Overall haemostatic potential assay for prediction of outcomes in venous and arterial thrombosis and thrombo-inflammatory diseases

Thromboembolic diseases including arterial and venous thrombosis are common causes of morbidity and mortality globally. Thrombosis frequently recurs and can also complicate many inflammatory conditions through the process of 'thrombo-inflammation,' as evidenced during the COVID-19 pandemic. Current candidate biomarkers for thrombosis prediction, such as D-dimer, have poor predictive efficacy. This limits our capacity to tailor anticoagulation duration individually and may expose lower risk individuals to undue bleeding risk. Global coagulation assays, such as the Overall Haemostatic Potential (OHP) assay, that investigate fibrin generation and fibrinolysis, may provide a more accurate and functional assessment of hypercoagulability. We present a review of fibrin's critical role as a central modulator of thrombotic risk. The results of our studies demonstrating the OHP assay as a predictive biomarker in venous thromboembolism, chronic renal disease, diabetes mellitus, post-thrombotic syndrome, and COVID-19 are discussed. As a comprehensive and global measurement of fibrin generation and fibrinolytic capacity, the OHP assay may be a valuable addition to future multi-modal predictive tools in thrombosis.

Heparin-mediated PCR interference in SARS-CoV-2 assays and subsequent reversal with heparinase I

Heparin is postulated to block the interaction of SARS-CoV-2 with highly glycosylated proteins which are critical for binding the angiotensin-converting enzyme 2 (ACE2), an essential mechanism for host-cell entry and viral replication. Intranasal heparin is under investigation for use as a SARS-CoV-2 preventative in the IntraNasal Heparin Trial (INHERIT, NCT05204550). Heparin directly interferes with real-time quantitative polymerase chain reaction (RT-qPCR), the gold standard for SARS-CoV-2 detection. This study aimed to investigate the magnitude of heparin interference across various clinical laboratory testing platforms, and the reversal of any interference by degradation of heparin using the heparinase I enzyme in nasopharyngeal swab (NP) samples for SARS-CoV-2 analysis by RT-qPCR. Heparin-mediated PCR interference was evident at heparin concentrations as low as 10 IU/mL across all platforms tested, with the exclusion of the Hologic Panther Aptima SARS-CoV-2 assay. Rates of false negative or invalid results increased with increasing heparin concentrations on all platforms, except the Hologic Panther Aptima and Roche Cobas LIAT. Heparinase I reversed heparin-mediated PCR inhibition across in all samples tested, except those with initial Ct values >35. Our study shows that the use of heparin-containing nasal sprays interferes with the detection of SARS-CoV-2 in NP swab samples by RT-qPCR, a phenomenon that is not well recognised in the literature. Furthermore, this study has also demonstrated that heparin-mediated PCR inhibition can be prevented through heparinase I treatment, demonstrating restoration of clinically significant results with Ct values <35.

A ten-year comparison of treatment and outcomes of cancer-associated thrombosis to non-cancer venous thromboembolism: from traditional anticoagulants to direct oral anticoagulants

DOACs have emerged as first-line treatment in most cancer-associated thrombosis (CAT), representing a paradigm shift in its management. However, CAT management remains challenging and requires careful risk-benefit considerations. A retrospective analysis of CAT presentations to a tertiary referral centre from January 2011 to December 2020. Outcomes in CAT patients were compared to VTE patients without malignancy. Subgroup analysis was also conducted for CAT according to anticoagulation type. 514 CAT cases from 491 patients were identified from 3230 total VTE cases. CAT patients had higher rates of major VTE (PE and/or proximal DVT) compared to patients without malignancy (78.4% vs. 66.8%, p < 0.001). CAT patients also had higher rates of VTE recurrence (HR 1.66, 95%CI 1.23-2.26), major bleeding (HR 3.41, 95%CI 2.36-4.93), VTE-related mortality (HR 2.59, 95%CI 1.46-4.62) and bleeding-related mortality (HR 2.66, 95%CI 1.05-6.73). There were no significant differences in rates of VTE recurrence, major bleeding, VTE-related mortality or fatal bleeding between CAT patients treated with DOACs, enoxaparin or warfarin. In the subgroup of CAT treated with DOACs, there was no significant difference in rates of GI bleeding compared to the enoxaparin subgroup (HR 0.17, 95%CI 0.02-1.26). CAT was associated with a larger clot burden and higher rates of VTE recurrence, major bleeding and mortality compared to VTE patients without malignancy in this large real-world study. This study demonstrated no significant differences in complication rates for CAT patients treated with DOACs over enoxaparin, suggesting that DOACs can be safely used in most cases of CAT.

Current challenges in the prevention and management of post-thrombotic syndrome-towards improved prevention

Post-thrombotic syndrome (PTS) is a common and potentially debilitating complication of deep vein thrombosis (DVT), affecting up to 50% of DVT patients. The consequence of this chronic condition includes reduced quality of life, increased use of the healthcare system and decreased productivity. The societal impact of this condition is projected to increase, given our ageing population and increased burden of thrombotic diseases. Despite significant recent advances in our understanding of PTS, many unanswered questions remain. Currently, there are few effective and proven options for established PTS; hence, the emphasis should be on instituting effective prevention to reduce the progression to PTS. Effective anticoagulation lowers the risk of PTS, with direct oral anticoagulants appearing to outperform vitamin-K antagonists. However, the evidence for elastic compression stockings and endovascular thrombolysis or thrombectomy techniques remains unclear. Accurate identification of individuals at high risk of developing PTS may also improve the targeting of preventative interventions. This review will examine the current body of evidence regarding PTS, with a focus on preventative strategies as well as novel biomarkers.

A systematic review of venous thromboembolism mechanical prophylaxis devices during surgery

PURPOSE

Hospitalisation and surgery are major risk factors for venous thromboembolism (VTE). Intermittent pneumatic compression (IPC) and graduated compression stockings (GCS) are common mechanical prophylaxis devices used to prevent VTE. This review compares the safety and efficacy of IPC and GCS used singularly and in combination for surgical patients.

METHODS

Ovid Medline and Pubmed were searched in a systematic review of the literature, and relevant articles were assessed against eligibility criteria for inclusion along PRISMA guidelines.

RESULTS

This review is a narrative description and critical analysis of available evidence. Fourteen articles were included in this review after meeting the criteria. Results of seven studies comparing the efficacy of IPC versus GCS had high heterogeneity but overall suggested IPC was superior to GCS. A further seven studies compared the combination of IPC and GCS versus GCS alone, the results of which suggest that combination mechanical prophylaxis may be superior to GCS alone in high-risk patients. No studies compared combination therapy to IPC alone. IPC appeared to have a superior safety profile, although it had a worse compliance rate and the quality of evidence was poor. The addition of pharmacological prophylaxis may make mechanical prophylaxis superfluous in the post-operative setting.

