[Show abstract][Hide abstract] ABSTRACT: It is unclear whether anticoagulation guidelines intended for the general population are applicable to patients with polycythemia vera (PV) and essential thrombocythemia (ET). In the present study, the risk of thrombotic recurrence was analyzed in 150 patients with PV and ET treated with vitamin K antagonists (VKA) because of an arterial or venous thrombosis. After an observation period of 963 patient-years, the incidence of re-thrombosis was 4.5 and 12 per 100 patient-years under VKA therapy and after stopping it, respectively (P < 0.0005). After a multivariate adjustment for other prognostic factors, VKA treatment was associated with a 2.8-fold reduction in the risk of thrombotic recurrence. Notably, VKA therapy offset the increased risk of re-thrombosis associated with a prior history of remote thrombosis. Both the protective effect of VKA therapy and the predisposing factors for recurrence were independent of the anatomical site involved in the index thrombosis. Treatment periods with VKA did not result in a higher incidence of major bleeding as compared with those without VKA. These findings support the use of long-term anticoagulation for the secondary prevention of thrombosis in patients with PV and ET, particularly in those with history of remote thrombosis.
Annals of Hematology 02/2015; · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:Despite the good safety of rivaroxaban, there is limited information on strategies for urgent reversal of its antihemostatic effects.Methods and Results:Alterations of hemostasis induced by rivaroxaban (230 ng/ml) were assessed by using several tests applied to steady and circulating human blood. Effects on thrombin generation (TG) and thromboelastometry (TEM) parameters were measured. Modifications in platelet adhesive, aggregating and procoagulant activities were evaluated in studies with circulating blood. The potential reversal of prothrombin complex concentrates (PCCs; 50 IU/kg), activated PCCs (aPCCs; 75 IU/kg), or recombinant factor VIIa (rFVIIa; 270 μg/kg) was evaluated. Impairment of TG parameters induced by rivaroxaban were corrected by the different concentrates (aPCC≥PCC>rFVIIa). Prolonged clotting times and reduced clot firmness caused by rivaroxaban on TEM tests were improved by different concentrates (rFVIIa≥aPCC>PCC). Rivaroxaban significantly reduced platelets and fibrin interactions with damaged vascular surfaces in perfusion studies. While alterations of platelet interactions were favourably counteracted by rFVIIa or aPCCs, reductions in fibrin formation were only partially restored by the different factor concentrates (rFVIIa>aPCC≥PCC).Conclusions:Rivaroxaban-induced alterations on coagulation parameters measured through assays performed under static conditions were easily reversed by the different concentrates. Studies under flow conditions revealed that these concentrates normalized the action of rivaroxaban on platelets, and significantly improved fibrin formation; although in the later case, levels were not restored to the pre-treatment value.
[Show abstract][Hide abstract] ABSTRACT: Introduction: Thromboembolic diseases will become the most important contributors to mortality and morbidity for modern societies. Current antithrombotic strategies using heparins or vitamin K antagonists are inconvenient, with limitations and inherent side effects. A series of new oral anticoagulants with powerful and reliable antithrombotic actions have been developed in the last decade. Areas covered: Edoxaban is a direct and specific inhibitor of activated factor X, delivered orally. This article reviews literature from PubMed and articles referenced within. The text explores the pharmacological aspects of its antithrombotic action. Pharmacokinetics, metabolism and drug interactions are examined. The review places the results of recent clinical trials that have evaluated the antithrombotic potential of edoxaban versus standard antithrombotic therapies in the prophylaxis and treatment of venous thromboembolism into perspective. The possible relationship between the pharmacokinetic profile of edoxaban and the favorable results in clinical trials is discussed. Expert opinion: Edoxaban is perceived as a major advance, compared to vitamin K antagonists, in the prevention and treatment of thromboembolic disease given its favorable efficacy, safety, pharmacokinetic profile and renal clearance. The results of ongoing large international trials exploring the prevention of thrombotic complications in patients in different clinical settings should ensure the approval of edoxaban to treat new indications.
