Background: The majority of patients with clinically unprovoked thrombosis do not have a demonstrable hypercoagulable state identified by routine tests. The Overall Haemostatic Potential (OHP) assay is an inexpensive global coagulation assay measuring fibrin generation and fibrinolysis, and has previously been shown to identify hypercoagulable states in patient groups with antiphospholipid syndrome and during pregnancy.
Aims: Our aim was to compare OHP assay results from a retrospectively identified group of patients with clinically unprovoked arterial or venous thrombosis and no identified thrombophilia, with a gender-matched control group from the normal population and a group with thrombosis and a known inherited thrombophilia.
Method: Patients referred for investigation of thrombosis had OHP assays performed and recorded in a database from which a study group of 20 patients were identified with no known clinical provocation and no inherited or acquired thrombophilia. The results were compared with 64 normal controls, and 14 patients with inherited thrombophilia. An independent samples T-test was used to test for significant differences.
Results: The study group showed significantly impaired fibrinolysis compared to normals (p≤0.01), but no difference in overall fibrin generation. No difference in fibrinolysis was seen between the normal controls and the group with inherited thrombophilias.
Conclusion: Impaired fibrinolysis appears to contribute to hypercoagulable states in patients with no known cause for unprovoked thrombosis, but not in patients with an inherited thrombophilic defect. The OHP assay is a simple global test that can identify hypercoagulability, and may ultimately be used to inform recurrence risk assessment and anticoagulation duration in these patients.