CONCLUSION

IPC may be superior to GCS when used as a single prophylactic device. A combination of IPC and GCS may be more efficacious than GCS alone for high-risk patients. Further high-quality research is needed focusing on clinical relevance, safety and comparing combination mechanical prophylaxis to IPC alone, particularly in high-risk surgical settings when pharmacological prophylaxis is contraindicated.

Clinical predictors of pulmonary embolism for inpatients: are computed tomography pulmonary angiograms being requested appropriately?

BACKGROUND

The heterogeneity of inpatient pulmonary embolism (PE) presentations may lead to computed tomography pulmonary angiograms (CTPA) being over-requested. Current clinical predictors for PE, including Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC), have predominantly focussed on outpatient and emergency department populations.

AIM

To determine the clinical indicators for ordering inpatient CTPA and the predictors of positive scans for PE.

METHODS

Consecutive inpatient CTPA (performed >24 h after admission) from January 2017 to December 2017 were retrospectively reviewed. Variables including baseline characteristics, vital signs and risk factors for PE were extracted.

RESULTS

A total of 312 CTPA was reviewed (average patient age 67 years; 46% male) and 36 CTPA were positive for PE (11.5%). The average time to inpatient CTPA request was 7 days. Clinical indicators associated with positive scans were hypoxia (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.1-5.6), tachypnoea (OR 2.5; 95% CI 1.2-6.0), recent surgery or immobilisation (OR 2.7; 95% CI 1.2-6.4), S1Q3T3 pattern on electrocardiogram (ECG; OR 7.2; 95% CI 1.4-35.7) and right bundle branch block pattern on ECG (OR 4.7; 95% CI 1.6-13.1). Hypotension, fever and malignancy were not significant. Both PERC and Wells criteria had poor positive predictive value (12% and 27% respectively), but the negative predictive value for PERC and Wells was 100% and 95.8% respectively.

CONCLUSION

Inpatient CTPA appear to be over-requested and can potentially be rationalised based on a combination of clinical predictors and Wells criteria and/or PERC rule. Further prospective studies are needed to develop accurate clinical decision tools targeted towards inpatients.

Global coagulation assays in patients with chronic kidney disease and their role in predicting thrombotic risk

BACKGROUND

Despite cardiovascular diseases and thrombosis being major causes of death in patients with chronic kidney disease (CKD), there remains no effective biomarker to predict thrombotic risk in this population.

OBJECTIVE

To evaluate global coagulation assays in patients with CKD and correlate the biomarkers to clinical outcomes.

MATERIAL AND METHODS

Patients with eGFR<30 mL/min/1.73m² were recruited (n = 90) in this prospective observational study. Blood samples were collected for global coagulation assays, including thromboelastography, calibrated automated thrombogram (CAT), overall hemostatic potential (OHP) and tissue factor pathway inhibitor (TFPI).

RESULTS

Following adjustment for age and gender, CKD subjects (mean age 66 years, 36 % female) had increased maximum amplitude on thromboelastography (70.1 vs 60.2 mm, p < 0.001), higher peak thrombin (233.2 vs 219.7 mm, p = 0.030) and increased OHP (16.1 vs 6.4 units, p < 0.001) compared to healthy controls (n = 153). TFPI was also increased in CKD patients (36.4 vs 14.5 ng/mL, p < 0.001). Compared to hemodialysis patients (n = 43), peritoneal-dialysis patients (n = 25) had more hypercoagulable parameters. Thirty-five CKD patients reported thrombotic complications - key predictors included dialysis, higher fibrinogen, reduced endogenous thrombin potential, elevated D-dimer and increased TFPI. Using the dialysis cohort, the predictive risk model based on the key predictors performed better than Framingham heart score and number of cardiovascular risk factors (Harrell's C-stat 0.862 vs 0.585 vs 0.565).

CONCLUSION

CKD appears to confer a hypercoagulable state compared to healthy controls. Interestingly, reduced thrombin generation and raised TFPI was paradoxically associated with increased thrombotic risks, highlighting possible complex compensatory mechanisms within the coagulation system, which may be important in predicting clinical outcomes.

A 10-year Australian experience of rare intraabdominal venous thrombosis with comparison to deep vein thrombosis and pulmonary embolism

OBJECTIVE

Intra-abdominal venous thromboembolism is rare with heterogeneous management. We aim to evaluate these thrombosis and compare them to deep vein thrombosis and/or pulmonary embolism.

METHOD

A 10-year retrospective evaluation of consecutive venous thromboembolism presentations (January 2011-December 2020) at Northern Health, Australia, was conducted. A subanalysis of intraabdominal venous thrombosis involving splanchnic, renal and ovarian veins was performed.

RESULTS

There were 3343 episodes including 113 cases of intraabdominal venous thrombosis (3.4%) - 99 splanchnic vein thrombosis, 10 renal vein thrombosis and 4 ovarian vein thrombosis. Of the splanchnic vein thrombosis presentations, 34 patients (35 cases) had known cirrhosis. Patients with cirrhosis were numerically less likely to be anticoagulated compared to noncirrhotic patients (21/35 vs. 47/64, P  = 0.17). Noncirrhotic patients ( n  = 64) were more likely to have malignancy compared to those with deep vein thrombosis and/or pulmonary embolism (24/64 vs. 543/3230, P  < 0.001), including 10 patients diagnosed at time of splanchnic vein thrombosis presentation. Cirrhotic patients reported more recurrent thrombosis/clot progression (6/34) compared to noncirrhotic patients (3/64) (15.6 vs. 2.3 events/100-person-years; hazard ratio 4.7 (95% confidence interval 1.2-18.9), P  = 0.030) and other venous thromboembolism patients (2.6/100-person-years; hazard ratio 4.7, 95% confidence interval 2.1-10.7; P  < 0.001) with comparable major bleeding rates. All renal vein thrombosis were provoked including five malignant-related cases while three ovarian vein thrombosis occurred postpartum. No recurrent thrombotic or bleeding complications were reported in renal vein thrombosis and ovarian vein thrombosis.

CONCLUSION

These rare intraabdominal venous thromboses are often provoked. Splanchnic vein thrombosis (SVT) patients with cirrhosis have a higher rate of thrombotic complications, while SVT without cirrhosis was associated with more malignancy. Given the concurrent comorbidities, careful assessment and individualized anticoagulation decision is needed.

Thrombosis Risk Assessment in Myeloproliferative Neoplasm-Is There a Role for Viscoelastic Testing?

