Supratherapeutic dabigatran: a cause of life-threatening haemorrhage.

In this case report, we present a rare case of life-threatening gastrointestinal haemorrhage associated with deranged coagulation due to supratherapeutic levels of dabigatran. Dabigatran is a potent, synthetic, reversible non-peptide thrombin inhibitor which is increasingly used for stroke prevention in patients with non-valvular atrial fibrillation. It is generally accepted that dabigatran dosing does not require titration or the monitoring of plasma levels due to its predictable pharmacokinetics and pharmacodynamics. However, this case report challenges this viewpoint while identifying an important knowledge gap in relation to the effect of altered gastrointestinal motility on the absorption of direct oral anticoagulants. Furthermore, it demonstrates the successful use of high-dose idarucizumab in a critical care setting. Idarucizumab is a monoclonal antibody fragment that binds specifically to dabigatran and its metabolites, thereby reversing the anticoagulant effect.

Vaccine-induced thrombosis and thrombocytopenia (VITT) in Ireland: A review of cases and current practices.

Since the beginning of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2) virus pandemic, several highly effective and safe vaccines have been produced at remarkable speed. Following global implementation of vaccination programmes, cases of thrombosis with thrombocytopenia following administration of adenoviral vector-based vaccines started being reported. In this review we discuss the known pathogenesis and epidemiology of so-called vaccine induced thrombocytopenia and thrombosis (VITT). We consider the available guidelines, diagnostic laboratory tests and management options for these patients. Finally, we discuss important unanswered questions and areas for future research in this novel pathoclinical entity.

Dual endothelin-1 receptor antagonism attenuates platelet-mediated derangements of blood coagulation in Eisenmenger syndrome.

Essentials Eisenmenger syndrome is characterised by thrombotic and hemorrhagic risks of unclear aetiology. Calibrated automated thrombography was used to assess these coagulation derangements. Platelet activity supported abnormalities in procoagulant and anticoagulant pathway function. Endothelin-1 antagonism appeared to ameliorate these derangements. SUMMARY: Aims The mechanisms underlying the competing thrombotic and hemorrhagic risks in Eisenmenger syndrome are poorly understood. We aimed to characterize derangements of blood coagulation and to assess the effect of dual endothelin-1 receptor antagonism in modulating hemostasis in this rare disorder. Methods In a 10-month recruitment period at a tertiary cardiology referral center, during which time there were over 14 000 outpatient consultations, consecutive subjects with Eisenmenger syndrome being considered for macitentan therapy (n = 9) and healthy volunteers (n = 9) were recruited. Plasma thrombin generation in platelet-rich and platelet-poor plasma was assessed by calibrated automated thrombography prior to and following therapy. Results Median peak plasma thrombin generation was higher in platelet-rich plasma obtained from Eisenmenger syndrome subjects relative to controls (median peak thrombin [25th-75th percentile]: 228.3 [206.5-258.6] nm vs. 169.9 [164.3-215.8] nm), suggesting a critical mechanistic role for platelets in supporting abnormal hypercoagulability in Eisenmenger syndrome. Abnormal enhanced sensitivity to the anticoagulant activity of activated protein C was also observed in platelet-rich plasma in Eisenmenger syndrome, suggesting that derangements of platelet activity may influence the activity of anticoagulant pathways in a manner that might promote bleeding in this disease state. Following 6 months of macitentan therapy, attenuations in the derangements in both procoagulant and anticoagulant pathways were observed. Conclusions Abnormal platelet activity contributes to derangements in procoagulant and anticoagulant pathways in Eisenmenger syndrome. Therapies targeting the underlying vascular pathology appear to ameliorate these derangements and may represent a novel strategy for the management of the competing prothrombotic and hemorrhagic tendencies in this disorder.

Preferences of Jehovah's Witnesses regarding haematological supports in an obstetric setting: experience of a single university teaching hospital.

