Antiplatelet Therapy With Vitamin K Antagonists Does Not Reduce Stroke in Afib After TAVR

Concomitant antiplatelet therapy with vitamin K antagonists in atrial fibrillation patients who receive transcatheter aortic valve replacement (TAVR) does not appear to reduce stroke, major adverse cardiovascular events (MACE), or death, according to research published in JACC: Cardiovascular Interventions.

Omar Abdul-Jawad Altisent, MD, of the Quebec Heart and Lung Institute at Laval University in Quebec City and colleagues examined different antithrombotic strategies in patients undergoing TAVR with concomitant atrial fibrillation.

“Current guidelines recommend antiplatelet therapy following TAVR to reduce the risk of stroke,” the authors wrote. “However, up to 30% of patients undergoing TAVR have an indication for vitamin K antagonist therapy, largely due to concomitant atrial fibrillation.” 

They explained this is an especially high-risk patient population, as antithrombotic agents increase bleeding risk, which then has a negative impact on morbidity and mortality.

Dr Altisent and colleagues used data from 12 centers with patients undergoing TAVR between 2007 and 2015 (n=621). Patients were prescribed either monotherapy with vitamin K antagonists (n=101) or multiple antithrombotic therapy with vitamin K antagonists plus 1 or 2 antiplatelet agents (aspirin or clopidgrel; n=520).

The study end point was defined by Valve Academic Research Consortium-2 (VARC-2) criteria. Researchers assessed rates of stroke, MACE (stroke, myocardial infarction, or cardiovascular death), major or life-threatening bleeding events, and death.

They reported no differences between therapy groups in rates of stroke (monotherapy: 5%; multiple antithrombotic therapy: 5.2%; adjusted hazard ratio [HR]: 1.25; 95% confidence interval [CI]: 0.45-3.48; P=.67), MACE (monotherapy: 13.9%; multiple antithrombotic therapy: 16.3%; adjusted HR: 1.33; 95% CI: 0.75-2.36; P=.33), or death (monotherapy: 22.8%; multiple antithrombotic therapy: 19.2%; adjusted HR: 0.93; 95% CI: 0.58-1.50; P=.76).

However, the multiple antithrombotic therapy group had a higher risk of VARC-2 major or life-threatening bleeding events, compared with the monotherapy group (24.4% vs 14.9%, respectively; adjusted HR: 1.85; 95% CI: 1.05-3.28; P=.04). When patients who received vitamin K antagonist therapy plus only 1 antiplatelet agent, the results remained similar.

Over the 13 month follow-up, 123 patients died (17.9% per person-year); 61 specifically due to cardiovascular reasons (8.9% per person-year). Researchers found no significant differences between the monotherapy and multiple antithrombotic groups in the incidence of all-cause death (18.5% per person-year vs 17.8% per person-year, respectively; adjusted HR: 0.93; 95% CI: 0.58-1.50; P=.76) or death for cardiovascular causes (8.1% per person-year vs 9.1% per person-year, respectively; adjusted HR: 1.09; 95% CI: 0.54-2.22; P=.80). There were 12 (1.8% per person-year) fatal bleeding events, with a similar incidence between the groups (P=.86).

“Adding an antiplatelet agent to a VKA [vitamin K antagonist] 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 bleed risk,” the authors concluded. “Further prospective randomized studies are required for identifying the optimal antithrombotic strategy in TAVR patients with AF.”

Disclosures: Several authors disclosed financial relationships from Edwards Lifesciences, Medtronic, and St. Jude Medical.

Reference

Altisent OA-J, Durand E, Munoz-Garcia AJ, et al. Warfarin and antiplatelet therapy vs warfarin alone for treating patients with atrial fibrillation undergoing transcatheter aortic valve replacement. JACC Cardiovasc Interv. 2016;9(16):1706-1717. doi:10.1016/j.jcin.2016.06.025.