Riitta Lassila

Anti-Inhibitor Coagulant Complex Prophylaxis in Hemophilia with Inhibitors

BACKGROUND Patients with severe hemophilia A and factor VIII inhibitors are at increased risk for serious bleeding complications and progression to end-stage joint disease. Effective strategies to prevent bleeding in such patients have not yet been established. METHODS We enrolled patients with hemophilia A who were older than 2 years of age, had high-titer inhibitors, and used concentrates known as bypassing agents for bleeding in a prospective, randomized, crossover study comparing 6 months of anti-inhibitor coagulant complex (AICC), infused prophylactically at a target dose of 85 U per kilogram of body weight (±15%) on 3 nonconsecutive days per week, with 6 months of on-demand therapy (AICC at a target dose of 85 U per kilogram [±15%] used for bleeding episodes). The two treatment periods were separated by a 3-month washout period, during which patients received on-demand therapy for bleeding. The primary outcome was the number of bleeding episodes during each 6-month treatment period. RESULTS Thirty-four patients underwent randomization; 26 patients completed both treatment periods and could be evaluated per protocol for the efficacy analysis. As compared with on-demand therapy, prophylaxis was associated with a 62% reduction in all bleeding episodes (P<0.001), a 61% reduction in hemarthroses (P<0.001), and a 72% reduction in target-joint bleeding (≥3 hemarthroses in a single joint during a 6-month treatment period) (P<0.001). Thirty-three randomly assigned patients received at least one infusion of the study drug and were evaluated for safety. One patient had an allergic reaction to the study drug. CONCLUSIONS AICC prophylaxis at the dosage evaluated significantly and safely decreased the frequency of joint and other bleeding events in patients with severe hemophilia A and factor VIII inhibitors. (Funded by Baxter BioScience; Pro-FEIBA ClinicalTrials.gov number, NCT00221195.).

Association of Chronic Stress With Plasminogen Activator Inhibitor–1 in Healthy Middle-aged Men

The effect of chronic stress on tissue-type plasminogen activator (TPA) and plasminogen activator inhibitor-1 (PAI-1) antigens was studied in 69 healthy middle-aged men. Chronic stress, defined as feelings of fatigue, lack of energy, increased irritability, and demoralization, was positively associated with plasma concentrations of PAI-1 antigen but was unrelated to TPA. The association remained unaltered after controlling for age, smoking, alcohol consumption, and physical activity but became nonsignificant after further controlling for abdominal obesity, BMI, and serum insulin and triglyceride levels. This attenuated association implies that the relationship between vital exhaustion and PAI-1 may be secondary to the effects of the metabolic variables. Thus, the present study shows that long-term stress affects the fibrinolytic system and suggests that obesity and insulin and triglyceride concentrations, which are closely correlated with the fibrinolytic parameters, may mediate the association. These findings are consistent with the hypothesis that chronic stress causes increased synthesis of PAI-1, thus promoting the risk for atherothrombotic disease by decreasing the likelihood of spontaneous fibrinolysis and increasing the likelihood of fibrin deposition.

Studies of Adhesion-Dependent Platelet Activation Distinct Roles for Different Participating Receptors Can Be Dissociated by Proteolysis of Collagen

The molecular differences between native-type collagen type I fibrils (NC) and their pepsinated monomers (PC) were used to uncover receptors involved in platelet-collagen interaction along the adhesion-activation axis. The platelet-depositing capacity of NC and PC under blood flow and their adhesive properties and respective morphologies, aggregation, procoagulant capacity, and tyrosine phosphorylation were compared under different cationic milieus, including or excluding the glycoprotein (GP) Ia/IIa. NC was consistently a more preferable and activating substrate than PC during flow (5 minutes) and in platelet aggregation. In PPACK-treated blood, both NC (3.3-fold) and PC (2.7-fold) increased platelet attachment on elevation of the shear rate from 500 to 1640 s(-1), whereas in citrated blood, adhesion and thrombus growth on PC were negligible under the high shear rate, unlike on NC (1.9-fold increase). The complete lack of platelet deposition on PC in citrated blood could be overcome by restoring physiological Mg(2+) concentration, and in contrast to NC, platelets interacting with PC were highly dependent on Mg(2+) during adhesion, aggregation, and procoagulant response. Monoclonal antibody (mAb 131.7) against GP IV inhibited platelet deposition to NC in citrated blood (2 minutes) by 49%, which was not further increased by coincubation with mAb against GP Ia (6F1). These results stress the importance of GP Ia/IIa in shear-resistant platelet deposition on collagen monomers. In native fibers, however, the preserved quaternary structure with telopeptides activates additional platelet receptors capable of substituting GP Ia/IIa and GP IV.

