Ten years of cerebral venous thrombosis: male gender and myeloproliferative neoplasm is associated with thrombotic recurrence in unprovoked events

Cerebral venous thrombosis (CVT) is a rare venous thrombotic event. We review our local experience in the management of CVT in comparison to other venous thromboembolism (VTE) with specific focus on risk factors for thrombotic recurrence. Retrospective evaluation of consecutive CVT presentations from January 2005 to June 2015, at two major tertiary hospitals in Northeast Melbourne, Australia. This population was compared to a separate audit of 1003 consecutive patients with DVT and PE. Fifty-two patients (30 female, 22 male) with a median age of 40 (18-83) years, presented with 53 episodes of CVT. Twenty-nine episodes (55 %) were associated with an underlying risk factor, with hormonal risk factors in females being most common. The median duration of anticoagulation was 6 months with 11 receiving life-long anticoagulation. Eighty-one percent had residual thrombosis on repeat imaging, which was not associated with recurrence at the same or distant site. Nine (17 %) had CVT-related haemorrhagic transformation with two resultant CVT-related deaths (RR 22.5; p = 0.04). All three VTE recurrences occured in males with unprovoked events (RR 18.2; p = 0.05) who were subsequently diagnosed with myeloproliferative neoplasm (MPN). Compared to the non-cancer VTE population, non-cancer CVT patients were younger, had similar rate of provoked events and VTE recurrence, although with significantly higher rate of MPN diagnosis (RR 9.30 (2.29-37.76); p = 0.002) CVT is a rare thrombotic disorder. All recurrences in this audit occurred in male patients with unprovoked events and subsequent diagnosis of MPN, suggesting further evaluation for MPN may be warranted in patients with unprovoked CVT.

Prevalence and predictors of fatigue in haemo-oncological patients

BACKGROUND

Fatigue is a common symptom in patients with advanced malignancy, and has been associated with both physiological and psychological factors in patients with solid tumours.

AIM

This study sought to explore the predictors of fatigue in a population with haematological malignancy.

METHODS

Consecutive outpatients and inpatients attending a haematology centre completed the Memorial Symptom Assessment Scale, and clinical, treatment and demographic information were noted.

RESULTS

Of 180 patients, fatigue was present in 69%, and causing considerable distress in 26%. Univariate analysis revealed fatigue was associated with poor performance status, low haemoglobin, feeling sad, worried, irritable and nervous. Multivariate modeling revealed that those factors predictive of fatigue were poor performance status, having active disease, feeling sad and irritable, while haemoglobin level was not predictive of fatigue.

CONCLUSIONS

Fatigue is a multidimensional symptom in patients with haematological malignancy whose presence must prompt a holistic assessment of potential contributors that goes beyond correction of haemoglobin levels.

Ibrutinib inhibits collagen-mediated but not ADP-mediated platelet aggregation

The BTK (Bruton's tyrosine kinase) inhibitor ibrutinib is associated with an increased risk of bleeding. A previous study reported defects in collagen- and adenosine diphosphate (ADP)-dependent platelet responses when ibrutinib was added ex vivo to patient samples. Whereas the collagen defect is expected given the central role of BTK in glycoprotein VI signaling, the ADP defect lacks a mechanistic explanation. In order to determine the real-life consequences of BTK platelet blockade, we performed light transmission aggregometry in 23 patients receiving ibrutinib treatment. All patients had reductions in collagen-mediated platelet aggregation, with a significant association between the degree of inhibition and the occurrence of clinical bleeding or bruising (P=0.044). This collagen defect was reversible on drug cessation. In contrast to the previous ex vivo report, we found no in vivo ADP defects in subjects receiving standard doses of ibrutinib. These results establish platelet light transmission aggregometry as a method for gauging, at least qualitatively, the severity of platelet impairment in patients receiving ibrutinib treatment.

New oral anticoagulants: a practical guide on prescription, laboratory testing and peri-procedural/bleeding management. Australasian Society of Thrombosis and Haemostasis

New oral anticoagulants (NOAC) are becoming available as alternatives to warfarin to prevent systemic embolism in patients with non-valvular atrial fibrillation and for the treatment and prevention of venous thromboembolism. An in-depth understanding of their pharmacology is invaluable for appropriate prescription and optimal management of patients receiving these drugs should unexpected complications (such as bleeding) occur, or the patient requires urgent surgery. The Australasian Society of Thrombosis and Haemostasis has set out to inform physicians on the use of the different NOAC based on current available evidence focusing on: (i) selection of the most suitable patient groups to receive NOAC, (ii) laboratory measurements of NOAC in appropriate circumstances and (iii) management of patients taking NOAC in the perioperative period, and strategies to manage bleeding complications or 'reverse' the anticoagulant effects for urgent invasive procedures.

