ISTH 2021: five presentations by Australian haematologists

The 2021 annual scientific meeting of the International Society on Thrombosis and Haemostasis (ISTH 2021) brought together thousands of the world’s leading experts on thrombosis, haemostasis and vascular biology. While it should have been held in Philadelphia, here are some of the Australian contributions made during the virtual meeting held between 17-21 July:

People with diabetes have hypercoagulable profile

Global coagulation assays show that people with diabetes have a higher thrombotic risk, particularly those with type 2 diabetes, according to research presented at ISTH 2021 by haematologists at Australian Centre for Blood Diseases in Melbourne.

In a study involving 184 patients recruited from an endocrinology outpatient clinic, diabetic patients demonstrated more hypercoagulable thromboelastography parameters with increased clot strength global) compared to a control group of 154 healthyy individuals.

While there was no difference in thrombin generation (CAT), diabetic patients showed higher fibrin generation and lower overall fibrinolytic potential on the overall haemostatic potential assay.

The tissue factor pathway inhibitor (TFPI) was also significantly increased in diabetic patients while plasminogen activator inhibitor-1 (PA1-1) assay was similar to that of the control group.

Assays also showed that T2D patients were more hypercoagulable than T1D patients  patients.

Real world outcomes with DOACs in VTE prophylaxis

Lower bleeding rates with DOACs compared to warfarin in real world use support their use as first-line therapy for VTE prophylaxis in selected patients, according to a Victorian study.

A review of 2055 VTE events managed at Northern Health, Melbourne from 2012 to 2019 showed an overall recurrent thrombosis rate of 11% and a 4% rate of clinically significant major bleeding after a median follow-up of 5.6 years.

The median duration of anticoagulation was six months, with one third (33%) of VTE patients managed with DOACs, 42%) with warfarin and 18% with enoxaparin.

Patients on DOACs had a 2% rate of clinically significant major bleeding compared to 4% with warfarin and 8% with enoxaparin, the investigators reported.

Aspirin resistance common in arthroplasty patients

Aspirin may not be an appropriate agent for VTE prophylaxis for high risk patients undergoing total hip or knee arthroplasties, according to Queensland study that found more than half had aspirin resistance.

A study of 34 patients undergoing arthoplasties at the Princess Alexandra Hospital, Brisbane showed that aspirin was commonly prescribed in doses of 150mg daily for six for VTE prophylaxis. The incidence of aspirin resistance was 53% (n=18), of which four patients were diabetic, eleven were obese, and eleven were elderly (over 65).

Age-specific variations in von Willebrand Factor

A team at the Haematology Research Laboratory, Murdoch Children’s Research Institute, Melbourne has confirmed that there are age-related variations in von Willebrand Factor and its multimers.

Blood samples obtained from 20 healthy neonates and 60 healthy children  up to 17 years of age showed that the mean values for vWF low molecular weight multimer (lmwm) and vWF intermediate molecular weight multimer (imwm) differed significantly between neonates and adults.

The findings emphasised the importance of developing age-specific reference ranges to correctly diagnose neonates and children with haematological complications. The results also showed that age-specific differences were not detected using less sensitive measures that, in this case, do not account for the specific forms of the VWF multimers.

Australian use of high dose dexamethasone in ITP

Haematologists at Sir Charles Gardiner Hospital, Perth reported the outcomes for patients with idiopathic thrombocytopenic purpura (ITP) after high-dose dexamethasone replaced long-term prednisolone as the first line treatment in 2016.

For the 19 patients who received high-dose dexamethasone  as initial treatment the response to cycle 1 treatment was 88%, compared to 90% in a previous group of 21 patients treated with prednisolone. Most patients (16) received intravenous immunoglobulin (IVIG) and eight were retreated with HD-DXM: two achieved response, five switched to PDN/alternate therapies and one never responded.

Overall, 66% achieved sustained remission. The bleeding rate was similar between both treatment groups, with 11 actionable bleeds in each. Two of the high-dose dexamethasone patients had major gastrointestinal haemorrhage, resulting in one death.

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