Key result
Prothrombin time was significantly prolonged in atrial fibrillation patients when blood was collected within 12 hours of rivaroxaban intake compared to after 12 hours (32.9 vs 20.5 seconds, p=0.003).
Why the study?
Disadvantages and adverse effects of vitamin K inhibitors have led to their replacement by direct oral anticoagulants such as factor Xa inhibitors, prompting evaluation of PT/INR performance in patients taking rivaroxaban.
Does the time elapsed since the last dose of rivaroxaban affect prothrombin time and INR in patients with atrial fibrillation?
Cross-Sectional (n=34)
Yes
Does the time elapsed since the last dose of rivaroxaban affect prothrombin time and INR in patients with atrial fibrillation?
Absolute Event Rate: 32.9% vs 20.5%
p-value: p=0.003
Prothrombin time and INR are sensitive to the anticoagulant effect of rivaroxaban up to 12 hours after ingestion, but drop to near-normal levels closer to the next dose, highlighting the importance of knowing the time of last intake when interpreting these tests.
PT/INR interpretation in rivaroxaban-treated AF requires last-dose timing; cross-sectional data leaves open prospective validation of timed testing.
Background Traditionally, the most effective therapy in the prevention of stroke in patients with atrial fibrillation (AF) has been oral anticoagulation with vitamin K inhibitors, particularly warfarin, whose disadvantages and adverse effects have led to their replacement by “direct oral anticoagulants”, as factor X inhibitor. Objectives This study aimed to conduct a brief approach on atrial fibrillation (AF) and use of Rivaroxaban, and to comparatively evaluate the prothrombin time / International Normalized Ratio (PT/INR) in patients with AF in [...]
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Duarte et al. (2020) conducted a cross-sectional in Atrial Fibrillation (n=34). Rivaroxaban (blood collection ≤ 12 hours post-dose) vs. Blood collection > 12 hours post-dose was evaluated on Prothrombin time (PT) in seconds (p=0.003). Prothrombin time was significantly prolonged in atrial fibrillation patients when blood was collected within 12 hours of rivaroxaban intake compared to after 12 hours (32.9 vs 20.5 seconds, p=0.003).
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