Increased coagulation factor VIII, IX, XI and XII activities in non-alcoholic fatty liver disease

Background and aims: Obesity and the metabolic syndrome are established risk factors of venous thromboembolism. As most coagulation factors are produced exclusively by the liver and non‐alcoholic fatty liver disease (NAFLD) is tightly related to metabolic disorders, we aimed at studying the association of liver fat with various coagulation factor activities.

Association of spontaneous and procedure-related bleeds with short- and long-term mortality after acute coronary syndromes: an analysis from the PLATO trial

AIMS We sought to describe the differential effect of bleeding events in acute coronary syndromes (ACS) on short- and long-term mortality according to their type and severity. METHODS AND RESULTS The PLATO trial randomised 18,624 ACS patients to clopidogrel or ticagrelor. Post-randomisation bleeding events were captured according to bleeding type (spontaneous or procedure-related), with PLATO, TIMI, and GUSTO definitions. The association of bleeding events with subsequent short-term (<30 days) and long-term (>30 days) all-cause mortality was assessed using time-dependent Cox proportional hazard models. A model was fitted to compare major and minor bleeding for mortality prediction. Of 18,624 patients, 2,189 (11.8%) had at least one PLATO major bleed (mean follow-up 272.2±123.5 days). Major bleeding was associated with higher short-term mortality (adjusted hazard ratio [HR] 9.28; 95% confidence interval [CI]: 7.50-11.48) but not with long-term mortality (adjusted HR 1.28; 95% CI: 0.93-1.75). Spontaneous bleeding was associated with short-term (adjusted HR 14.59; 95% CI: 11.14-19.11) and long-term (adjusted HR 3.38; 95% CI: 2.26-5.05) mortality. Procedure-related bleeding was associated with short-term mortality (adjusted HR 5.29; 95% CI: 4.06-6.87): CABG-related and non-coronary-procedure-related bleeding were associated with a higher short-term mortality, whereas PCI or angiography-related bleeding was not associated with either short- or long-term mortality. Similar results were obtained using the GUSTO and TIMI bleeding definitions. CONCLUSIONS Major bleeding is associated with high subsequent mortality in ACS. However, this association is much stronger in the first 30 days and is strongest for spontaneous (vs. procedure-related) bleeding.

FEIBA prophylaxis in haemophilia patients: a clinical update and treatment recommendations

Summary.  In patients with severe haemophilia and inhibitors, regular factor VIII inhibitor bypassing activity (FEIBA) prophylaxis has been shown to reduce the frequency of bleeding by up to 85% and to improve patient quality of life. FEIBA is well tolerated; the incidence of thrombotic events and of allergic reactions is extremely low. The concept of prophylaxis in haemophilia patients with inhibitors is relatively new and some clinicians may be unsure of how to use FEIBA in this context. These treatment recommendations, based on published evidence plus the collective experience of a group of haematologists (with practical knowledge of managing inhibitor patients with FEIBA prophylaxis), are intended to provide guidance to clinicians considering initiating and maintaining patients on FEIBA prophylaxis with specific focus on practical aspects of patient selection, dosing, monitoring and stop criteria.

Early thrombin generation and impaired fibrinolysis after SCT associate with acute GVHD

The evolution of coagulation and fibrinolysis has not been thoroughly evaluated in allogeneic SCT. In this pilot study, we characterized the adaptive mechanisms of coagulation and fibrinolysis during allogeneic SCT and 3-month follow-up and studied possible associations with outcome, including acute GVHD. Thirty patients underwent SCT for a haematological malignancy after myeloablative conditioning. Nineteen patients received the transplant from an HLA-identical sibling and 11 from an unrelated donor. GVHD prophylaxis consisted of CYA and MTX, with methylprednisolone in sibling transplants. Serial coagulation and fibrinolytic activity markers were assessed, including prothrombin fragments 1+2 (F1+2), thrombin time, D-dimer, tissue-type plasminogen-activator (tPA) and plasminogen-activator inhibitor (PAI-1). Early during conditioning therapy, F1+2 and D-dimer increased threefold indicating thrombin generation and fibrin turnover. TPA activity peaked before engraftment, concurring with diminished PAI-1. At 10 days after transplantation shortened thrombin time (<15 s), F1+2 exceeding 0.7 nmol/L and PAI-1 3.0 IU/mL were associated with the development of GVHD. In conclusion, early maladaptation, that is, upregulated thrombin generation and inhibition of fibrinolysis, occurred in one-third of the SCT patients associating with the development of GVHD, a finding suggesting an interplay between coagulation and immunology during SCT.

