August 24, 2016
By Will Boggs MD
NEW YORK - The addition of antiplatelet therapy to warfarin is not associated with fewer thrombotic events, but appears to increase the risk of bleeding in patients with atrial fibrillation (AF) who undergo transcatheter aortic valve replacement (TAVR), according to a multicenter study.
"Antithrombotic therapy with warfarin alone may be a good option following TAVR in patients with concomitant AF," Dr. Josep Rodés-Cabau from Québec Heart and Lung Institute, Laval University in Québec City, Canada, told Reuters Health by email.
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Antiplatelet therapy is currently recommended following TAVR to reduce the risk of stroke, but as many as 30% of patients undergoing TAVR have another indication for vitamin K antagonist (VKA) therapy, largely due to concomitant AF. The optimal antithrombotic regimen in these patients remains unclear.
Dr. Rodés-Cabau and colleagues from 12 centers evaluated the risk of cardiovascular and bleeding events in a real-world TAVR setting among 520 patients who had an antiplatelet agent added to warfarin following TAVR versus 101 patients who maintained their warfarin monotherapy.
During a median follow-up of 13 months, there were no significant differences of all-cause death rates between patients on warfarin monotherapy and those warfarin-antiplatelet (18.5% vs. 17.8% per person-year, respectively).
The monotherapy and warfarin-antiplatelet groups did not differ in deaths from cardiovascular causes or stroke incidence either, the researchers report August 22 in JACC: Cardiovascular Interventions.
However, the incidence of major or life-threatening bleeding was higher in the warfarin-antiplatelet group than in the warfarin monotherapy group (14.8% vs. 5.9%, p=0.02).
Bleeding events occurred at a higher rate in the warfarin-antiplatelet group than in the warfarin-monotherapy group (23.1% vs. 12.1% per person-year, p=0.05).
Twenty patients on warfarin monotherapy and 155 on warfarin-antiplatelet (16.1% vs. 27.6% per person-year, respectively) experienced the combined endpoint of stroke, myocardial infarction, or any type of bleeding.
"Adding an antiplatelet agent to a VKA in patients with AF undergoing TAVR does not seem to be superior to VKA therapy alone in terms of stroke prevention, while posing a significantly greater bleeding risk," the researchers conclude.
"Our results are preliminary and need to be confirmed by further larger prospective studies," Dr. Rodés-Cabau cautioned.
Dr. Thierry Lefevre from Institut Cardiovasculaire Paris Sud in Massy, France, who wrote a linked editorial, told Reuters Health by email, "Six-month double-antiplatelet treatment after TAVR is not useful. Patients already on anticoagulant do not need antiplatelet treatment except if they received a drug-eluting stent in the last 3 months."
"These data are not randomized so it is difficult to conclude, but it is possible that anticoagulant for 3 to 6 months after TAVR will become the gold standard and probably with the new oral anticoagulant will be better," he concluded.
Dr. Jeffrey Rossi from Cleveland Clinic Foundation in Cleveland, Ohio, who recently reported on the variability in antithrombotic therapy regimens around the time of TAVR, said, "Antithrombotic therapy following TAVR still needs to be individualized, though if a physician feels anticoagulation is important in a patient that also has a high bleeding risk, a strategy of warfarin alone appears to be reasonable."
"Unfortunately, this study only included patients taking warfarin, so I would not extrapolate these results to the novel oral anticoagulants (rivaroxaban, dabigatran, etc.) at this time," he told Reuters Health by email. "However, there are studies currently underway evaluating the use of these newer agents post-TAVR, and this study certainly adds to the potential for a positive outcome of these trials."
"A major caveat to this study is that significantly more patients on warfarin and an antiplatelet had a history of coronary artery disease than patients treated with warfarin alone," Dr. Rossi said. "Though it may be safe for patients with coronary disease to forego antiplatelet therapy if on warfarin, I would be hesitant to take a patient with coronary disease off all antiplatelet therapy based on these results alone."
SOURCE: bit.ly/2bJjDHI and bit.ly/2c22kGj
J Am Coll Cardiol Intv 2016.
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