BACKGROUND: Jehovah's Witnesses have been shown to be at increased risk of mortality and morbidity as a consequence of obstetric haemorrhage and refusal of blood products. Since 2004, however, Jehovah's Witnesses have been allowed to accept minor fractions of blood at their own discretion. We sought to determine the preferences of pregnant Jehovah's Witnesses regarding haematological supports since this policy change. METHODS: This is a retrospective observational study of consecutive Jehovah's Witnesses attending a university-affiliated tertiary referral centre between 1 January 2007 and 31 December 2013. The main outcome measure was the proportion of women who would be willing to accept blood products and other haematological supports in the event of life-threatening bleeding, should it occur. RESULTS: Seventy-six Jehovah's Witnesses attended for obstetric care during the study period. Major fractions of blood (red cells, plasma or platelets) were acceptable to 7.9% and 50% would accept some minor fractions. Some blood components were acceptable to 70.3% of nulliparous women compared to 48.9% of multiparous women. In women with advance directives some blood components were acceptable to 70.5% compared with 37.5% of those without. Recombinant factor VIIa was acceptable to 53.9%. Black African women had the lowest acceptance of any ethnic group of any blood products. CONCLUSION: The spectrum of acceptance of blood products is wide ranging within our obstetric Jehovah's Witnesses population. Recombinant factors are not universally acceptable despite their identification as non-blood products. A multidisciplinary approach with individualized consent is recommended.

Coagulation indices in very preterm infants from cord blood and postnatal samples.

BACKGROUND: Very premature infants are at high risk of bleeding complications; however, few data exist on ranges for standard coagulation tests. OBJECTIVES: The primary objective of this study was to measure standard plasma coagulation tests and thrombin generation in very premature infants compared with term infants. The secondary objective was to evaluate whether an association existed between coagulation indices and intraventricular hemorrhage (IVH). PATIENTS/METHODS: Cord and peripheral blood of neonates < 30 weeks gestational age (GA) was drawn at birth, on days 1 and 3 and fortnightly until 30 weeks corrected gestational age. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and coagulation factor levels were measured and tissue factor-stimulated thrombin generation was characterized. Control plasma was obtained from cord blood of term neonates. RESULTS: One hundred and sixteen infants were recruited. Median (range) GA was 27.7 (23.7-29.9) weeks and mean (SD) birth weight was 1020 (255) g. Median (5th-95th percentile) day 1 PT, APTT and fibrinogen were 17.5 (12.7-26.6) s, 78.7 (48.7-134.3) s and 1.4 (0.72-3.8) g L(-1) , respectively. No difference in endogenous thrombin potential between preterm and term plasma was observed, where samples were available. Levels of coagulation factors II, VII, IX and X, protein C, protein S and antithrombin were reduced in preterm compared with term plasma. Day 1 APTT and PT were not associated with IVH. CONCLUSION: In the largest cross-sectional study to date of very preterm infants, typical ranges for standard coagulation tests were determined. Despite long clotting times, thrombin generation was observed to be similar in very preterm and term infants.

Incidence and significance of the JAK2 V617F mutation in patients with chronic myeloproliferative disorders.

BACKGROUND: The chronic myeloproliferative disorders (MPD) are clonal haemopoietic stem cell disorders. AIMS: The incidence of JAK2 V617F mutation was sought in a population of patients with MPD. METHODS: The JAK2 V617 mutation status was determined in 79 patients with known MPD and 59 patients with features suggestive of MPD. RESULTS: The mutation was found in patients with polycythaemia vera, essential thrombocythaemia, idiopathic myelofibrosis and in patients with other chronic myeloproliferative disorders. Eight JAK2 V617F positive cases were identified amongst those patients with features suggestive of MPD. CONCLUSIONS: The incidence of the JAK2 V617F mutation in MPD patients is similar to that reported by other groups. The assay confirmed and refined the diagnosis of several patients with features indicative of MPD. We suggest screening for this mutation in all patients with known and suspected MPD as identification is valuable in classification and is a potential target for signal transduction therapy.

Autologous stem cell transplantation in myeloma: the St James's Hospital experience, 1997-2003.

BACKGROUND: High-dose treatment with autologous stem cell transplantation (ASCT) has become the standard of care for patients with myeloma below the age of 65 years. AIMS: We report an audit of 60 patients (median age: 52.5 years) who underwent ASCT in the National Bone Marrow Transplant centre in St James's Hospital in Dublin between 1997 and 2003 inclusive. METHODS: Clinical and laboratory data were retrieved from patient medical records and hospital information management systems. RESULTS: Thirty-six patients had IgG, 11 IgA, 1 IgD, 9 light chain and 3 non-secretory MM. Fifty-seven (95%) patients received anthracycline-corticosteroid combination chemotherapy prior to autografting. There was no transplant-related mortality (TRM). Complete (CR) and Partial Responses (PR) were seen in 16 (29.6%) and 29 (53.7%) of those evaluable (n = 54 (90%)). The actuarial Progression-Free (PFS) and Overall Survival (OS) rates at five years are 13% and 55% respectively. CONCLUSION: Centre outcome is comparable to published international series and supports the use of ASCT in the treatment of this malignancy.