Expert Opinion on Drug Metabolism & Toxicology 01/2014; · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Apixaban is a new oral anticoagulant with a specific inhibitory action on FXa. No information is available on the reversal of the antihemostatic action of apixaban in experimental or clinical settings. We have evaluated the effectiveness of different factor concentrates at reversing modifications of hemostatic mechanisms induced by moderately elevated concentrations of apixaban (200 ng/ml) added in vitro to blood from healthy donors (n = 10). Effects on thrombin generation (TG) and thromboelastometry (TEM) parameters were assessed. Modifications in platelet adhesive, aggregating and procoagulant activities were evaluated in studies with blood circulating through damaged vascular surfaces, at a shear rate of 600 s(-1). The potential of prothrombin complex concentrates (PCCs; 50 IU/kg), activated prothrombin complex concentrates (aPCCs; 75 IU/kg), or activated recombinant factor VII (rFVIIa; 270 μg/kg), at reversing the antihemostatic actions of apixaban, were investigated. Apixaban interfered with TG kinetics. Delayed lag phase, prolonged time to peak and reduced peak values, were improved by the different concentrates, though modifications in TG patterns were diversely affected depending on the activating reagents. Apixaban significantly prolonged clotting times (CTs) in TEM studies. Prolongations in CTs were corrected by the different concentrates with variable efficacies (rFVIIa≥aPCC>PCC). Apixaban significantly reduced fibrin and platelet interactions with damaged vascular surfaces in perfusion studies (p<0.05 and p<0.01, respectively). Impairments in fibrin formation were normalized by the different concentrates. Only rFVIIa significantly restored levels of platelet deposition. Alterations in hemostasis induced by apixaban were variably compensated by the different factor concentrates investigated. However, effects of these concentrates were not homogeneous in all the tests, with PCCs showing more efficacy in TG, and rFVIIa being more effective on TEM and perfusion studies. Our results indicate that rFVIIa, PCCs and aPCCs have the potential to restore platelet and fibrin components of the hemostasis previously altered by apixaban.
PLoS ONE 11/2013; 8(11):e78696. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Conventional anticoagulant therapies can significantly reduce the risk of stroke and related complications in patients with atrial fibrillation (AF). Classic oral anticoagulants based on vitamin K antagonism have shown effectiveness in the prevention of thromboembolic complications in this clinical setting. Unfortunately, vitamin K antagonists that have shown effectiveness in the prevention of thromboembolic complications in patients with nonvalvular AF hold inherent limitations including delayed onset of action, narrow therapeutic index, variability of their response, need for repeated control and numerous interactions with food and other drugs. Since the frequency of stroke related to AF increases with age, guidelines from different scientific societies advise that the risk of bleeding for a patient should be quantified before exposure to anticoagulation and balanced against the risk of stroke with and without anticoagulation. A consequence of assessing this risk/benefit balance is that not all patients with AF at thromboembolic risk receive adequate anticoagulant treatment. Apixaban is a new oral anticoagulant with a direct, specific and reversible inhibitory action on coagulation factor Xa and with demonstrated safety and efficacy in the prophylaxis and treatment of venous thromboembolism in several clinical studies involving thousands of patients subjected to major orthopedic surgery. Results of two large phase III trials have demonstrated the efficacy and safety of apixaban compared with aspirin or warfarin, in the prevention of stroke in patients with AF. Apixaban demonstrated superiority over classic vitamin K antagonists on the previously specified outcomes of stroke, systemic embolism, major bleeding and death. For those patients unsuitable for treatment with vitamin K antagonists because of an excessive bleeding risk, apixaban showed more efficacy than aspirin in stroke prevention with a not statistically significant modest increase of major bleeding.
[Show abstract][Hide abstract] ABSTRACT: The effectiveness of low-dose aspirin in the primary prevention of thrombosis in patients with high-risk essential thrombocythaemia (ET) treated with cytoreductive drugs is not well established. The risk-benefit balance of low-dose aspirin plus cytoreductive therapy compared with cytoreduction alone was retrospectively analysed in 247 patients with high-risk ET without prior thrombosis. Follow-up was 763 and 685 person-years for cytoreduction plus low-dose aspirin and cytoreduction alone, respectively. The rate of thrombosis was not significantly reduced in patients on cytoreduction plus aspirin (14·4 events per 1000 person-years) when compared with those on cytoreduction alone (24·8 events per 1000 person-years; P = 0·2). However, in the subgroup of patients older than 60 years, the addition of low-dose aspirin was associated with a significantly lower rate of thrombosis (8·6 vs. 29·2 thrombosis per 1000 person-years for combined treatment and cytoreduction alone, respectively, P = 0·02). The rate of major bleeding was significantly higher with combined therapy than with cytoreduction alone both in the whole series (14·4 vs. 1·4 haemorrhagic events per 1000 person-years, respectively, P = 0·006) and in the subgroup of patients older than 60 years. In conclusion, low-dose aspirin benefits high-risk ET patients older than 60 years receiving cytoreductive therapy as primary prophylaxis of thrombosis.