Philadelphia chromosome-negative myeloproliferative neoplasms include polycythemia vera, essential thrombocythemia, and myelofibrosis. They are associated with increased thrombotic events, and the primary goal of therapy, in particular those with polycythemia vera and essential thrombocythemia, is the prevention of thrombotic complications typically with antiplatelet therapy and/or cytoreduction. While several patient-, disease-, and genomic-related factors have been identified to influence thrombotic risks, there are no routine laboratory investigations to date that are sufficiently accurate to assess the underlying procoagulant state and predict the thrombotic risks. Conventional coagulation testing only measures time to clot formation and cannot reliably predict bleeding and thrombotic risks. Global coagulation assays such as thromboelastography, thrombin, and fibrin generation may provide a more thorough assessment of hemostatic function. Thromboelastography and thromboelastometry are viscoelastic tests which measure the mechanical properties of the hemostatic process, including the global dynamics of clot formation, stabilization, and dissolution. While viscoelastic testing is gaining traction in the investigations of coagulopathies and goal-directed blood product replacement in trauma and massive transfusion settings, the role of these assays in thrombosis is less well defined. Here, we provide a review of the current evidence of the role of viscoelastic testing in myeloproliferative neoplasm, particularly in the thrombotic risk assessment.

DOAC-stop can remove direct oral anticoagulants and allow analysis by global coagulation assays

INTRODUCTION

Activated charcoal based compounds such as DOAC-stop™ (DS) have been developed to remove direct oral anticoagulant (DOAC) interference in-vitro. However, few studies have used this approach with global coagulation assays (GCAs), such as thrombin generation assays, which are sensitive to the effect of DOACs.

METHODS

Thrombin generation with and without thrombomodulin (TM) via the automated ST-Genesia system, and the overall haemostatic potential (OHP) assay, a spectrophotometric fibrin generation assay in which fibrin formation (triggered by small amounts of thrombin (overall coagulation potential, OCP)) and fibrinolysis (by the addition of thrombin and tissue plasminogen activator) were measured on (i) pooled normal plasma (PNP) spiked with varying amounts of rivaroxaban, apixaban, and dabigatran, and (ii) platelet poor plasma (PPP) from 21 non-anticoagulated adults, before and after DS addition.

RESULTS

Following the addition of DS to spiked PNP without thrombomodulin, thrombin and velocity index increased by 21.9% and 42.6%, respectively, while ETP increased by 6.93%. A decrease in OCP (-10.6%) and OHP (-12.7%) was observed following DS. Similar changes were seen post-DS to plasma from non-anticoagulated patients. Also in this group, pre- and post-DS thrombin generation parameters showed high correlation, with the strongest observed for ETP (R²  = 0.94). There was a strong correlation for OHP parameters, with the closest seen with OCP (R²  = 0.96) and OHP (R²  = 0.95).

CONCLUSION

DS causes some changes to the ETP and OHP assay, however, strong correlations were seen pre- and post-DS in all GCA parameters. These findings support the use of DS to facilitate GCA testing in anticoagulated individuals for evaluation of the underlying thrombotic state.

Laboratory markers of severity across three COVID-19 outbreaks in Australia: has Omicron and vaccinations changed disease presentation?

COVID-19 has rapidly evolved since it was first discovered in December 2019. We aimed to retrospectively review our experience with COVID-19 infection across 2020-2022, focusing on differences in laboratory markers at presentation. Consecutive adult patients admitted to hospital with confirmed COVID-19 infection were retrospectively reviewed across three periods (29/3/2020-29/9/2020, 16/8/2021-13/10/2021 and 1/1/2022-31/1/2022), correlating with the lineages B.1.338, Delta (B.1.617.2) and Omicron (B.1.1.159), respectively. Laboratory findings of the first requested blood test within 24 h of presentation were recorded and correlated with patient outcome. The primary outcome was requirement for oxygen therapy at any point. Inflammatory markers, namely serum ferritin, lactate dehydrogenase (LDH), C-reactive protein (CRP) were significantly lower on presentation during 2022 compared to 2021, corresponding to a milder disease course. More than 80% of 2022 patients had received 2 or more vaccine doses and fully vaccinated patients displayed significantly lower inflammatory markers at presentation. Using 2022 data, a multivariate prediction model was constructed to predict for oxygen requirement, with c-statistic 0.86. Patients in 2022, corresponding with the Omicron variant, displayed a milder disease course, even in hospitalised patients, with the majority not requiring oxygen and lower inflammatory markers. We constructed a simple-to-use risk prediction model with c-statistic 0.86 which may identify individuals who can be safely managed as outpatients in the era of highly transmissible variants.

Impaired Fibrinolytic Potential Predicts Oxygen Requirement in COVID-19

Abnormal coagulation and fibrinolysis contributes to the respiratory distress syndrome in COVID-19. We aimed to explore the association of impaired fibrinolytic potential with disease severity and oxygen requirement in hospitalized patients. Adults admitted to hospital with confirmed COVID-19 infection between 1–31 January 2022 were included, corresponding to the first Omicron outbreak in Melbourne, Victoria. The first citrated plasma sample requested within 24 h of the patient’s presentation was obtained and analyzed by the overall hemostatic potential (OHP) assay, a spectrophotometric assay in which fibrin formation (triggered by small amounts of thrombin (OCP)) and fibrinolysis (by the addition of thrombin and tissue plasminogen activator (OHP and OFP%)) were simultaneously measured. There were 266 patients (median 72 years, 52.9% male), of which 49.6% did not require oxygen therapy. COVID-19 severity and requirement for oxygen was significantly associated with higher OCP, OHP, and lower OFP%. Vaccinated individuals compared with non-vaccinated individuals had significantly lower OHP (16.5 vs. 23.1, p = 0.015) and higher OFP (72.0% vs. 65.1%, p = 0.005), as well as significantly lower AST, ferritin, LDH, CRP, and D-dimer. A multivariate model containing OHP was constructed with the outcome of oxygen requirement, with c-statistic of 0.85 (95%CI 0.81–0.90). In this pilot study, we show a significant correlation between OHP results and requirement for oxygen supplementation in hospitalized patients during a period dominated by the Omicron variant. The results were incorporated into a multivariate model that predicted for oxygen requirement, with high discriminative ability.

A ten-year review of the impact of the transition from warfarin to direct oral anticoagulant - Has venous thromboembolism treatment become safer?

BACKGROUND

The introduction of direct oral anticoagulants (DOAC) has resulted in a paradigm shift in the management of venous thromboembolism (VTE). We evaluate the impact of the transition to DOAC, over the last decade, on overall VTE clinical outcomes including in first unprovoked major VTEs.

METHOD

A retrospective analysis of all VTE admissions in non-cancer patients from January 2011 to December 2020 at Northern Health, Victoria, Australia. "Warfarin era" included events that occurred between January 2011 and December 2014 and "DOAC era" from January 2016.

