From the Journals

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

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Timely results, but further investigations required

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.



In patients with atrial fibrillation (AFib) who have undergone transcatheter aortic valve replacement (TAVR) and had a CHA2DS2-VASc score of at least 2, oral anticoagulant (OAC) therapy alone was not linked to reduced stroke risk.

By contrast, antiplatelet therapy was linked to a reduced risk of stroke in those AFib-TAVR patients, regardless of whether an oral anticoagulant was on board, according to results of a substudy of the randomized PARTNER II (Placement of Aortic Transcatheter Valve II) trial and its associated registries.

“Anticoagulant therapy was associated with a reduced risk of stroke and the composite of death or stroke when used concomitantly with uninterrupted antiplatelet therapy following TAVR,” concluded authors of the analysis, led by Ioanna Kosmidou, MD, PhD, of Columbia University in New York.

Taken together, these findings suggest OAC alone is “not sufficient” to prevent cerebrovascular events after TAVR in patients with AFib, Dr. Kosmidou and colleagues reported in JACC: Cardiovascular Interventions.

The analysis of the PARTNER II substudy included a total of 1,621 patients with aortic stenosis treated with TAVR who had a history of AFib and an absolute indication for anticoagulation as evidenced by a CHA2DS2-VASc score of at least 2.

Despite the absolute indication for anticoagulation, more than 40% of these patients were not prescribed an OAC upon discharge, investigators wrote, though the rate of nonprescribing decreased over the 5-year enrollment period of 2011-2015.

OAC therapy alone was not linked to reduced stroke risk in this cohort, investigators said. After 2 years, the rate of stroke was 6.6% for AFib-TAVR patients on anticoagulant therapy, and 5.6% for those who were not on anticoagulant therapy, a nonsignificant difference at P = 0.53, according to the reported data.

By contrast, uninterrupted antiplatelet therapy reduced both risk of stroke and risk of the composite endpoint of stroke and death at 2 years “irrespective of concomitant anticoagulation,” Dr. Kosmidou and coinvestigators wrote in the report.

The stroke rates were 5.4% for antiplatelet therapy plus OAC, versus 11.1% for those receiving neither antithrombotic treatment (P = 0.03), while the rates of stroke or death were 29.7% and 40.1%, respectively (P = 0.01), according to investigators.

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

The PARTNER II study was funded by Edwards Lifesciences. Senior author Martin B. Leon, MD, and several other study coauthors reported disclosures related to Edwards Lifesciences, in addition to Abbott Vascular, Cordis, Medtronic, Boston Scientific, and other companies. Dr. Kosmidou reported no disclosures.

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

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