Low-molecular-weight heparin biosimilars: potential implications for clinical practice. Australian Low-Molecular-Weight Heparin Biosimilar Working Group (ALBW)

A working group of clinicians and scientists was formed to review the clinical considerations for use of low-molecular-weight heparin (LMWH) biosimilars. LMWH are biological molecules of significant complexity; the full complexity of chemical structure is still to be elucidated. LMWH biosimilars are products that are biologically similar to their reference product and rely on clinical data from a reference product to establish safety and efficacy. The complex nature of LMWH molecules means that it is uncertain whether a LMWH biosimilar is chemically identical to its reference product; this introduces the possibility of differences in activity and immunogenicity. The challenge for regulators and clinicians is to evaluate the level of evidence required to demonstrate that a LMWH is sufficiently similar to the reference product. The consensus opinion of the working group is that prior to clinical use a LMWH biosimilar should have proven efficacy and safety, similar to the reference product with prospective studies, which should be confirmed with a proactive post-marketing pharmacovigilance programme.

The association of antiphospholipid antibodies with cardiopulmonary manifestations of systemic sclerosis

OBJECTIVES

To determine the prevalence and correlates of antiphospholipid antibodies (APLA) in systemic sclerosis (SSc).

METHODS

Nine hundred and forty SSc patients were tested for APLA using an ELISA assay at recruitment. Clinical manifestations were defined as present, if ever present from SSc diagnosis. Logistic regression analysis was used to determine the associations of APLA.

RESULTS

One or more types of APLA were present in 226 (24.0%) patients. Anticardiolipin (ACA) IgG (ACA-IgG) antibodies were associated with right heart catheter-diagnosed pulmonary arterial hypertension (PAH), with higher titres corresponding with a higher likelihood of PAH (moderate titre (20-39 U/ml) ACA-IgG odds ratio [OR] 1.70, 95% CI: 1.01-2.93, p=0.047; high titre (>40 U/ml) ACA-IgG OR 4.60, 95% CI:1.02-20.8, p=0.047). Both ACA-IgM (OR 2.04, 95% CI: 1.4-3.0, p<0.0001) and ACA-IgG (OR 1.84, 95% CI: 1.2-2.8, p=0.005) were associated with interstitial lung disease (ILD). Increasing ACA-IgM and IgG titres were associated with increased likelihood of ILD. ACA-IgG was a marker of coexistent pulmonary hypertension and ILD (ILD-PH) (OR 2.10, 95% CI: 1.1-4.2, p=0.036). We also found an association between ACA-IgG and digital ulcers (OR 1.76, 95% CI: 1.16-2.67, p=0.008) and ACA-IgM and Raynaud's phenomenon (OR 2.39, 95% CI: 1.08-5.27, p=0.031). There was no association between APLA and SSc disease subtype, peak skin score, presence of other autoantibodies, mortality or other disease manifestations.

CONCLUSIONS

The association of APLA with PAH, ILD, ILD-PH, Raynaud's phenomenon and digital ulcers suggests that endothelial abnormalities and small vessel thrombosis may be important in the pathogenesis of these disease features.

Should patients with systemic sclerosis-related pulmonary arterial hypertension be anticoagulated?

Pulmonary arterial hypertension (PAH) is a major cause of mortality in scleroderma and despite 'advanced' therapies confers a median survival of less than 5 years. Anticoagulation in systemic sclerosis-related PAH (SSc-PAH) is currently one of the most contentious issues in the management of patients with connective tissue disease. While some studies have shown a survival benefit with warfarin therapy in this disease, others have not. Accordingly, a state of clinical equipoise exists in relation to anticoagulation in SSc-PAH. With an over fivefold reduction in mortality demonstrated in some observational studies, the issue of anticoagulation in SSc-PAH demands resolution through a well-designed randomised controlled trial.

The inositol polyphosphate 5-phosphatases and the apurinic/apyrimidinic base excision repair endonucleases share a common mechanism for catalysis

Inositol polyphosphate 5-phosphatases (5-phosphatase) hydrolyze the 5-position phosphate from the inositol ring of phosphatidylinositol-derived signaling molecules; however, the mechanism of catalysis is only partially characterized. These enzymes play critical roles in regulating cell growth, apoptosis, intracellular calcium oscillations, and post-synaptic vesicular trafficking. The UCLA fold recognition server (threader) predicted that the conserved 300-amino acid catalytic domain, common to all 5-phosphatases, adopts the fold of the apurinic/apyrimidinic (AP) base excision repair endonucleases. PSI-BLAST searches of GENPEPT, using the amino acid sequence of AP endonuclease exonuclease III, identified all members of the 5-phosphatase family with highly significant scores. A sequence alignment between exonuclease III and all known 5-phosphatases revealed six highly conserved motifs containing residues that corresponded to the catalytic residues in the AP endonucleases. Mutation of each of these residues to alanine in the mammalian 43-kDa, or yeast Inp52p 5-phosphatase, resulted in complete loss of enzyme activity. We predict the 5-phosphatase enzymes share a similar mechanism of catalysis to the AP endonucleases, consistent with other common functional similarities such as an absolute requirement for magnesium for activity. Based on this analysis, functional roles have been assigned to conserved residues in all 5-phosphatase enzymes.