RESULTS

There were 2687 cases involving 2508 patients (45.9 % males; median age 63 years). 98 % were symptomatic and 1261 events (47 %) were unprovoked. 1003 events occurred during the warfarin era (79 % warfarin, 6 % DOAC) and 1479 during the DOAC era (18 % warfarin, 70 % DOAC). While recurrent thrombosis during the acute phase of treatment was comparable, there were fewer recurrences during the long-term preventative phase of treatment in the DOAC era compared to warfarin era (HR 0.602, 95 % CI: 0.393-0.924, p0.020). Clinically significant bleeding events were lower in the DOAC era (HR 0.623, 95 % CI: 0.395-0.985, p = 0.043). A subanalysis of first unprovoked major VTE events (n = 602) demonstrated a significant reduction in recurrent VTE during the long-term preventative phase of treatment in the DOAC era (HR 0.296, 95 % CI: 0.097-0.901, p = 0.032) with no difference in clinically significantly bleeding rates (HR 0.529, 95 % CI 0.219-1.280, p = 0.158) between the eras.

CONCLUSION

Treatment outcomes for VTE appear to have improved over time with reduced rate of thrombotic and clinically significant bleeding complications in the DOAC era.

Risk stratification for pregnancy-associated venous thromboembolism: Potential role for global coagulation assays

Risk assessment for venous thromboembolism in pregnancy and the puerperium is currently limited to stratifying clinical surrogate risk factors without high-quality evidence. While the absolute risk of pregnancy-associated venous thromboembolism is low for the vast majority of women, associated morbidity and mortality remains significant. As guidelines for thromboprophylaxis vary widely, some women may be under- or over-anticoagulated, contributing to poor outcomes. New global coagulation assays provide a holistic view of coagulation and may have the potential to detect hypercoagulability in pregnancy, unlike clinically available coagulation assays. However, there are major technical challenges to overcome before global coagulation assays can be realistically proposed as an adjunct to risk assessment for pregnancy-associated venous thromboembolism. This review summarises the literature and controversies in the prediction and prevention of pregnancy-associated venous thromboembolism and outlines the new tools in haematology that may assist in our future understanding of hypercoagulability in pregnancy.

The Need for Individualized Risk Assessment in Cardiovascular Disease

Cardiovascular disease remains the leading cause of death in the era of modern medicine despite major advancements in this field. Current available clinical surrogate markers and blood tests do not adequately predict individual risk of cardiovascular disease. A more precise and sophisticated tool that can reliably predict the thrombosis and bleeding risks at an individual level is required in order for clinicians to confidently recommend early interventions with a favorable risk–benefit profile. Critical to the development of this tool is the assessment and understanding of Virchow’s triad and its complex interactions between hypercoagulability, endothelial dysfunction and vessel flow, a fundamental concept to the development of thrombosis. This review explores the pathophysiology of cardiovascular disease stemming from the triad of factors and how individualized risk assessment can be improved through the multimodal use of tools such as global coagulation assays, endothelial biomarkers and vessel flow assessment.

POS0035 GENE REGULATION IN T-CELLS FROM PsA PATIENTS DIFFERS BETWEEN PERIPHERAL BLOOD AND THE INFLAMED JOINTS: IMPLICATIONS FOR THE INTERPRETATION OF GWAS SIGNALS

Background

Genome-wide association studies (GWAS) have identified variants that are associated with complex diseases such as Psoriatic Arthritis (PsA). The majority of these variants do not affect the coding sequence of proteins but rather regulatory elements which are highly cell type and state specific, and can affect distally located genes via chromatin interaction mechanisms.

We and others have previously analysed GWAS loci for multiple conditions (including PsA and Rheumatoid Arthrtitis) in cell lines using functional genomics techniques, providing putative mechanisms to many loci with previously unknown function [1].

However, multiple studies have identified large differences in gene regulatory mechanisms between cell lines and primary cells, which could significantly alter the proposed mechanisms. Differences between between samples from healthy volunteers and patients, in particular from the affected tissue, have although not been exhaustively investigated.

Objectives

To assess the impact of using primary cells derived from PsA patients compared to healthy volunteers in functional genomics studies.

Methods

CD4+ and CD8+ T cells were isolated from peripherial blood from 10 healthy controls and 48 PsA patients and from 6 PsA synovial fluid samples.

We performed RNA-seq and ATAC-seq on these two cell types to analyse the global patterns of gene expression and chromatin activity.

Results

We find subtle differences between PsA patients and healthy controls in cells isolated from blood. RNA-seq analysis identified only a handful of differentially expressed genes whilst ATAC-seq analysis identified only 28 differential loci.

On the other hand, T cells isolated from synovial fluid showed significant differences compared to T cells isolated from patient’s blood. Interestingly, we find that CD4+ T cells show substantially more differentially expressed genes compared to CD8+ T cells (1168 vs 346 Log2FoldChange > 1, FDR < 0.01). Genes overexpressed in synovial CD4+ T cells are more strongly enriched for immune pathways such as cytokine signaling and T cell proliferation compared to synovial CD8+ T cells

We also find that synovial CD4+ T cells highly overexpress MHC class II genes (Figure 1).

Figure 1.

Normalized counts of the alpha chains of MHC class 2 genes in CD4+ and CD8+ T cells purified from blood from healthy subjects and patients and synovial fluid.

Conclusion

This preliminary analysis suggests that T cells isolated from peripherial blood do not seem to differ significantly between PsA patients and healthy controls. In contrast, cells isolated from synovial fluid are highly specialized and activated. Moreover, these cells do not resemble canonically activated T cells which means that this state can not be easily emulated in vitro.

This study indicates the importance of not only studying GWAS loci in relevant primary cells from patients, but also that attention needs to be given to cells isolated from the affected site.

References

[1]Shi C, Ray-Jones H, Ding J, et al (2021) Chromatin Looping Links Target Genes with Genetic Risk Loci for Dermatological Traits. J Invest Dermatol 141:1975–1984. https://doi.org/10.1016/J.JID.2021.01.015

Acknowledgements

This work was funded by the Wellcome Trust (award references 207491/Z/17/Z and 215207/Z/19/Z), the Versus Arthritis (award reference 21754), the NIHR Manchester Biomedical Research Centre, and the Medical Research Council (award reference MR/N00017X/1).

Disclosure of Interests

None declared

AB0345 THERAPEUTIC DRUG LEVELS TO ACHIEVE GOOD EULAR RESPONSE IN PATIENTS WITH RHEUMATOID ARTHRITIS RECEIVING ADALIMUMAB: RESULTS FROM THE BIOLOGICS IN RHEUMATOID ARTHRITIS GENETICS AND GENOMICS STUDY SYNDICATE (BRAGGSS) COHORT

Background

Rheumatoid arthritis (RA) is a systemic inflammatory disease often treated with biologic disease-modifying anti-rheumatic drugs (bDMARDs) such as Adalimumab (ADL), a tumour-necrosis factor inhibitor (TNFi). However, it is known that about a third of patients do not respond to ADL treatment. Previous studies have reported associations between poor response, decreased serum drug levels (SDLs) and poor adherence, but a therapeutic SDL has not been defined nor applied in clinical practice.

