONCLUSIONS: Rivaroxaban was safe but did not significantly decrease coagulation activation, endothelial activation, or inflammation. Rivaroxaban did not improve microvascular blood flow. Adequately powered studies are required to further evaluate the efficacy of rivaroxaban in SCD. Clinicaltrials.gov Identifier: NCT02072668.

Papaverine improves sublingual blood flow in patients with septic shock.

BACKGROUND: In recent years, microcirculatory blood flow alterations have been recognized to be stronger predictors of septic shock treatment outcomes than global hemodynamic variables. METHODS: In our self-controlled, interventional pilot clinical trial study, we investigated the effects of a single papaverine injection on the microcirculation in sepsis patients undergoing fluid resuscitation combined with vasopressor treatments. Fourteen septic shock patients admitted to the Peking University Third Hospital were included in the study, and each patient received 30 mg papaverine, which is the approximate dosage used to treat a conventional arterial spasm. Papaverine was administered as an intravenous bolus injection after systemic hemodynamic stabilization had been achieved by means of fluid resuscitation combined with dopamine and/or norepinephrine vasopressor medication. Baseline characteristics, as well as global hemodynamic and blood gas parameters, before and 60 min after papaverine injection were recorded and sublingual microcirculatory data at baseline and 15, 30, and 60 min after papaverine administration obtained using sidestream dark-field video microscopy. RESULTS: The perfused vessel density of small vessels was significantly increased 30 and 60 min after papaverine administration (P < 0.01), and the proportion of perfused small vessels (PPV), as well as the microvascular flow index, was significantly increased 30 min after papaverine (P < 0.05). There were no visible systemic effects, arrhythmia, or hypotension during the observation period in each patient. CONCLUSIONS: In our pilot study, papaverine transiently improved sublingual microcirculatory blood flow without influencing systemic hemodynamics in patients with septic shock, who required vasoconstrictors to maintain blood pressure during fluid resuscitation.