Study Background and Disease Burden
Atrial fibrillation (AF) frequently emerges as a complication following cardiac surgery, affecting a substantial proportion of patients and complicating postoperative management. New-onset AF is associated with increased risk of stroke, thromboembolic events, prolonged hospitalization, and higher healthcare costs. Traditionally, warfarin has been the anticoagulant cornerstone for stroke prevention in patients with AF, including post-surgical cases. However, direct oral anticoagulants (DOACs) such as rivaroxaban have gained prominence in non-surgical populations due to predictable pharmacokinetics, rapid onset of action, fewer monitoring requirements, and comparable efficacy and safety profiles compared to warfarin. Despite these advantages, DOACs have not been systematically evaluated in the postcardiac surgery population, leaving uncertainty about their role and benefits in this group. The NEW-AF trial addresses this knowledge gap by directly comparing rivaroxaban and warfarin in patients with new-onset AF after cardiac surgery to inform clinical decision-making.
Study Design
The NEW-AF trial was a pragmatic, prospective, randomized controlled study enrolling 100 patients who developed new-onset AF following cardiac surgery. Participants were randomly assigned in equal numbers to receive either rivaroxaban (n=50) or warfarin (n=50) as anticoagulation therapy. The study focused on real-world applicability, with follow-up extending to 30 days after hospital discharge. Patient-reported outcomes were evaluated approximately two weeks postdischarge using validated tools: the Perception of Anticoagulant Treatment Questionnaire (PACT-Q) and the EuroQol-5D-3L quality of life survey. The primary endpoint was length of hospital stay (LOS) from day of surgery to discharge, a clinically meaningful measure reflecting patient recovery and resource utilization. Secondary endpoints included LOS from anticoagulation initiation to discharge, safety outcomes such as bleeding and thromboembolic events, and patient satisfaction domains.
Key Findings
The primary analysis demonstrated no statistically significant difference in overall LOS between the rivaroxaban and warfarin groups, with median LOS of 7 days (IQR 6–9) versus 8 days (IQR 6–9), respectively (P=0.460). Likewise, LOS measured from initiation of anticoagulation to discharge was similar: 2 days (IQR 1–4) for rivaroxaban and 2 days (IQR 1–3) for warfarin (P=0.738). This indicates that rivaroxaban does not confer an advantage in shortening hospitalization in this setting.
Importantly, safety outcomes were reassuring. No major bleeding, stroke, or arterial thromboembolism events were reported in either arm. Minor bleeding occurred at low rates and was comparable between groups (6% for rivaroxaban versus 2% for warfarin; P=0.617), with no cases necessitating blood transfusion. One patient on rivaroxaban developed a pericardial effusion requiring drainage, an isolated event not statistically different from the warfarin arm.
Patient-reported outcomes revealed that those receiving rivaroxaban rated their treatment as significantly more convenient (P<0.001) and reported a better overall anticoagulation experience (P=0.006) compared with the warfarin group. Treatment satisfaction levels, however, did not differ significantly (P=0.494). Notably, mobility difficulties were more frequently reported in the rivaroxaban group (42.2%) than in the warfarin group (18.6%, P=0.021), a finding that requires further exploration to understand underlying factors.
All outcomes were consistent when analyzed by intention-to-treat and as-treated populations, reinforcing the robustness of the results.
Expert Commentary
The NEW-AF trial adds valuable randomized clinical evidence to a field previously reliant on observational studies and clinician extrapolation from nonsurgical AF populations. Given that rivaroxaban did not reduce hospitalization length compared to warfarin, it suggests that factors beyond anticoagulant choice influence hospital discharge timing after postcardiac surgery AF. These may include surgical recovery parameters and clinical protocols. Nonetheless, the improved patient convenience and favorable perception associated with rivaroxaban align with well-documented benefits of DOACs such as fixed dosing and no routine INR monitoring.
The comparable safety profile observed supports the cautious expansion of rivaroxaban use in this population, with the caveat that mobility issues noted in the rivaroxaban cohort warrant attention. Possible contributors include medication side effects or confounding factors not captured in the trial. This finding underscores the necessity for individualized patient assessment and ongoing monitoring.
Current guidelines acknowledge warfarin as standard for postcardiac surgery AF but have not extensively addressed DOACs due to lack of trial data. The NEW-AF trial’s findings may influence updates by providing evidence to support shared decision-making that incorporates patient preferences and clinical context when selecting anticoagulation.
Conclusion
In patients with new-onset atrial fibrillation following cardiac surgery, anticoagulation with rivaroxaban does not reduce hospital length of stay compared to warfarin. Both treatments displayed similar safety profiles without major bleeding or thromboembolic complications. Rivaroxaban offers enhanced patient convenience and a more positive overall anticoagulation experience, which may improve adherence and quality of life. These outcomes endorse rivaroxaban as a viable anticoagulant option alongside warfarin for postcardiac surgery AF, facilitating patient-centered care. Future research should explore the observed mobility differences, long-term outcomes, and optimal protocols to integrate DOACs effectively in the surgical setting.
References
Moonsamy P, Zhao Y, Makarem A, Paneitz DC, Wolfe S, Turco I, Colon KM, Ethridge BR, Li SS, Leya G, Verma S, D’Alessandro DA, Jassar AS, Langer NB, Tolis G, Villavicencio MA, Melnitchouk SI, Bloom JP, Michel E, Kreso A, Rabi SA, Akeju O, Sundt TM, Osho AA. Randomized Controlled: Trial of New Oral Anticoagulants Versus Warfarin for Postcardiac Surgery Atrial Fibrillation: The NEW-AF Trial. Ann Surg. 2025 Oct 1;282(4):630-638. doi: 10.1097/SLA.0000000000006853. Epub 2025 Jul 24. PMID: 40704706.