Objectives

To assess median ADL SDLs in RA European Alliance of Associations for Rheumatology (EULAR) good vs non/moderate responders, and to determine cut-off SDLs associated with a “Good” response in fully adherent RA patients.

Methods

In a prospective observational cohort study, patients with RA were treated with ADL. At baseline, 3-, 6-, and 12-months patients had 4-component DAS28 scores, self-reported treatment adherence data and SDLs measured. Median drug levels and receiver-operator characteristics (ROC) curves were used to compare SDLs between responders and non-responders, and to establish cut-off SDLs in self-reported fully adherent patients. Serum drug levels were measured using a sandwich ELISA produced by Progenika Biopharma. Patients were considered fully adherent if they self-reported never having altered, forgotten or omitted any dose of their biologic drug at follow-up. Between group comparisons were assessed using Fisher’s exact test, with a threshold for significance set at p<0.05. Statistical analyses were performed in R Version 4.1.0 and RStudio Version 1.4.1106.

Results

A total of 283 RA patients taking ADL were included in the analysis. Baseline characteristics are shown in Table 1. Of these patients 93 (32.9%) self-reported being fully adherent to treatment at 3 months follow-up and had SDLs measured.

Table 1.

Baseline characteristics of patient cohort with RA taking ADL (n=283)

CharacteristicnMissing (%)Age at baseline, median years (IQR)58 (51, 64)0Disease duration, median years (IQR)7 (3, 16)0Female Sex, n (%)206 (73)0BMI, median (IQR)27.4 (23.7, 31.9)0Smoking Status132 (46)Current, n (%)57 (38)-Ex, n (%)32 (21)-Non, n (%)62 (41)-On concurrent DMARD(s)1 (0.4)No, n (%)34 (12)-Yes, n (%)248 (88)-Baseline DAS Score, median (IQR)5.61 (5.18, 6.14)On MTX at baseline38 (13)No, n (%)44 (18)Yes, n (%)201 (82)

In 93 fully adherent RA patients taking ADL at 3 months, good EULAR responders had significantly higher SDLs compared to non/moderate EULAR responders (p=0.0234). In 47/93 (50.5%) fully adherent good responders median SDL at 3 months was 10.94mg/L (IQR 7.75 to 12.0), whereas in 46/93 (49.5%) non/moderate responders, median SDL at 3 months was 9.014 (IQR 6.96 to 11.1).

ROC analysis (see Figure 1) reported a 3-month non-trough ADL SDL cut-off of 7.5mg/L in fully adherent RA patients which discriminated Good EULAR responders compared to non/moderate responders with an AUC of 0.63 (95% CI 0.52 – 0.75), 39.1% specificity, and 80.9% sensitivity.

Figure 1.

ROC curve analysis: EULAR non/moderate vs good responders with 3 month ADL SDLs.

Conclusion

In keeping with previous work, SDLs were higher in adherent compared with non-adherent patients, but this is the first study to demonstrate that SDLs are higher in fully adherent good EULAR responders compared with non/moderate responders. Based on our methods, cut-offs of 7.5mg/L for ADL may be useful targets in clinical practice to achieve good EULAR response.

References

[1]Jani M, Chinoy H, Warren RB, Griffiths CEM, Plant D, Fu B, et al. Clinical Utility of Random Anti–Tumor Necrosis Factor Drug–Level Testing and Measurement of Antidrug Antibodies on the Long-Term Treatment Response in Rheumatoid Arthritis. Arthritis & Rheumatology. 2015;67(8):2011-9.

[2]Pouw MF, Krieckaert CL, Nurmohamed MT, van der Kleij D, Aarden L, Rispens T, et al. Key findings towards optimising adalimumab treatment: the concentration-effect curve. Ann Rheum Dis. 2015;74(3):513-8.

Disclosure of Interests

None declared

Age, sex and racial differences in fibrin formation and fibrinolysis within the healthy population

Increased fibrin generation and reduced fibrinolytic potential have been detected using global coagulation assays in several hypercoagulable states including cardiovascular disease and venous thromboembolism. We aimed in this study to define the impact of age, sex and race on fibrin generation and lysis using the Overall Haemostatic Potential (OHP) assay in a group of stringently defined healthy adults. Healthy adult patients not receiving anticoagulation and without a history of thrombotic disease were prospectively recruited. Iindividuals with cardiovascular risk factors (e.g. hypertension, diabetes, smoking), receiving hormonal therapy, antiplatelet agents or with abnormal routine blood tests were also excluded. Platelet-poor plasma was obtained and the OHP assay, which evaluates fibrin formation with and without tissue plasminogen activator, was performed on all plasma samples. 144 healthy subjects (34.7% male) with median age 42 years (interquartile range 20, 77) were recruited. After multivariate analysis, age at least 50 years and female sex were associated with significantly increased fibrin generation parameters (overall coagulation potential, OHP, maximum optical density, fibrin) as well as reduced markers of fibrinolysis (overall fibrinolytic potential and time-to-50% lysis). There were no significant differences in OHP parameters between whites, East Asians and South Asians after accounting for age and sex. This study defines age, sex and racial differences of fibrin generation and fibrinolysis as measured by the OHP assay in a sample of healthy subjects. Further studies are warranted in diseased populations, where there is growing awareness of the role of global coagulation assay in defining prothrombotic and hypofibrinolytic states.

Global coagulation assays in hypercoagulable states

Thrombosis is one of the major global causes of morbidity and mortality, and predicting the risk of thrombotic and cardiovascular complications remains one of the key challenges in modern medicine. Conventional coagulation testing does not provide sufficient information, primarily because they measure the time to start of blood clotting and do not evaluate total thrombin generation. Possible adjunctive tools that may be helpful are global coagulation assays, which includes the assessment of the final products of the coagulation cascade, namely thrombin and fibrin. Whilst these assays have been more widely investigated in bleeding states, their role in thrombotic disorders is less established. We have previously investigated the use of assays such as thromboelastography, calibrated automated thrombogram and overall haemostatic potential assay in several hypercoagulable states including cardiovascular disease, haematological disorders and influence of hormone status as well as healthy controls. We provide a review of the use and limitations of global coagulation assays in healthy controls as well as hypercoagulable conditions.

Risk factors and early prediction of clinical deterioration and mortality in adult COVID-19 inpatients: an Australian tertiary hospital experience

BACKGROUND

Early recognition of severe COVID-19 is essential for timely patient triage.

AIMS

We aim to report clinical and laboratory findings and patient outcomes at a tertiary hospital in Melbourne, Australia.

METHODS

This is a retrospective study of adult inpatients with COVID-19 admitted to Northern Health from March to September 2020. Data were extracted from electronic medical records.

