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Post-TAVR anticoagulation alone fails to cut stroke risk in AFib

Key clinical point: In patients with atrial fibrillation who have undergone TAVR and had a CHA2DS2-VASc score of at least 2, oral anticoagulation (OAC) therapy alone was not linked to reduced stroke risk, while by contrast, antiplatelet therapy was linked to a reduced risk of stroke regardless of whether an OAC was used.

Major finding: After adjustment, stroke risk was not reduced for OAC when compared with no oral anticoagulation or antiplatelet therapy (hazard ratio, 0.61; P = .16), whereas stroke risk was reduced for antiplatelet therapy alone (HR, 0.32; P = .002) and for antiplatelet therapy with oral anticoagulation (HR, 0.44; P = .018).

Study details: Substudy of the PARTNER II trial including a cohort of 1,621 patients with a history of atrial fibrillation who underwent TAVR as treatment for aortic stenosis.

Disclosures: The PARTNER II study was funded by Edwards Lifesciences. Study authors reported disclosures related to Edwards Lifesciences, Abbott Vascular, Cordis, Medtronic, Boston Scientific, and others.

Citation:

Kosmidou I et al. JACC Cardiovasc Interv. 2019;12:1580-9.

Commentary:

Results of this PARTNER II substudy investigation by Kosmidou and colleagues are timely and thought provoking because they imply that some current recommendations may be insufficient for preventing stroke in patients with atrial fibrillation (AFib) undergoing transcatheter aortic valve replacement (TAVR).

Specifically, the results showed no difference in risk of stroke or the composite of death and stroke at 2 years in oral anticoagulant (OAC) and non-OAC patient groups, whereas by contrast, antiplatelet therapy was linked with reduced stroke risk versus no antithrombotic therapy, whether or not the patients received OAC.

The substudy reinforces the understanding that TAVR itself is a determinant of stroke because of mechanisms that go beyond thrombus formation in the left atrial appendage and are essentially platelet mediated.

How to manage antithrombotic therapy in patients with AFib who undergo TAVR remains a residual field of ambiguity.

However, observational studies cannot be conclusive, they said, so results of relevant prospective, randomized trials are eagerly awaited.

For example, the effects of novel oral anticoagulants versus vitamin K antagonists will be evaluated in the ENVISAGE-TAVI study, as well as the ATLANTIS trial, which will additionally include non-OAC patients.

The relative benefits of OAC alone versus OAC plus antiplatelet therapy will be evaluated in the AVATAR study, which will include AFib-TAVR patients randomized to OAC versus OAC plus aspirin, while the POPular-TAVI and CLOE trials will also include cohorts that help provide a more eloquent answer regarding the benefit-risk ratio of combining antiplatelet therapy and OAC in these patients.

Davide Capodanno, MD, PhD, and Antonio Greco, MD, of the University of Catania (Italy) made these comments in an accompanying editorial (JACC: Cardiovasc Interv. 2019 Aug 19. doi: 10.1016/j.jcin.2019.07.004). Dr. Capodanno reported disclosures related to Abbott Vascular, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi-Sankyo, and Sanofi. Dr. Greco reported having no relevant disclosures.