The residual megakaryocyte and platelet production in c-mpl-deficient mice is not dependent on the actions of interleukin-6, interleukin-11, or leukemia inhibitory factor

Mice lacking thrombopoietin (TPO) or its receptor c-Mpl are severely thrombocytopenic, consistent with a dominant physiological role for this cytokine in megakaryocytopoiesis. However, these mice remain healthy and show no signs of spontaneous hemorrhage, implying that TPO-independent mechanisms for platelet production exist and are sufficient for hemostasis. To investigate the roles of cytokines that act through the gp130 signaling chain in the residual platelet production of mpl (-/-) mice, mpl (-/-)IL-6(-/-), mpl(-/-)LIF(-/-), and mpl(-/-)IL-11Ralpha(-/-) double-mutant mice were generated. In each of these compound mutants, the number of circulating platelets was no lower than that observed in mice lacking only the c-mpl gene. Moreover, the deficits in the numbers of megakaryocytes and megakaryocyte progenitor cells in the bone marrow and spleen were no further exacerbated in mpl(-/-)IL-6(-/-), mpl(-/-)LIF(-/-), or mpl(-/-)IL-11Ralpha(-/-) double-mutant mice compared with those in Mpl-deficient animals. In single IL-6(-/-), LIF(-/-), and IL-11Ralpha(-/-) mutant mice, platelet production was normal. These data establish that, as single regulators, IL-6, IL-11, and LIF have no essential role in normal steady-state megakaryocytopoiesis, and are not required for the residual megakaryocyte and platelet production seen in the c-mpl(-/-) mouse. (Blood. 2000;95:528-534)

Aminopeptidase-N (CD13; gp 150): contrasting patterns of enzymatic activity in blood from patients with myeloid or lymphoid leukemia

We have investigated the compartmentalization of aminopeptidase-N-like activity in various blood fractions obtained from patients with acute lymphoid (ALL) or myeloid (AML) leukemia. The primary difference appears not to be the absolute level of overall activity, but rather the relative proportions of the different forms of activity detected. Thus, despite similar levels of total aminopeptidase-N-like activity detected in cells from different leukemic groups, true aminopeptidase-N/CD13 activity was only detected in cells derived from AML patients. Even in these patients, however, most of the detected aminopeptidase-N-like activity ( > 80%) could not be attributed to aminopeptidase-N/CD13. In marked contrast, plasma from leukemic patients also contained substantial total aminopeptidase-N-like activity, of which (irrespective of leukemic group) most could be attributed to aminopeptidase-N/CD13. Whilst slightly higher levels of total activity were obtained in plasma from AML patients compared to ALL patients, there was no difference in the relative proportion attributable to aminopeptidase-N/CD13 (approximately 80% of total aminopeptidase-N-like activity). Evaluation of total aminopeptidase-N-like activity present in whole blood gave differential patterns, and whilst only a proportion (20-40% of total aminopeptidase-N-like activity) could be attributed to true aminopeptidase-N/CD13, blood from patients with CD13+ AML showed the greatest activity so attributable. In total, our results outline the complexities of peptidase activities present within blood of leukemic individuals, and may, in part, explain the variability of previous studies attempting to associate prognostic features with phenotypic expression of CD13.

The hepatobiliary disease marker serum alanine aminopeptidase predominantly comprises an isoform of the haematological myeloid differentiation antigen and leukaemia marker CD-13/gp150

In clinical chemistry, determination of serum alanine aminopeptidase (AAP) levels has been found to be useful for detecting or confirming biliary obstructions from either intra- or extra-hepatic disorders. In haematology, 'gp150' is a surface-expressed protein molecule, recognised by monoclonal antibodies belonging to the so-called 'Cluster of Differentiation' (CD-) 13, which has independently been found to be a useful marker of myeloid leukaemia in addition to providing potential prognostic value. The current report links these two independent research streams and provides evidence that the hepatobiliary disease marker, serum AAP, predominantly comprises a circulating isoform of 'gp150'. Thus, a (CD-13) monoclonal antibody raised to, and specifically reactive with, cell surface myeloid 'gp150' is able to specifically and almost completely block serum (or plasma) AAP activity otherwise observed in its absence. This holds true for serum (or plasma) derived both from normal individuals or from patients suffering hepatic dysfunction, with or without associated biliary obstruction. In the case of patients with obstructive jaundice, raised levels of AAP are observed, which fall to near normal levels following preincubation with this monoclonal antibody. In addition, data are presented to support the view of varying isoforms of AAP within flowing blood. Finally, preliminary data is provided on AAP activity in cases of leukaemia. These studies should thus prove of use to clinical laboratories investigating the involvement of AAP activity in various pathological processes.