RESULTS

Key admission data was available for 182 patients (median age 67.0 years (interquartile range, 47.9-83.1; 51.1% female). 56 (30.8%) were from residential care. 117 (64.3%) patients were assigned Goals-of-Patient-Care (GOPC) A or B and 65 (35.7%) GOPC C or D. Comorbidities were present in 135 patients (74.2%). 63.2% of patients received antibiotics, 6.6% had antivirals, 45.6% received systemic glucocorticoid and 3.3% had tocilizumab. 56 (30.8%) developed clinical deterioration (24 requiring ventilation, 21 receiving critical care, 34 died). Overall, in-hospital clinical deterioration was significantly associated with older age (p<0.001), history of diabetes (p=0.038), lower lymphocyte count (p=0.002) and platelet count (p=0.004), higher neutrophil-to-lymphocyte ratio (p=0.002), elevated fibrinogen (p=0.004), higher serum ferritin (p=0.027) and CRP (p=0.002). The accuracy of the 4C Deterioration model was moderate, with an area under the curve (AUC) of 0.79 (95% CI, 0.68-0.90) compared with an AUC of 0.77 (95% CI, 0.76-0.78) in the original validation cohort.

CONCLUSIONS

In this study, high neutrophil-to-lymphocyte ratio, abnormal d-dimer, high serum CRP and ferritin appear to be useful prognostic markers. This article is protected by copyright. All rights reserved.

Global coagulation assays in patients with diabetes mellitus

BACKGROUND

There is significant heterogeneity in the incidence and severity of diabetes-associated vascular complications and there is no routine biomarker that accurately predicts these outcomes. This pilot study investigates the role of global coagulation assays in patients with diabetes mellitus.

METHODS

In this cross-sectional study, patients with diabetes not on anticoagulation or dialysis and without active malignancy were recruited from endocrinology clinics. Blood samples were collected for global coagulation assays including thromboelastography (TEG), thrombin generation using calibrated automated thrombogram (CAT), and fibrin generation and fibrinolysis using the overall hemostatic potential (OHP) assay. The results were compared with healthy controls.

RESULTS

A total of 147 adult patients including 19 with type 1 diabetes (T1DM), 120 with type 2 diabetes (T2DM), and eight with latent autoimmune diabetes were recruited. Compared with 153 healthy controls, patients with diabetes demonstrated higher maximum amplitude (68.6 vs 60.2 mm, p < 0.001) on TEG, and higher OHP (9.3 vs 6.4, p < 0.001) with comparable CAT parameters. Patients with T2DM were more hypercoagulable than those with T1DM on most biomarkers. Higher maximum amplitude, velocity index, and OHP were associated with increased risk of complications (C-stat 0.82). Patients with history of microvascular complications appear to have more hypercoagulable thrombin and fibrin generation than those without.

CONCLUSION

Patients with diabetes have more hypercoagulable profiles on global coagulation assays, particularly patients with T2DM and those with microvascular complications. Further studies with longitudinal follow-up are ongoing to evaluate the utility of global coagulation assays in predicting long-term patient outcomes.

Assessing maternal clotting function with novel global coagulation assays: A prospective pilot study

INTRODUCTION

Women are at higher risk of venous thromboembolism (VTE) during pregnancy and the puerperium. Global coagulation assays (GCAs), including thromboelastography (TEG), thrombin generation using the calibrated automated thrombogram (CAT) and fibrin generation using the overall haemostatic potential assay (OHP), provide a more comprehensive assessment of the coagulation process than conventional coagulation assays. We aimed to evaluate the ability of these GCAs to analyse the coagulability among pregnant women of varying VTE risk profile.

METHODS

Women undergoing term elective caesarean delivery provided a single predelivery blood sample for conventional and novel coagulation testing (TEG, CAT and OHP). Data from 47 healthy nonpregnant women aged 18-45 years were used as controls.

RESULTS

Sixty women with term singleton pregnancies were included. Samples from pregnant women were hypercoagulable on most GCA parameters compared to nonpregnant controls, demonstrating increased maximum amplitude (clot strength) (71.5 vs 60.6 mm, P < .001) on whole blood TEG and increased endogenous thrombin potential (1895.22 vs 1399.33 nmol/L·min, P < .001) and overall coagulation potential (fibrin generation) (57.58 vs 36.21 units, P < .001) on platelet-poor plasma. Pregnant women with booking BMI ≥ 30 kg/m² had significantly higher maximum amplitude compared to pregnant women of normal BMI (18.5-25 kg/m² ) (73.2 vs 66.1 mm, P < .001).

CONCLUSIONS

Global coagulation assays reliably detect the physiological hypercoagulability of pregnancy. Thromboelastography in particular appears to correlate with obesity in the pregnant population. GCAs may be potential adjuncts to risk factor-based criteria to guide VTE thromboprophylaxis during pregnancy and the puerperium.

Global Coagulation Assays in Transgender Women on Oral and Transdermal Estradiol Therapy

CONTEXT

The thrombotic effects of estradiol therapy in transgender women are unclear. Global coagulation assays (GCA) may be better measures of hemostatic function compared with standard coagulation tests.

OBJECTIVE

To assess the GCA profiles of transgender women in comparison to cisgender controls and to compare how GCA differ between routes of estradiol therapy in transgender women.

DESIGN

Cross-sectional case-control study.

SETTING

General community.

PARTICIPANTS

Transgender women, cisgender male and cisgender female controls.

MAIN OUTCOME MEASURES

Citrated blood samples were analyzed for (i) whole blood thromboelastography (TEG®5000), (ii) platelet-poor plasma thrombin generation (calibrated automated thrombogram); and (iii) platelet-poor plasma fibrin generation (overall hemostatic potential assay). Mean difference (95% confidence intervals) between groups are presented.

RESULTS

Twenty-six transgender women (16 oral estradiol, 10 transdermal estradiol) were compared with 98 cisgender women and 55 cisgender men. There were no differences in serum estradiol concentration (P = 0.929) and duration of therapy (P = 0.496) between formulations. Transgender women demonstrated hypercoagulable parameters on both thromboelastography (maximum amplitude + 6.94 mm (3.55, 10.33); P < 0.001) and thrombin generation (endogenous thrombin potential + 192.62 nM.min (38.33, 326.91); P = 0.009; peak thrombin + 38.10 nM (2.27, 73.94); P = 0.034) but had increased overall fibrinolytic potential (+4.89% (0.52, 9.25); P = 0.024) compared with cisgender men. No significant changes were observed relative to cisgender women. Route of estradiol delivery or duration of use did not influence the GCA parameters.

CONCLUSION

Transgender women on estradiol therapy demonstrated hypercoagulable GCA parameters compared with cisgender men with a shift towards cisgender female parameters. Route of estradiol delivery did not influence the GCA parameters.