British Journal of Haematology 04/2013; · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study investigates whether the response criteria proposed by the European LeukemiaNet (ELN) to evaluate cytoreductive therapies in essential thrombocythemia (ET) correlate with clinically relevant outcomes in patients receiving anagrelide. We evaluated 154 ET patients treated with anagrelide (upfront in 87) for a median of 2.9 years. Complete response (CR), partial response, and no response were observed in 56, 30.5, and 13.5 % patients, respectively. Only 38 patients (25 %) achieved a sustained CR. Overall, the aggregated time on CR and without CR was 200.1 and 333.6 person-years, respectively. The incidence rate of thrombosis and hemorrhage was independent of the CR status. The only factor associated with shorter survival after anagrelide start was the patient's age, whereas achieving a CR with anagrelide had no predictive value for subsequent survival. In conclusion, CR according to the ELN definition is not associated with any measurable clinical benefit in ET patients treated with anagrelide.
Annals of Hematology 01/2013; · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Criteria of response and definition of resistance and intolerance to hydroxyurea (HU) in polycythemia vera (PV) were proposed by the European LeukemiaNet (ELN). Such criteria were evaluated in 261 PV patients (median follow-up, 7.2 years) treated with HU for a median of 4.4 years. Complete response, partial response, and no response were observed in 24%, 66%, and 10% of patients, respectively. Achieving ELN response (complete or partial) or hematocrit response did not result in better survival or less thrombosis and bleeding. On the contrary, having no response in leukocyte count was associated with higher risk of death (HR, 2.7; 95% confidence interval [CI], 1.3%-5.4%; P = .007), whereas lack of response in platelet count involved a higher risk of thrombosis and bleeding. Resistance and intolerance to HU was registered in 11% and 13% of patients, respectively. Resistance to HU was associated with higher risk of death (HR, 5.6; 95% CI, 2.7%-11.9%; P < .001) and transformation (HR, 6.8; 95% CI, 3.0%-15.4%; P < .001). In summary, fulfilling the ELN definition for response to HU was not associated with a benefit in the clinical outcome in PV, whereas response in platelet and white blood cell counts were predictive of less thrombohemorrhagic complications and better prognosis, respectively. Resistance to HU was an adverse prognostic factor.
[Show abstract][Hide abstract] ABSTRACT: Neutrophil and platelet activation are consistently found in essential thrombocythemia (ET), but the techniques employed to demonstrate such abnormalities are complex. To ascertain whether the ADVIA 120 analyzer can be employed to assess neutrophil and platelet activation status in ET, 55 such patients and the same number of matched healthy individuals were studied and the results correlated with neutrophil CD11b and platelet P-selectin expressions measured by flow cytometry. Compared with controls, ET patients had significantly higher values of neutrophil myeloperoxidase index (MPXI), mean platelet volume (MPV), platelet distribution width (PDW), and platelet component distribution width, and significantly lower values of neutrophil lobularity index and mean platelet component (MPC). Patients with the JAK2 mutation had significantly lower values of MPC and higher values of MPV and PDW than those with wild-type allele. A positive correlation was observed between MPXI and neutrophil CD11b expression and a negative correlation between MPC and platelet P-selectin expression. The intensity of the agreement between the variables obtained by the two methods was moderate. These results support the possible value of MPC as surrogate parameter of platelet activation in ET.
[Show abstract][Hide abstract] ABSTRACT: Hydroxyurea (HU) is frequently given as treatment for myelofibrosis (MF), but data on its efficacy and tolerability are scarce. The results of HU therapy were evaluated in 40 patients with hyperproliferative manifestations of primary (n = 32), post-polycythemia vera (n = 6), or post-essential thrombocythemia (n = 2) myelofibrosis. Median interval between diagnosis and HU start was 6.2 months (range 0-141.7). Reasons for treatment were constitutional symptoms (55%), symptomatic splenomegaly (45%), thrombocytosis (40%), leukocytosis (28%), pruritus (10%), and bone pain (8%). The starting dose was 500 mg/day, subsequently adjusted to the individual efficacy and tolerability. Response was bone pain 100%, constitutional symptoms 82%, pruritus 50%, splenomegaly 40%, and anemia 12.5%. According to the International Working Group for Myelofibrosis Research and Treatment criteria, clinical improvement was achieved in 16 patients (40%). Median duration of response was 13.2 months (range 3-126.2). Worsening of the anemia or appearance of pancytopenia were observed in 18 patients, requiring administration of erythropoietin-stimulating agents (n = 17) and/or danazol (n = 9). Oral or leg ulcers appeared in five patients and one had gastrointestinal symptoms. HU is an effective and generally well-tolerated therapy for the hyperproliferative manifestations of MF. The accentuation of the anemia often induced by HU is usually manageable with concomitant treatment.
