PB0142 - Overall Haemostatic Potential (OHP) assay can risk stratify for venous thromboembolism recurrence in anticoagulated patients

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

JW

Julie Wang

Haematologist
Northern Health
Melbourne, Victoria, Australia
HL

Hui Yin Lim

Haematologist
Northern Clinical Pathology, Thrombosis and Radiology (NECTAR) Research Group
Epping, Victoria, Australia
RB

Rowena Brook

Haematology registrar
Northern Health
Melbourne, Victoria, Australia
Harshal Nandurkar, MD, PhD, FRACP, FRCPA

Director of Clinical Haematology, Alfred Health. Head of the Australian Centre for Blood Diseases
Alfred Health and Monash University
Melbourne, Victoria, Australia

Presenting Author(s)

PH

Prahlad Ho, MBBS(Hons), BMedSc, PhD, FRACP, FRCPA

Haematologist
Northern Clinical Pathology, Thrombosis and Radiology (NECTAR) Research Group
Epping, Victoria, Australia

Background: Assessing the risk of recurrent venous thromboembolic (VTE) events, particularly when patients remain on anticoagulation, remains a major challenge largely due to lack of biomarkers.

Aims: We aimed to investigate the use of the OHP assay in newly diagnosed patients following VTE and explore its role in the risk stratification of VTE recurrence, including in patients whilst receiving anticoagulation.

Methods: Adult patients following VTE were recruited between January 2018 and September 2020. Platelet-poor plasma was obtained whilst patients remained on therapeutic anticoagulation. Overall haemostatic potential (OHP) assay, which evaluates fibrin formation with and without tissue plasminogen activator (tPA), was performed on all plasma samples. Time-to-event analysis was performed with recurrent VTE or recurrent unprovoked VTE as endpoints.

Results: OHP assay results were obtained from 196 patients (52.6% male) with a mean age of 57.1 years. Compared to healthy subjects, VTE patients displayed significantly higher overall coagulation potential (without tPA) (39.6 v 34.5 units, p< 0.001) and OHP (with tPA) (9.3 v 6.4 units, p< 0.001) as well as lower overall fibrinolytic potential (OFP) (75.6 v 81.1%, p< 0.001). There were 16 VTE recurrences including 11 unprovoked, all of which occurred above an OCP cut-off of 40th percentile (recurrence rate 4.32 per 100 patient-years, 95% confidence interval (CI) 2.39-7.80, p=0.002). Of 97 patients who subsequently ceased anticoagulation, all unprovoked VTE recurrences (n=9) occurred above the 40th OCP percentile (recurrence rate 9.10 per 100 patient-years, 95% CI 4.74-17.49, p=0.005) and the 40th OHP percentile (recurrence rate 8.46 per 100 patient-years, 95% CI 4.40-16.25, p=0.009). OCP performed better than D-dimer at predicting unprovoked VTE recurrence (AUC 0.72 vs 0.43).

Conclusion(s): Our pilot study demonstrates that the OHP assay can detect a hypercoagulable and hypofibrinolytic state in anticoagulated VTE patients and may be able to risk stratify for VTE recurrence, allowing for more individualised targeting of long-term anticoagulation.