FRI0649-HPR HYDROXYCHLOROQUINE PRESCRIBING AND OPHTHALMOLOGY SCREENING WITHIN RHEUMATOLOGY DEPARTMENTS IN THE NORTH-WEST OF THE UNITED KINGDOM: A PROSPECTIVE REGIONAL AUDIT

Background:

Hydroxychloroquine (HCQ) is widely used in the management of rheumatoid arthritis and connective tissue disease. The prevalence of retinopathy in patients taking long-term HCQ is approximately 7.5%, increasing to 20-50% after 20 years of therapy. Hydroxychloroquine prescribed at ≤5 mg/kg poses a toxicity risk of <1% up to five years and <2% up to ten years, but increases sharply to almost 20% after 20 years. Risk factors for retinopathy include doses >5mg/kg/day, concomitant tamoxifen or chloroquine use and renal impairment. The UK Royal College of Ophthalmologists (RCOphth) 2018 guidelines for HCQ screening recommend optimal treatment dosage and timing for both baseline and follow-up ophthalmology review for patients on HCQ, with the aim of preventing iatrogenic visual loss. This is similar to recommendations made by the American Academy of Ophthalmology (2016).

Objectives:

To determine adherence to the RCOphth guidelines for HCQ screening within the Rheumatology departments in the North-West of the UK.

Methods:

Data for patients established on HCQ and those initiated on HCQ therapy were collected over a 7 week period from 9 Rheumatology departments.

Results:

473 patients were included of which 56 (12%) were new starters and 417 (88%) were already established on HCQ. 79% of the patients were female, with median ages of 60.5 and 57 years for new and established patients respectively. The median (IQR) weight for new starters was 71 (27.9) kg and for established patients, 74 (24.7) kg.

20% of new starters exceeded 5mg/kg daily HCQ dose. 16% were identified as high risk (9% had previously taken chloroquine, 5% had an eGFR <60ml/min/m2and 2% had retinal co-pathology). Of the high-risk group, 44% were taking <5mg/kg. In total, 36% of new starters were referred for a formal baseline Ophthalmology review.

In the established patients, 74% were taking ≤5mg/kg/day HCQ dose and 16% were categorized as high risk (10% had an eGFR less than 60ml/min/m2, 3% had previous chloroquine or tamoxifen use and 2% had retinal co-pathology). In the high-risk group, 75% were not referred for spectral domain optical coherence tomography (SD-OCT). 41% of patients established on HCQ for <5 years, and 33% of patients on HCQ for >5 years were not referred for SD-OCT. Reasons for not referring included; awaiting 5 year review, previous screening already performed and optician review advised.

Since the introduction of the RCOphth guidelines, 29% patients already established on HCQ had an alteration in the dosage of HCQ in accordance with the guidelines. In the high-risk group, 16% were not on the recommended HCQ dose.

Conclusion:

This audit demonstrates inconsistencies in adherence to the RCOphth guidelines for HCQ prescribing and ophthalmology screening within Rheumatology departments in the North-West of the UK for both new starters and established patients. Plans to improve this include wider dissemination of the guidelines to Rheumatology departments and strict service level agreements with ophthalmology teams to help optimize HCQ prescribing and screening for retinopathy.

Acknowledgments:

Drs. S Jones, E MacPhie, A Madan, L Coates & Prof L Teh. Co-1st author, T David.

Disclosure of Interests:

None declared

Intravascular ultrasound-guided laparoscopic division of the median arcuate ligament

Median arcuate ligament syndrome is a rare and poorly understood condition that can have a significant impact on the quality of life of patients. Diagnosis is often difficult and delayed because of the need to exclude other pathologic processes. Treatment strategies traditionally involve open or laparoscopic division of the median arcuate ligament, with or without vascular reconstruction. This report portrays a case of median arcuate ligament syndrome with compression of two visceral arteries and distal embolic complications. A novel hybrid technique is described using intravascular ultrasound technology to aid in laparoscopic median arcuate ligament division. This allowed real-time intravascular visualization of the compressive segment, guided release of the ligament fibers, and demonstrated confirmation of decompression.

Enhanced sample filling and discretization in thermoplastic 2D microwell arrays using asymmetric contact angles

Sample filling and discretization within thermoplastic 2D microwell arrays is investigated toward the development of low cost disposable microfluidics for passive sample discretization. By using a high level of contact angle asymmetry between the filling channel and microwell surfaces, a significant increase in the range of well geometries that can be successfully filled is revealed. The performance of various array designs is characterized numerically and experimentally to assess the impact of contact angle asymmetry and device geometry on sample filling and discretization, resulting in guidelines to ensure robust microwell filling and sample isolation over a wide range of well dimensions. Using the developed design rules, reliable and bubble-free sample filling and discretization is achieved in designs with critical dimensions ranging from 20 μm to 800 μm. The resulting devices are demonstrated for discretized nucleic acid amplification by performing loop-mediated isothermal amplification for the detection of the mecA gene associated with methicillin-resistant Staphylococcus aureus.

Incidence and associated risk factors for falls in adults with intellectual disability

BACKGROUND

People with intellectual disability (ID) experience age-related changes earlier in life, and as such, falls among people with ID are of serious concern. Falls can cause injury and consequently reduce quality of life. Limited studies have investigated the incidence of falls among people with ID and the associated risk factors. The purpose of this study was to investigate the incidence of falls and risk factors for falling in people with ID living in the community.

METHODS

A prospective observational cohort (n = 78) of community-dwelling adults with ID. Characteristics measured at baseline included falls history, medication use, balance and mobility. Falls were reported for 6 months using monthly calendars and phone calls. Data were analysed using univariate and multivariate logistic regression to identify risk factors associated with falling.

RESULTS

Participants [median (interquartile range) age 49 (43-60) years, female n = 32 (41%)] experienced 296 falls, with 36 (46.2%) participants having one or more falls. The incidence of falls was 5.7 falls (injurious falls = 0.8) per person year (one outlier removed from analysis). A history of falls [adjusted odds ratio (OR): 6.37, 95% confidence interval (CI) (1.90-21.34)] and being ambulant [adjusted OR: 4.50, 95% CI (1.15-17.67)] were associated with a significantly increased risk of falling. Falls were significantly less frequent among participants taking more than four medications [adjusted OR: 0.22, 95% CI (0.06-0.83)] and participants who were continent [adjusted OR: 0.25, 95% CI (0.07-0.91)].

CONCLUSIONS

People with ID fall at a younger age compared with the broader community. The associated falls risk factors also differ to older community-dwelling adults. Health professionals should prioritise assessment and management of falls risk in this population.

A review of global coagulation assays - Is there a role in thrombosis risk prediction?

