Following transcatheter aortic valve replacement (TAVR), the optimal antithrombotic regimen for some people may be no antithrombotics at all, according to provocative registry data from Japan.

Compared with the single antiplatelet (SAPT) or dual antiplatelet (DAPT) approaches for TAVR patients without any other indications for antiplatelet or anticoagulation therapy, the non-antithrombotic strategy was not associated with an increased risk of adverse events counting cardiovascular death, stroke, myocardial infarction, and life-threatening or major bleeding at 3 years post-TAVR (log-rank P=0.972):

• Non-antithrombotic strategy: 14.0%
• SAPT: 14.7%
• DAPT: 16.2%

Additionally, bleeding rates stayed similarly low, below 10%, for people assigned no antiplatelets or SAPT, whereas it crossed 10% for the DAPT cohort (log-rank P=0.018). The latter group trended toward more major or life-threatening bleeds in particular without reaching significance (4.1% for no antiplatelet group vs 6.5% for SAPT vs 8.4% for DAPT, log-rank P=0.07).

As for valve performance, mean pressure gradients and indexed effective orifice areas were similar across the three medication regimens, Kentaro Hayashida, MD, of Keio University School of Medicine in Tokyo, and colleagues reported in JACC: Cardiovascular Interventions.

These findings from the OCEAN-TAVI registry suggest that the 8.2% of TAVR patients who were prescribed no antiplatelets at discharge — their high bleeding risk cited frequently as the reason for the non-antithrombotic strategy — really did not need antithrombotics to reduce ischemic events and to prevent leaflet or valve thrombosis.

“Contrary to the current guidelines recommending lifelong SAPT after TAVR, our findings indicate that even lifelong low-dose aspirin and short-term DAPT may not be necessary after TAVR,” Hayashida and colleagues said. Current preference for SAPT after TAVR is based on trials like POPular TAVI, in which SAPT was associated with a lower bleeding incidence without an increased risk of ischemic events compared with DAPT.

Yet the necessity of any antiplatelets at all was questioned by Hayashida and colleagues, who noted that the assumption had been drawn from the field of coronary stenting without direct evidence from the older, more bleeding-prone TAVR population.

“The study opens up a novel and interesting perspective, which warrants further confirmation in a European or North American population,” according to an accompanying editorial by a French group led by Vincent Auffret, MD, PhD, of Université de Rennes in France.

The editorialists warned of a narrow path ahead for the non-antithrombotic approach, as many patients will still require these medications for prior or new-onset atrial fibrillation and concomitant coronary or peripheral artery disease.

OCEAN-TAVI is a nationwide observational TAVR registry that covers 15 hospitals in Japan. The present analysis included people who underwent elective TAVR for symptomatic severe aortic stenosis from October 2013 to May 2020 and excluded those who received anticoagulation or had procedural complications.

Participants were divided into groups receiving non-antithrombotic therapy (n=293), SAPT (n=1,354), or DAPT (n=1,928) at discharge. Prescriptions of SAPT after TAVR increased during the study period, in contrast with falling DAPT and stable non-antithrombotic therapy.

Overall, the study cohort had a median age in the mid-80s, and approximately one in three were men. Over 57% received a Sapien 3 TAVR valve. The non-antithrombotic therapy group tended to be younger and to have relatively few comorbidities despite high bleeding risk.

The median follow-up period was 841 days. Proportions of patients staying on their antithrombotic regimen from discharge to 1 year were 51.9% of the no-antiplatelets group, 69.4% of the SAPT group, and 40.4% of the DAPT group.

Leaflet thrombosis was detected in 8.5% of the non-antithrombotic group. This compares favorably with prior reports of aortic valve replacement patients receiving antithrombotic therapy, though study authors acknowledged that this may be an underestimate as comprehensive imaging was not routinely performed in OCEAN-TAVI. Moreover, comparative data on leaflet thrombosis after SAPT or DAPT were not collected by Hayashida’s group.

Auffret and colleagues emphasized that systematic evaluation of subclinical leaflet thrombosis is necessary for future work on the non-antithrombotic strategy.

Hayashida’s group also highlighted the “puzzling finding” of numerically lower all-cause mortality in DAPT patients at 3 years. As cause of death was not included in the analysis, the possibility remains that inherent selection bias was at play in the retrospective, observational report, as patients without severe comorbidities were likely to be on DAPT.

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