Inhibitor development in non-severe haemophilia across Europe

Evidence about inhibitor formation in non-severe haemophilia and the potential role for clotting factor concentrate type is scant. It was the aim of this study to report inhibitor development in non-severe haemophilia patients enrolled in the European Haemophilia Safety Surveillance (EUHASS) study. Inhibitors are reported quarterly and total treated patients annually. Incidence rates and 95% confidence intervals (95% CI) were calculated according to diagnosis and concentrate used. Between 1-10-2008 and 31-12-2012, 68 centres reported on 7,969 patients with non-severe haemophilia A and 1,863 patients with non-severe haemophilia B. For haemophilia A, 37 inhibitors occurred in 8,622 treatment years, resulting in an inhibitor rate of 0.43/100 treatment years (95% CI 0.30-0.59). Inhibitors occurred at a median age of 35 years, after a median of 38 exposure days (EDs; P25-P75: 20-80); with 72% occurring within the first 50 EDs. In haemophilia B, one inhibitor was detected in 2,149 treatment years, resulting in an inhibitor rate of 0.05/100 years (95% CI 0.001-0.26). This inhibitor developed at the age of six years, after six EDs. The rate of inhibitors appeared similar across recombinant and plasma derived factor VIII (FVIII) concentrates. Rates for individual concentrates could not be calculated at this stage due to low number of events. In conclusion, inhibitors in non-severe haemophilia occur three times more frequently than in previously treated patients with severe haemophilia at a rate of 0.43/100 patient years (haemophilia A) and 0.05/100 years (haemophilia B). Although the majority of inhibitors developed in the first 50 EDs, inhibitor development continued with increasing exposure to FVIII.

Platelet Function Tests in Bleeding Disorders

Functional disorders of platelets can involve any aspect of platelet physiology, with many different effects or outcomes. These include platelet numbers (thrombocytosis or thrombocytopenia); changes in platelet production or destruction, or capture to the liver (Ashwell receptor); altered adhesion to vascular injury sites and/or influence on hemostasis and wound healing; and altered activation or receptor functions, shape change, spreading and release reactions, procoagulant and antifibrinolytic activity. Procoagulant membrane alterations, and generation of thrombin and fibrin, also affect platelet aggregation. The above parameters can all be studied, but standardization and quality control of assay methods have been limited despite several efforts. Only after a comprehensive clinical bleeding assessment, including family history, information on drug use affecting platelets, and exclusion of coagulation factor, and tissue deficits, should platelet function testing be undertaken to confirm an abnormality. Current diagnostic tools include blood cell counts, platelet characteristics according to the cell counter parameters, peripheral blood smear, exclusion of pseudothrombocytopenia, whole blood aggregometry (WBA) or light transmission aggregometry (LTA) in platelet-rich plasma, luminescence, platelet function analysis (PFA-100) for platelet adhesion and deposition to collagen cartridges under blood flow, and finally transmission electron microscopy to exclude rare structural defects leading to functional deficits. The most validated test panels are included in WBA, LTA, and PFA. Because platelets are isolated from their natural environment, many simplifications occur, as circulating blood and interaction with vascular wall are omitted in these assays. The target to reach a highly specific platelet disorder diagnosis in routine clinical management can be exhaustive, unless needed for genetic counseling. The elective overall assessment of platelet function disorder primarily aims at better management of hemostasis in case of emergency surgery or other interventions and acute bleeding events.

Quality of warfarin therapy and risk of stroke, bleeding, and mortality among patients with atrial fibrillation: results from the nationwide FinWAF Registry

The most important management strategy in atrial fibrillation (AF) patients is preventing stroke with oral anticoagulants. Warfarin is still used as a first‐line anticoagulant, although non‐vitamin K antagonist oral anticoagulants are currently recommended to manage AF. Using a large, unselected national sample of AF patients, we evaluated the relationships between quality of warfarin therapy and the risks of thromboembolism, bleeding complications, and mortality.