ABSTRACT
Residual perfusion defects (RPD) as detected by lung scintigraphy occur in over 50% of patients with acute pulmonary embolism (PE) treated with vitamin K antagonists but there is lack of data in patients treated with direct oral anticoagulants. The aim of this retrospective study was to estimate the incidence of RPD detected by ventilation perfusion (VQ) scan at 3-6 months in patients with first acute symptomatic PE treated with rivaroxaban compared to warfarin. Consecutive eligible patients treated with rivaroxaban as part of a previous study were identified. The Monash Health Radiology database was used to identify a historical cohort of age matched (± 5 years) patients treated with warfarin. Follow-up VQ scans were classified as normal (no perfusion defect) or abnormal (matched or unmatched perfusion defects) by two independent nuclear medicine physicians blinded to treatment. Any disagreement was resolved by consensus. One hundred and ninety patients with PE (95 in each cohort) were included (mean age 56.8 years; 41.1% males; 54.2% unprovoked). In the overall cohort, 31.1% had RPD with a significantly lower incidence of RPD in rivaroxaban treated patients 23.2% (95% CI 15.8-32.6), compared to warfarin 38.9% (95% CI 29.8-49.0). Treatment with rivaroxaban was associated with a significantly lower incidence of RPD detected by VQ scan at 3-6 months compared to warfarin. This supports recent in-vitro data suggesting an indirect enhancement of fibrinolysis by direct oral Xa inhibitors but requires confirmation in larger studies.
Subject(s)
Anticoagulants/administration & dosage , Factor Xa Inhibitors/administration & dosage , Perfusion Imaging/methods , Pulmonary Embolism/diagnostic imaging , Pulmonary Embolism/drug therapy , Rivaroxaban/administration & dosage , Warfarin/administration & dosage , Acute Disease , Adult , Aged , Anticoagulants/adverse effects , Cohort Studies , Factor Xa Inhibitors/adverse effects , Female , Follow-Up Studies , Humans , Incidence , Lung/diagnostic imaging , Lung/drug effects , Male , Middle Aged , Radionuclide Imaging/methods , Retrospective Studies , Treatment OutcomeABSTRACT
The highest risk of adverse events for patients with acute venous thromboembolism (VTE) is during the early anticoagulation period. However, no established model exists for early clinical monitoring of patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). The authors' aim was to evaluate the utility of a nurse-led pathway to minimize adverse events in acute VTE patients starting on rivaroxaban. The rivaroxaban VTE treatment pathway is a prospective cohort study of consecutive patients with objectively confirmed VTE between July 2015 and May 2017. Primary outcome was the proportion of patients identified at major risk of adverse events (bleeding or recurrent VTE). Secondary outcomes were rates of interventions, major or clinically relevant nonmajor bleeding (CRNMB), recurrent VTE, and all-cause mortality at 90 days. Among 304 participants, 5% (n = 15) were identified to be at major and 9% (n = 28) at possible risk for adverse events. Appropriate interventions to prevent harm were required in 40 patients. Rates of major bleeding, CRNMB, recurrence, and all-cause mortality were 0.3% (95% confidence interval [CI]: 0.1-1.8), 7.2% (95% CI: 4.8-10.7), 1.0 (95% CI: 0.3-2.9), and 1.6% (95% CI: 0.7-3.8), respectively. In conclusion, following discharge of acute VTE patients, a nurse-led pathway identified one in seven (14%) patients at major or possible risk of adverse events. Preemptive interventions to reduce harm translated into the low rates of bleeding and recurrence. The authors' experience highlights the feasibility and importance of a structured clinical surveillance pathway for acute VTE patients initiating NOAC therapy.