Normal haemostasis requires maintenance of a careful equilibrium between the necessity to clot when bleeding and the retention of fluid phase at all other times. Disruption of this equilibrium can result in catastrophic outcomes, e.g. acute myocardial infarction and pulmonary embolism. However, despite the significant therapeutic advances in cardiovascular medicine over recent years, our ability to provide an accurate cardiovascular risk assessment remains an unmet need. Routine coagulation testing is not a useful reflection of haemostasis and cannot be reliably used to predict bleeding and thrombosis risks. Global coagulation assays such as viscoelastic testing, thrombin and fibrin generation have been proposed as better measures of the haemostatic function. These assays, particularly viscoelastic testing, have been increasingly used to assess bleeding risks and guide blood product replacement in trauma and massive transfusion settings. However, the role of these assays in thrombosis is less well-defined but given the complexities of the coagulation system, these global coagulation assays when used in combination may provide a better assessment of cardiovascular and thrombosis risk at an individual level. Hence, we explore the role of some of the currently available global coagulation assays - the viscoelastic, thrombin generation and fibrin generation tests - and provide a review of the literature of the current evidence for these assays specifically in the field of venous thromboembolism and cardiovascular diseases.

A comparison of global coagulation assays between normal controls and patients with thrombocytopenia

INTRODUCTION

Some patients with thrombocytopenia may be at risk of bleeding although quantitative platelet count is not always a sufficient predictive factor. Global coagulation assays such as thromboelastography (TEG^® ), calibrated automated thrombogram (CAT) and overall haemostatic potential (OHP) may provide a better assessment of an individual's haemostatic profile.

METHODS

Blood samples were collected from thrombocytopenic patients. TEG^® was performed on citrated whole blood, while CAT and OHP were performed on platelet-poor plasma. Results were compared to our previously collected normal controls.

RESULTS

Fifty-eight participants (24 immune thrombocytopenia, 34 chemotherapy/malignancy-related) with mean age of 57.5 years were recruited. Compared to normal controls, thrombocytopenic participants had comparable maximum amplitude but reduced clot lysis (0.0% vs 0.6%; P < 0.001) on TEG^® with reduced endogenous thrombin potential on CAT (1252.2 vs 1353.0 nmol/L/min; P = 0.040). No differences were seen in the OHP parameters. TEG^® showed significant difference between marked and mild thrombocytopenia groups with minimal differences seen on CAT and OHP. Those with marked thrombocytopenia showed reduced maximum amplitude (47.2 vs 57.8 mm; P = 0.002) as expected while participants with mild thrombocytopenia (platelet count 100-150 × 10⁹ /L) paradoxically demonstrated increased maximum amplitude (66.4 vs 57.8 mm; P < 0.001).

CONCLUSION

Global coagulation assays, particularly TEG^® , can detect subtle differences in coagulation in thrombocytopenic patients. While patients with marked thrombocytopenia showed reduced maximum amplitude, patients with mild thrombocytopenia appear to paradoxically show increased maximum amplitude, suggesting compensatory activity within the coagulation pathway which may in part explain why not all thrombocytopenic patients have bleeding complications.

Direct Oral Anticoagulants and the Paradigm Shift in the Management of Venous Thromboembolism

The advent of direct oral anticoagulants (DOACs) has revolutionized anticoagulation management in both stroke prevention and venous thromboembolism (VTE) treatment/prevention. Clinical trials and secondary real-world data have shown that DOACs have similar efficacy and, in some cases, improved bleeding safety profiles compared with vitamin K antagonists. Together with benefits of patient convenience, this has shifted the risk–benefit ratio toward long-term anticoagulation. However, current VTE risk assessment models are based on vitamin K antagonists and do not take into account the new paradigm of DOACs. Therefore, challenges to the thrombosis community remain to determine patients who would benefit from long-term anticoagulation in the DOAC era. Here, the authors review the current literature on risks and benefits of DOACs and their potential role in long-term VTE thromboprophylaxis as well as in current risk assessment models. The increasing use of DOACs, led by their convenience of use and generally lower bleeding rates, calls for a reevaluation of the current models as the benefits of long-term anticoagulation may begin to outweigh risks and inconvenience associated with their predecessors.

Retrospective evaluation of venous thromboembolism: Are all transient provoking events the same?

OBJECTIVES

Venous thromboembolism (VTE) provoked by transient risk factors has traditionally been classified as a single entity with lower risk of recurrence. We evaluated the association between different categories of transient provoking factors and the relative risk of recurrence.

METHODS

Retrospective evaluation of VTE events in non-cancer patients from July 2011 to December 2012 at two tertiary institutions in Australia with a minimum follow-up of 24 months.

RESULTS

A total of 747 VTE cases were identified, and following exclusion of cases with mortality within 30 days of presentation (n=26), unprovoked cases (40.2%) had a higher risk of recurrence (4.6 vs 2.3/100 event-years, P=.01). Provoking factors included surgery (40.4%), injury (16.7%), medical-related factors including non-surgical hospitalisation or active infection (22.0%), travel (13.2%) and oestrogen related (6.5%). Air travel had the highest recurrence rate of 5.9/100 event-years, comparable to unprovoked VTE. VTE provoked by surgery showed lower recurrence rate at 1.8/100 event-years (P=.03). 62.5% of patients with provoked VTE recurred with an unprovoked event.

CONCLUSION

Transient provoking factors for VTE are heterogeneous with varying potency and should not be considered a single entity. The high recurrence rate after travel-provoked VTE suggests that it is a "minor," if not negligible provoking factor with higher thrombotic predisposition.

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.

Retrospective review on isolated distal deep vein thrombosis (IDDVT) - A benign entity or not?

INTRODUCTION

Isolated distal deep venous thrombosis (IDDVT) is traditionally associated with less severe clinical sequelae, with ongoing debate on multiple aspects of its management. Despite numerous studies evaluating its acute management, there remains a paucity of data evaluating long-term complications such as recurrence and subsequent malignancy. We aim to evaluate the characteristics of IDDVT in institutions that routinely perform whole leg ultrasonography, and the risks of recurrence and complications in comparison to major venous thromboembolism (major VTE; defined as above-knee or proximal DVT and pulmonary embolism (PE)).

METHODS

Retrospective evaluation of consecutive IDDVT and major VTE from July 2011 to December 2012 in a hospital network in Melbourne, Australia. Patients were followed up for a minimum of 24months. Patients with active malignancy were excluded.

RESULTS

Of 1024 VTE cases, there were 164 non-cancer patients (92 males, 72 females, median age of 61years) with IDDVT. Compared to major VTE, IDDVT was more likely to be provoked (73% vs 59%, p<0.01), has shorter duration of anticoagulation (median 3.5months vs 6.0months, p<0.01) and less clinically significant bleeding (2.4% vs 6.7%, p=0.05), independent of duration of therapy. Recurrence was non-inferior compared to major VTE (10% vs 7%, p=0.36) and 60% recurred with major VTE. Three (1.8%) were subsequently diagnosed with cancer (vs 1.9% in major VTE, p=0.97).

CONCLUSIONS

IDDVT has non-inferior rates of recurrence and subsequent cancer detection compared to major VTE and hence, its clinical significance should not differ from major VTE. Further studies are required to determine the adequate length of anticoagulation.