RESUMO
BACKGROUND: The acute vascular disease deep vein thrombosis (DVT) requires oral anticoagulants to prevent progression. Monitoring therapeutic efficacy of direct oral anticoagulants (DOAC), including rivaroxaban, is problematic as no reliable test is available. Advances in rheometry have led to the development of a functional coagulation biomarker using Gel Point (GP) analysis which assesses clot structure formation. The biomarker measures incipient clot formation time (TGP) and quantifies fibrin clot structure in terms of fractal dimension (df). OBJECTIVE: This study aimed to investigate clot structure formation in first time DVT and the effect of rivaroxaban treatment. METHODS: This prospective observational cohort study measured the GP and standard laboratory markers at three sample points: pre-treatment and at 20 and 60 days following 15âmg BD and 20âmg OD rivaroxaban respectively. RESULTS: Forty DVT patients (mean age 64 years [SD±14.8]; 23 males, 17 female) were recruited. The results show that DVT vs non-DVT patients did not have a significantly different GP profile (df: 1.72±0.06âvs 1.70±0.06 and TGP: 267±68âsec vs 262±73âsec) with both within the defined healthy index. In addition, rivaroxaban therapy increased TGP to 392âs (±135âs) after 20 days, and subsequently increased to 395âs (±194âs) at 60 days but did not significantly increase df (from 1.69±0.05 to 1.71±0.06). CONCLUSIONS: The results indicate in this cohort of DVT patients there was no underlying hypercoagulable effect as determined by gel point analysis. Furthermore, the anticoagulant effect of rivaroxaban prolonged clotting, suggesting a protective effect against clot formation, without significantly reducing clot microstructural properties.