Direct Oral Anticoagulants May Best Vitamin K Agonists For post-TAVR A-Fib

In patients with atrial fibrillation (AF) after transcatheter aortic valve replacement (TAVR), direct oral anticoagulants (DOACs) were associated with lower long-term all-cause mortality than vitamin K agonists (VKAs) in a Japanese registry study.

"We are surprised by the result," Dr. Yusuke Watanabe of Teikyo University School of Medicine told Reuters Health by email. "For clinicians right now, we think in patients undergoing TAVR with a high risk for bleeding, DOACs should be the first choice for an antithrombotic regimen. A contraindication is severe renal dysfunction. Also, concomitant use of antiplatelet therapy should be kept to a minimum."

As reported in JACC: Cardiovascular Interventions, the study included 403 TAVR patients with AF on anticoagulant therapy (mean age 84; 33% men) enrolled in the multicenter Optimized Transcatheter Valvular Intervention (OCEAN) registry from 2013-2017. Median follow-up was 568 days.

Among those successfully discharged after TAVR, rates were comparable between the groups for all bleeding; life-threatening, major, minor and gastrointestinal bleeding; and hemorrhagic stroke, and ischemic stroke.

However, the DOAC group was significantly associated with a lower incidence of all-cause mortality compared with the VKA group: 10.3% vs. 23.3% (Cox-adjusted hazard ratio, 0.391) and 10.2% vs. 20.6% (inverse probability of treatment weighting-adjusted hazard ratio: 0.531), respectively.

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Further, type 2 diabetes was an independent predictor of all-cause mortality (adjusted hazard ratio, 2.226)

Dr. Watanabe said, "Patients with DOACs were less likely to have bleeding events compared to the VKA group in this study, (which may be) due to the concomitant antiplatelet regimen; patients with DOACs had less antiplatelet therapy than the VKA group. Chronic kidney disease also influenced mortality, and was common among patients (taking) VKAs."

A randomized trial comparing outcomes in TAVR patients with AF who are taking DOACs plus a concomitant antiplatelet regimen versus DOCs alone "is of great interest," he added, as would be a randomized study comparing left atrial appendage closure or DOACs alone in patients at very high risk for bleeding.

Cardiac electrophysiologist Dr. Pedram Kazemian, Medical Director of Clinical Research at Deborah Heart and Lung Center in Browns Mills, New Jersey, commented by email to Reuters Health, "There are many benefits to using DOACs - better safety profile, ease of use, better drug/food interaction profile, and lower bleeding risk compared to (warfarin) - which is now established in the area of AF."

"The current large observational study certainly confirms these findings in the subgroup of patients with AF after TAVR," he said. "However, despite the attempt to account for baseline differences between groups, all observational studies do have inherent biases stemming from selection of patients and other sources. Therefore, this study should be followed by a randomized trial to confirm the findings before widespread recommendation is made for clinicians to use DOACs instead of warfarin."

The OCEAN-TAVI registry is supported by industry. Dr. Watanabe and nine coauthors are clinical proctors for Edwards Lifesciences and/or Medtronic, two of the supporters.

—Marilynn Larkin

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