Annals of Hematology 12/2010; 89(12):1233-7. · 2.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effectiveness of antiplatelet therapy as primary prophylaxis for thrombosis in low-risk essential thrombocythemia (ET) is not proven. In this study, the incidence rates of arterial and venous thrombosis were retrospectively analyzed in 300 low-risk patients with ET treated with antiplatelet drugs as monotherapy (n = 198) or followed with careful observation (n = 102). Follow-up was 802 and 848 person-years for antiplatelet therapy and observation, respectively. Rates of thrombotic events were 21.2 and 17.7 per 1000 person-years for antiplatelet therapy and observation, respectively (P = .6). JAK2 V617F-positive patients not receiving antiplatelet medication showed an increased risk of venous thrombosis (incidence rate ratio [IRR]: 4.0; 95% CI: 1.2-12.9; P = .02). Patients with cardiovascular risk factors had increased rates of arterial thrombosis while on observation (IRR: 2.5; 95% CI: 1.02-6.1; P = .047). An increased risk of major bleeding was observed in patients with platelet count greater than 1000 x 10(9)/L under antiplatelet therapy (IRR: 5.4; 95% CI: 1.7-17.2; P = .004). In conclusion, antiplatelet therapy reduces the incidence of venous thrombosis in patients with JAK2-positive ET and the rate of arterial thrombosis in patients with associated cardiovascular risk factors. In the remaining low-risk patients, this therapy is not effective as primary prophylaxis of thrombosis, and observation may be an adequate option.
[Show abstract][Hide abstract] ABSTRACT: To describe the outcome of pregnancy in women with inherited antithrombin (AT) deficiency.
A descriptive retrospective study was performed. Medical records were reviewed in order to collect data about maternal thrombotic complications and pregnancy outcomes. All women with known inherited AT deficiency and at least one pregnancy looked after at the Vall d'Hebron University Hospital were included. Relatives with known AT deficiency but no pregnancies looked after in our institution were excluded. Eighteen pregnancies were registered among nine AT-deficient women during 1991-2005. This cohort included women without antithrombotic treatment because AT deficiency was not known at the time of their pregnancies.
In 12 pregnancies (66.7%) anticoagulant therapy with low-molecular weight heparin was given, while not in the other six (33.3%) because AT deficiency was not known at this time. Three episodes of venous thromboembolism were recorded (16.7%). Among all pregnancies 10 suffered an adverse outcome (55.6%), including miscarriage (11.1%), stillbirth (11.1%), intrauterine growth restriction (33.3%), placental abruption (6.7%), preeclampsia (6.7%) and intrapartum fetal distress (23.1%). No relation between AT activity and pregnancy complications was found. A lower incidence of pregnancy complications was observed among women with antithrombotic treatment.
Inherited antithrombin deficiency is associated with a high risk of venous thromboembolism during pregnancy and the puerperium. We also observed a high incidence of poor pregnancy outcome among AT-deficient women.
European journal of obstetrics, gynecology, and reproductive biology 03/2010; 149(1):47-51. · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Patients with essential thrombocythemia (ET) have an increased frequency of thrombosis, but the relationship of both thrombosis and JAK2 V617F allele burden with platelet turnover, acquired activated protein C resistance (aAPCR), and levels of coagulation factors and soluble markers of platelet, and endothelial activation is not well known. In 53 ET patients (26 with a history of thrombosis), reticulated platelets (RP) percentage, aAPCR, platelet tissue factor (TF) expression, and plasma levels of TF, coagulation factors, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D-dimer and prothrombin fragment 1 + 2 were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 mutational load. ET patients with thrombosis had significantly higher values for RP percentage, aAPCR, and levels of factors V and VIII, VWF:Ag, sP-selectin, and sCD40L than patients without thrombosis and controls. At multivariate study, RP percentage, factor V levels, and aAPCR were independently associated with an increased risk of thrombosis. Patients with JAK2 mutation had significantly lower levels of free protein S (PS) and higher levels of TF, sP-selectin, sCD40L, VWF:Ag, and sTM than those with wild-type allele. A mutant allele dosage effect (>or= 12%) was observed for TF, sP-selectin, sCD40L, VWF:Ag, and PS levels. These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation.
American Journal of Hematology 11/2008; 84(2):102-8. · 3.48 Impact Factor